Search

[Display omitted] • Simultaneous Fe coordination and P/O co-doping in g-C 3 N 4 was achieved by a novel one-step thermal polymerization method; • Electrons migration driven by coordinated Fe and lone electron pairs delocalization from doped P/O promoted charge transfer; • Uranium capture rate increased by 3-folds over original g-C 3 N 4 through simultaneous introduction of Fe, P and O; • A higher uranium capture was achieved with the lowest catalyst consumption compared with previously reported g-C 3 N 4 -based photocatalysts; • The presence of dissolved O 2 in this system facilitated photoreduction of uranium(VI) instead of inhibiting; The risk of radionuclide leakage always threats ecological security and human health, making the recovery of uranium from nuclear wastewater a meaningful and urgent issue. However, the low-cost and efficient capture of uranium remains a challenge at present. In this study, a homemade photocatalyst of iron coordinated graphitic carbon nitride (g-C 3 N 4) co-doped with phosphorus and oxygen (OPFCN), which was facilely synthesized through a novel one-step thermal polymerization method, exhibited superior photoelectric efficiency and photocatalytic activity towards the photo-reductive capture of uranium(VI). The simultaneous Fe coordination and P/O co-doping in framework of g-C 3 N 4 played a synergistic effect in charge reconstruction, in which electrons migration driven by coordinated Fe and lone electron pairs delocalization from doped P/O enormously increased electron density and enhanced charge transfer, thus effectively promoting the separation of photogenerated charge carriers. The specific surface area, pore volume and average pore size of OPFCN reached 70.2 m2·g−1, 0.157 cm3·g−1 and 7.78 nm, respectively, exhibiting a trend increasingly beneficial for photocatalytic adsorption and mass transfer with successive introduction of Fe, P and O into original g-C 3 N 4. With the simultaneous introduction of Fe, P and O, the optical absorption edge underwent a significant redshift and fluorescence emission intensity dropped by 75 % compared to that of CN, demonstrating the enhanced visible light capturing ability and significantly inhibited recombination of photogenerated charge carriers in OPFCN. As a result, a uranium capture rate of over 98 % was achieved with catalyst dosage of only 5:1 at pH 5 with OPFCN, demonstrating its competitive photo-reductive activity towards uranium(VI) uptake compared with previously reported g-C 3 N 4 -based photocatalysts. Meanwhile, OPFCN exhibited remarkable reusability and stability with even over 65 % uranium recovery rate and almost unchanged peak patterns in XRD and FT-IR in fifth reuse recycle. Additionally, it was demonstrated that e− and O 2 •− were the direct active species to realize the photoreduction of uranium(VI) over OPFCN, in which e− played the dominant role. The modification method of simultaneous Fe coordination and P/O co-doping would be expected to effectively promote the utilization of g-C 3 N 4 -based photocatalysts towards photo-reductive recovery of uranium(VI) from radioactive wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • TpPa-1/{0 1 0}-BVO was synthesized through a surfactant-assisted microwave solvothermal route. • The hybrid photocatalysts showed enhanced photocatalytic activity for H 2 O 2 production. • Heterojunction fabricated with different crystal facets showed distinct built-in electric field. • The mechanism of the hybrid photocatalysts toward H 2 O 2 generation was revealed. The rational fabrication of inorganic–organic S-scheme heterojuncion hybrid photocatalysts on specific crystal facets is challenging but significant. Herein, we report that TpPa-1-covalent organic framework (COF) selectively grown on {0 1 0} crystal facets of decahedral BiVO 4 (TpPa-1/{0 1 0}-BVO, denoted as TB-1) was synthesized through a surfactant-assisted microwave solvothermal route. The experimental results and theoretical calculations showed that TB-1 was more beneficial to separation of photogenerated carriers than the heterojunction randomly formed at all crystal facets ({0 1 0} + {1 1 0}) of BiVO 4 (TpPa-1/BVO, denoted as TB-2). As a result, photocatalytic oxygen reduction reaction (ORR) activity for H 2 O 2 production over TB-1 reached 723 μmol·g cat −1·h−1, which is 72.3-times, 5.7-times, and 2.4-times higher than individual BiVO 4 (10 μmol·g cat −1·h−1), TpPa-1 (127 μmol·g cat −1·h−1), and TB-2 (305 μmol·g cat −1·h−1). In addition, the introduction of TpPa-1 could inhibit the decomposition of H 2 O 2. This study not only provides a new hybrid photocatalyst for artificial H 2 O 2 production but also highlights the importance of crystal facet engineering in the design of highly efficient photocatalysts. [ABSTRACT FROM AUTHOR]

• Multi-functional FWO/BOC heterostructured photocatalysts have been constructed. • They are identified to exhibit efficient Z-scheme transfer/separation of photocarriers. • They exhibit excellent photocatalysis for CO 2 reduction and BPA degradation. • Synergistically enhanced piezo-photocatalysis is observed and deeply elucidated. • They have capability of activating PMS or H 2 O 2 to facilitate piezo-photodegradation of BPA. • Experiment and theory were combined to deeply study the underlying catalysis mechanism. Development of multi-functional photocatalysts for CO 2 reduction and pollutant elimination is practically significant for solving the environmental problems and energy shortages. In this study, we have immobilized FeWO 4 (FWO) nanoparticles on the surface of (0 0 1)-facet-exposed BiOCl (BOC) nanosheets through their strong electrostatic interaction to form FWO/BOC heterojunctions. Experimental and theoretical studies corroborate that the FWO/BOC heterojunctions exhibit high-efficiency Z-scheme transfer and separation of photocarriers, and possess excellent photocatalysis for CO 2 reduction and bisphenol A (BPA) degradation. Under simulated-sunlight irradiation, the 9 %FWO/BOC heterojunction exhibits a photoreduction performance with CH 4 /CO yield rates of 4.25/9.41 μmol g−1 h−1 (5 h reaction), which are 3.86/5.26 times higher than those for bare BOC; whereas its photodegradation performance (η (60 min) = 66.8 %, k app = 0.01755 min−1) is enhanced by 4.3 and 2.7 times compared with that of bare FWO and BOC, respectively. Furthermore, when ultrasonic vibration is simultaneously employed during the simulated-sunlight illumination, the ultrasonic-induced piezoelectric polarization field in BOC nanosheets accelerates the bulk photocarrier separation, resulting in a further improvement in the BPA degradation, and the calculated SF = 1.79 quantifies the degree of enhancement achieved by piezo-photocatalysis collaboration. The introduction of a moderate amount of H 2 O 2 or peroxymonosulfate (PMS) in the reaction solution plays a significant role in promoting the BPA degradation due to the generation of additional •OH and •SO 4 − reactive species. The mechanisms for photocatalytic CO 2 reduction and piezo-photodegradation of BPA catalysis were deeply studied by combining experiments and theory. [ABSTRACT FROM AUTHOR]

[Display omitted] • Visible light-assisted CO 2 -PR) studied by (CoFeNiMnCu)S 2 embedded in ultrathin g-C 3 N 4. • An excellent activity toward generation of CH 4 and CO was attained by CO 2 -PR). • Composite showed a long-term reusability during photocatalytic reduction of CO 2. • The mechanism of CO 2 -PR) over (CoFeNiMnCu)S 2 /ultrathin g-C 3 N 4 was studied in detail. Sustainability is a key issue in developing stable and efficient catalysts for solar-catalyzed CO 2 conversion. The concept of structural stabilization by quenching the Gibbs free energy, which is achieved by increasing the configurational entropy level of the system, introduced high-entropy materials. However, because alloying immiscible multimetallic atoms into a unit system is still an arduous process, the potential of high-entropy materials has not yet been fully exploited. Surprisingly, although metal sulfide photocatalysts have an enviable reputation for CO 2 photoreduction (CO 2 -PR) owing to their optical/electronic merits and more negative redox potential than other materials, the capability of high-entropy metal sulfides has been completely disregarded. Herein, an adaptable, self-templating metal alkoxide appropriately addresses the immiscibility of metallic constituents by the well-blended metal ions with polyalcohol in the metal glycerate. Consequently, (CoFeNiMnCu)S 2 high-entropy metal sulfide nanoparticles (HEMS-Nps) were grown in situ on crossed ultrathin g-C 3 N 4 (UCN) monolayers during the sulfidation of the metal glycerate. The as-synthesized HEMS-Np has a crystalline–amorphous structure, which is conducive to the acceleration of charge transfer to/from reaction sites, and a convincing orientation for CO 2 adsorption. These features are combined with synergistic electronic multimetallic interactions, facilitating a heterogeneous valence electron distribution and atomic disorder. The CO 2 -PR power of the (CoFeNiMnCu)S 2 @UCN nanostructure was noticeable in realizing added-value products in both the liquid–solid (1063 µmol/g h of syngas and 250 µmol/g h of methane) and gas–solid phases (1883 µmol/cm2 h of syngas and 321 µmol/cm2 h of methane). To prove its utility, long-term and corresponding time-equivalent cycling experiments were conducted, demonstrating a highly stable system that endured for a long time. Overall, this approach simultaneously exploits the advantages of sulfide-based materials and high-entropy materials in stable structures to generate sustainable CO 2 -PR materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface oxygen regulates the local microenvironment of heterojunctions for disrupting the localization effects of sulfur vacancies. • Surface oxygen induces local charge polarization and creates a charge transport channel. • Surface oxygen enhance the chemisorption and activation of NO 3 −. • MOSZ3 exhibited excellent photocatalytic activity and stability. Constructing sulfur vacancies to increase the active edge sites of molybdenum disulfide (MoS 2) is an effective strategy for enhancing the catalytic activity of cocatalysts in heterojunction materials. However, defects in the interface of traditional research can serve as carrier capture centers that significantly impede carrier migration. In this study, we propose an innovative carrier migration pathway to mitigate carrier recombination at interface vacancies by regulating the local microenvironment of MoS 2−x /ZnIn 2 S 4−x heterojunction (MOSZ). Fortunately, the optimized MOSZ3 exhibits outstanding NO 3 − reduction performance (185.59 µmol g−1 h−1) without the need for sacrificial agents. Density functional theory (DFT) calculations and experimental results collectively confirm that surface oxygen regulates the local microenvironment of heterojunctions, disrupting the localization effects of sulfur vacancies by inducing local charge polarization and creating a charge transport channel. This contributes to enhancing carrier migration and exciton dissociation. Furthermore, it also regulates the chemisorption and activation of NO 3 − as well as the energy required for deoxygenation and hydrogenation of intermediates. Our work not only provides a novel perspective on alleviating charge trapping in interfacial vacancies, but also offers new insights for environmental remediation and sustainable energy production. [ABSTRACT FROM AUTHOR]

• MOF-based catalysts for the photocatalytic CO 2 reduction reaction (PCO 2 RR) • Introduction of chelating sites into NH 2 -UiO-66 by an amine–aldehyde condensation. • Ni(II)- and Co(II)-chelated MOF catalysts with excellent PCO 2 RR performance. • High stability and catalytic performance after 16 h of catalytic cycling. The photocatalytic reduction of carbon dioxide (CO 2) to carbon-based materials is challenging because of its intricate nature and the generation of multiple byproducts. Hence, developing photocatalysts with a high CO 2 -reduction yield and selectivity is critical. In this study, new photocatalysts (U-B-M, M = Co, Ni) were synthesized by incorporating 1,2-benzisothiazolin-3-one (BIT) into NH 2 -UiO-66, to create N, N'-chelating sites via an amine–aldehyde condensation reaction, followed by metal-ion chelation. The introduction of BIT decreased the resistance of the catalyst and enhanced the separation of photogenerated carriers. The catalytic performance of U-B-Ni (rate: 3.10 mmol·g−1·h−1; selectivity: 97 %) surpasses those most of all previously reported MOF-based photocatalysts. Moreover, U-B-Ni shows high stability and negligible deactivation on catalytic cycling for over 16 h. This study expands the utility of metal–organic frameworks (MOF) in photocatalysis and highlights the importance of amine–aldehyde condensation in MOF modification. [ABSTRACT FROM AUTHOR]

[Display omitted] • A homojunction solid solution, Zn 0.7 Cd 0.3 S, capable of piezo-photocatalytic reduction of U(VI) was designed and synthesized. • A new photo- and piezoelectric synergistic catalysis strategy was provided for the efficient reduction of U(VI). • This work achieved the ability to reduce U(VI) without sacrificial agents. • A new view of the effect of h+ sacrificial agent is presented on U(VI) reduction. Photocatalysis has been applied to the reduction of U(VI), but how to improve the separation of photogenerated carriers, realize photocatalysis without sacrificial agents, and still have a certain catalytic activity in the absence of light are still problems that need to be solved. In this paper, a series of Zn x Cd 1-x S (0 ≤ x ≤ 1) solid solutions with different Zn/Cd molar ratios are synthesized for piezo-photocatalytic reduction of U(VI) under air atmosphere and without the addition of sacrificial agent. Under combined visible light and ultrasound irradiation, the homojunction with bicrystalline structure, i.e., wurtzite (WZ) and zinc-blende (ZB) formed from Zn 0.7 Cd 0.3 S solid solution, provides effective space charge separation and exhibits a prominently synergetic piezo-photocatalytic U(VI) removal rate of 99.3 % for 15 min, which is 34.2 times higher than that of ultrasound alone (2.9 % in 15 min) and 1.2 times greater than that of light alone (80.7 % in 15 min). Meanwhile, the charge transfer in Zn 0.7 Cd 0.3 S homojunction was revealed in this study through DFT calculations and a mechanism for the piezo-photocatalytic synergistic reduction of U(VI) was proposed. This work promises to provide a new coupled catalytic reaction design strategy for the efficient reduction of U(VI). [ABSTRACT FROM AUTHOR]

The internally formed Ov-ZAF with spatially separated Ov-ZAF can reduce 498.3 mg/g of U(VI) in 100 ppm uranium solution in 200 min with a reduction efficiency of 99.8 %. [Display omitted] • It has excellent solar photocatalytic reduction of uranium and antibacterial properties. • Homogeneous flower-like microspheres of O v -ZAF were synthesized. • Z- Scheme heterojunction structure promotes photogenerated carrier migration. • O v -ZAF surface energy band alignment promotes separation of electrons and holes. • This strategy opens up new ideas for the design of specific nanocatalysts. Designing an efficient reduction of soluble U(VI) to insoluble U(IV) is a challenge, and efficient electron-hole transfer efficiency is the key to the conversion of U(VI) to U(IV). Herein, defective transition metal sulfide (O v -ZAF) Z-Scheme tandem heterojunctions with spatial separation were synthesized using an in situ self-assembly method. O v -ZAF has excellent electron-hole separation, stabilized reactive active sites, and excellent visible light absorption. O v -ZAF is able to realize the photocatalytic U(VI) reduction reaction (URR) and water oxidation reaction (WOR) synergistically. The results showed that O v -ZAF was able to reduce 498.3 mg/g of U(VI) in 100 ppm uranium solution for 200 min, with a reduction efficiency of 99.8 %. O v -ZAF showed excellent reduction ability in a variety of uranium-containing waste solutions as well as in real seawater. In addition, O v -ZAF is capable of generating reactive oxygen radials (ROS) and has excellent antimicrobial activity against Escherichia coli, Staphylococcus aureus and Pseudoalteromonas xiamen. Oxygen vacancies and tandem components can tune both occupied and unoccupied orbitals near the Fermi level of O v -ZAF. This work provides a possibility of efficient uranium reduction engineering through tunable compositions and electronic structures. [ABSTRACT FROM AUTHOR]

A novel design strategy of donor–acceptor-catalyst configuration is proposed for CTFs, wherein the photoexcited electrons undergo stepwise transfer from the donor unit to the acceptor unit and ultimately reach the catalytic center. This process effectively suppresses electron-hole recombination. Additionally, the built-in catalytic unit enhances both catalytic activity and product selectivity. [Display omitted] • A novel design strategy of donor–acceptor-catalyst configuration is proposed for CTF photocatalyst. • It enables the stepwise transfer of photoexcited electron, inhibiting electron-hole recombination. • CTF-TT-Ir exhibits a superior HCOOH production rate with an excellent selectivity. • The photocatalytic CO 2 reduction process was investigated via DRIFTS. • To elucidate the selectivity towards HCOOH, the transformation pathway was investigated through DFT calculations. Covalent triazine frameworks (CTFs) have great potential for photocatalysis. However, the electron-hole recombination and the lack of efficient catalytic sites constrain the activity and selectivity. Herein, a novel design strategy of donor–acceptor-catalyst (D-A-C) configuration is proposed. This configuration enables the photoexcited electron undergoes stepwise transfer from donor unit to acceptor unit and ultimately reaches catalytic center, effectively inhibiting electron-hole recombination. The proof-of-concept model CTF-TT-Ir, in which thieno[3,2-b]thiophene (TT) serves as the donor unit, triazine as the acceptor unit, and Cp*Ir(bpy) (Ir) as the built-in catalytic site, was prepared for the photocatalytic reduction of CO 2 to HCOOH. The stepwise transfer of photoexcited electrons in the ternary structure has been demonstrated through the in-situ XPS measurements and the theoretical calculations. Photoluminescence and photocurrent tests have indicated CTF-TT-Ir exhibits superior charge separation efficiency. Without additional photosensitizer and co-catalyst, the photocatalytic HCOOH yield rate of CTF-TT-Ir reached 245 μmol g−1h−1 (selectivity of 97 %). [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) with bioinspired N,S-sites were constructed. Single Co atoms were coordinated with N,S-sites to create Co-THD-COF, which photocatalyzed CO 2 conversion to CO with 95.1 % selectivity in water and natural seawater. The synergistic interaction between THD-COF and the single atomic Co center enhanced CO 2 adsorption, activation, and reduced reaction energy barriers for *COOH intermediates, resulting in good performance. [Display omitted] • Learning from natural carbon monoxide dehydrogenase, we delicately designed a THD-COF with bioinspired N,S-coordination sites and constructed Co-THD-COF by anchoring single Co atoms on the N,S-sites. • Co-THD-COF can photocatalyze CO 2 conversion to CO with 95.1 % selectivity in water and natural seawater with reusability. • Under visible light, Co-THD-COF displayed dramatically enhanced photocatalytic CO 2 RR activity, exhibiting the CO generating rate of 9357 μmol g−1h−1. • The synergistic interaction between THD-COF and the single atomic Co center enhanced CO 2 adsorption, activation, and reduced reaction energy barriers for *COOH intermediates, resulting in good performance. Photocatalytic CO 2 reduction reaction (CO 2 RR) has promising potential to address global energy and environmental challenges but is severely limited by sluggish kinetics and poor selectivity, where the chemical microenvironments and electronic structures of the catalytic center play pivotal roles. Herein, inspired by carbon monoxide dehydrogenase, which can accelerate CO 2 to CO reduction, we delicately design a covalent organic framework (THD-COF) with bioinspired N,S-coordination sites from thiophene and imine modules on the skeleton and construct Co-THD-COF by anchoring single Co atoms on the N,S-sites. Under visible light, employing binary mixed sacrificial agents, with the help of photosensitizer [Ru(bpy) 3 ]Cl 2 ·6H 2 O, Co-THD-COF displays dramatically enhanced photocatalytic CO 2 RR activity, exhibiting an astounding CO generating rate of 9357 μmol g−1h−1 with the selectivity of 95.1 %. Additionally, Co-THD-COF can photocatalyze CO 2 conversion smoothly in real seawater without loss of CO selectivity. Experimental and computational analysis further manifest that the single Co atom is the catalytic active center. Co-THD-COF significantly promotes CO 2 adsorption and activation, charge separation dynamics, and is also beneficial to the formation of the crucial *COOH intermediates. The current study offers deep insights into the effective conversion of CO 2 and enlightens the design of novel bioinspired coordination sites for single-atom photocatalysts. [ABSTRACT FROM AUTHOR]

A simultaneous application of CO 2 reduction and biomass selective oxidation within a shared photocatalytic redox system by an MoS 2 @GCN S-scheme heterojunction with rich sulfur vacancies. [Display omitted] • An Sv-rich MoS 2 @GCN S-scheme heterojunction was successfully fabricated. • CO 2 reduction and biomass refining were applied in a shared photocatalytic system. • The synergism of the Sv and S-scheme heterojunction accelerated charge transfer. • Xylonic acid and CO can be produced from liquid and gas simultaneously. Photocatalytic CO 2 reduction and biomass selective oxidation have considerable practical implications in addressing environmental challenges. However, developing efficient photocatalyst is the key to realize the mass-market applications. Herein, an MoS 2 @GCN S-scheme heterojunction, rich in sulfur vacancies (Sv), was fabricated by a dicyandiamide-blowing and calcination strategy using NH 4 Cl as the gas template. With the synergistic effects of Sv and the S-scheme charge migration mechanism, the 30%-Sv-MoS 2 @GCN demonstrated exceptional performance, showcasing a CO evolution rate of 68.3 μmol g−1 h−1 and a xylonic acid yield of 64.2%, without using any sacrificial agents. The formation of Sv was confirmed through electron paramagnetic resonance (EPR) analysis. The S-scheme charge transfer mechanism of the Sv-MoS 2 @GCN heterojunction was verified by in-situ X-ray photoelectron spectroscopy (XPS) spectra, EPR analysis, and density functional theory (DFT) calculations. This study establishes a framework for enhancing photocatalytic CO 2 reduction and biomass selective oxidation by regulating charge transfer through sensible structural design. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel strong coupling ternary photocatalyst BMCN/300 was prepared by low-temperature annealing. • Annealing induces the activation of NiCu sites, makes Cu 2 O a high-density catalytic site. • In-situ DRIFT and DFT prediction reveal the catalytic pathways. • CO 2 photocatalytic reduction to CH 4 yields 165.3 µmol g−1h−1. To achieve the "carbon neutrality" goal, a core-crust-based Cu 2 O/NiCu-MOF and graphite carbon–nitrogen (g-C 3 N 4) strongly coupled ternary photocatalyst (BMCN/300) was prepared by using a simple low-temperature annealing induction effect and heterojunction interface engineering strategy. The BMCN/300 efficiently converts CO 2 to CH 4 (165.3 μmol h−1 g−1) and CO (51.3 μmol h−1 g−1) under simulated sunlight in the gas–solid mode without additional sacrifice agents and photosensitizer. The experimental and theoretical calculation results indicate that the annealing treatment achieves strong coupling between g-C 3 N 4 and Cu 2 O/NiCu-MOF, promotes the migration of interface electrons to Cu 2 O/NiCu-MOF catalytic unit, NiCu sites are heat-activated to an electron-rich state under annealing induction, and Cu 2 O becomes a high density of photo-excited electron accepting catalyst sites. The strong coupling of Cu 2 O/NiCu is conducive to the formation of the key intermediate *CHO, thus achieving highly selective photocatalytic CO 2 reduction to CH 4. [ABSTRACT FROM AUTHOR]

Intercomponent electron transfer channels were established via various interface structures formed between amorphous Pd or crystalline Pd and In 2 O 3 , Pd A acted as electronic pump, facilitating the transfer and separation of photogenerated electrons, resulting in their subsequent enrichment on the surface of amorphous Pd. [Display omitted] • Amorphous Pd is constructed exploiting hydrogen-induced amorphization effects. • Pd-In 2 O 3 exhibited 3-fold improvement selectivity of CH 3 OH + CO as compared with In 2 O 3. • The progressive electrons transfer between reactant molecules and catalysts. • Amorphous Pd as an electron pump to optimize electron transfer. • The number of electrons received by CO 2 is the key to improving product selectivity. The progressive transfer of photogenerated electrons between the catalyst components and reactants is of great significance for photocatalysis. Amorphous Pd (Pd A) and oxygen vacancies (V O s) were simultaneously introduced in Pd-In 2 O 3 exploiting hydrogen-induced amorphization effects; 0.6 wt% Pd-In 2 O 3 exhibited a 4.5-fold increase in activity and a 3.2-fold higher selectivity toward CH 3 OH + CO (63.62 %) compared with In 2 O 3. Multiple in situ techniques and theoretical calculations revealed that intercomponent electron transfer channels were established via various interface structures formed between Pd A or crystalline Pd (Pd C) and In 2 O 3 ; Pd A acted as electronic pump, facilitating the transfer and separation of photogenerated electrons, resulting in their subsequent enrichment on the surface of Pd A. Simultaneously, Pd A acted as electron-donating adsorption site for H 2 O, increasing the number of electrons received by H 2 O, further inhibiting the competitive adsorption of H 2 O and CO 2 on V O sites, and promoting the hydrogen evolution reaction. Additionally, the electronic coupling between Pd C and V O s could significantly decrease the electron-donating ability of V O s, reducing the number of electrons received by CO 2 , thus effectively regulating the degree of CO 2 reduction. This study employs Pd A /Pd C and V O s to synergistic optimize the progressive transfer of photogenerated electrons, and presents a novel approach for elucidating the catalytic mechanism. [ABSTRACT FROM AUTHOR]

• We dope paramagnetic iron ions (Fe2+) into colloidal metal halide perovskite nanocrystal (PNC). • Incorporating a magnetic dopant and applying an external magnetic field induce spin polarization. • The spin polarized photo-excited electrons enhance the photocatalytic CO 2 reduction efficiency. • Applying an external magnetic field with Fe-doped PNCs, we achieve a CO 2 reduction rate of 133.04 μmol g−1. • This shows a 1.68-fold increase in CO 2 reduction rate compared to magnetic field-free Fe-doped PNCs. Spin manipulation offers an effective strategy to enhance photocatalytic activity in metal halide perovskites by suppressing the recombination of photo-excited electrons. However, the scope of the magnetic dopant inducing spin polarization is still limited. Here, we introduce synergetic strategies to polarize the spin in photo-excited electrons and boost their photocatalytic activity for CO 2 reduction. We dope iron cation (Fe2+) into CsPbBr 3 perovskite nanocrystals (PNCs). Fe ions induce paramagnetism, fostering spin polarization within the Fe-doped CsPbBr 3 PNCs (Fe-CsPbBr 3 PNCs) under magnetic fields. The magnetic compositions in PNC tend to stabilize the spin polarized electrons within the PNC, mitigate the recombination of photo-excited electrons and enhance the redox reaction for photocatalytic CO 2 reduction. The synergistic effects of magnetic element doping and the application of magnetic fields resulted in a photocatalytic CO 2 reduction of 133.04 μmol g−1, which is 1.68-fold increase compared to the Fe-PNC without a magnetic field. This work provides a simple and environmentally friendly approach to CO 2 reduction based on PNCs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Core-sheath MOF@TiO 2 composites with covalent heterointerfaces have been fabricated. • MOFs modification offers tunable CO 2 photoreduction selectivity from CO to C 2 H 5 OH. • Amino modification promotes the CO selectivity to 98.3% by enhancing CO 2 affinity. • 94.2% of C 2 H 5 OH production is achieved using Cu NPs as the C C coupling site. Photocatalytic CO 2 reduction is a potential promising strategy for eliminating the global energy crisis and environmental issue. However, the complex reduction pathway leads to multiple possible products with limited efficiency, representing a great barrier for the further development. Herein, we report a Metal-organic framework (MOF) based heterostructure model for the efficient photoreduction of CO 2 with full controllable product selectivity between CO and C 2 H 5 OH. Novel core-sheath like MOF@TiO 2 heterostructures could be efficiently prepared by the layer-by-layer (LBL) growth of HKUST-1 onto Cu-embedded TiO 2 nanofibers (NFs), affording covalent heterointerfaces for efficient S-scheme charge separation and promising potential in photocatalytic activity regulation. By improving the CO 2 capture and retention via in situ amino-functionalization of HKUST-1, the photocatalytic CO production rate could be greatly promoted from 8.76 ± 0.84 to 43.46 ± 0.86 μmol g−1h−1 accompanied by an enhancement of selectivity from 91.7 % to 98.3 %. Moreover, the product could be efficiently engineered into ethanol with a C 2 product selectivity of 94.2 % by introducing Cu nanoparticles (NPs) as the additional C C coupling site. The in situ FT-IR and DFT calculations reveal the mechanistic process and decisive role of amino-functionalization and Cu NPs deposition in photocatalytic activity engineering. This work highlights the key factors and significance of fabricating MOFs based heterostructures with tunable photocatalytic activity for achieving CO 2 neutralization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu-based metal covalent organic framework (Cu-TMT) was prepared for the extraction of uranium. • Cu-TMT has unsaturated Cu centers that serve as chemical reduction sites. • Cu-TMT has excellent visible light conversion efficiency and low band gap. • Cu-TMT reduced uranium by chemical reduction and photocatalytic reduction reached 1438.8 mg g−1. The reduction of hexavalent uranium to tetravalent uranium is an effective strategy for controlling uranium contamination in wastewater. Herein, a C C bonded metal-covalent organic framework (Cu-TMT) was synthesized via the Aldol condensation reaction by using the metal cluster Cu 3 (PyCA) 3 and 2,4,6-trimethyl-1,3,5-triazine (TMT) for the chemical and photocatalytic synergistic reduction of uranium. In the Cu-TMT, the low-valent Cu in the metal clusters provides the framework with numerous distributed redox sites being capable of chemically reducing UVI. Meanwhile, the encapsulating Cu clusters in long-range ordered frameworks can provide fast transport channels for intramolecular charge transfer and effectively inhibit electron/hole complexation, making Cu-TMT suitable for photocatalytic reduction of uranium. The chemical reduction of uranium by Cu-TMT was verified under light-avoidance conditions, reaching 659.5 mg g−1. After exposure of Cu-TMT to light, the amount of reduced uranium further increases to 1438.8 mg g−1 with 98.1 % removal rate of actual uranium containing wastewater. This study not only expands the range of applications of variable valence metal covalent organic frameworks, but also provides unique insights into the effective combination of chemical and photocatalytic reduction strategies for removing UVI in a single material. [ABSTRACT FROM AUTHOR]

• The hierarchical CuS@SnS 2 p-n heterojunction hollow cubes were fabricated. • The synergy of hollow cubes and p-n heterojunction enhanced photocatalytic CO 2 reduction. • The addition of Au nanoparticles was conducive to binding and reducing CO 2 molecules. • The synergy of p-n heterojunction and Schottky junction accelerated charge transfer and separation. During the photocatalytic CO 2 reduction process, fast charge transport, abundant active sites, and high visible light utilization in photocatalysts are key to achieving excellent CO 2 conversion efficiency. In this work, we have designed and prepared hierarchical CuS@SnS 2 p-n heterostructure hollow cubes for photocatalytic CO 2 reduction. First, a monolayer of CuS was in situ generated on the pre-prepared Cu 2 O cubes to construct core–shell Cu 2 O@CuS cubes by sulfidation of Cu 2 O cubes. The following etching process led to the formation of CuS hollow cubes. Finally, the hierarchical CuS@SnS 2 p-n heterostructure hollow cubes were obtained by growing SnS 2 nanosheets on the CuS hollow cubes. The prepared CuS@SnS 2 p-n heterostructure hollow cubes showed an improved photocatalytic CO 2 reduction activity compared with the bare CuS and SnS 2 control samples. The p-n heterojunction formed between SnS 2 and CuS as well as its hollow structure enhanced the charge carrier separation efficiency and the light absorption capacity of the hybrid catalyst. Furthermore, after the decoration of Au nanoparticles, the formed Schottky junction further discouraged the charge carrier recombination. Thus, the cooperative p-n heterojunction and Schottky junction greatly facilitated photocatalytic CO 2 reduction, and exhibiting the maximum CO and CH 4 yields of 140.1 and 77.5 μmol g−1 h−1, respectively. This work presents an efficient design of high-performance catalysts for photocatalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]

[Display omitted] • A charge transfer routeway was tailored in NiO/BiOCl-7 heterostructures via a transform from type-II to S-scheme. • The S-scheme NiO/BiOCl-7 heterojunctions were prepared by pH-modulation to optimize the energy band structure of BiOCl. • The S-scheme NiO/BiOCl-7 heterojunctions achieved a significantly enhanced production of CO with a selectivity of 97.1 %. • The strategy of energy band modulation sheds light on the customization of Bi-based heterostructures with favorable charge transfer. • Possible mechanism for boosting CO 2 photoreduction was proposed by the analysis of DFT calculation and in-situ experiments. The photo-driven CO 2 reduction holds significant potential in facilitating carbon fuel conversion. However, the inefficiency of charge conversion severely limits its spractical applications. Herein, the charge transfer routeway was tailored in NiO/BiOCl-7 heterostructures via a transform from type-II to S-scheme for enhancing CO 2 photoreduction to CO. Such S-scheme NiO/BiOCl-7 heterojunctions were prepared by pH-modulation to optimize the energy band structure of BiOCl and introduce abundant oxygen vacancies. Surprisingly, the S-scheme NiO/BiOCl-7 heterojunctions exhibited a significantly enhanced production of CO (78.11 μmol·g−1·h−1) with an impressive selectivity of 97.1 %, representing a remarkable 1.7- and 4.3-fold improvement in CO yield compared to the type-II NiO/BiOCl heterojunctions and pure BiOCl samples, respectively. The in-situ spectral experiments and DFT calculations reveal that the superior CO production can be attributed to a lower energy barrier for COOH* and a smoother potential energy surface of the S-scheme heterojunction with abundant oxygen vacancies. This meticulous strategy of energy band modulation sheds light on the deliberate customization of Bi-based heterostructures with favorable charge transfer for highly effecient photocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni-Cu/C achieved a brilliant CO yield in pure water system. • Ni-Cu/C displayed a high CO 2 conversion selectivity. • Ni-Cu/C optimized the charge transfer dynamics and *CO formation. • The reaction mechanism was revealed by in-situ FT-IR and DFT calculations. The metal–organic frameworks (MOFs) rich in porous structures and their derivatives have been widely developed and applied to heavy metal adsorption. However, little attention has been paid to the subsequent treatment and reutilization of spent MOFs adsorbents. A potential feasible strategy is to develop MOFs-derived bimetallic catalysts for energy conversion. Herein, a bimetallic Ni-Cu 2 O-Cu/C nanocomposite (Ni-Cu/C) derived from spent Cu-based MOFs (CuBTC) adsorbents was fabricated and applied to improve the performance of photocatalytic CO 2 reduction. The results demonstrate that Ni doping could improve the charge transfer dynamics. The synthesized Ni-Cu/C catalyst exhibits a high CO yield (12.45 μmol g−1 h−1) in the pure water system in the absence of other photosensitizers and sacrificial agents, which is 2.05 folds higher compared to Cu/C. The CO 2 conversion selectivity of the synthesized Ni-Cu/C catalyst reaches up to 99.0%. The mechanism of photocatalytic CO 2 reduction reaction was further investigated by in-situ experiments and density functional theory calculation. The in-situ FT-IR characterization show that photogenerated electrons could effectively adsorb CO 2 to produce CO 2 − and optimize *CO immediate. This work not only emphasizes the unique design of bimetallic catalyst derived from spent MOFs adsorbent, but also contributes a feasible solution to its reutilization for enhanced CO 2 conversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • The electron transfer is markedly accelerated by −H-C=N-H- bond between materials. • Pt2+/Pt4+ induces the simultaneous photocatalytic oxidation and reduction of NO. • Bifunctional single platinum atom further enhances the production of •O 2 – • DFT calculations elucidate the pathways of photocatalytic oxidation and reduction. This study presents a chemically bonded Pt/TP-BPY-CN/g-C 3 N 4 composite photocatalyst created through an in-situ growth method via Schiff base reaction between g-C 3 N 4 and aldehyde-functionalized TP-BPY-COF. The −H-C-N-H- bonds formed at the g-C 3 N 4 and TP-BPY-COF interface significantly boost electron communication, thereby substantially enhancing transfer efficiency between these two constituents. Besides, single-atom platinum incorporation via coordination establishes a Pt2+/Pt4+ redox cycle, aiding both oxidation and reduction of nitric oxide (NO). Consequently, the Pt/40TPBPY-CN composite achieves 65.3 % NO conversion, with almost 100 % oxidation selectivity towards NO 3 –. In-situ XPS analysis confirms the robust electron communication between TP-BPY-COF and g-C 3 N 4 facilitated by −H-C-N-H- bonds, and the redox transformation between Pt2+ and Pt4+. In addition, DFT calculation provides a deeper insight into photocatalytic oxidation and reduction pathways, confirming an inhibition of N 2 desorption. This research underscores the benefits of chemically bonded heterostructures for improved electronic interactions and highlights the efficacy of bifunctional single-atom platinum in photocatalysis. [ABSTRACT FROM AUTHOR]

Gd/CdS-PW 12 AO showed excellent adsorption performance at low concentration (10 mg/L) with the maximum adsorption of 205.29 mg/L. Meanwhile, without using any sacrificial electron reagent, Gd/CdS-PW 12 AO achieved a degradation rate of 90.0% at a concentration of 300 mg/L. The photocatalytic removal rates of U(VI) reached over 95% even in the presence of co-existing ions, demonstrating the high selectivity of the photocatalytic removal of U(VI) on Gd/CdS-PW 12 AO nanocomposite. These results offer valuable insights into covalently modified polyoxometalates based photocatalysts in the field of radioactive waste treatment. [Display omitted] • Amidoxime functionalized PPICs were prepared. • The Gd/CdS-PW 12 AO exhibits both adsorption and photocatalytic properties. • Uranium removal rate is 90 % at 300 mg/L without any hole trapping reagent. • The Z-scheme heterostructures facilitate the transport and separation of charges. The efficient removal of uranium-containing wastewater is essential for the advancement of the nuclear industry. The photocatalytic reduction of hexavalent uranium is a highly effective and environmentally friendly process, making it a promising technology. Hence, the idea of functionalizing PPICs with amidoxime was first proposed. DFT theoretical calculation showed that amidoxime functionalized PPICs had excellent uranium adsorption capacity. Then, PW 12 AO and Gd/CdS were combined to form Z-scheme heterojunction to improve the photocatalytic ability of the catalysts. Gd/CdS-PW 12 AO achieved a 90 % uranium removal rate at 300 mg/L without any sacrificial reagents, surpassing most reported photocatalysts. After five cycles, the removal rate consistently remained above 80 %, which indicated that Gd/CdS-PW 12 AO had excellent structural stability and repeatability. Ultimately, this study holds significant importance for the future research and development of photocatalytic materials aimed at uranium removal. [ABSTRACT FROM AUTHOR]

A series of isostructural covalent organic frameworks (COFs) were developed for CO 2 photoreduction. The strong coordination conformation guides atomically dispersed metal sites to chelate in the predesigned imine-pyridine position on the ordered channel walls of COFs. The COFs exhibited substantially enhanced activity even using diluted CO 2 under sunlight owing to the single-Ni site engineering and electronic structures of COF configuration. [Display omitted] • A series of isostructural COFs bearing imine-pyridine moieties formed by pyridine units and their adjacent imine groups anchoring single-Ni sites. • Local charge distribution of single Ni sites can be regulated by tuning the electron character of chemical structural units. • The optimal Ni-TAPT-COF achieved a record-high CO production rate, even for natural-sunlight-driven low-concentration CO 2. • The synergetic effect of the COF configuration and single-Ni site can promote charge separation/transfer efficiency and CO 2 adsorption and activation. Covalent organic frameworks (COFs) engineered by single-atom sites have attracted significant attention for CO 2 photoreduction. However, precisely manipulating the chemical environment of active sites on the COFs is a grand challenge. Herein, we synthesized a series of isostructural COFs for photocatalytic CO 2 reduction, where the strong coordination conformation guides atomically dispersed metal sites to chelate spontaneously in the predesigned imine-pyridine position of COFs. Experimental and theoretical results revealed the crucial influence of the single-Ni site engineering and electronic structures of COF configuration on improving extended π-conjugation, exciton dissociation, charge separation efficiency, and charge carrier migration. Benefiting from the synergistic effect, the optimal Ni-TAPT-COF exhibited a record-high CO production rate of 25.5 mmol g-1h-1 and a selectivity of 98.8%, even natural-sunlight-driven diluted CO 2 (10%). This work paves the way for the rational design of high-performance COF-based photocatalysts at the molecular level, highlighting their practical potential for CO 2 photoreduction. [ABSTRACT FROM AUTHOR]

• TiO 2 was modified by a novel quaternary ammonium structure of CDs. • CPC-CDs/TiO 2 attains excellent reduction of Cr(VI) under a wide pH range. • CPC-CDs/TiO 2 shows the remarkable reduction of Cr(VI) under natural sunlight. • CPC-CDs/TiO 2 demonstrates outstanding recyclability and antibacterial properties. Cr(VI) pollution in water caused by industrialization poses a serious threat to human health and ecosystems, necessitating a rapid reduction of Cr(VI) treatment method. Therefore, We have established a photocatalytic method for the rapid reduction of Cr(VI) by modifying TiO 2 with carbon dots (CPC-CDs) that possess a quaternary ammonium structure in the first time. The CPC-CDs widens the band gap of TiO 2 and increases the electrostatic interactions between CPC-CDs/TiO 2 and Cr(VI), thus improving the reduction efficiency. CPC-CDs/TiO 2 (0.1 g, 2 % CPC-CDs) exhibited excellent reduction performance and fully reduced Cr(VI) (50 mg/L) under neutral conditions within 150 min using a xenon lamp to simulate sunlight. Moreover, CPC-CDs/TiO 2 achieved more than 95 % reduction efficiency over a wide pH range (pH = 3, 5, 7, and 9) and showed excellent reduction of Cr(VI) at various concentrations (10, 20, 30, 40 and 50 mg/L). CPC-CDs/TiO 2 maintained high Cr(VI) reduction efficiency (93.57 %) after five cycles. Tests under real sunlight revealed that CPC-CDs/TiO 2 thoroughly reduced Cr(VI) (10 mg/L) within 30 min, and exhibited excellent structural stability under conditions with interfering ions. Furthermore, CPC-CDs/TiO 2 exhibited prominent antibacterial activity against Escherichia coli. In addition, free-radical trapping experiments verified that the superoxide radicals (• O 2 -) was the main active species. This study aims to overcome the limitations of photocatalytic reduction under conditions of high concentration Cr(VI), neutral and alkaline environments, and natural sunlight, thereby providing technical support for the rapid reduction of Cr(VI). [ABSTRACT FROM AUTHOR]

The formation of ultra-low resistance interface by the Ohmic contact (Pd nanocubes/In 2 O 3) and the built-in electric field enhanced by the metal–carbon (Pd nanocubes/HMC) interaction significantly inhibits the recombination of electron-hole pairs, facilitates the migration of charge carriers, and greatly enhances photoredcution activity of CO 2 -to-CO. [Display omitted] • An Ohmic contact-structured Pd/In 2 O 3 /C (PIC) photocatalyst is designed with an ultra-low interfacial resistance. • The enhanced built-in electric field in PIC significantly accelerates photogenerated charge transfer. • The PIC achieves a high CO yield of 99.4 μmol∙g−1∙h−1 under full spectrum irradiation. The utilization of CO 2 photoreduction into valuable hydrocarbon fuels presents a promising avenue for mitigating climate change and providing a sustainable energy source. However, photogenerated carriers are highly prone to recombination, which adversely affects photocatalytic activity. In our study, we introduce a novel photocatalyst synthesis method, featuring an Ohmic contact (OC) structure that incorporates biomass-derived hollow carbon microspheres (HCM), Pd nanocubes (NC), and Indium Oxide (In 2 O 3) through a simple yet effective thermal reduction method. This modification significantly enhances the photocatalytic efficiency of the Pd NC/In 2 O 3 /HCM (donated as PIC) system, achieving an optimal value of 496.89 μmol∙g−1 over 5 h without the need for additional additives, 8.7-fold higher than that of the pristine In 2 O 3. Experimental and theoretical results reveal that the substantial enhancement in CO 2 photoreduction performance can be attributed to the ultra-low resistance (122 Ω) interfaces within the PIC system, facilitating accelerated transfer of photogenerated electrons. This work provides a strategy for boosting CO 2 photoreduction efficiency by the reduction of interface resistance to promote rapid photogenerated electron migration. [ABSTRACT FROM AUTHOR]

[Display omitted] • The ZIF-67 was firmly loaded onto nanofibers by in situ growth method. • The membranes expose more active sites, showing outstanding CO 2 reduction efficiency. • Thermal treatment enhances the membrane photothermal effect, boosting CO 2 reduction. • Thermal-treated membranes achieve solvent resistance and cycling stability. The photocatalytic Metal-organic frameworks (MOFs) membrane addresses challenges faced by MOF powders in practical applications such as aggregation and difficult recovery, but its current application is mainly confined to wastewater treatment. Expanding the application of MOFs membranes to CO 2 reduction could unleash their greater potential in energy conversion and storage field. In this study, ZIF-67 was deposited on polyacrylonitrile (PAN) nanofiber membranes (NFMs) using an in-situ growth technique, followed by thermal stabilization to produce SZIF-67/PAN NFMs for photocatalytic CO 2 reduction. ZIF-67 was uniformly and densely distributed on the NFMs, with a mass loading of up to 8 wt%. The thermal stabilization process significantly enhanced the photothermal conversion capability and solvent resistance of the NFMs, enabling SZIF-67/PAN NFMs to exhibit outstanding photocatalytic activity even under mild environmental conditions, with a remarkable CO generation rate of 39,250 μmol g−1h−1. Furthermore, the performance remained at 70 % even after five consecutive tests. This study presents a novel and effective method for preparing MOF NFMs with excellent photocatalytic CO 2 reduction performance, offering valuable insights for advancing the practical application of MOF materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Structural simulations of halogen modified h -BCN were systematically conducted. • Morphology of BCN-F-4 was highly consistent with theoretical calculations. • Local spatial polarization enables efficient electron transfer. • Carrier separation and CO 2 reduction efficiency was significantly enhanced. • The mechanism of photocatalytic performance enhancement has been proposed. CO 2 photoreduction into highly value-added chemicals over metal-free h -BCN has emerged as a promising strategy to address the issue of global warming. However, the serious carrier recombination caused by disordered charger transfer has limited its practical application. To circumvent this issue, fluorine modified h -BCN were synthesized using a facile heat treatment method. The surface halogenation created local spatial polarized electric field, which facilitated the local charge separation and transmission efficiency. Among them, BCN-F-4 exhibited the best photocatalytic CO 2 reduction activitiy with CO and CH 4 yield of 25.38 and 14.11 µmol g−1h−1, respectively. The turnover number (TON) of BCN-F-4 reached up to 163.6 μmol g−1h−1, 4.4 times that of BCN. Both theoretical simulation and experimental analysis demonstrated a strong covalent interaction between the F atoms and the h -BCN matrix, which gain deep understanding of the mechanism of prominent photocatalytic CO 2 reduction activity boosted by surface halogenation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phosphate functionalized COF/rGO was synthesized using post-synthetic modification. • Tb-BD-P/rGO exhibited excellent physicochemical stability and rapid uranyl mass transfer ability. • TB-BD-P/rGO enabled photoelectrothermal synergistic photocatalytic reduction of uranium. • Tb-BD-P/rGO performed excellent removal rates (>95 %) in actual strong acid nuclear wastewater. Photocatalytic reduction is becoming an effective method to remove UVI from uranium mine wastewater. Herein, 1,3,5-benzotrialdehyde (Tb) and 4,4′-diaminobiphenyl (BD) used as monomers of covalent organic framework (COF) are in situ growth on graphene oxide (GO) surfaces to obtain Tb-BD/rGO. Then, Tb-BD/rGO is converted into Tb-BD-P/rGO by asymmetric hydrogen phosphorylation, which is served as a new material for photocatalytic reduction of uranium via photoelectrothermal synergy. Benefiting from the transformation of dynamic imine bonds into irreversible carbon–nitrogen single bonds, Tb-BD-P/rGO expresses remarkable chemical and thermal stability. The introduction of phosphate groups improve the electronegativity and hydrophilicity of Tb-BD-P/rGO, which contribute to rapid transportation of uranium. In addition, the introduction of rGO achieves excellent photothermal conversion, accelerating the adsorption kinetics of uranium. Meanwhile, the π-π interaction between Tb-BD-P and rGO promotes inter-interfacial electron transfer and reduces the complexation of electron-hole pairs during the photocatalytic process, further improving photocatalytic performance. Therefore, Tb-BD-P/rGO demonstrates exceptional removal uranium rates (>95 %) in uranium mine wastewater by synergistically photoelectrothermal integration, offering a pathway for developing multifunctional and integrated photocatalysts. [ABSTRACT FROM AUTHOR]

• Strong metal–oxygen hybridization was successfully incorporated in Ag cluster /TiO 2. • Ag cluster /TiO 2 shows a high photocatalytic CH 4 generation activity and selectivity. • Ag–O hybridization effectively optimizes photogenerated carrier dynamics. • Ag–O hybridization promotes the multiple-proton–electron coupling transfer process. Selective photocatalytic reduction of CO 2 to CH 4 is one of the most efficient ways to achieve carbon neutralization. However, the formation of methane remains a challenge due to the slow multiple-proton-coupled electron transfer process and the involvement of various C1 intermediates. Herein, an Ag cluster /TiO 2 catalyst with Ag-O hybridization was synthesized by supporting Ag clusters on anatase phase TiO 2 microspheres for photocatalytic CO 2 methanation. The Ag cluster /TiO 2 sample presents an electron selectivity of 86 % for CH 4 production with a yield of 25.25 μmol g–1 h−1. Mechanistic study reveals that Ag clusters accelerate the separation and migration of photogenerated carriers, and enhance the adsorption of CO 2. Moreover, the Ag-O hybridization promotes the multiple-proton–electron coupling transfer process by effectively stabilizing intermediates and facilitating *CO hydrogenation to *CHO, resulting in selective CO 2 reduction to CH 4. This work provides a new insight into the development of selective photocatalytic conversion of CO 2 to methane by constructing supported cluster catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Development of a scalable and robust Cu-ASTO/Au/CoO x -WO 3 composite photocatalyst sheet. • The sheet demonstrated enhanced charge separation efficiency via an indirect Z-scheme mechanism. • Efficient photoconversion of CO 2 and H 2 O using this innovative photocatalyst system. • Comprehensive testing of the photocatalytic CO 2 reduction performance in both indoor and outdoor settings. Perovskite oxides have emerged as promising photocatalysts for CO 2 reduction to valuable chemicals and fuels. However, conventional perovskite oxide photocatalysts often suffer from inefficient charge separation and bulk charge recombination, negatively impacting overall photoactivity. In this work, we present a novel immobilized perovskite oxide-based photocatalyst sheet featuring an indirect Z-scheme heterostructure composed of Cu-loaded Al-doped SrTiO 3 (Cu-ASTO) and CoO x -loaded WO 3 (CoO x -WO 3) with an ultrathin (20 nm) gold interlayer serving as a conductive bridge. We tested this photocatalyst sheet in a sealed reactor containing a CO 2 -saturated aqueous solution of 0.1 M NaHCO 3 and a side window to allow irradiation. Under irradiation with a 300 W Xe lamp, the Cu-ASTO/Au/CoO x -WO 3 immobilized photocatalyst sheet produced methane (CH 4) at a rate of 2.676 µmol cm-2 h−1 and methanol (CH 3 OH) at 0.517 µmol cm-2 h−1. We attribute the superior activity of this catalyst to the all-solid-state indirect Z-scheme heterostructure that greatly extends the lifespan of photoinduced charge carriers and enhances the CO 2 photoconversion reaction. In experiments conducted outside, we demonstrated the immobilized photocatalyst's performance under natural sunlight, producing CH 4 at 0.307 µmol cm-2 h−1 and CH 3 OH at 0.069 µmol cm-2 h−1. This work provides design ideas for developing robust immobilized photocatalyst systems for the scalable operation of the CO 2 photoreduction process and broadening the scope of applications for perovskite heterostructure photocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • N-GQDs/Bi 2 Fe 4 O 9 suppress charge recombination and electron accumulation. • N-GQDs/Bi 2 Fe 4 O 9 enhances in-situ H 2 O 2 generation and H 2 O 2 activation. • Electrons accumulation around N-GQDs accelerate the redox cycles of Fe(II)/Fe(III). • N-GQDs/Bi 2 Fe 4 O 9 achieves simultaneous toxic Cr(VI) reduction and BPA oxidation in wastewater. • N-GQDs/Bi 2 Fe 4 O 9 enables energy self-sufficient and simplified wastewater treatment methods. Synergistic coexistence of toxic chromium and organic contaminants in wastewater has made treatments highly complicated. As solar-driven wastewater treatments become increasingly environmentally and economically attractive, a photocatalyst (denoted as N-GQDs/Bi 2 Fe 4 O 9) is developed for photocatalytic reduction of Cr(VI) and simultaneous oxidation of organic contaminants in wastewater. Incorporating N-GQDs (as electron reservoir) into Bi 2 Fe 4 O 9 modulates the band structure (from 2.40 to 2.24 eV), facilitating charge transfer and electron accumulation at N-GQDs. Due to the photo-Fenton synergistic reaction between N-GQDs/Bi 2 Fe 4 O 9 photocatalysis process, N-GQDs/ Bi 2 Fe 4 O 9 demonstrates excellent H 2 O 2 generation (1.64 μM min−1) and H 2 O 2 activation (0.0063 min−1) performance, leading to generation of more highly reactive species (i.e., OH radicals), achieving BPA removal of 99.9 % under visible-light irradiation for 100 min. Interestingly, the photo-Fenton synergistic reaction enhances the reduction of Cr(VI) (99.8 %), while the Fe(II) active sites on the N-GQDs/Bi 2 Fe 4 O 9 can also promote the synchronized Cr(VI) reduction. Also, the accumulated electron around N-GQDs enhances redox cycles of Fe(II)/Fe(III) reactions to realize the sustainable photo-Fenton catalytic reaction. This new N-GQDs/Bi 2 Fe 4 O 9 photocatalyst demonstrates the feasibility of concurrent reduction of toxic Cr(VI)-to-Cr(III) and oxidation of organic contaminants in wastewater with a simple process via nearly unlimited solar energy. [ABSTRACT FROM AUTHOR]

• A stronger internal electric field was achieved by increasing dipole moment of catalyst due to the Sn doping. • Surface frustrated Lewis pairs were constructed near the oxygen vacancies due to Sn dopant. • Enhanced internal electric field synergistic frustrated Lewis pairs promoted selective CO 2 photoreduction. • The catalytic mechanism was systematically explored by in-situ FTIR and DFT calculations. Photocatalytic conversion of CO 2 into valued chemicals is limited by the CO 2 adsorption and activation capability on catalyst surface. In this work, Sn element was successfully doped in ultrathin BiOCl with oxygen vacancies. The dipole moment of catalyst efficient increased due to the Sn doping, leading to a stronger internal electric field. In addition, the surface frustrated Lewis pairs were simultaneously constructed near the oxygen vacancies due to Sn dopant. The formed region of frustrated Lewis pairs-oxygen vacancies as active sites enable an improved CO 2 adsorption, and the enhanced internal electric field intensity promoted the charge carrier separation and transfer, leading to the enhanced CO 2 reduction performances. This work provides light on enhancing internal electric field by increasing dipole moment and presents feasible tunability of catalytic active sites at atom-scale, providing fundamental insights for understanding of mechanism of element doping in catalyst for improving CO 2 photoreduction performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • This study presents a synthesis strategy for a porous core–shell structure photocatalyst from self-assembled supramolecular precursors. • In situ experimental results and calculation results revealed the Z-scheme heterojunction of TNPs@CN. • The synergistic effect of core–shell structure and Z-scheme electron transfer contribute to high-efficient CO 2 photoreduction. • In situ DRIFTS and Gibbs free energy calculation revealed the overall reaction pathway, and confirmed the key rate-determining step for CO and CH 4 production. Core-shell structure photocatalysts are favored due to their confinement effect that enhances photoreaction efficiency, but their synergistic effect with heterojunctions is frequently overlooked. Herein, we synthesized a porous core–shell photocatalyst TiO 2 nanoparticles@graphitic carbon nitride (labeled as TNPs@CN) from self-assembled supramolecular precursors for high-efficient photocatalytic CO 2 reduction. The porosity facilitates CO 2 transport and adsorption, while Z-scheme on the core–shell interface enhances electron transfer. Both in situ experimental and theoretical calculations have proved the Z-scheme heterojunction of TNPs@CN with a high photoreduction CO 2 rate of 26.89 and 8.91 μmol g−1h−1 for CO and CH 4 , respectively, which are far higher than those of amorphous TNPs-CN. A 13CO 2 labeled isotopic experiment and in situ FT-IR results laid the foundation for the mechanism of CO 2 photoreduction, which was then investigated in-depth by calculating free energy profile. This work provides valuable insights for designing high-performance photocatalysts that leverage the synergistic effect of core–shell structure and Z-scheme electron transfer for artificial photosynthesis. [ABSTRACT FROM AUTHOR]

• Synthesis of various 3D C 3 N 4 -based photocatalysts for CO 2 photoreduction. • In depth study of the characteristics of 3D C 3 N 4 crucial to CO 2 photoreduction. • Understanding of the mechanisms of CO 2 photoreduction via 3D C 3 N 4. • Overview of the photocatalytic performance of 3D C 3 N 4. CO 2 concentration in the atmosphere has reached an all-time high, leading to global warming. The scientific community has suggested photocatalytic CO 2 reduction as a reliable method to reduce CO 2 concentration and produce clean energy. Carbon nitride-based photocatalysts have caught community attention due to their activity in visible light, easy and inexpensive synthesis, and higher reduction potential than required for CO 2. Morphology engineering is one of the ways to enhance photocatalytic properties, as 3D carbon nitrides (C 3 N 4) have larger surface areas, higher light harvesting ability, and slower charge carrier recombination than the bulk form. This review article summarizes the synthesis and characteristics of 3D C 3 N 4 -based photocatalysts reported for CO 2 photoreduction. 3D C 3 N 4 -based photocatalysts have executed an excellent performance in the field of CO 2 photoreduction. This review will aid in understanding the use of 3D C 3 N 4 in CO 2 photoreduction, the related present studies, and research gaps that will be of service in future research. [ABSTRACT FROM AUTHOR]

• The C-/N- vacancies and hydroxyl co-modified g-C 3 N 4 nanorod was prepared. • The catalyst showed efficient Cr(VI) photoreduction rate in citric acid solution. • The vacancies and OH can promote the charge transfer from g-C 3 N 4 to citric acid. • Citric acid plays a vital role of charge transfer bridge and H proton donor. Photocatalysis is an energy-efficient and environment-friendly method to reduce Cr(VI) in water. The rapid spatial separation of photogenerated electrons and holes is still full of challenge. Microenvironment regulation of photocatalyst is a promising strategy. In this work, defined C- and N-vacancies were simultaneously successfully introduced to g-C 3 N 4 , accompanied by surface hydroxyl modification. Unlike traditional bulk g-C 3 N 4 , constructing C-/N- defects and surface hydroxyl can significantly improve the surface-interface microenvironment, thus leads to the enhanced photocurrent density and efficient charge separation. In a citric acid involved solution, the apparent rate constant of CN-160 for Cr(VI) photoreduction under visible light irradiation (λ ≥420 nm) reaches up to 2.02×10−2 min−1, which is 3.89-fold higher compared to bulk g-C 3 N 4. While there is almost no photoactivity in the absence of citric acid. The experimental and DFT calculations results show that C- and N-vacancies and surface OH can significantly promote the charge transfer from g-C 3 N 4 to citric acid, and subsequently to Cr(VI). Most importantly, citric acid not only plays a vital role of charge transfer bridge between Cr(VI) and g-C 3 N 4 , but also provides H proton to activate Cr(VI) as well as adjusts the solution pH values. All of these finally facilitate the photoreduction activity of Cr(VI). This study firstly demonstrates the definite role of citric acid during photocatalysis and provides a deep insight into the microenvironment regulation on the effect of charge separation. [ABSTRACT FROM AUTHOR]

• Waste-to-fuel strategy combining orange peel valorization and CO 2 conversion. • Metal-free orange peel waste–derived carbon nanodots were synthesized. • Highly active and selective system in CO 2 photoreduction to methanol. • Maximum methanol production rate of 416.6 µmol MeOH.g cat -1.h−1. • Highly stable methanol rate of 12.9 µmol MeOH.g cat -1.h−1 after 72 h. Addressing the major challenge of global warming by implementing a circular carbon cycle involving CO 2 conversion is currently an urgent priority for a more sustainable future. The design of efficient, stable, cheap and eco-friendly systems for such purpose is a remarkable challenge. This study reports an unprecedented metal-free, co-catalyst-free orange peel waste–derived carbon nanodot highly active and selective system for the photoreduction of CO 2 into methanol. The waste-derived photocatalyst exhibited a maximum methanol production rate of 416.6 µmol MeOH.g cat -1.h−1 and a highly stable methanol production rate of 12.9 µmol MeOH.g cat -1.h−1 after 72 h. This work proposes a successful waste-to-fuel strategy that combines the valorization of orange peel waste and CO 2 conversion for the synthesis of green methanol. [ABSTRACT FROM AUTHOR]

• The first comprehensive study incorporating excited states to analyze reaction mechanism across diverse surfaces. • Unlike most studies conducted solely in the ground state, our research explicitly incorporates excited states. • The significance of excited states in obtaining accurate results is demonstrated by microkinetic models. Photocatalysis is a promising method for reducing CO 2 in an environmentally friendly way. Despite extensive experimental studies, theoretical studies lag behind and often resort to describing catalysts in the excited state, while the reaction mechanism is mostly studied at the ground level. We theoretically calculate a full reaction mechanism of CO 2 reduction to CO in the excited state for five surfaces: Cu(1 1 1), anatase(1 1 0), rutile(1 0 1) and Cu/anatase, Cu/rutile using the ΔSCF approach. We show that excited states considerably lower activation barriers, making it necessary in describing the experimental performance. The density functional theory calculations in the excited state are used to construct a microkinetic model, which is used to predict the performance of each catalytic surface. We show that Cu(1 1 1) is photocatalytically inactive, TiO 2 is only active in the UV range and catalyzes water splitting. Only Cu/rutile is active for CO 2 reduction to CO, while Cu/anatase produces more H 2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Microfluidics for photocatalytic reduction of hexavalent chromium. • Rector design for effective photocatalytic conversion of Cr(VI) to Cr(III). • Efficiency of 95 % at a flow rate of 50 µl/min using serpentine microreactor. • Superior reduction efficiency of TiO 2 in the anatase phase than in the rutile phase. • Quantification of reduction efficiency using paper-based devices. The presence of hexavalent chromium (Cr(VI)) in water exceeding 0.05 mg/L constitutes a threat to both human health and the environment. Hence, the development of efficient methods for the removal and quantification of Cr(VI) in wastewater is of utmost importance. The photocatalytic reduction represents a valuable approach for transforming the toxic Cr(VI) into a non-toxic trivalent form of chromium (Cr(III)). However, this method encounters several challenges, including a slow reaction rate, the need for an acidic environment, high catalyst loading, and limited recovery efficiency. This study introduces an efficient microfluidic platform for the conversion of Cr(VI) in wastewater by integrating various reactor designs. We explored the use of nanosized TiO 2 as a photocatalyst in both pure anatase and rutile phases and a combination of anatase/rutile phases to assess their reduction performance. A remarkable conversion efficiency of 95 % was attained by utilizing a serpentine microreactor coated with a photocatalyst in the anatase phase. In contrast to the traditional batch photoreduction method, which reported a conversion efficiency of only 72 %, microreactor technology demonstrates a superior photoreduction performance. The pseudo-first-order kinetics was observed and the rate of reaction was calculated to be 0.199 sec −1. In addition to confirming the photoreduction of Cr(VI), we have also presented a robust yet user-friendly approach for quantifying Cr(VI) by combining paper-based devices with a smartphone-enabled colorimetric technique. Finally, we employed machine learning (ML) algorithms to predict photoreduction efficiencies using a multiple linear regression model to gain an understanding of the impact of various parameters and the root mean square error (RMSE) for the model prediction was calculated to be equal to 0.92 indicating the overall performance of the ML model was excellent. [ABSTRACT FROM AUTHOR]

• The NVCN was successfully synthesized by thermal treatment using NaBH 4. • The band structure was further manipulated by altering the calcination temperature. • The modulated band structure suppressed charge recombination. • The incorporation of NVs and B dopants synergistically boosts the PcNRA process. Photocatalytic nitrate reduction to ammonia (PcNRA) not only tackles nitrate pollution in wastewater but also transforms it into valuable ammonia, attracting attention as an eco-friendly and carbon-free ammonia synthesis technology. However, it still suffers from insufficient ammonia selectivity due to active side reactions such as nitrogen gas formation and hydrogen production. In this work, we synthesized B-doped and N-deficient g-C 3 N 4 (NVCN) by thermal treatment using NaBH 4 as a reduction reagent for selective photocatalytic nitrate-ammonia conversion. The simultaneous introduction of B dopants and nitrogen vacancies (NVs) into the g-C 3 N 4 (CN) framework modulated the band structure: the narrowed band gap and the generated mid-gap states suppressed charge carrier recombination and allowed more electrons to participate in the reduction reaction, while the reduced conduction band energy effectively inhibited hydrogen evolution, defining possible reaction pathways to nitrate reduction. Moreover, nitrate species were strongly adsorbed and activated on the catalyst surface in the co-presence of B dopants and NVs, which consequently facilitated selective and active nitrate-to-ammonia conversion. The optimal catalyst, NVCN475, achieved exceptional ammonia selectivity (96.9 %) and production activity (8.83 μmol h−1) with negligible H 2 evolution (0.52 μmol h−1) under visible light irradiation. [ABSTRACT FROM AUTHOR]

• The side-chains were modified to construct D-A COFs to photocatalytic U(VI) reduction. • The exciton dissociation energy and carrier lifetimes were applied to analysis carrier behavior. • TpBD-(OH) 2 and TpBD-(NO 2) 2 exhibited the strongest photocatalytic performance. • Multi-coordination sites and built-in electric field promoted electron-transfer. • The generation of H 2 O 2 during the photocatalytic process facilitated the U-extraction. Photoreduction of uranium(U) is recognized as an effective U-enrichment method that converts soluble U(VI) into insoluble U(IV). However, deficient exciton dissociation and low charge mobility in COFs limit their photocatalytic activity. Excitonic dissociation and charge transfer in COFs could be regulated by grafting different polar functional groups, but the relevant studies are still insufficient. In this work, we constructed a series of donor–acceptor (D-A) COFs (TpBD-X, X = –OH, NH 2 , –OCH 3 , –NO 2 , -SO 3 H) materials with electric built-in fields by different functional groups for U(VI) adsorption-photoreduction. The research results showed that, due to the introduction of functional groups, the exciton dissociation energy was decreased to 22.91 m·eV, the carrier lifetime was prolonged to 3.109 ns, light-absorption capacity was significantly improved, the forbidden bandwidth was reduced and the carrier transfer impedance was lowered. Thereby, the U(VI) reduction efficiency was enhanced from TpBD (33.34 %) to TpBD-(NO 2) 2 (73.11 %), and the corresponding reduction reaction rate constants were 1.40–5.58 times higher than that of TpBD, among which TpBD-(OH) 2 and TpBD-(NO 2) 2 exhibited the strongest photocatalytic performance. In addition, DFT calculations revealed that the calculated E ads of TpBD-X was much lower than that of TpBD, and the chelating sites were increased from the single benzidine cluster to multi-coordination sites (internal H-bonds, keto-O, and bridged-N), which improved the adsorption affinity for UO 2 2+ and stabilized the adsorption conformation, as well as these sites were platforms for electron-transfer contributing to the U(VI) reduction. More importantly, the generation of H 2 O 2 during the photocatalytic process facilitated the U-extraction (in the form of UO 2 and (UO 2)O 2 ·2H 2 O) from water, wherein TpBD-(OH) 2 and TpBD-(NO 2) 2 exhibited the strongest H 2 O 2 generating capacity of 166.14 and 223.31 mM, respectively. This study provided a valuable example of rationally designed and constructed COFs photocatalysts for light-assisted U-extraction with the purpose of regulating carrier behavior. [ABSTRACT FROM AUTHOR]

A catalyst with both photocatalytic and biomimetic catalytic activity for H 2 O 2 production has been successfully prepared by loading gold nanoparticles on graphite carbon nitride nanosheets using polyethyleneimine (PEI) as the "bridge". The biomimetic-photo-coupled catalysis endows PEI-GCN/Au with a high H 2 O 2 production efficiency (270 μmol g−1h−1). This work establishes a paradigm of coupling biomimetic catalysis and photocatalysis for co-production of chemicals. [Display omitted] • A catalyst with bi-functional catalytic activity was developed for H 2 O 2 production. • PEI and AuNPs facilitate the rapid separation of photogenerated carriers on GCN. • Surface plasmon resonance (SPR) of AuNPs promotes the activation of the glucose. • PEI and glucose enhance the O 2 adsorption on the catalyst surface. Inspired by the photo-enzyme-coupled catalytic system in chloroplasts, we developed a composite catalyst with both photocatalytic and biomimetic catalytic activity for H 2 O 2 production by loading gold nanoparticles (AuNPs, enzyme mimics) on graphite carbon nitride (GCN, photocatalyst) nanosheets using polyethyleneimine (PEI) as the "bridge". The introduction of PEI and AuNPs can adjust the electronic structure of GCN, facilitating the rapid separation of photogenerated carriers. Moreover, surface plasmon resonance of AuNPs excited by incident light promotes the activation of glucose molecules, elevating their reactivity with O 2 , thereby improving the glucose oxidase-mimicking catalytic production of H 2 O 2. Furthermore, the grafting of PEI and the addition of glucose enhance the O 2 adsorption on the catalyst surface. Thus, both biomimetic catalytic and photocatalytic reduction of O 2 to H 2 O 2 are boosted, achieving a significant synergistic enhancement effect of 175%. This study provided a novel design strategy for catalysts and a green routine for efficient H 2 O 2 production. [ABSTRACT FROM AUTHOR]

• Z-scheme ZIS/BTO heterojunction with piezoelectric effect was synthesized. • ZIS/BTO heterojunction promoted charge separation and prolonged carrier lifetime. • Charge transfer mechanism was investigated by DFT calculations and experiments. • ZIS/BTO heterojunction exhibited significant CO yield under light and ultrasound. Converting CO 2 into high-value-added chemicals by artificial photosynthesis technology effectively solves environmental problems and energy shortages. Nevertheless, it remains challenging to improve CO 2 conversion rates due to low photo-utilization and rapid electron-hole recombination. In this study, we successfully synthesized direct Z-scheme ZnIn 2 S 4 /BaTiO 3 heterojunction structure by a hydrothermal method. Specifically, compared with previous studies of various heterojunction catalysts, ZnIn 2 S 4 /BaTiO 3 heterojunction structure achieved a remarkably high yield of 105.89 μmol g-1 h-1, increasing 2.55 and 3.62-fold over the individual performance of ZnIn 2 S 4 and BaTiO 3 , respectively. Our investigation of photocatalytic mechanism suggest that the improved photocatalytic CO 2 reduction performance can be attributed to the synergistic effects of the piezoelectric effect and Z-scheme electron transfer mechanism. These effects can synergistically enhance space charge separation and retain photogenerated electrons, thereby facilitating a more efficient CO 2 reduction process. Consequently, this innovative piezoelectric effect-assisted Z-scheme heterojunction demonstrates immense potential to offer a novel strategy for addressing CO 2 reduction challenges and advancing sustainable energy development. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hollow CdS@Ni(OH) 2 hybrid photocatalysts were synthesized. • The yield of CO was 3.12 mmol g-1h−1 with an apparent quantum efficiency of 2.05 % at 420 nm. • The photocatalytic system and mechanism for CO 2 reduction were investigated. • Structure-activity relationship and the local chemical environment in hollow microreactors were explored. The controllable hollow sphere, serving as an excellent light-trapping cavity, represents one of the most appealing structures in photocatalytic CO 2 reduction but is plagued by limited catalytic active sites. Herein, we report an in situ self-assembly strategy to decorate cadmium sulfide hollow spheres (CdS HS) with ultrathin nickel hydroxide (Ni(OH) 2) nanosheets to boost CO 2 photoreduction. The as-grown CdS@Ni(OH) 2 photocatalyst affords a higher CO yield of 3.12 mmol g-1h−1 and a good apparent quantum efficiency (AQE) of 2.05 % compared with the pristine CdS HS (0.38 mmol g-1h−1). The superior performance could be assigned to the unique hollow nanostructure and the synergistic effect between CdS HS and Ni(OH) 2 nanosheets. The interior CdS HS strengthens the multiple light reflections that leads to optimized light harvesting. The ultrathin Ni(OH) 2 nanosheet shell effectively prevents photocorrosion of CdS while providing a suitable local chemical environment that promotes CO 2 adsorption and activation. Additionally, the close contact interface of CdS@Ni(OH) 2 facilitates efficient separation and migration of photoinduced electrons and holes, thus boosting photocatalytic kinetics. This study presents a facile route for the controllable engineering of hollow microreactors toward CO 2 photoreduction and sheds light on the structure-dependent photocatalytic mechanisms. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new type of P and C co-doped g-C 3 N 4 nanosheet for CO 2 photoreduction. • Phytic acid is used as the single precursor for phosphorous and carbon co-doping. • Greatly improved CH 4 evolution rate, which is 12.5 times higher than that of the pristine CN. • Opposite charge distribution from the dopants facilitates the charge transfer and separation. Graphitic carbon nitride (CN) is a promising candidate for visible-light CO 2 photoreduction, but suffers severe charge recombination due to its intrinsic π-conjugated skeleton. Herein, exogenous phosphorous (P) and carbon (C) are co-doped into the polymeric structure of CN to modulate the electronic structure. In virtue of the different electronegativity and valence electron structure of the co-dopants, an internal driving force is formed within the π-conjugated framework, which greatly accelerates the charge transfer and separation. The P and C co-doped CN (PCCN) exhibits a significantly improved CH 4 evolution rate (41.85 μmol g−1h−1) under visible light irradiation, which is 12.5 times higher than the pristine CN. The P and C co-doping causes enhanced light absorption, promoted CO 2 adsorption as well as inbuilt charge centers for efficient charge separation. This work offers new insights into the mutual effect of co-dopants on electronic structure rearrangement of novel photocatalysts for elevated photocatalytic activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Efficient MOF-on-MOF composite fabricated for synergistic CO 2 capture and reduction. • Self-assembled array on substrate facilitates the interphase contacts between MOFs. • 2D crystal morphology prompts macroscopic flexibility and built-in electric field. • Enhanced interface contacts and strong Lewis acidity improve CO 2 RR performance. • Captured CO 2 was converted to CO and CH 4 at high rates with H 2 barely detected. MOF-on-MOF composites are deemed promising candidates to accomplish synergistic CO 2 capture and photoreduction thanks to their plentiful active sites, extended light response range, timely separation of photoexcited electron-hole pairs, and large CO 2 adsorption capacities. Unfortunately, the controllable growth of the designed MOF-on-MOF heterostructure is challenging. Deficient interphase contact and the consequent mass transfer deprivation is one of the primary obstacles severely impairing the catalytic efficiency. Herein, the contact between two widely-employed MOFs of Ni-BDC and NH 2 -MIL-125 was significantly strengthened by exploiting a self-assembled array of Ni-BDC microsheets. In contrast to the spontaneously formed spheroidal aggregate, the loosely-packed array exhibits amplified accessible surfaces to interact with NH 2 -MIL-125, contributing to a radically improved interfacial built-in electric field and 7∼9 times rises in the product yields. Moreover, the preferably thin thickness of Ni-BDC microsheets prompts its macroscopic flexibility, permitting intensified deformation for enhanced interphase contact. Coupled with the additional contribution from its copious Lewis acid sites, the developed NH 2 -MIL-125@Ni-BDC array simultaneously converted CO 2 into CO and CH 4 at rates that cannot be matched by its isostructural Co counterpart with declined acidity and flexibility. This work innovatively reveals the immense importance of morphology tailoring and assembly tactic to interphase contact modulation and the upgrade of catalyst performances. [ABSTRACT FROM AUTHOR]

• Bi single atoms and nanoparticles dual-sites are presented on TiO 2 for the first time. • A reverse etching route was firstly used to achieve confined dual-sites. • The porous dual-Bi/TiO 2 catalyst achieves a CH 4 generation rate of 103.89 μmol·g−1·h−1 with an impressive selectivity of 96.87 %. Synchronizing the directional photogenerated transfer of electrons and regulating the CO 2 photocatalytic reduction process are key to achieving the efficient and highly selective photocatalytic reduction of CO 2. The design of highly-dispersed active sites and the efficient collaboration of multiple sites are of great importance in attaining the above target. Herein, a reverse etching route was first proposed to confine Bi single atoms and nanoparticles as dual-sites for assisting CO 2 photoreduction on TiO 2 , avoiding the mutual masking of the active sites. The Synergism of the dual-sites achieves the hydrodeoxygenation of * COOH and ushers the directional conversion of CO 2 to CH 4. Highly dispersed single Bi atoms could induce the transfer of photogenerated electrons, enhance CO 2 absorption, and further provide active sites for reducing CO 2 to *COOH intermediates. Besides, appropriate Bi nanoparticles could promote the separation and transfer of photogenerated and inhibit the formation of hydroxyl groups; more importantly, they could promote the release of protons, which would further accelerate the conversion of *COOH to CH 4. After being integrated, the optimized dual-Bi/TiO 2 catalyst achieves a CH 4 generation rate of 103.89 μmol·g−1·h−1 with an impressive selectivity of 96.87 % as well as remarkable durability for photocatalytic CO 2 reduction. This work provides new insights into developing robust catalysts through the artful design of synergistic catalytic sites for efficient photocatalytic CO 2 conversion. [ABSTRACT FROM AUTHOR]

• Mineralization rate of antibiotics is increased by 3–10 times. • Mechanism of high mineralization is investigated and explained. • Toxicity of treated wastewater decreases sharply, allowing bacteria to survive. • Loaded catalysts and designed reactors are used to treat antibiotic wastewater. The in-depth mineralization and detoxification of trace antibiotics in water by advanced oxidation process (AOPs) is crucial for its industrial application. In this work, deep mineralization and detoxification of antibiotics are achieved through FeOCl/H 2 O 2 /Vis system, and regeneration mechanism of light-induced electron transfer surface active sites has been proposed. The system can degrade multitudinous antibiotics and increase mineralization rate by 3–10 times. Toxicity of treated wastewater decreases sharply, allowing bacteria to survive normally. Mechanistic studies show that intermediates containing carboxyl groups formed by free radical oxidation complex with Fe(Ⅲ) on surface of FeOCl, thereby hindering Fe(Ⅲ)/Fe(Ⅱ) cycle and further mineralization of antibiotics. While electron transfer occurs between catalyst and intermediates through visible light irradiation, breaking though oxidation of intermediates and reduction of Fe(Ⅲ), and Fe(Ⅲ)/Fe(Ⅱ) ratio decreases from 2.57 to 1.5. This work provides a promising strategy for solving the problems of low mineralization and difficult detoxification of antibiotics by AOPs. [ABSTRACT FROM AUTHOR]

[Display omitted] • The adsorption modes of CO 2 on the active sites are discussed in depth. • The reaction pathways of photocatalytic CO 2 reduction are discussed meticulously. • The strategies for enhancing the adsorption and activation of CO 2 are summarized. • The future and challenges of photocatalytic CO 2 reduction are outlooked. Photocatalytic CO 2 reduction (PCR) technology is one of the potential strategies to mitigate the greenhouse effect, solve the energy crisis and achieve goals of carbon dioxide emissions peak and carbon neutrality. However, it is extremely difficult to adsorb and activate CO 2 due to the high dissociation energy of C = O bond in CO 2 molecule (750 kJ·mol−1), resulting in poor performance of PCR. In addition, in the heterogeneous reaction process, adsorbing and activating CO 2 are closely related to the active sites on the surface of photocatalyst. Therefore, in-depth and detailed exploration of the adsorption and activation of CO 2 on active sites is critical to developing high-performance photocatalysts. Herein, this review firstly explores adsorption modes of CO 2 on the active sites of photocatalyst, including physisorption and chemisorption, where chemisorption includes oxygen, carbon and mixed adsorption. Secondly, reaction pathways for the formation of different high value-added chemical products are introduced, including formaldehyde, carbene, glyoxal and mixed pathways. Then, strategies for enhancing the adsorption and activation of CO 2 are briefly summarized. Finally, the future prospects and challenges of PCR development are discussed. This work provides insights and references for further designing photocatalysts that can enhance the adsorption and activation of CO 2 and improve the performance of PCR. [ABSTRACT FROM AUTHOR]

During the photocatalytic reduction of CO 2 , Pd 4 /SnO 2 @rGO ternary catalyst exhibited outstanding CH 4 yield and selectivity. Palladium nanoparticles facilitated the selective formation of low energy-barrier CHO* intermediates with the help of rGO. The addition of HCOOH* intermediates further facilitated this process. [Display omitted] • Ultrafine, highly dispersed Pd nanoparticles exhibit excellent photocatalytic CO 2 reduction performance. • rGO coating modulates the band gap structure to enhance CH 4 selectivity of catalyst. • The hybrid catalyst drives fast transfer and separation of charge carriers. • Optimising the reaction pathway to reduce the CHO* energy barrier is critical for the reduction of CO 2 to CH 4. Tailoring catalytic reaction pathways by using reduced graphene oxide (rGO) to tune the electron-hole separation channels in the active sites of noble metals for achieving ideal yield and selectivity in photocatalytic CO 2 reduction of hydrocarbon fuels remains a challenge. Herein, ternary catalyst of rGO-coated SnO 2 -supported noble metal Pd nanoparticles (Pd 4 /SnO 2 @rGO) has been prepared by coassembly between negatively charged graphene oxide and positively charged Pd nanoparticles. By coating with ultrathin rGO, the selectivity can be shifted from CO (44.69 % for Pd 4 /SnO 2) toward CH 4 as the prevalent species, in which the Pd nanoparticles acted as catalytic sites and electron capture sites. The rGO coating reduced the recombination of the photogenerated carriers as well as optimized the band gap and reduction potential of the catalyst. The in situ spectroscopic tests and density functional theory calculations revealed that CO 2 adsorbed on Pd nanoparticles selectively formed dominant low-energy CHO* intermediates because of the generation of HCOOH* intermediates, thus providing a unique reaction pathway for the reduction of CO 2 to CH 4. Therefore, under sunlight irradiation, the CH 4 selectivity of the catalyst is enhanced to 94.1 % with a production rate of up to 77.8 μmol·g−1·h−1. This work demonstrated the prospect to tune the electronic structure of Pd using rGO, which provided a strategy for enhancing the carbon dioxide reduction reaction and selectively obtaining CH 4 products in photocatalytic systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cyanamide molecules are successfully decorated onto the surface of sulphide photocatalysts. • The cyanamide decorated sulphide is among the most active photocatalysts for CO 2 reduction. • Cyanamide groups make the neighboring Zn atoms effective in activating and reducing CO 2. • Our work opens a new pathway for developing highly efficient catalysts for targeted reactions. The using of reductive cocatalysts to dictate the transfer path of electrons towards targeting products is indispensable for photocatalytic CO 2 reduction reaction (CRR). However, the development of low-cost and highly selective cocatalysts for photocatalytic CRR remains a daunting challenge. Herein, a functional molecule decoration strategy is proposed to tune the surface electronic structures of semiconductor photocatalysts, in order to promote their photocatalytic performance in CRR. We employ cyanamide groups as the chemical modifiers to regulate the CRR performance of solid solution metal sulphide photocatalysts. The synthesized photocatalysts exhibit excellent photocatalytic performance in CRR, and the highest CO evolution rate exceeds 1400 μmol g−1h−1, being among the best results reported to date. Multiple characterizations in combination with theoretical simulations further demonstrate that the decorated cyanamides do not act as active sites, but changes the electronic structures of the neighboring surface lattice metal atoms and decreases the kinetic barrier of the rate determining *CO 2 →*COOH step, thereby making the surface much more active for photocatalytic CRR. These findings explicitly verify the effectiveness of the functional molecule decoration strategy in promoting the CRR performance of photocatalysts, and also open up a new pathway for the development of highly efficient and selective catalysts for specific catalytic reactions. [ABSTRACT FROM AUTHOR]

[Display omitted] • A trilayer reaction interface of liquid–liquid-solid (L EL -L IM -S) was successfully constructed. • The interfacial microenvironment self-adapts and adjusts the ionic composition according to changes in the pH environment. • Wide pH photocatalytic NO 3 – application was achieved at adaptive L IM -dominated L EL -L IM -S trilayer reaction interface. • This strategy of L EL -L IM -S can be used to tune the activity and selectivity of heterogeneous catalysts. Developing highly efficient photocatalysts with a wide pH application range is the key to achieving widespread practical application of photocatalytic denitrification. However, the current study neglects the limitations of diffusion and mass transfer efficiency in the reaction interfacial microenvironment on high activity and selectivity, resulting in the inability to achieve the ideal results. Herein, the photocatalytic NO 3 – reduction system with a microenvironment-dominated trilayer reaction interface of liquid (external liquid)-liquid (adaptive interfacial microenvironment)-solid (Br-Bi 2 WO 6-x photocatalysts with different charge transfer mechanisms under acid/base conditions and hydrophilic surfaces) (L EL -L IM -S) was successfully constructed. The interfacial microenvironment in the system can self-adapt and adjust its ion composition according to the changes in the pH environment, which facilitates timely supplementation of NO 3 –/HCOO– required for the reaction from external liquid, thus maintaining the relative stability of the microenvironment and achieving an excellent NO 3 – removal rate of over 90 % in a wide pH range from 3 to 9. Meanwhile, the trilayer reaction interface of L EL -L IM -S collectively constitutes a unique carrier shuttle and molecular reaction channel from the catalyst interior to the surface contaminants. Highly selective NO 3 – to NH 3 conversion (NH 3 selectivity of 91.7 %, NH 3 yield of 750 μmol g-1h−1) could be accomplished utilizing this channel. [ABSTRACT FROM AUTHOR]