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• Recent advances in POFs for photocatalytic H 2 O 2 production are summarized. • The effective strategies to improve H 2 O 2 production are highlighted. • Elucidates photocatalytic H 2 O 2 production efficiency and possible reaction mechanism. • The current challenges and future perspectives of photocatalytic H 2 O 2 production in POFs is declared. Hydrogen peroxide (H 2 O 2) has been recognized as a rather important chemical with extensive applications in environmental protection, chemical synthesis, military manufacturing, etc. However, the mature industrial strategy (i.e., anthraquinone oxidation) for H 2 O 2 production is featured with heavy pollution and high energy consumption. Photocatalytic technology has been regarded as a sustainable strategy to convert H 2 O and O 2 into H 2 O 2. Recently, porous organic framework materials (POFs) including metal-organic frameworks (MOFs), covalent organic frameworks (COFs), covalent triazine frameworks (CTFs), covalent heptazine frameworks (CHFs), and hydrogen-bonded organic frameworks (HOFs) have exhibited significant potential for green H 2 O 2 photosynthesis by virtue of their diverse synthesis methods, enormous specific surface areas, flexible design, adjustable band structure, and photoelectric property. In this review, the recent advances in H 2 O 2 photosynthesis based on POFs are comprehensively investigated. The modification strategies to improve H 2 O 2 production and their photocatalytic mechanisms are systematically analyzed. The current challenges and future perspectives in this field are highlighted as well. This review aims to give a complete picture of the research effort made to provide a deep understanding of the structure-activity relationship of H 2 O 2 photogeneration over POFs, thus inspiring some new ideas to tackle the challenges in this field, and finally stimulating the efficient development of organic semiconductors for sustainable photogeneration of H 2 O 2. [Display omitted] [ABSTRACT FROM AUTHOR]

• A simple and mild method was used for the synthesis of Fe-doped Ni 2 P nanosheets. • Designed ohmic Schottky heterojunctions to improve photogenerated carrier separation efficiency. • Composites showed excellent activity and stability in photocatalytic hydrogen production and NO 3 − reduction tests. • The optimization of the surface adsorption energy of the NO 3 − reduction reaction by doping a small amount of Fe was investigated using DFT calculations. • Ohmic Schottky heterojunction enables higher utilization of visible light in semiconductor composites. Capacitive Fe-doped Ni 2 P(Fe 2 x Ni 2(1- x) P) is synthesized via the modified solvothermal method to form Ohmic Schottky heterojunctions with monolayer Ti 3 C 2 (MLTC). The composite (10 % 0.1FNP/CdS-2 % MLTC) achieved a high hydrogen evolution rate (HER) of 19.18 mmol h−1 with a 50 mg sample. In a mere span of 3 h, an impressive NO 3 − reduction of 0.42 mg/L was achieved, accompanied by an exceptional 92 % N 2 selectivity. Quantum efficiency (QE) can reach 56.22 % (λ = 475 nm) by adding 0.1FNP and MLTC. In contrast to previous catalysts, the QE of visible light after 500 nm has been improved to 45.2 % (λ = 500 nm) or 36.4 % (λ = 550 nm). The significant enhancement of HER and NO 3 − reduction is attributed to the enhanced adsorption of oxygen-containing reactants, the lowering of the reduction overpotential, further enhanced separation efficiency of photogenerated carriers through the ohmic Schottky heterojunction after iron doping. Additionally, the observed capacitor-like nature of 0.1FNP is also an essential factor for the enhanced reduction ability of the composites. The optimised method synthesises 0.1FNP and MLTC together to form an Ohmic contact Schottky heterojunction to achieve efficient photogenerated electron-hole separation and obtain high performance photocatalytic HER and NO 3 − reduction catalysts. [Display omitted] [ABSTRACT FROM AUTHOR]

• A series of chromium doped ZnS photocatalysts with accompanying vs were prepared. • Chromium doped ZnS exhibited significantly enhanced photoactivity for H 2 evolution and CO 2 reduction. • The photoactivity enhancement mechanism of Cr-doped ZnS was systematically investigated. Driven by endless solar energy, photocatalytic H 2 evolution from water splitting and CO 2 conversion to hydrocarbon fuels over semiconductor photocatalysts are of great potential to simultaneously settle the greenhouse effect and energy shortage. Herein, Cr-doped zinc sulfide (ZnS) with accompanying sulphur vacancies (Vs) photocatalytic materials is developed by a facile hydrothermal method. The Cr dopants centralize photoinduced holes and Vs trap electrons, forming a synergistic effect for accelerating charge separation and transfer. The reaction energy barrier for both H 2 evolution and CO 2 reduction has been optimized. Therefore, in the absence of a cocatalyst, the optimal catalyst (Zn 0.94 Cr 0.06 S) achieves an outstanding H 2 evolution activity of 20.3 mmol g−1 h−1, which is approximately 2.9 times higher than 6.9 mmol g−1 h−1 for pristine ZnS. In addition, in the gas-solid reaction system without co-catalysts or sacrificial agents, the Zn 0.94 Cr 0.06 S exhibits a considerable CO evolution rate of 19.56 μmol g−1 h−1, about 10.1 times higher than ZnS (1.94 μmol g−1 h−1). Both the performances for H 2 evolution and CO 2 reduction of Zn 0.94 Cr 0.06 S outperform most of the previously reported photocatalysts. Particularly, the Zn 0.94 Cr 0.06 S possesses superior stability, the photoactivity of which exhibits no noticeable deactivation after six cycles' reactions. This work may shed light on the rational design and fabrication of highly efficient materials via combining individual element doping and defect engineering. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel S-scheme oxygen vacancy-rich CoMoO 4 /CN heterojunction was constructed. • 4.6-fold increase in photocatalytic H 2 evolution was achieved over the heterojunction. • Activation energy for H 2 O dissociation was reduced and oxygen vacancy density was enhanced. • Defect engineering and S-scheme heterostructure functioned synergistically. • In-situ characterizations and DFT calculation support S-scheme charge transfer pathway. Developing highly efficient S-scheme photocatalysts is a subject of immense interest for harnessing solar energy towards sustainable hydrogen production. Herein, a novel S-scheme heterojunction of oxygen vacancy-rich CoMoO 4 /CN (CMO/CN) photocatalyst was rationally constructed through loading CoMoO 4 nanorods on carbon nitride (CN) nanosheets via a direct one-pot calcination method. The CMO/CN S-scheme heterojunction exhibited enhanced surface area, fine CN dispersion, rich oxygen vacancies, and accelerated charge separation/transfer efficiency, which were conducive to improving photocatalytic H 2 evolution performance. Of note, the optimal 3 %CMO/CN sample displayed the highest H 2 production rate of 8.35 mmol g−1 h−1, which is 4.6 folds that of pristine CN. In situ irradiated X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) characterizations confirmed the S-scheme charge transfer path between CN and CMO, which greatly promoted spatial charge separation. Density functional theory (DFT) calculations together with contact angle tests revealed the reduced activation energies for H 2 O dissociation and enhanced hydrophilicity of the CMO/CN. The CMO/CN photocatalysts also presented high stability and fine reusability. This work may provide insights into the combination of defect engineering and heterojunction designing for high-efficiency solar-to-chemical energy conversion. [Display omitted] [ABSTRACT FROM AUTHOR]

• The photocatalytic properties and mechanism of medium entropy alloys coupled Z-scheme heterojunction are reported for the first time. • The mechanism of alloying enhancing LSPR effect has been thoroughly investigated. • Three working ways of enhancing photocatalytic performance by LSPR effect has been studied. • The as-prepared material realizes the multi-gradient transfer of photogenerated carriers. Optimizing the local surface plasmon resonance (LSPR) effect of non-noble metals through alloying has been crucial for improving its practical application in the field of photocatalysis. Rare studies capture the detail that the change in the electronic structure of metal elements caused by alloying affects plasma carrier concentration and the local surface plasmon resonance effect. Herein, NiCuCoFe medium-entropy alloys (MEAs) nanoclusters were designed and used to modify the Bi 3 O 4 Br/CNNs Z-scheme heterojunction. The cocktail effect of MEAs causes the 3d-orbital hybridization of various metal elements, which promotes the release of charge carriers. The higher the carrier concentration, the stronger the LSPR effect of MEAs. In addition, the mechanism of three typical working pathways of the LSPR effect to improve the photocatalytic performance of heterojunction is discussed. And compared with those of Bi 3 O 4 Br, CNNs, and Bi 3 O 4 Br/CNNs, the rate constant of MEAs-Bi 3 O 4 Br/CNNs was 3.26, 11.16, and 3.17 times higher during the degradation of norfloxacin, respectively. This study provides a new strategy for understanding the mechanism of LSPR and the rational design of plasmonic coupling architectures for enhanced photocatalysis. [Display omitted] Mechanism of MEAs enhancing photocatalytic performance of Z-Scheme heterojunction in NiCuCoFe-Bi 3 O 4 Br/CNNs by LSPR effect. [ABSTRACT FROM AUTHOR]

• H 2 production coupled with selective organic synthesis is realized using an inorganic/organic S-scheme photocatalyst composed of ZnIn 2 S 4 and the UiO-66-NH 2 metal-organic framework. • The benzylamine reactant not only acts as the precursor for N-benzylidenebenzylamine production but also provides hydrogen atoms for H 2 production under water-free conditions. • The S-scheme charge carrier transfer mechanism was validated by in-situ irradiated X-ray photoelectron spectroscopy and femtosecond transient absorption spectroscopy. • This work provides new insights into concurrent photocatalytic H 2 production and selective organic oxidation from organic amines using S-scheme photocatalysts. Photocatalytic water splitting is a popular pathway for H 2 evolution, but the slow water oxidation greatly hampers the overall activity. To harness photogenerated holes in an efficient and lucrative way, the water oxidation reaction is replaced by selective oxidation of organic compounds to achieve simultaneous production of H 2 and value-added chemicals. Herein, an alternative tactic is reported where an organic compound (benzylamine, BA) not only serves as the precursor for N-benzylidene-benzylamine (NBBA) production but also provides hydrogen sources for H 2 evolution, achieving the goal under anhydrous conditions. This process is realized using an S-scheme photocatalyst composed of ZnIn 2 S 4 and the UiO-66-NH 2 (U6N) metal-organic framework (MOF). The S-scheme carrier transfer mechanism was validated by in-situ irradiated X-ray photoelectron spectroscopy (ISI-XPS) and femtosecond transient absorption (fs-TA) spectroscopy. With increased carrier efficiency and reinforced redox power endowed by the S-scheme heterojunction, the composite performed better than ZnIn 2 S 4 and MOF. The performance was further ameliorated by Pt-cocatalyst modification, achieving an H 2 production rate of 5275 μmol h−1 g−1 as well as BA conversion of 94.3% with 99.3% NBBA selectivity. Mechanistic studies reveal that BA is initially oxidized to carbon-centered radicals and further to imines along with the release of protons. The imine reacts with another BA molecule to form NBBA, while the protons are reduced to H 2. This work provides new insights into concurrent photocatalytic H 2 production and selective organic oxidation from organic amines using S-scheme photocatalysts. [Display omitted] [ABSTRACT FROM AUTHOR]

• High performance of photocatalytic H 2 O 2 production over 2 mmol per gram (catalyst) per hour. • Z-scheme heterojunction enhance the charge transfer efficiency for photocatalytic H 2 O 2 production. • The synergistic and couple effect of different types vacancy over heterojunction components was proposed. Defect engineering represents a potent strategy for the modification of electronic properties by introducing atomic vacancies in photocatalysts. However, the synergistic enhancement attributable to different types of atomic vacancies within a heterojunction, as well as their underlying mechanisms, remains sparsely studied. Here, the flexible g-C 3 N 4 materials with varying nitrogen vacancies were prepared via a facile calcination method under different atmospheric conditions and then composited with CeO 2 nanocubes to construct Z-scheme heterojunction. It was observed that CeO 2 has abundant O vacancies, and the g-C 3 N 4 form tertiary nitrogen defects at the center of the heptazine units under an NH 3 atmosphere treatment. The resulting enhancement in the interfacial built-in electric field, coupled with the synergistic effect of O and N vacancies within the Z-scheme heterojunction, has been demonstrated to significantly enhance charge transfer efficiency. This results in an optimized photoactivity with a H 2 O 2 generation rate of 2.01 mmol g–1 h–1. This work opens an avenue for constructing and optimizing the heterogeneous photocatalysts by defect engineering technology, and provides deep insight to understand the nature of vacancy engineering in designing effective catalysts for solar energy conversion. [Display omitted] The O deficient CeO 2 and N deficient g-C 3 N 4 constructed the Z-scheme heterojunction and enhanced interfacial built-in electric field to synergistically boost photocatalytic H 2 O 2 production. [ABSTRACT FROM AUTHOR]

• 2D/2D layered BiOIO 3 /g-C 3 N 4 S-scheme photocatalyst was prepared. • S-scheme BiOIO 3 /g-C 3 N 4 demonstrates high photocatalytic NO oxidation ability. • The formation of hazardous NO 2 was significantly reduced over S-scheme BiOIO 3 /g-C 3 N 4. • S-scheme BiOIO 3 /g-C 3 N 4 heterojunction was confirmed experimentally and theoretically. It is essential to promote interfacial separation and charge migration in heterojunctions for effectively driving surface photocatalytic reactions. In this work, we report the construction of a 2D/2D layered BiOIO 3 /g-C 3 N 4 (BIO/CN) heterojunction for photocatalytic NO removal. The BIO/CN heterojunction exhibits a remarkably higher NO photo-oxidation removal rate (46.9%) compared to pristine BIO (20.1%) and CN (25.9%) under visible-light irradiation. Additionally, it effectively suppresses the formation of toxic NO 2 intermediates during photocatalytic reaction. The improved photocatalytic performance of BIO/CN composite is caused by its S-scheme charge carrier transport mechanism, which is supported by Density Functional Theory simulations of work function and electron density difference, along with in-situ irradiated X-ray Photoelectron Spectroscopy and Electron Paramagnetic Resonance analyses. This S-scheme structure improves the interfacial carrier separation efficiency and retains the strong photo-redox ability. Our study demonstrates that construction of a S-scheme heterojunction is significant in the design and preparation of highly efficient photocatalysts for air purification. [Display omitted] [ABSTRACT FROM AUTHOR]

• Self-assembly synthesis of tubular carbon nitride co-modified with benzene ring and oxygen. • The tubular structure enhances light absorption and charge transfer. • Oxygen and benzene rings regulate the redox capacity and redox sites of carbon nitride, respectively. Photocatalytic hydrogen production technology offers a means of converting solar energy into chemical energy contained in hydrogen for human consumption. However, traditional photocatalysts restrict the progress of photocatalytic technology owing to the straightforward complexation of carriers and lack of active sites. Thus, in this work, the number of active sites and carrier separation efficiency have been significantly improved by non-metallic modification and modulation of the geometry of carbon nitride. It has been demonstrated that oxygen doping enhances the energy band structure of benzene-substituted O-doped g-CN nanotubes (BOCN). Oxygen, in conjunction with the benzene ring, creates redox energy level positions that are spatially separated. One-dimensional tubular structures synthesised by supramolecular self-assembly have a thin-walled structure capable of exposing more active sites. Additionally, the adsorption equilibrium of H+ on the catalyst is further enhanced. The in-depth analysis of each component through experiments and theoretical calculations contributes to a reasonable photocatalytic mechanism for decomposing aquatic hydrogen. [Display omitted] [ABSTRACT FROM AUTHOR]

• The band gap of g-C 3 N 4 was regulated by Ti 3 C 2 -SO 3 H loading. • The TiCSOHCN composite was prepared for TC photodegradation. • The synergistic effect of Ti 3 C 2 -SO 3 H MXene boosted photodegradation activity. • Coexisting ions on TC photodegradation were investigated. • Investigated degradation products and ecotoxicity of intermediate products. Due to inherent limitations such as high carrier recombination efficiency, limited active sites, and suboptimal utilization of visible light, graphite-like carbon nitride (g-C 3 N 4) has constrained its widespread application in water treatment within photocatalytic systems. In addressing this issue, the present study employed acid etching and sonochemistry to fabricate a Ti 3 C 2 -SO 3 H/g-C 3 N 4 (TiCSOHCN) composite photocatalyst for the removal of tetracycline hydrochloride (TC). The amalgamation of Ti 3 C 2 -SO 3 H (TiCSOH) with g-C 3 N 4 engendered the establishment of a discernible Schottky barrier, facilitating an expedited electron transfer rate. Photocatalytic degradation experiments demonstrate that, compared to individual components, the TiCSOHCN composite photocatalyst exhibits significantly enhanced photocatalytic activity. The removal efficiency of TC reaches 75.42 % within 2 h, and even after five cycles of experimentation, the degradation efficiency remains close to 70 %, indicating excellent stability. The augmentation can be predominantly ascribed to the cooperative influence arising from the synergy between Ti 3 C 2 -SO 3 H and g-C 3 N 4. The augmentation of visible light responsiveness in g-C 3 N 4 , achieved through its modification with TiCSOH, resulted in the mitigation of photoelectron-hole pair recombination, consequently leading to an amelioration in the photocatalytic efficacy of the TiCSOHCN composite catalyst. Intermediate species arising from the degradation of tetracycline were discerned utilizing LC-MS, and conjectures regarding plausible degradation pathways were postulated. Evaluations of the ecotoxicological impact of tetracycline and its intermediates indicated a progressive diminution in toxicity throughout the course of the photocatalytic degradation process. Furthermore, through free radical capture and EPR tests, it was confirmed that ·O 2 – and ·OH are the primary active species responsible for the photocatalytic degradation of TC, substantiating the proposed rational photocatalytic degradation mechanism. This research provides an innovative approach to developing high-performance and stable photocatalysts. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel Z‑scheme Bi-ZFO/BMO-Vo heterostructure was prepared, which possessed excellent photocatalytic activity and recyclability. • Bi-ZFO/BMO-Vo combined photocatalysis with PMS oxidation processes to synergistically remove organic pollutants. • The Z-scheme charges transfer of Bi-ZFO/BMO-Vo heterostructure for promoting catalytic performance was unveiled. • The biological toxicity of RhB and its degradation intermediates were evaluated. Given the urgency of organic pollutant removal and the low efficiency of advanced oxidation processes (AOPs), a novel Bi-ZFO/BMO-Vo photocatalyst was fabricated via the solvothermal method. A coupling system was constructed to combine photocatalysis with peroxymonosulfate (PMS) oxidation processes, which synergistically degrade organic pollutants. Bi-ZFO/BMO-Vo exhibited excellent photocatalytic performance, which could remove 100 % RhB in 110 min and degrade 100 % MG in 70 min, and 88 % H-TC in 50 min. The excellent catalytic performance of Bi-ZFO/BMO-Vo was not only attributed to the synergistic effect of PMS activation and photocatalysis, but also attributed to the SPR effect of Bi nanoparticles, electron capture of oxygen vacancies, and intense contact of Bi-ZFO/BMO-Vo heterojunctions. The active species capture experiments and EPR tests indicated that 1O 2 , SO 4 –·, ·OH, and O 2 –· worked together for the RhB removal. The degradation intermediates of RhB were identified by LC-MS. Based on the experimental results, the band structure and Z-scheme charge transfer mechanism were proposed. Toxicity evaluation indicated that Bi-ZFO/BMO-Vo-Vis/PMS could significantly reduce RhB toxicity. This efficient and stable catalyst is expected to be used in organic wastewater degradation and practical applications. The excellent catalytic performance of Bi-ZFO/BMO-Vo was not only attributed to the synergistic effect of PMS activation and photocatalysis, but also attributed to the SPR effect of Bi nanoparticles, electron capture of oxygen vacancies, and intense contact of Bi-ZFO/BMO-Vo heterojunctions. [Display omitted] [ABSTRACT FROM AUTHOR]

• 4Cl-H 2 PDI and 4Cl-H 2 PDI/GQD are prepared for photocatalytic ORR to H 2 O 2 (λ > 420 nm). • Formation of S-scheme 4Cl-H 2 PDI/GQD heterojunction is proved via Cl–H bond. • Effect of end-/bay-substituted PDI and GQD doping on H 2 O 2 evolution is studied. • 4Cl-H 2 PDI and 4Cl-H 2 PDI/GQD show 7 and 16 times H 2 O 2 rate than H 2 PDI. • Two-step single-electron ORR process is proved for enhanced H 2 O 2 evolution. Here, 1D bis(N-carboxymethyl) peryleneimide (H 2 PDI), 0D 1,6,7,12-tetrachloro-bis(N-carboxymethyl) peryleneimide (4Cl-H 2 PDI), and 2D 4Cl-H 2 PDI/graphene quantum dot (4Cl-H 2 PDI/GQD) nanostructures are synthesized and carefully analyzed. The effect of bay-/end-substitution and S-scheme heterojunction of PDI-based materials as main catalysts on the photocatalytic H 2 O 2 evolution is first studied through the oxygen reduction reaction (ORR). Under the visible-light irradiation (> 420 nm), 4Cl-H 2 PDI and 4Cl-H 2 PDI/GQD as photocatalysts exhibit the ∼7 and ∼16 times H 2 O 2 evolution rate than H 2 PDI (1059.6 vs. 2484.0 vs. 160.0 µM g−1 h−1), respectively. The systematical experiments reveal that 4Cl-H 2 PDI and 4Cl-H 2 PDI/GQD should prefer a two-step single-electron ORR process, while H 2 PDI may involve a 4e‒ water oxidation and one-step 2e‒ ORR process. Further experiments confirm that the bay-substitution and GQD doping of H 2 PDI can promote the generation, transportation, and separation of photogenerated electrons and holes, and prolong the carrier lifetime. This work provides insight into PDI-based photocatalytic H 2 O 2 production. [Display omitted] [ABSTRACT FROM AUTHOR]

• ZnO/Cd x Zn 1- x S/CdS heterojunctions are prepared by the alkaline dissolution etching method. • The internal electric field at the interface improved the effective charge separation. • The Zn atoms in Cd x Zn 1- x S are of great significantce for producing strong interfacial electric fields. • Excellent performance: the H 2 generation efficiency of 15.67 mmol g−1 h−1 maintained 82.9 % in 24-hour cycles. • The CH 4 and CO precipitation performances are achieved at 3.47 μmol g−1 h−1 and 23.5 μmol g−1 h−1. The difficulty in fabricating a multifaceted composite heterojunction system based on Cd x Zn 1- x S limits the enhancement of photocatalytic performance. In the present scrutiny, novel ZnO/Cd x Zn 1- x S/CdS composite heterojunctions are successfully prepared by the alkaline dissolution etching method. The internal electric field at the interface of I-type and Z-scheme heterojunction improved the effective charge separation. The ZC 8 sample exhibits excellent photocatalytic performance and the H 2 production efficiency is 15.67 mmol g−1 h−1 with good stability up to 82.9 % in 24-hour cycles. The performance of CH 4 and CO capacity in the CO 2 RR process is 3.47 μmol g−1 h−1 and 23.5 μmol g−1 h−1, respectively. The photogenerated accelerated charge transport is then examined in detail by in situ X-ray photoelectron spectroscopy (ISXPS) and density functional theory (DFT) calculations. This work presents a new idea for the synthesis of Cd x Zn 1- x S solid-solution-based materials and provides a solid reference for the detailed mechanism regarding the electric field at the heterojunction interface. [Display omitted] [ABSTRACT FROM AUTHOR]

• g-C 3 N 4 is modified with Gd species and then integrated with WO 3. • Characterization techniques suggested intimate contact between the components. • S-scheme heterojunction was established through computational studies. • Superoxide and hydroxyl radicals dominated the degradation mechanisms. Modifying the surface structures of g-C 3 N 4 through interfacial coupling with other semiconductors has been spotlighted as an efficient approach for improving photocatalytic efficiency. With the surge of S-scheme heterojunctions, the research is intensified towards designing this kind of composite for energy-environmental-related applications. In this context, a new approach involving surface modifications of g-C 3 N 4 through Gd species and integrating with monoclinic-WO 3 via a wet chemical approach to form S-scheme heterojunctions is investigated. The characterization results attested that the adopted protocol promotes the better dispersion of Gd species over the g-C 3 N 4 surface and rigidly integrates with WO 3. The optical response of the composite spanned a significant portion of the visible region in the solar spectrum. The computational studies and the findings of the Mott-Schottky plot collectively suggested that the position of band edges qualifies for the formation of S-scheme heterojunction. The results derived from photocurrent response measurements and photoluminescence technique attribute to the effective charge carrier separation in the heterostructure. The rate constant of Gd-g-C 3 N 4 /WO 3 was 1.48 × 10−2 min−1 which was approximately 4.35 and 2.27 times greater than that of WO 3 (0.34 × 10−2 min−1) and g-C 3 N 4 /WO 3 (0.65 × 10−2 min−1) respectively. Furthermore, RhB degradation in the presence of scavengers validated the participation of superoxide and hydroxyl radicals in the degradation mechanisms. This was possible only when the conduction band electrons of WO 3 recombined with the valence band holes of Gd-modified g-C 3 N 4. The present work helps to understand the S-scheme heterojunction formation between surface-modified g-C 3 N 4 and metal oxides and retain the involvement of energetic charge carriers in the desired redox reactions. [ABSTRACT FROM AUTHOR]

• 1D alkali-metal hexatitanate (AHT) nanomaterials are versatile photocatalysts for environmental and energy applications. • The state-of-the-art advancements of AHT-based photocatalysts are comprehensively reviewed. • The fundamentals, synthesis, modification and applications of AHT photocatalysts are thoroughly summarized. • The key challenges and prospects on the future directions of 1D AHT photocatalysts are also discussed. The global energy crisis and environmental problems have become two unprecedented challenges. Semiconductor photocatalysis offers a promising strategy to solve them, while its practical application requires advanced photocatalytic materials. In recent years, one-dimensional (1D) alkali-metal hexatitanate (AHT) photocatalysts have attracted considerable attention in energy and environmental fields due to their high chemical stability, excellent photoactivity, unique ion-exchange, environment-friendly, and cost-effective properties. In this review, we firstly introduce the basic properties of AHT including crystal and electronic band structure, photoactivity, and structure-property-performance relationship. Secondly, the recent advances in synthesis and modification strategies of 1D AHT photocatalysts are summarized thoughtfully, followed by a comprehensive discussion on their various environmental and energy applications, including pollutant degradation, H 2 generation, and CO 2 reduction. Finally, the key challenges and prospects are also highlighted for the development of high-performance 1D AHT-based photocatalysts for practical applications. We hope that this review will shed some light on the rational design of 1D Ti-O-based nanomaterials for efficient environmental remediation and solar fuel production. The state-of-the-art progress in 1D AHT photocatalysts, including the fundamental properties, synthesis methods, modification strategies, various environmental and energy applications, and the key challenges and prospects for their further development were comprehensively summarized. [Display omitted] [ABSTRACT FROM AUTHOR]

• The novel all organic poly (barbituric acid)/poly (triazine imide) S-scheme heterojunction has been prepared successfully. • The formed internal electric field and band bending can induce charges separation efficiently. • The heterojunctions show a superior photocatalytic performance of H 2 production. • The S-scheme photocatalytic mechanism is well discussed. Poly (triazine imide), as a kind of highly crystalline g-C 3 N 4 , exhibits a promising potential for photocatalytic hydrogen production, however, some drawbacks still limit its photocatalytic performance. The strategy of constructing S-scheme heterojunction with different semiconductor photocatalysts enables the effective separation of photogenerated electrons and holes, and the strong oxidative and reductive properties of the original photocatalysts could be retained, which will significantly improve the photocatalytic activity. In this work, we synthesized the organic-organic S-scheme heterojunction between PTI and organic small molecule poly (barbituric acid) (PBA) by hydrogen bond self-assembly method, which results in a significant enhancement of photocatalytic H 2 production activity. The H 2 production rate of the optimum PBA/PTI-2 sample under visible light irradiation is about 0.92 mmol g–1, which is 5.5 times higher than that of PTI and 14.4 times higher than that of PBA. This excellent photocatalytic performance is attributed to the successful construction of S-scheme heterojunction between PTI and PBA, which effectively accelerates carrier transport and spatial segregation by the formation of a built-in electric field and band bending at the interface. In addition, the S-scheme heterojunction could also reserve the maximum redox capability and enhance the light absorption of the prepared photocatalytic system. This work provides a new strategy and understanding for the design and development of organic-organic S-scheme heterojunction photocatalysts. [Display omitted]. [ABSTRACT FROM AUTHOR]

• Multifunctional photocatalysis-in-situ-self-Fenton system was designed and synthesized. • The degradation rate of TC over MTR was 4.8 times that of MR heterojunction. • MTR could remove more than 97.4 (95.5 %) of TC (RhB) after 5 cycling tests. • 97.8 % of E. coli and 94.9 % of S. aureus were inactivated by MTR in 120 min. • Fenton reaction and photocatalytic reaction collaborate for catalytic processes. The applicability of the conventional Fenton reaction is limited due to several factors, including the high cost and slow redox cycle of Fe3+/Fe2+, the requirement for harsh acidic conditions, and the insufficient presence of hydroxyl radicals for the ring-opening reaction. The combination of photocatalysis and Fenton technology to create a photocatalysis-in-situ-self-Fenton (PISF) system is a viable approach for addressing the inherent limitations of conventional Fenton reactions. Herein, a multifunctional PISF system, MIL-88A(Fe)/Ti 3 C 2 MXene/resorcinol-formaldehyde (MIL-88A(Fe)/Ti 3 C 2 /RF, MTR) Z-scheme heterojunction, was designed and constructed for degradating organics and inactivating bacteria. With the assistance of Ti 3 C 2 , the degradation rate of TC by MTR catalyst was 4.8 times that of MIL-88A(Fe)/RF catalyst under visible light irradiation. Meanwhile, good degradation performance was maintained after 5 cycling tests. The remarkable TC removal efficiency (97.4 %) and durability were attributed to the synergistic effect of the photocatalytic reaction and Fenton reaction. The photoinduced holes (h +) assist hydroxyl radicals (•OH) generated by the Fenton reaction for deeply mineralizing TC. The degradation intermediates, potential degradation pathways, and intermediates toxicity were comprehensively investigated to gain a deeper understanding of the catalytic process. Moreover, under visible light irradiation, the MTR killed 97.8 % of E. coli and 94.9 % of S. aureus within 120 min, demonstrating good antibacterial activity. This work provides a novel strategy to design PISF catalysts for environmental remediation. [Display omitted] [ABSTRACT FROM AUTHOR]

• A double Z-scheme SnO 2 /SnS 2 /Cu 2 SnS 3 was synthesized by one-pot method. • SnO 2 /SnS 2 /Cu 2 SnS 3 catalyst improves ethanol selectivity without sacrificial agent. • The introduction of SnS 2 and Cu 2 SnS 3 broadened the light absorption. Photocatalytic reduction of CO 2 to chemical fuels enables a sustainable way of reducing carbon emissions but faces a high reduction potential due to the high stability of CO 2 molecules. Here, we prepared a SnO 2 /SnS 2 /Cu 2 SnS 3 double Z-scheme heterojunction photocatalyst, in which SnO 2 , SnS 2 , and Cu 2 SnS 3 absorb ultraviolet, visible, and near-infrared light, respectively. Based on the comprehensive analysis of in-situ X-ray photoelectron spectroscopy and photo(chemical) characterizations, we find that the photogenerated electrons would transfer from SnO 2 to SnS 2 to Cu 2 SnS 3. The optimized SnO 2 /SnS 2 /Cu 2 SnS 3 –0.3 double Z-scheme heterojunction could achieve 28.44 µmol g–1 h–1 ethanol yield and 92% selectivity, which is roughly 3 folds higher than SnO 2 /SnS 2 single Z-scheme heterojunction. By using in-situ diffuse reflectance infrared Fourier-transform spectroscopy, we observe that ethanol is produced through a *COCOH pathway, in which Cu 2 SnS 3 would decrease the activation energy barrier from *COOH to *CO. The low efficiency of solar-to-fuel conversion and the poor selectivity of products have also been the main challenges of photocatalytic CO 2 reduction. The construction of heterojunction is of great significance for the broadening of near-infrared light absorption, strengthening CO 2 reduction capacity, and increasing product selectivity and yield. The SnO 2 /SnS 2 /Cu 2 SnS 3 double Z-scheme heterojunction was prepared for photocatalytic CO 2 reduction without the sacrificial agent, and its ethanol yield and selectivity reached 28.44 mmol g–1 h–1 and 92 %, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

• Flower-like superstructure of semiconducting boron carbon nitride was successfully synthesized. • FS-BCNNSs with optimized band structure promoted efficient photocatalytic H 2 O 2 production. • The catalytic role of carbon sites with controlled chemical environments was investigated. The self-assembly of two-dimensional (2D) semiconductor nanosheets into three-dimensional (3D) ordered superstructures represents an ingenious way to avoid aggregation, expose massive available active sites and benefit the mass transfer, which maximizes the advantages of the 2D nanostructures in photocatalysis. Herein, a flower-like superstructure of ternary semiconducting boron carbon nitride nanosheets (FS-BCNNSs) was synthesized through the morphology-preserved thermal transformation of a flower-like superstructure of boron-containing metal-organic framework nanosheets (FS-MOFNSs). Taking advantage of this functional superstructure, FS-BCNNSs was employed for the pioneering application in the field of photocatalytic hydrogen peroxide (H 2 O 2) production and exhibited excellent photocatalytic performance, yielding an impressive rate of 1415.9 μmol g−1 h−1 for the production of H 2 O 2. The results of this work offer not just a promising catalyst for photocatalytic H 2 O 2 production but also a facile strategy to fabricate unique superstructures constructed from 2D nanosheets for catalysis, energy conversion, and other related fields. [Display omitted] [ABSTRACT FROM AUTHOR]

• Five Z-scheme heterojunctions MoS 2 @UiO-66-NH 2 with different geometries. • The miniature UiO-66-NH 2 and hierarchical flowerlike MoS 2 form intimate interface. • The optimal-matched geometry endows f-MoS 2 @UiO-66-NH 2 with excellent performances. • Maximized heterointerface with high charge throughput accelerates CO 2 methanation. Z-scheme heterojunction is an effective strategy in photocatalysis, when hetero-interfacial intimate contact is the center of high-performance Z-scheme heterojunction structure. Here, x -MoS 2 [ x = plate (p), flower (f), and solid sphere (s)] with extensive optical absorption and high conductivity and stable UiO-66-NH 2 (y) (y = 100, 300, and 500 nm) with rich Lewis's acid sites were integrated to a series of x -MoS 2 @UiO-66-NH 2 (y) Z-scheme heterojunctions, which were fully characterized and used for photocatalytic reduction of CO 2 (pCO 2 RR) into CH 4 and CO. In response to the difficult modification of MoS 2 and loose contact of composite bulk materials, the micro-geometric configurations on the size of UiO-66-NH 2 and the morphology of MoS 2 were optimized to achieve an intimate contact. The Z-scheme heterojunction f-MoS 2 @UiO-66-NH 2 (100 nm) with perfectly matched micro-geometric configuration exhibited an excellent electron consumption rate (R ele) of 263.78 μmol g–1 h–1 and a high CH 4 yield of 27.18 μmol g–1 h–1 with a selectivity of 82.44%, being far superior to most MoS 2 - and MOFs-based heterojunctions. Comprehensive investigations with extensive photoelectric characterizations, control experiments, and density functional theory (DFT) calculations demonstrate that the excellent photocatalytic performance of f-MoS 2 @UiO-66-NH 2 (100 nm) could be attributed to that (i) the low size of UiO-66-NH 2 strengthens mutual alignment and increases outer surface to maximize heterointerface contact with MoS 2 , accelerating the interfacial charge transfer; (ii) the hierarchical structure of f-MoS 2 with optimal basal plane curvature greatly reduces contact barriers to present a high charge throughput with a charge excitation rate of 1.967 mV, smooth initiating the 8-electron CO 2 methanation. Additionally, the durability of f-MoS 2 @UiO-66-NH 2 (100 nm) was also investigated. [Display omitted] [ABSTRACT FROM AUTHOR]

• Cs 3 Bi 2 Br 9 /BiOBr is synthesized through an in-situ growth approach. • In-situ XPS characterization confirms the S-scheme charge transfer mode. • Cs 3 Bi 2 Br 9 /BiOBr has strong redox abilities and high charge separation efficiency. • Cs 3 Bi 2 Br 9 /BiOBr can selectively photo-oxidize benzylic C‒H bonds. Converting hydrocarbons into aldehydes in a green and environmentally benign way is of great significance in fine chemistry. In this work, all-inorganic Cs 3 Bi 2 Br 9 perovskite nanoparticles were uniformly loaded on BiOBr nanosheets via an in-situ growth method, which can selectivity photoactivate aromatic C(sp3) H bond of toluene to generate benzaldehyde. According to the in-situ X-ray photoelectron spectroscopy characterization, the photogenerated electrons of BiOBr transfer to Cs 3 Bi 2 Br 9 enforced by the internal electric field under light irradiation, resulting in S-scheme heterojunction. Furthermore, theoretical calculations indicate that toluene molecules are inclined to adsorb on the BiOBr surface, subsequently involving the oxidation reaction to generate benzyl radical (PhCH 2 •) by using the energetic holes of BiOBr, while the remaining photoinduced electrons in the conduction band (CB) of Cs 3 Bi 2 Br 9 with powerful reduction ability reduce O 2 into •O 2 −, which is the vital oxidative active species working on toluene selective oxidation process. Such an unexceptionable charge carrier utilization mode and tendentious adsorption behavior of reactants contribute to the optimized Cs 3 Bi 2 Br 9 /BiOBr heterojunction with excellent photocatalytic performance, achieving a maximum of 22.5% toluene conversion and 96.2% selectivity towards benzaldehyde formation. This work provides a rational photocatalyst heterojunction construction protocol for the selective oxidation of saturated aromatic C H bonds. [Display omitted] [ABSTRACT FROM AUTHOR]

• A Bi 7 O 9 I 3 /carbon paper composite was fabricated using an in-situ annealing method. • Flexible Bi 7 O 9 I 3 /carbon paper possesses hierarchical structure. • Bi 7 O 9 I 3 /carbon paper exhibited improved photocatalytic performance. • Improved carrier separation and hierarchical structure are key to performance enhancement. Although Bi 7 O 9 I 3 is an oxygen-rich bismuth oxyiodide with higher photocatalytic activity than BiOI, its applicability for photocatalytic oxidation is limited by the rapid recombination of photogenerated carriers and poor reusability. Depositing Bi 7 O 9 I 3 on flexible macro-sized carbonaceous materials is a promising approach for promoting photogenerated electron migration and improving reusability. In this study, a composite consisting of Bi 7 O 9 I 3 supported on graphitic carbon paper (Bi 7 O 9 I 3 -CP) was synthesized via the in situ transformation of a BiOI-deposited carbon paper precursor (BiOI-CP). The as-prepared Bi 7 O 9 I 3 -CP exhibited higher visible-light-driven photocatalytic activity than both Bi 7 O 9 I 3 and BiOI-CP precursor for phenol removal. The improved photocatalytic activity of Bi 7 O 9 I 3 -CP was attributed to its hierarchical structure and promoted carrier separation, as revealed by photoluminescence, pore structure, and reactive radical analyses. Moreover, owing to its macroscale size and flexibility, the Bi 7 O 9 I 3 -CP composite could be easily operated and reused, which are favorable for practical applications. [ABSTRACT FROM AUTHOR]

• The development of LnVO 4 (Ln=La, Ce, Pr, Nd, etc.)-based photocatalysts are systematic studied. • The effects of morphology, doping, phase structure, crystal facet, defect, heterostructure are thoroughly summarized. • Various photocatalytic applications of LnVO 4 -based photocatalysts are presented. • Current issues are discussed and future research directions are provided. LnVO 4 (Ln = La, Ce, Pr, Nd, etc.) is an emerging photocatalyst for solving the energy and environmental crisis, due to its suitable band gap, special valence electronic structure, high thermal, and chemical stability, as well as excellent photocatalytic performance. Although exhibiting great promise, the low solar power employment efficiency of LnVO 4 materials has limited its further development and application. However, recent breakthroughs have been made in both heightening its photocatalysis efficiency and elucidating the essential photocatalytic mechanisms. Therefore, it is important to review and summarize recent research progress on LnVO 4 nanomaterials and their applications. In this review, we systematically report on and examine recent computational and experimental advances in the modification of LnVO 4 -based photocatalysts through morphology adjustment, elemental doping, phase structure modulation, crystal facet modulation, defect modulation, heterostructure, and beyond. Thereafter, we outline current promising photocatalytic applications and discuss challenges/expected upcoming research aims for LnVO 4 -based photocatalysts. Our goal is to furnish guidance for the reasonable design and preparation of highly efficient LnVO 4 (Ln = La, Ce, Pr, Nd, etc.)-based photocatalytic materials for sundry applications. [Display omitted] [ABSTRACT FROM AUTHOR]

• Photocatalytic mechanism of carbon dots/nanomaterial system is discussed. • Four typical carbon dots-synergistic enhancement effects are highlighted. • Summary of carbon dots-based nanocomposites with the synergistic effect. • Application of carbon dots-based nanocomposite photocatalysts. Carbon dots (CDs), as a class of promising and multifunctional carbon nanomaterials, have become a research hotspot in the field of photocatalysis owning to strong absorption of visible light, favorable photoelectric properties, and tunable energy-level configuration. Although numerous efforts have been made to improve photocatalytic performance by combining CDs with other semiconductors in recent years, the summary of enhancement mechanisms for this emerging technology is few reported. Fully understanding the synergistic effect of CDs and nanomaterials in photocatalytic applications is extremely important for the further development of photocatalysis in the future. Here, the photocatalytic mechanism of carbon dots/nanomaterial system is discussed. Four typical carbon dots-synergistic enhancement effects are highlighted, namely, energy band regulation, local electric construction, active site engineering, and multiple carrier activation. Second, the recent progress of carbon dots-based nanocomposites in efficient solar energy conversion is reviewed and examples are given. Finally, the future research development direction and challenges are emphasized on this basis. In this review, the mechanism of CDs enhanced photocatalysis in CDs-based nanocomposites for photocatalytic applications is summarized. [Display omitted] [ABSTRACT FROM AUTHOR]

Chemists have developed a special type of paint that can clean itself and potentially remove pollutants from the air. The paint uses titanium oxide nanoparticles that react with pollutants when exposed to ultraviolet light, breaking them down and preventing discoloration. A recent study has shown that this self-cleaning paint can be activated by ordinary sunlight, making it more practical to use. However, some chemists remain cautious about the effectiveness and sustainability of these photocatalytic paints. [Extracted from the article]

• CIS QDs modified CN S-scheme photocatalysts are successfully prepared. • The photocatalytic performance of CN is improved by modification of CIS QDs. • CIS QDs promoted the separation efficiency of photogenerated carriers of CN. CuInS 2 quantum-dot (CIS QD)-modified g-C 3 N 4 (CN) catalysts (CIS/CN) were prepared with the aid of an in-situ growth process. The as-obtained photocatalysts were explored by measuring their crystallinity, surface morphology, binding energy and light absorption activity. The photocatalytic efficiency of the photocatalysts was evaluated through photocatalytic water splitting for hydrogen production and tetracycline (TC) antibiotic degradation under the simulated solar light and visible light respectively. The optimized sample (10CIS/CN) showed the best photocatalytic activity: producing 102.4 µmol g−1 h−1 of hydrogen in 1 h, or degrading 52.16% of TC in 120 min, which were respectively 48 or 3.4 times higher than the photocatalytic activity of CN itself. The enhancement in the efficiency of the composite system was principally accredited to the enlargement of light absorption, the more effective in charge transfer and the dropping of the charge carrier pair recombination through a formed S-scheme heterojunctional interface. This work is an effort to adjust CN-based polysulfide QD for speedy photocatalysis. The enriched photocatalytic activity grants a new sense for adjusting the optical properties of CN. [Display omitted] [ABSTRACT FROM AUTHOR]

• Review of recent advances in CdS-based S-scheme heterojunction photocatalysts. • Design concepts, basic principles and charges transfer of CdS-based S-scheme heterojunctions are discussed. • The potential applications of CdS-based S-scheme heterojunctions are reviewed. • The possible tendency of CdS-based S-scheme photocatalysts is proposed. Photocatalytic technology with sunlight as driving force can convert solar energy into other energy sources for storage and further use. Cadmium sulfide (CdS), as a typical reducing semiconductor of metal sulfides, represents an interesting research hotspot in photocatalysis due to its suitable bandgap (2.4 eV) for utilizing visible light and strong reducing ability for inducing surface catalytic reactions. Unfortunately, the photocatalytic performance of CdS is still limited by its fast carrier recombination and serious photocorrosion. So far, CdS semiconductor has been widely developed as a typical reducing photocatalyst in constructing novel S-scheme heterojunction to overcome the above drawbacks. In this review, the design concepts, basic principles, and charge transfer characteristics of CdS-based S-scheme heterojunction photocatalysts have been comprehensively introduced. Several advanced and effective characterization methods for studying the mechanism of CdS-based S-scheme heterojunction are analyzed in detail. Furthermore, we also summarize the typical applications of CdS-based S-scheme heterojunctions for water splitting, CO 2 reduction, pollutant degradation, etc. Eventually, according to the current investigation status, some drawbacks in the current synthetic strategy, mechanism exploration, and application prospect of CdS-based S-scheme heterojunction are proposed, which need to be addressed by further expansion and innovative research. [Display omitted] [ABSTRACT FROM AUTHOR]

• BBN/BWO S scheme heterojunctions are successfully synthesized. • BBN/BWO heterojunctions exhibit efficient photocatalytic SMZ degradation. • The toxicity of SMZ and its intermediates is significantly reduced. • The photogenerated carriers' separation is extensively promoted through IEF. The S-scheme heterojunction has garnered increasing attention due to its remarkable oxidation capacity and efficient separation of photogenerated carriers. In this study, a one-pot glycerol-assisted hydrothermal process was utilized to successfully synthesize S-scheme heterojunction photocatalysts comprising basic bismuth nitrate (BBN) and bismuth tungstate (BWO). Interestingly, the BBN/BWO heterogeneous photocatalysts exhibited the highest photocatalytic properties. The optimized product achieved the degradation of sulfamethazine (SMZ) within 1 h, with a kinetic constant (k) value of 0.05818 min−1. The degradation process was influenced significantly by ·O 2 − and h+ species. To determine the degradation pathway of SMZ in the presence of BBN/BWO-0.6, liquid chromatography–mass spectrometry (LC–MS) analysis was performed, which revealed a decrease in the toxicity of intermediates and products. The enhanced photocatalytic activity can be attributed to the internal electric field (IEF) of the S-scheme heterojunction between BBN and BWO, effectively promoting the separation of photogenerated carriers. This research presents a viable approach for developing S-scheme heterojunctions in SMZ photodegradation and other environmental applications. [Display omitted] [ABSTRACT FROM AUTHOR]

• Pt single atom is steadily anchored in the structure of COF via a N–Pt–C 2 linkage. • Pt loading reduces the band gap of COF. • Pt loading improves CO 2 adsorption and activates the adsorbed CO 2 molecule. • Pt loading decreases the energy barrier in the rate-determining step (CO 2 → COOH). • DFT calculation results show that Pt-COF is an ideal CO 2 reduction photocatalyst. Photocatalytic CO 2 reduction provides a promising strategy for the alleviation of greenhouse effect and energy shortage problem. Metal single atom modification is an effective method to improve the CO 2 reduction performance of covalent organic framework (COF) photocatalysts, while the intrinsic mechanism is not revealed in depth. Herein, a Pt-COF photocatalytic system was constructed by embedding Pt single atom in TFPT-TMT-COF (TFPT: 1,3,5-tris(4-formylphenyl)-triazine, TMT: 2,4,6-trimethyl-1,3,5-triazine). Based on density functional theory (DFT) calculation, the geometric structure and electronic property of Pt-COF were investigated, and the CO 2 adsorption and reduction reaction process on Pt-COF were simulated. The results show that the Pt atom can be steadily anchored in COF via the formation of Pt–N and Pt–C bonds. Moreover, there is strong electronic interaction between Pt and COF. The incorporation of Pt atom benefits the CO 2 reduction activity of COF from multiple aspects: (ⅰ) reducing the band gap and improving light absorption; (ⅱ) enhancing CO 2 adsorption and activating the CO 2 molecule; (ⅲ) decreasing the energy barrier in the hydrogenation step of CO 2 →COOH, thus facilitating CO 2 conversion to CO; (ⅳ) inhibiting the hydrogenation of CO, thereby increasing the selectivity of CO. This work brings a novel insight into the excellent CO 2 reduction performance of Pt modified COF, and provides useful references for the design of single atom photocatalysts. [ABSTRACT FROM AUTHOR]

• The CW/4Co/2BNQDs/PMS/Vis system reached a TC elimination of 94.8% within 30 min. • The Cu2+/Cu+ and Co2+/Co3+ dual redox cycles were remarkably boosted by introducing the BNQDs. • BNQDs acted as efficient hole extractors to hinder the recombination of the phoinduced electron-hole pairs. • Degradation pathways and products toxicity were discussed in detail. In the metal-based peroxymonosulfate (PMS) activation process, the sluggish surface redox cycle of metal ions generally hampered the efficiency of PMS activation for pollutant removal. Herein, Co-doped CuWO 4 /BN quantum dots (CW/Co/BNQDs) photocatalysts were developed to realize Cu2+/Cu+ and Co2+/Co3+ dual ions redox cycles for PMS activation, which would facilitate the tetracycline (TC) removal. CW/4Co/2BNQDs could degrade 94.8% TC within 30 min in PMS/Vis system, and the apparent rate constant of CW/4Co/2BNQDs was 2.7 times and 1.2 times higher than those of CW and CW/4Co, respectively. The improved TC degradation performance could be attributed to the synergetic effect between BNQDs and dual redox cycles. X-ray photoelectron spectroscopy (XPS) spectra of samples before and after the reaction demonstrated that BNQDs were beneficial for accelerating the Cu2+/Cu+ and Co2+/Co3+ redox cycles in CW/4Co/2BNQDs, further boosting the activation of PMS in TC degradation. Experiments of different radical scavengers revealed that the SO 4 ·−/·OH/h+/1O 2 reactive species participated in the PMS activation for the TC degradation process. The possible TC degradation pathway and intermediate toxicity were detailed investigated. In addition, CW/4Co/2BNQDs exhibited outstanding photocatalytic activity over five consecutive cycles, which illustrated that it was supposed to be a reliable PMS activator over antibiotic elimination for practical application. And this work shed new light on constructing dual redox cycles for efficient PMS activation. [Display omitted] [ABSTRACT FROM AUTHOR]

• The Bi 2 WO 6 /AgInS 2 S-scheme heterojunction is successfully fabricated. • Bi 2 WO 6 /AgInS 2 can efficiency degrade RhB, norfloxacin and levofloxacin. • A possible degradation pathway of RhB is proposed. • Toxicity experiments are performed to research the reusability of the water. • Enhanced photocatalytic activity is believed to accelerate spatial charge transfer. Constructing of heterojunction was identified as a feasible way to improve photocatalytic activity of photocatalyst. In this work, a n-p type Bi 2 WO 6 /AgInS 2 S-scheme heterojunction was successfully prepared for organic pollutants degradation. This Bi 2 WO 6 /AgInS 2 S-scheme heterojunction exhibited much higher photocatalytic activity towards Rhodamine B (92.24%, expose to visible light for 60 min), norfloxacin (81.73%, expose to visible light for 90 min) and levofloxacin (87.46%, expose to visible light for 90 min) than pure Bi 2 WO 6 and pure AgInS 2. Toxicity analysis indicated the low environmental toxicity of Rhodamine B degradation intermediates for Rye seeds and Sudangrass seeds germination and growth. Mechanism study displayed that AgInS 2 and Bi 2 WO 6 work as the primary photocatalyst to form ·O 2 − and ⋅OH, respectively. The improved photocatalytic activity of the Bi 2 WO 6 /AgInS 2 S-scheme heterojunction was due to the improved light response range and intensified carrier separation capability. Additionally, a S-scheme charge transfer mechanism including multiple charge transfer channels was proposed. This work could provide an effective strategy for organic pollutants degradation in wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

• The S-scheme heterojunctions based on different typical photocatalysts are summarized. • Advanced characterization used to directly demonstrate the mechanism of S-scheme heterojunction is comprehensively summarized. • The future challenges and development trends of S-scheme heterojunction in the field of photocatalytic hydrogen evolution are pointed out. As an ideal secondary energy source, hydrogen has the title of clean energy and the product of its complete combustion is only water, which is not polluting to the environment. Photocatalytic hydrogen production technology is an environmentally friendly, safe, and low-cost strategy that requires only an inexhaustible amount of solar energy and water as feedstock. This paper provides a detailed and detailed review of S-scheme heterojunction photocatalysts for photocatalytic hydrogen production, mainly including TiO 2 -based, Perovskite-based, CdS-based, Graphitic phase carbon nitride-based, COF-based graphdiyne-based, ZnO-based, and ZnIn 2 S 4 -based S-scheme heterojunction photocatalysts. The classification of S-scheme heterojunctions is summarized. What's more, various characterizations for direct verification of the charge migration mechanism of S-scheme heterojunctions are outlined. Based on the present study, the future potential challenges and future research trends for S-scheme heterojunctions in photocatalytic hydrogen evolution technology are pointed out, which provides feasible strategies for the development and design of S-scheme heterojunction photocatalysts in the field of photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

• The homojunction of biphasic manganese dioxide was constructed by using the phase. • Using the crystal surface engineering to improve homojunctions design. • Treatment of bacterial infection with the novel MnO 2 homojunction. Photocatalysis has been a research hotspot in recent years, and the design and modification of photocatalysts have been the key points. Common methods for designing photocatalysts, including constructing heterojunctions and homojunctions, have been developed on the basis of heterojunctions. In this study, two homojunctions of manganese dioxide (MnO 2), including a high-index crystal plane homojunction and a general homojunction, are prepared using a stepwise hydrothermal method. Using a capping agent, the high-index crystal surface of the MnO 2 is exposed. It is found that the electron transport efficiency between the two components of the homojunction with high-index planes is higher and the adsorption capacity of the oxygen is stronger, which leads to higher photocatalytic efficiency. In addition, the newly designed high-index homojunction is used for the treatment of bacterial infections, and it kills Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) at rates of 99.95% ± 0.04% and 99.31% ± 0.25%, respectively. It also has excellent therapeutic effects on mouse wounds, which implies superb practical application value. This work provides a new strategy for the improved design of homojunctions and the application of photocatalytic materials. Schematic illustration of the band structure electron transfer of two manganese dioxide homojunctions and their photothermal and photodynamic effects, with application to wound infection treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

• The research background and mechanism of ZnIn 2 S 4 -based S‐scheme heterojunctions have been scientifically introduced. • The design, preparation and characterization strategies of ZnIn 2 S 4 -based S‐scheme heterojunctions have been systematically summarized. • The photocatalytic applications of ZnIn 2 S 4 -based S‐scheme heterojunctions have been detailly described. Photocatalytic technologies have been universally applied in the domains of hydrogen production, environmental purification, CO 2 reduction, catalytic organic synthesis, and other major fields owing to their environmental friendliness, convenient operation, and absorbing sunlight as the driving force. The core of photocatalytic technology is photocatalyst. Hence, it is greatly essential to fabricate stable, high-efficiency, and visible-light response photocatalysts. Among various visible-light-response photocatalysts, ZnIn 2 S 4 , a ternary metal sulfide, has attracted extensive attention due to its prominent advantages of simple synthesis, excellent stability, and appropriate band structure. However, the low utilization of solar energy and rapid recombination of photogenerated charges as same as inferior redox capacity are still the distinct shortcomings that significantly block the increase of photocatalytic efficiency for ZnIn 2 S 4 photocatalyst. Fortunately, the above evident shortcomings can be simultaneously resolved by constructing heterojunctions between ZnIn 2 S 4 with other semiconductors. In recent years, various semiconductor photocatalysts (such as oxides (TiO 2 , WO 3 , In 2 O 3), sulfides (ZnS, FeS 2 , CoS), oxysalts (Bi 2 MoO 6 , ZnWO 4 , NaTaO 3), organics (g-C 3 N 4 , COF, PDIIM), etc.) have been combined with ZnIn 2 S 4 to construct ZnIn 2 S 4 -based S-scheme heterojunctions with the aim at greatly increasing its photocatalytic efficiency. Herein, this review presents a systematic description of the currently popular ZnIn 2 S 4 -based S-scheme heterojunction photocatalyst, which includes the research background, scientific mechanism, design principles, preparation strategies, and characterization methods of ZnIn 2 S 4 -based S‐scheme heterojunctions. Moreover, the extensive photocatalytic applications of ZnIn 2 S 4 -based S-scheme heterojunctions have been detailly described by classification examples, including hydrogen production, CO 2 reduction, environmental purification, and other applications. Finally, several drawbacks on the synthetizations, modifications, and applications of ZnIn 2 S 4 -based S-scheme heterojunction have been proposed, and their corresponding prospects have also been propounded in terms of their future development. [Display omitted] [ABSTRACT FROM AUTHOR]

• Enhanced SMSI between pt and Bi 2 MoO 6 under light irradiation. • Promoted charge separation efficiency of Bi 2 MoO 6 by pt NPs. • Synergistic activation of surface oxygen species by pt NPs and light irradiation. • Promoted O 2 activation due to the transfer of photoelectrons from Bi 2 MoO 6 to Pt. • Proposed langmuir-hinshelwood mechanism for photocatalytic HCHO oxidation. The strong metal-support interaction (SMSI) plays a pivotal role in regulating electronic properties and activating surface oxygen species. In this work, we report light-irradiation-modulated SMSI for enhanced formaldehyde (HCHO) oxidation. Specifically, the SMSI between Pt nanoparticles (NPs) and Bi 2 MoO 6 created surface-active oxygen at Pt-Bi 2 MoO 6 interfaces to activate HCHO to dioxymethylene (DOM). Notably, light irradiation boosted the SMSI and catalytic activity. Moreover, photogenerated holes in Bi 2 MoO 6 improved HCHO adsorption and activation, while photogenerated electrons migrated from Bi 2 MoO 6 to Pt NPs to promote O 2 adsorption and activation, accelerating the oxidation of DOM to CO 2 and H 2 O. The light-modulated SMSI and the synergy between photocatalysis and thermocatalysis lead to enhanced catalytic oxidation activity, providing a practical strategy for indoor volatile organic compound (VOC) decomposition under ambient conditions. [Display omitted] [ABSTRACT FROM AUTHOR]

• A review focuses on the concept and advantages of inorganic–organic S-scheme heterojunction photocatalysts. • Current research on the design and synthesis of inorganic–organic S-scheme heterojunction photocatalysts. • Advanced characterization techniques for inorganic–organic S-scheme heterojunctions are focused. • The proposed inorganic–organic S-scheme heterojunction electron-transfer mechanism is favored. The inorganic–organic S-scheme heterojunction photocatalyst demonstrates exceptional light absorption capacity, high photogenerated charge separation efficiency, and remarkable redox ability, while also inheriting diverse advantages of both inorganic and organic semiconductors. This paper provides a comprehensive review of recent advances in photocatalysis in relation to the inorganic–organic S-scheme heterojunction photocatalyst. Firstly, the fundamental aspects and benefits of the S-scheme heterojunction photocatalyst are outlined, followed by a discussion of several synthetic techniques for producing the inorganic–organic S-scheme heterojunction photocatalyst, as well as various advanced characterization methods that can verify the S-scheme heterojunction photocatalyst in both steady-state and transient processes. The impact of the inorganic–organic S-scheme heterojunction photocatalyst is illustrated with examples in fields such as carbon dioxide reduction, water splitting for hydrogen production, hydrogen peroxide synthesis, nitrogen fixation, organic pollutant degradation, organic transformation, and sterilization. Finally, suggestions are presented for designing the inorganic–organic S-scheme heterojunction photocatalyst and enhancing its photocatalytic performance. Undoubtedly, the inorganic–organic S-scheme heterojunction photocatalyst has emerged as a prominent and promising technology in the field of photocatalysis. [Display omitted] [ABSTRACT FROM AUTHOR]

• A device of photocatalysis assisted MFC was designed for tetracycline removal. • Synergistic effect of photocatalysis and biodegradation enhanced the mineralization. • The biotoxicity of the effluent was greatly reduced by the photo-MFC. • CdS cage exhibited higher photocatalytic activity than CdS cube. Tetracycline (TC) as a common broad-spectrum antibiotic, has been frequently detected in soil and surface water. It becomes a great threat to the ecological environment. Here, a device of photocatalysis assisted microbial fuel cell (photo-MFC) was constructed for TC degradation and energy recovery. In this photo-MFC, cadmium sulfide(CdS) cage photocatalysis can degrade most of TC in a short time. While the Co 3 O 4 @C–CC (carbonization and calcination of the ZIF-67 precursor in-situ grown on the carbon cloth (CC)) bioanode degrades the rest of TC as well as the photocatalytic products, thus improving the mineralization. The co-existence of photocatalysis with bioanode changes the microbial community structure of the biofilms. The dominant phylum is Geobacter (60.2%) in normal MFC while that in photo-MFC are Proteobacteria (43.5%) and Geobacter (33.2%). Therefore, the synergistic effect of photocatalytic degradation and biodegradation achieves a chemical oxygen demand (COD) removal of 98.6%, which is higher than that of normal MFC (77.6%) or single CdS cage photocatalysis (23.8%). In addition, the photogenerated electrons can be transferred to the cathode, which reduces their combination with holes and increases the electricity generation of MFC, achieving a maximum power density of 3.37 W/m2. After degradation, the effluent with 200 mg L−1 TC exhibits no visible biotoxity. Furthermore, electrochemical test, finite-difference time-domain (FDTD), density functional theory (DFT) calculation and the free radical trapping experiments verify the possible mechanisms of photocatalytic degradation in this photo-MFC. This strategy paves a new way for low energy consumption removal and energy recovery of organic pollutants. [Display omitted] [ABSTRACT FROM AUTHOR]

• Ultrathin ZnIn 2 S 4 nanosheets/CdTe nanocrystals heterostructure is designed for the first time. • The photoelectrons transfer from CdTe to ZnIn 2 S 4 , which is verified by DFT calculation. • The sulfur vacancies existed in ZnIn 2 S 4 can capture the photoelectrons acting as reactive sites. • The ZnIn 2 S 4 can aggregate H+ and possesses low reaction barrier, expediting the kinetic process for the reactions. • The ZnIn 2 S 4 /1%CdTe sample exhibits an excellent H 2 evolution rate of 24.3 mmol/g/h. • The photocatalysts undergoes the photoactivation cycle and owns the photothermal effect. To suppress the inner charge recombination and inject vast electrons, CdTe nanocrystals are embedded into ultrathin ZnIn 2 S 4 nanosheets to construct ZnIn 2 S 4 /CdTe heterostructures, where the nanocrystals are generated by a laser irradiation method. The optimal ZnIn 2 S 4 /CdTe heterojunction exhibits an excellent catalytic activity of 24.3 mmol/h/g, which is relatively high among the ZnIn 2 S 4 -based photocatalysts without noble metals. This enhancement is ascribed to a win-win mechanism of nanoscale heterojunctions and sulfur vacancies. The strong electron coupling effect, which is verified by density functional theory (DFT) calculations, impels the photo-generated electrons transfer from CdTe to ZnIn 2 S 4 , boosting the charge separation. Meanwhile, the sulfur vacancies existing in ZnIn 2 S 4 can capture photoelectrons and act as active sites, facilitating the H 2 generation reaction. In addition, the ZnIn 2 S 4 base and the ZnIn 2 S 4 /CdTe heterojunction also possess an evident photothermal effect and renewable cycle phenomena, enhancing the photocatalytic performance. This research provides new insights into the regulation of charge transfer through embedding nanocrystals. [Display omitted] [ABSTRACT FROM AUTHOR]

Photocatalytic H 2 O 2 production provides a clean and sustainable strategy for artificial photosynthesis. Herein, an inorganic/organic composite photocatalyst was fabricated by in-situ growth of CdS nanoparticles on the surface of resorcinol–formaldehyde (RF) resin spheres. RF spheres played multiple roles: (i) acting as a substrate for the growth of CdS and constructing a core-shell structure with seamless contact; (ⅱ) improving visible light absorption of CdS; (ⅲ) forming an S-scheme heterojunction with CdS and promoting the charge separation and transfer. Consequently, under visible light illumination, CdS/RF composite presented remarkably enhanced H 2 O 2 production activity. Its H 2 O 2 yield in 60 min was 801 μmol L–1, which was 5.2 and 1.5 times higher than that of RF spheres and CdS hollow spheres, respectively. The charge migration between CdS and RF followed the S-scheme photocatalytic mechanism, which was verified by work function measurement, ex-situ and in-situ irradiated X-ray photoelectron spectroscopy. This work brings a novel insight into designing RF-based inorganic/organic S-scheme heterojunction photocatalysts for efficient H 2 O 2 production. [Display omitted] [ABSTRACT FROM AUTHOR]

• 3D ordered macroporous sulfur-doped g-C 3 N 4 /TiO 2 S-scheme photocatalysts were successfully prepared. • The composites show high photocatalytic H 2 O 2 -production activity in pure water. • In-situ DRIFTS measurements were performed to fully unveil the reaction pathways and the active sites. • The photocatalytic H 2 O 2 production proceeds through a double-channel pathway consisting of ORR and WOR. Photocatalytic hydrogen peroxide (H 2 O 2) production offers a clean and cost-efficient alternative to the traditional anthraquinone oxidation approach. Herein, a step-scheme (S-scheme) heterojunction photocatalyst is fabricated by coupling TiO 2 with three dimensionally ordered macroporous sulfur-doped graphitic carbon nitride (3DOM SCN/T) by electrostatic self-assembly. The optimized photocatalyst achieved a high photocatalytic H 2 O 2 production activity with a yield of 2128 μmol h−1g−1 without the addition of hole scavengers. The remarkable performance was attributed to the synergy between the 3DOM framework and the S-scheme heterojunction. The former enhances light harvesting and provides abundant active sites for surface reactions, while the latter promotes the spatial separation of photogenerated carriers and enhances the redox power. Finally, the mechanism of photocatalytic H 2 O 2 production over the 3DOM SCN/T S-scheme composite is proposed. This work provides novel insights into the development of efficient photocatalysts for H 2 O 2 production from water and O 2. [ABSTRACT FROM AUTHOR]

As a highly toxic heavy metal, Cr(VI) reduction by developing high-efficiency photocatalysts is of great significance. Herein, we firstly design few-layer Ti 3 C 2 MXene (FTM) by the hand-operated shaking, showing dual advantages of structural stability and more exposed reactive sites. Then, a refluxed process is performed to fabricate FTM/CaIn 2 S 4 (FTC) composites, where 2D CaIn 2 S 4 (CIS) nanoplates are closely connected with 2D FTM to form Schottky junction. The optimal 1-FTC with the FTM/CIS mass ratio of 1 wt.% exhibits the highest activity toward photocatalytic Cr(VI) reduction under visible light. It is well elucidated that the broadened light absorption range and promoted charge carrier separation rate induced by the introduction of FTM are responsible for improving photocatalytic activity of CIS. During Cr(VI) photoreduction, 1-FTC possesses excellent photo-stability and reusability. The effects of catalyst mass, coexisting ions, water sources and pH values on the Cr(VI) photoreduction efficiency are investigated. Photogenerated •O 2 − and e − are the main radical species accounting for Cr(VI) photoreduction over 1-FTC. The photocatalytic mechanism along with Cr(VI) removal pathway is exploited. This work may provide some insights into constructing FTM-based Schottky junctions for the efficient water purification. Few-layer Ti 3 C 2 MXene/CaIn 2 S 4 Schottky heterojunction exhibited the highly photocatalytic efficiency for Cr(VI) reduction under visible light, due to the synergistic effect of the broadened light absorption range and promoted charge carrier separation rate. [Display omitted] [ABSTRACT FROM AUTHOR]

• Summarized the difference dimensions of S-scheme heterojunctions. • Discussed the electron transfer process from the dimensionality of heterojunctions. • Concluded methods to prove the formation of S-scheme heterojunction. • Reviewed the applications of S-scheme heterojunction in different fields. S-scheme heterostructure photocatalysts utilize the synergistic and superposition effects of materials, effectively separating electrons and holes, maintaining strong redox capacity, and addressing issues encountered by current photocatalytic reactions. This review explores the origins and unique benefits of S-scheme heterojunctions. Specifically, we summarized and discussed the effects of different dimensions of semiconductors constituting S-scheme heterojunctions and the similarities and differences in electron transfer processes when constructing heterojunctions. Additionally, we analyzed several methods for proving the formation of S-scheme heterojunctions and the electron transfer process, both directly and indirectly. Finally, we review the applications of S-scheme heterojunctions in various fields of photocatalysis, including photocatalytic water splitting, pollution degradation, CO 2 reduction and other related photocatalytic applications. Our hope is that this review will provide an essential reference for the development and application of S-scheme heterojunction photocatalysis. [ABSTRACT FROM AUTHOR]

• Ferromagnetic TiO 2 was prepared by regulation of crystal structure and defects. • The saturation magnetisation (M S) was measured to be as high as 0.0014 emu/g. • Experiments and simulation are used to investigate the ferromagnetism mechanism. • The photoelectrochemical performance was improved by ferromagnetic field in the bulk. • The proposed approach can be used to other oxide systems. The use of the internal magnetic field of ferromagnets can effectively promote charge separation and transfer (CST) in photoelectrochemical energy conversion. However, photoelectrochemical materials with a ferromagnetic field are scarce, and the internal magnetic field is negligible in nonferromagnetic materials. To address this issue, we propose a rational method for preparing ferromagnetic TiO 2 powder using controllable oxygen vacancies in anatase TiO 2 with co-exposed {001} and {101} facets. Accordingly, an excellent saturation magnetisation of 0.0014 emu/g in TiO 2 is achieved owing to an asymmetric and uneven charge distribution. Compared with that of nonferromagnetic TiO 2 , the efficiency of photocatalytic hydrogen generation of ferromagnetic TiO 2 is improved by 0.64 times. The enhancement of photocatalytic hydrogen generation is due to the different forces exerted on the electrons and holes in the magnetic field, which significantly improve the photogenerated CST efficiency of ferromagnetic TiO 2. This result highlights the significant role of the synergistic regulation of the crystal structure and defects in regulating the ferromagnetic characteristics of materials. The findings of this study provide guidance for leveraging point defects to promote CST for high-efficiency solar-energy conversion systems. Ferromagnetic TiO 2 with co-exposed {001} and {101} facets was prepared via controllable oxygen vacancies. The different forces exerted on the electrons and holes in the magnetic field significantly improve the photogenerated CST efficiency of ferromagnetic TiO 2 [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel sponge-like carbon nitride (CN) was fabricated through a hybrid method. • A combination of supramolecular self-assembly and hard templet was employed. • Bisphenol A, was degraded by 95% after 60 min in pH=5. • DFT showed modified sample is energetically more favorable than the pristine CN. • Based on toxicity assessment the final products are not harmful. A unique and well-designed 2D graphitic carbon nitride (g-CN) with sponge-like architecture has been successfully synthesized by engineering supramolecular self-assembly and well-organized SiO 2 nanoparticles. The resulting material showed great optical and textural characteristics with plenty of open and uniform pores, which are very helpful whether for multiple light scattering or mass transfer. The formation of boosted delocalized π-conjugated electrons at the molecular level and condensed heptazine building blocks result in enhanced carrier density and charge transfer dynamics. Optical emission spectroscopy and time‐resolved fluorescence lifetime (TRPL) strongly confirmed the enhancement of light harvesting and prolonged charge carrier lifetime. The optimized sample exhibited a degradation performance of 95% of bisphenol A (BPA, 10 mg L–1) after 60 min under visible–light irradiation at pH = 5. All the scavenging experiments, probing experiments as well as electron paramagnetic resonance (EPR) confirm that •O 2 – is the dominant reactive species that fragments bisphenol A. Interestingly, density functional theory (DFT) calculations unveil that the BPA interaction with a modified g-CN containing porous structure is energetically more favorable than non-porous pure g-CN. Moreover, the toxicity assessment showed that the final degradation products were placed in the non-harmful category based on acute and chronic toxicity. This study presents a promising strategy to modify the g-CN properties and provides an efficient technique for boosting its visible–light photocatalytic activity. [Display omitted] [ABSTRACT FROM AUTHOR]

• An electron-reversal strategy was proposed to weaken S H ads bonds. • The essence of electron reversal and optimized H adsorption was revealed. • The charge transfer mechanism was characterized by fs-TA and in situ XPS. Recently, Yu and co-workers deeply explore the potential impact of free electron transfer between cocatalysts and photocatalyst carriers on H 2 evolution efficiency of active sites over MoS 2+ x. They propose an electron-reversal tactics to evade the unexpected electron transfer and synchronously regulate the above transfer in a beneficial orientation for weakening hydrogen adsorption on S sites. Herein, this highlight not only discusses and summarizes the essences of electron reversal and the optimized H adsorption/desorption mechanism, but also emphasizes the significance of femtosecond transient absorption spectroscopy (fs-TAS) and in-situ irradiated X-ray photoelectron spectroscopy (ISI-XPS) for revealing charge transfer dynamics and processes. We anticipate that this highlight can disseminate a new perspective on the roles of photocatalyst carriers in improving cocatalytic H 2 -production kinetics. [ABSTRACT FROM AUTHOR]

• Bi 2 S 3 was grown on BiOBr in situ by a high-temperature molten salt reaction. • Novel BiOBr/Bi 2 S 3 high-low junction with large contact area and unique energy band structure was constructed. • ·OH, ·O 2 − radicals and in-situ H 2 O 2 jointly improve the degradation activity of pollutants. • Improvement of O 2 promotes oxygen reduction reaction and makes positive contributions to H 2 O 2 production. The molten salt method focuses on improving the crystallinity of synthetic materials and avoiding the high energy consumption of traditional synthesis processes. In this work, a novel BiOBr/Bi 2 S 3 high-low junction with large contact area was constructed by the molten salt method combined with the ion exchange strategy. Its unique energy band structure and new charge transfer mechanism realize the rapid migration of photogenerated charges between different components. Specifically, Bi 2 S 3 was grown on BiOBr in situ by a high-temperature molten salt reaction. Due to the deep valence band position of BiOBr and the narrow band gap of Bi 2 S 3 , an intrinsic internal electric field and band bending are produced at the interface, forming a high-low junction photocatalyst with an intimate interface. In addition, the BiOBr/Bi 2 S 3 composite maintains a high oxidation potential and produces high and robust photocatalytic oxidation activity. In the molten state, the close binding of BiOBr and Bi 2 S 3 can be promoted through the ion-exchange strategy, resulting in excellent photocatalytic degradation rates of bisphenol A and tetracycline and in-situ generation of H 2 O 2. Finally, the mechanism of carriers separation and transfer in BiOBr/Bi 2 S 3 high-low junction is also discussed. Density functional theory (DFT) results found that the improvement of O 2 adsorption ability would promote the occurrence of oxygen reduction reaction (ORR), and make positive contributions to the enhanced H 2 O 2 production activity. This study will provide a new perspective for broadening the spectral response range of Bi-based photocatalytic materials and preparing high-low junction photocatalysts with dense interface by the molten salt method. [ABSTRACT FROM AUTHOR]

In this work, the determination of the mechanical and photocatalytic properties of asphalt modified with titanium dioxide through the Marshall tests and rhodamine B degradation was proposed as an object of study. The methodology was adapted to applied research, experimental design and focus quantitative. The study population included twenty-four specimens in total: six standard samples, six samples with 2 % titanium dioxide, six with 4 % titanium dioxide, and six with 8 % titanium dioxide. It was concluded that titanium dioxide is a good additive to improve mechanical properties. The addition of 2 % provides better results with adequate stability to allow the durability of the asphalt, with a flow of 3.85 mm within the 4 mm established by the standard, percentage of voids of 3.49 % for a more impermeable mixture with sufficient voids to prevent exudation and mineral aggregate voids of 14.74 % sufficient to optimally envelop the mineral aggregate. [ABSTRACT FROM AUTHOR]

• Various synthetic strategies of CDs/g-C 3 N 4 are classified and reviewed. • The photocatalytic enhancement mechanisms of CDs/g-C 3 N 4 photocatalysts are discussed in detail. • Recent advances and limitations of CDs/g-C 3 N 4 photocatalytic applications are presented. • Perspectives and challenges of CDs/g-C 3 N 4 photocatalysts are proposed. Carbon dots/graphite carbon nitride (CDs/g-C 3 N 4), a novel composite photocatalyst, has shown great potential for applications in energy regeneration and environmental remediation owing to its following advantages: metal-free, low cost, easily tunable, and excellent photocatalytic performance. Hence, we reviewed the development of synthetic strategies, photocatalytic enhancement mechanisms, and photocatalytic applications of CDs/g-C 3 N 4 in this study. First, the three composite strategies of CDs and g-C 3 N 4 -self-assembly, solvothermal, and calcination polymerization are outlined, and their advantages and disadvantages are described in detail. Moreover, the photocatalytic enhancement mechanism of the composite strategies was elucidated according to the variation trends of CDs/g-C 3 N 4 band structure, electronic properties, light absorption range, and interfacial charge transfer. Then, the applications of CDs/g-C 3 N 4 in hydrogen evolution, pollutant degradation, CO 2 reduction, and bacterial disinfection in recent years are reviewed systematically. Finally, the current obstacles and future research directions of CDs/g-C 3 N 4 are discussed from the perspective of preparation technology and practical applications, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

• The built-in electric field of the p-n junction promotes the transport of photogenerated carriers at the heterojunction interface. • The introduced VP served as the H 2 and CO 2 adsorption site and enhanced the adsorption capacity of 2D CNs/VP heterostructure. • The CNs/VP heterophotocatalyst exhibited much higher visible-light photocatalytic hydrogen and CO generation rates than CNs under visible-light irradiation. Two-dimensional (2D) carbon nitride sheets (CNs) with nanoscale thickness have great potential in solar energy conversion owing to their intrinsic bandgap. However, their photocatalytic efficiency falls far below the practical requirements because the generated electron-hole pairs rapidly recombine. We construct a metal-free 2D p–n junction heterophotocatalyst from CNs and violet phosphorene (VP) using a simple electrostatic self-assembly method. The experimental results and density functional theory calculations show that the built-in electric field of the p–n junction promotes photogenerated carrier transport at the heterojunction interface, thereby promoting the separation of photogenerated electron-hole pairs. Under visible-light illumination, the visible-light photocatalytic hydrogen and CO production rates of the CNs/VP heterojunction were increased by 5.85 and 1.51 times, respectively, when compared to that of CNs. This study provides new insights into the design of metal-free heterogeneous photocatalysts with high catalytic activity. [ABSTRACT FROM AUTHOR]

• Novel hierarchical network-like Bi 2 S 3 /Bi 5 O 7 I Z-scheme heterojunctions were prepared by an in-situ ion exchange method. • BSBI NHs were consisted of internal BiOI nanoplates and outside networks orderly interwoven by Bi 2 S 3 nanorods. • BSBI NHs displayed a significantly improved visible-light photocatalytic ability. • Z-scheme heterojunction and massive OVs resulted in the efficient separation of photogenerated charge carriers. • ∙OH, ⋅O 2 − and h+ played primary roles during the photocatalytic process. In this study, a novel Bi 2 S 3 /BiOI Z-scheme photocatalyst with 3D porous hierarchical network-like heterostructure (BSBI NHs) and rich oxygen vacancies (OVs) was fabricated by a facile ion exchange method followed by the in-situ growth process. A possible formation mechanism of BSBI NHs was studied, showing the self-assembled process of in-situ interwoven growth of 1D Bi 2 S 3 nanorods (NRs) on the surface of 2D BiOI disk-like nanoplates (NPs), which followed the Ostwald ripening and epitaxial growth. The modification of BiOI NPs by Bi 2 S 3 NRs brought about the formation of Z-scheme heterojunction and massive OVs, which improved the visible-light response property and promoted the separation of photoexcited charge carriers of BSBI NHs. BSBI NHs exhibited a significantly enhanced photocatalytic activity compared with Bi 2 S 3 and BiOI, and BSBI-1 can remove almost all bacteria and Rhodamine B (RhB) after 60 min visible light illumination. In addition, the photocatalytic mechanism was studied and speculated based on the tests of active species capture, electron spin resonance (ESR), and density functional theory (DFT) simulation calculation, proving the primary roles of ·OH, ·O 2 – and h+ during the photocatalytic reaction. This work provides new insights into the design and exploitation of novel heterojunctions with highly efficient photocatalytic performances for environmental remediation applications. [ABSTRACT FROM AUTHOR]