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Graphical abstract Highlights • The Fe(III) species act as electrons trapping centers to promote charge separation. • The self-induced Fenton reaction process of Fe(III) enhances the yield of OH. • The Fe(III)-BVO exhibits universal photoactivity for various organic pollutants. Abstract A novel self-induced Fenton-like photocatalyst (Fe(III) grafted BiVO 4) has been successfully synthesized via a simple wet-impregnation method, and it presents a universal enhancement for removing antibiotics and phenolic pollutants under visible light irradiation. Results reveal that the grafting of Fe(III) enhances the specific surface area of sample and possess more reaction sites. Meanwhile, the Fe(III) species serve as trapping centers for photogenerated electrons to improve the separation ability of charges, and the self-induced surface Fenton reaction of the self-redox cycles of iron ions significantly promote the generation of hydroxyl radicals. Additionally, the possible reaction mechanism and intermediate products are clearly revealed by radical trapping experiment, ESR, detection experiment of hydroxyl radicals and mass spectrometry. This strategy provides a promising insight to construct high-performance photocatalyst for solving environmental pollution problem. [ABSTRACT FROM AUTHOR]

A novel multidimensional heterojunction, the 1D trigonal Se nanorods (t-Se NRs) dissociated from CdSe QDs germinating on the 2D BiOCl ultrathin nanosheets, was successfully synthesized via a facile hybridization method. Such unique nanocomposite served as an efficient visible-light-driven photocatalyst for the photodegradation of the tetracycline hydrochloride (TC-HCl) solution. The obviously enhanced photocatalytic performance compared with pure BiOCl was mainly attributed to the introduction of Se NRs, which greatly enhanced the optical absorption in visible-light region and suppressed the recombination rate of electron-hole pairs by steering the charges migrating in a special manner. Specially, t-Se NRs in BiOCl system played an integral and important role as holes transfer channels, impelling more photogenerated electrons of BiOCl to participate in the photocatalytic process. Reactive species trapping experiments indicated the main reactive species were O 2 – radicals, which were generated by the collisions of excited electrons and molecular oxygen. Meanwhile, the radically increased ESR peak of O 2 – radicals for the heterogenous materials demonstrated successful release of abundant high-energy electrons. This work could be extended to the design of other robust 1D/2D heterojunction photocatalysts in application to the environmental demands. [ABSTRACT FROM AUTHOR]

In this paper, the biomass carbon quantum dots (CQDs) modified flower-like BiOI (CQDs/BiOI) composite photocatalyst was synthesized by a facile solvothermal method. Compared with the pristine BiOI, the biomass CQDs/BiOI exhibited outstanding photocatalytic activity for degradation of the typical methylene blue (MB) under visible light irradiation since the biomass CQDs could act as electron acceptors to effectively facilitate the separation efficiency of photon-generated carriers and prolong their lifetime. Furthermore, the mechanism detection experiment showed that the and H were major activity species, and the photocatalytic electron transfer mechanism was further investigated. This work provided a new insight into biomass CQDs effects and took an important step toward the development of improving Bi-based semiconductor photocatalyst activity. In this work, biomass carbon quantum dots/bismuth oxyiodide microflower was prepared by a facile solvothermal method, and their high photocatalytic activity was reported. The biomass carbon quantum dots worked as electron acceptors, which can improve the separation efficiency of the photo-generated electrons and holes to promote high photocatalytic activity. [ABSTRACT FROM AUTHOR]

Heterojunction with nano-level interfacial contact has an advantage in improving the transfer capacity of photongenerated carriers. In consequence, a heterojunction composite with nano-level interfacial contact was developed by establishing CdSe/Al 2 TiO 5 heterojunction composites. The heterojunction composite was established by combining Al 2 TiO 5 and CdSe nanocrystals. They provided superior nano-level interfacial contact. The photocatalytic activity of heterojunction composites were illustrated to be significantly improved compared to that of pure Al 2 TiO 5 and CdSe nanocrystals. Moreover, the photocurrent intensity of heterojunction composites displays a several times enhancement, implying the promotion of photocatalytic activity was owned to the nano-level interfacial contact with ideal photogenerated electron-hole pairs transfer behavior. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel CD-BVO/rGH photocatalyst was constructed by coupling Carbon dot-coupled BiVO 4 with rGH. • CD-BVO/rGH display enhanced photocatalytic activity for TCH degradation and CO 2 reduction. • The synergetic effects of CD-BVO and rGH can enhanced the separation of carriers. • Possible photocatalytic reaction mechanism of TCH degradation and CO 2 reduction was presented. In this study, we fabricated a novel hybrid photocatalyst (CD-BVO/rGH) by coupling carbon dot (CD)-decorated BiVO 4 (BVO) with a reduced graphene hydrogel (rGH). The CD-BVO/rGH photocatalyst significantly enhanced the photocatalytic efficiency for tetracycline hydrochloride (TCH) degradation compared with pure BVO and BVO/rGH under simulated solar irradiation. CD-BVO/rGH also showed a substantial performance in the photocatalytic reduction of CO 2. The enhanced photocatalytic activity of CD-BVO/rGH is attributed to synergistic effects, such as better light energy utilization via the upconversion effects of the CDs and the enhanced migration and separation of photoexcited carriers by the three-dimensional (3D) network structure of the rGH. The systematic analysis of the band structure, electron spin resonance, and free radical trapping revealed that h+ and O 2 – mediate the final photocatalytic degradation of pollutants. Our results provide insight into the design and construction of highly efficient hybrid photocatalysts combined with functional carbon nanostructures to enhance the photocatalytic activity for the photodegradation of environmental pollutants and CO 2 reduction. [ABSTRACT FROM AUTHOR]

In this study, we report the construction of a novel composite photocatalyst (BiVO 4 /rGH) composed of quantum dots (QDs) self-decorated BiVO 4 -nanoparticels (NPs) and reduced graphene hydrogel (rGH). The composite structures were prepared using an in-situ growth method. The BiVO 4 /rGH composite photocatalysts exhibited excellent photocatalytic efficiency for the degradation of tetracycline hydrochloride (TC HCl). The promoted photocatalytic activity of the BiVO 4 /rGH is attributed to the synergetic effects of the unique structure involving QDs self-decorated BiVO 4 NPs and a 3D network structure of rGH, which resulted in higher number of photogenerated charge carriers, surplus active sites, and enhanced charge separation. In addition, trapping measurements showed that ·O 2 − and h+, as the main active species, play a crucial role in the degradation of TC HCl over the composite photocatalyst. This study facilitates the design and construction of high efficiency hybrid photocatalysts with multifunctional materials for the removal of water pollutants. [Display omitted] • A novel QDs-BiVO 4 /rGH photocatalyst was constructed by coupling QDs self-decorated BiVO 4 with rGH. • QDs-BiVO 4 /rGH display enhanced photocatalytic activity for TC HCl degradation. • The synergetic effects of QDs-BiVO 4 and rGH can enhanced the separation of carriers. • A possible photocatalytic reaction mechanism of TC HCl degradation was presented. [ABSTRACT FROM AUTHOR]

• The direct Z-Scheme heterojunction improve the utilization efficiency of charge and retain great redox capacity. • ZCS/MOF-199 have excellent activity for photocatalytic hydrogen evolution. • The framework provided by MOF-199 allowed ZCS to expose more active sites. • The composite photocatalysts owned excellent chemical stability. This work reports a simple ultrasonic impregnation method, using MOF-199 as the carrier platform to construct direct Z-Scheme ZnCo 2 S 4 /MOF-199 (ZCS/M) for stable and efficient photocatalytic hydrogen (H 2) evolution. Under simulated sunlight, ZCS/M shows high photocatalytic activity, with H 2 evolution amount of 11.6 mmol·g−1·h−1, which is 48.4 and 83.3 times of MOF-199 and ZCS respectively, and the apparent quantum efficiency (AQY) reaches 4.92 % at 420 nm. The successful construction of direct Z-Scheme heterojunction greatly improves the separation of electron-hole pairs to promote photocatalytic H 2 evolution. In addition, ZCS is evenly anchored on the surface of MOF-199, which effectively solves the problem that ZCS is easy to agglomerate, and exposes more active sites. In-situ XPS, VB, band gap, work function and Fermi level is used to analyze the Fermi level alignment, interfacial built-in electric field and band bending, and photocatalysis mechanism and path of electron migration is speculated. This work provides a new strategy for the design and construction of direct Z-Scheme heterojunction with transition metal sulfide on the platform of MOF to enhance photocatalytic H 2 evolution during water splitting. [ABSTRACT FROM AUTHOR]

A novel biomass carbon quantum dots@Bi2WO6 (BC-QDs@Bi2WO6) photocatalyst with uniform dispersivity was prepared via a dialysis-assisted hydrothermal process. Multiple techniques including HR-TEM, XPS, UV-Vis, PL, photocurrent analysis, and electrochemical impedance spectroscopy were employed to investigate the morphology and structures as well as the optical and electronic properties of the as-prepared samples. The photocatalytic activity of BC-QDs@Bi2WO6 was assessed by the degradation of antibiotics (tetracycline, ciprofloxacin, and gatifloxacin). The improved photocatalytic activity was attributed to the quantum effect of BC-QDs, which acted as the light harvesting center, electron reservoir, and reaction center for degrading the pollutants. Furthermore, a plausible mechanism for photocatalysis was put forward according to the ESR and quenching experiments. The present work can have significant advantages in the construction of biomass carbon-based photocatalysts in pollutant degradation and improved light utilization. [ABSTRACT FROM AUTHOR]

Abstract A direct and facile "bottom-up" approach was carried out to prepare nitrogen doped graphene quantum dots (NGQDs) under hydrothermal conditions. The as-synthesized NGQDs exhibited an excellent excitation-independent upconversion and downconversion photoluminescent (PL) behavior. And further, the NGQDs/BiVO 4 composite photocatalysts were also fabricated to investigate enhanced visible-light photocatalytic performance. The addition of NGQDs in the NGQDs/BiVO 4 could improve the photocatalytic performance, and the results indicated 5.0 wt% NGQDs/BiVO 4 composites showed the optimal photocatalytic performance. The quenching of effects of different scavengers demonstrated that superoxide radical played a major role in MB degradation. A possible mechanism that NGQDs could enhance the photocatalytic performance of NGQDs/BiVO 4 composites had been also proposed. It was estimated that the photocatalytic performance of the NGQDs/BiVO 4 composites for the degradation of MB under visible light could be primarily ascribed to upconversion PL character of NGQDs and the efficient separation of photogenerated electrons and holes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mott Schottky junction is introduced into the traditional Z-scheme heterojunction. • The high conductivity of MXene improves the transport of photogenerated electrons. • Accelerated spatial charge separation and transfer on pCN/TC and TC/Sn-Bi-MOF interfacial Schottky junction. • The photocatalytic products are highly selective for CO production. a simple electrostatic self-assembly method is adopted, in which the Z-scheme heterojunction is directly constructed with Sn-Bi-MOF (SBM) using g-C 3 N 4 (pCN) as the support platform, and the Mott Schottky junction is introduced into the heterojunction (pCN/TC/SBM). This structure not only achieves efficient and stable CO 2 conversion, besides has a high degree of selectivity for CO due to the enhanced electrodynamic migration. Under simulated sunlight, pCN/TC/SBM showed high photocatalytic activity, and the amount of CO produced was 36.33 μmol·g−1·h−1, which was 4.36 and 3.5 times that of pCN and SBM, respectively, and the quantum apparent efficiency (AQY) was 3.2 % at 420 nm. The design method not simply improves the separation of electron-hole pairs, moreover accelerates the electrodynamic migration process, which increases the yield and improves the selectivity for CO. UPS, XPS, VB, DRS, ESR and work functions were used to analyze the Fermi level arrangement and band bending of the catalyst, and the photocatalytic mechanism and electron migration path were speculated. In situ FTIR is used to illustrate the specific path of the reaction. This work provides a new strategy for the design of heterojunctions and the enhancement of the yield and selectivity of carbon dioxide reduction products. [ABSTRACT FROM AUTHOR]

The graphitic carbon nitride (g-C 3 N 4 ), as one photocatalyst which possess the suitable band gap, is better for modified TiO 2 and enhanced photocatalytic degradation of organic pollutants. In this work, the g-C 3 N 4 /TiO 2 were successfully prepared via directly calcined the mixture of melamine and P25. The as-prepared g-C 3 N 4 /TiO 2 photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and high resolution electron microscopy (HRTEM), Raman and Fourier transform-infrared spectroscopy (FT-IR). The photocatalytic performances of g-C 3 N 4 /TiO 2 composites were investigated by degradation of ciprofloxacin. The results showed that the g-C 3 N 4 and P25 were successfully composited, and the bond of C–N was well formed, the calcined temperature for as-prepared photocatalysts and the ratio of melamine and P25 were important to the degradation rate of ciprofloxacin. When the mixture of melamine and P25 with 1:2, and calcined temperature at 600 °C, the degradation rate of ciprofloxacin could reach 95% in 60 min. The enhanced photocatalytic performances could be mainly attributed to the suitable band gap structure with heterojunction of CN-P25. Finally, the possible transferred processes of photoelectrons and photoholes were proposed. [ABSTRACT FROM AUTHOR]

A new-type photocatalyst of cadmium sulfide carbon nanotubes (/CNTs) was prepared by the hydrothermal method. This as-prepared /CNTs composite photocatalyst was proved to exhibit an excellent photocatalytic activity for degradation of tetracycline (TC). Specially, the 95%--5%-CNTs composite photocatalyst played the best degradation rate (81.2%) in 60 min under the visible light irradiation. Moreover, this 95%--5%-CNTs composite photocatalyst possessed great stability and could be used at least four cycles with almost no loss of photocatalytic efficiency. Furthermore, the as-synthesized /CNTs composite photocatalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis diffused reflectance spectra (UV-Vis), Raman and thermal gravimetry (TG). In addition, the possible mechanism and kinetics of photodegradation of TC with /CNTs photocatalyst was also discussed. The mechanism of the photodegradation process on the CdS/CNTs photocatalyst is shown. It can be found that CNTs not only suppress the photogenerated carrier recombination as an electron-transfer and acceptor, but also stabilize CdS in the solution. As the photogenerated electrons undergo such an interfacial electron transfer process, the recombination process of the electrons and holes are hindered, which improves the photocatalytic activity of the CdS Quantum Dots on the tetracycline under the visible light irradiation. [ABSTRACT FROM AUTHOR]

In this paper, coupling MoP onto ZIS surface using solvothermal method to form ohmic heterojunction. The photocatalytic performance of ZIS/MoP is significantly better than that of ZIS and MoP monomers, and the hydrogen evolution efficiency of the composite material reaches 2.031 mmol g−1 h−1, 50 and 18 times the hydrogen production efficiency of MoP and ZIS. The quantum apparent efficiency (AQE) reaches 10.5 %. The improvement of the photocatalytic performance of ZIS/MoP is attributed to the generation of Ohmic heterojunctions. An Ohmic heterojunction is formed when MoP attaches to the surface of ZIS as an electron acceptor, In one aspect, the electron transfer path of Ohmic heterojunctions improves the separation efficiency of electrons and holes, enhances the charge transfer efficiency. ln the other aspect, ZIS greatly improves the visible light absorption of ZIS/MoP. To confirm the photocatalytic mechanism and Ohmic heterojunction structure, characterization methods such as X-ray photoelectron spectroscopy (XPS), ultraviolet electron spectroscopy (UPS), and band structure were used. This study aims to improve photocatalytic performance by designing and constructing ohmic heterojunctions, and provides a new design approach for improving photocatalytic performance. [ABSTRACT FROM AUTHOR]

Building efficient catalysts is an urgent issue in the field of photocatalytic CO 2 reduction, and Z-scheme heterojunction structures can availably suppress the recombination of photo generated carriers and improve photocatalytic performance. This study successfully prepared a new type of Bi 4 O 5 Br 2 /Bi-MOF composite photocatalyst through self-assembly method. After 5 h of simulated sunlight exposure, the optimized sample 50-Bi 4 O 5 Br 2 /Bi-MOF photocatalytic reduction of CO 2 to CO efficiency (23.78 μmol·g−1·h−1) was 5.09 times higher than pure Bi 4 O 5 Br 2 , and the CH 4 yield (5.39 μmol·g−1·h−1) was 2.52 times that of pure Bi-MOF. In addition, in the cyclic experiment, the catalyst had high stability and reusability. The Z-scheme charge transfer mechanism was confirmed through band structure analysis, Electron spin resonance (ESR), Ultraviolet photoelectron spectroscopy (UPS) and other related characterizations. This work provided an important strategy for designing efficient Z-scheme heterojunction photocatalysts. [Display omitted] • Construct Bi 4 O 5 Br 2 /Bi-MOF Z-scheme heterojunction to improve reduction performance. • Bi 4 O 5 Br 2 /Bi-MOF composite photocatalyst exhibits excellent chemical stability. • The reaction intermediates were analyzed using in-situ infrared spectroscopy. • Proving the formation of Z-scheme heterojunction through series characterizations. [ABSTRACT FROM AUTHOR]

In this work, ZnSe/ZnCo 2 S 4 (ZCS) composites were synthesized by simple hydrothermal method and Z-scheme heterojunctions were formed. Under the simulated sunlight environment, The results show that the hydrogen production efficiency of 70 wt% ZnSe/ZCS composites was as high as 3402.4 μmol·g−1·h−1, which is 4.37 and 94.44 times that of ZnSe and ZCS monomers, respectively, and the apparent quantum efficiency (AQY) reaches 10.5%. Among them, the Z-scheme heterojunction improves the redox ability of the material, which is more conducive to charge separation, and ZCS also promotes absorption of visible light of ZnSe/ZCS. In addition, the Z-scheme heterojunction structure and material stability were verified by XPS, ESR.This work provides a new way to improve ZnSe in the field of photocatalytic hydrogen evolution. [Display omitted] • The Z-scheme heterojunction improve the utilization efficiency of charge and retain great redox capacity. • ZnSe/ZCS have excellent activity for photocatalytic hydrogen evolution. • The framework provided by ZCS allowed ZnSe to expose more active sites. • The composite photocatalysts owned excellent chemical stability. [ABSTRACT FROM AUTHOR]

The midgap states and amino groups resulted from bulk phase N defects and surface C defects synergistically catalyze the photocatalytic reduction of CO 2 to hydrocarbon fuels. Defect structure is one of the crucial factors for enhancing the catalytic activities of photocatalysts. However, rational design and construction of defect structures in catalysts to meet the aim of enhancing photocatalytic performance in a simple and cost-effective way is still a challenge. In this contribution, we report a strategy to construct defect structures in graphitic carbon nitride (g-CN) by simple copolymerizing of urea with polyethyleneimine (PEI). Among the prepared catalysts, u-0.05PEI presents the best photocatalytic activity for CO 2 reduction, with CO and CH 4 yields of 32.86 and 1.68 μmol g−1 in 4 h, which is about 3.2 and 2.5 times higher than that of g-CN, respectively. Characterization results show that both C and N defects are formed in the newly prepared catalysts. The C defects on the surface of u-xPEI result in the formation of more amino groups which are beneficial for CO 2 adsorption. Meanwhile, the N defects inside the samples lead to the generation of midgap states between the valance band and conduction band of u-xPEI. The midgap states greatly enlarge the light absorption extent, and enable the use of light with energy lower than the intrinsic absorption of g-CN in the photoreduction of CO 2. As confirmed by DRS, EPR, PL analysis, the excellent catalytic activity of u-0.05PEI is mainly attributed to the remarkably improved light utilization efficiency and fast charge transfer. Moreover, the reaction is performed in water without any additive or organic solvent, which makes it environmentally friendly. [ABSTRACT FROM AUTHOR]

Abstract In this work, a simple method to load of g-C 3 N 4 quantum dots (CN QDs) onto Bi 2 Ti 2 O 7 (BTO) microsphere with the amount of CN QDs (3, 7, 10 and 15%). The photocatalyst was used for the treatment of water pollutants under visible-light illumination, which proved that CNBTO composites showed improved photocatalytic activity matched up to pure BTO. Reformation of BTO with CN QDs enhanced the light assimilation capacity, and promoted the isolation of photo-induced electron-hole pairs. The trapping experiments and ESR were announced the holes (h+) and superoxide oxide (O 2 −) played the key role, and the relative mechanism of the photocatalytic process was proposed. Meanwhile, the effects of CN QDs content, pH and initial pollutant concentration on the removal efficiency of ciprofloxacin (CIP) were studied. Results showed that the CN QDs loaded on BTO presented higher photocatalytic efficiency, and an optimum value for the dosage of photocatalytic in pH 8.0. Graphical Abstract The g-C 3 N 4 quantum dots modified Bi 2 Ti 2 O 7 microsphere for enhancing separation efficiency of electron-hole pairs. Unlabelled Image Highlights • The CN QDs have superior electron transfer ability and enriched light harvesting. • The CN QDs were coupled with Bi 2 Ti 2 O 7 microsphere have exhibited enhanced photocatalytic activity. • The CN QDs extends the light absorption of Bi 2 Ti 2 O 7 microsphere. [ABSTRACT FROM AUTHOR]

The construction of a heterojunction is an effective way to improve the photocatalytic activity of a semiconductor. In this study, to improve the photocatalytic activity of BiPO4 in visible light and the quantum yield of In2S3, a novel In2S3/BiPO4 heterojunction photocatalyst was successfully synthesized via a solvothermal method. XRD and TEM characterizations reveal that In2S3 was irregularly loaded on the surface of BiPO4, leading to good dispersion of In2S3, greatly improving the catalyst active site. Meanwhile, In2S3 also greatly improves the visible light absorption of BiPO4. An ESR spin-trap technique and trapping experiments on active species indicate that ṖO2− and h+ are the main activated species during the photodegradation process. Finally, the as-obtained In2S3/BiPO4 heterojunction exhibits higher photocatalytic activity than those of pure In2S3 and BiPO4 for the photodegradation of rhodamine B (RhB) and tetracycline (TC). This work provides a promising way to photodegrade organic materials to reduce water pollution. [ABSTRACT FROM AUTHOR]

A novel Z-scheme CdS/Ag/g-C3N4 nanosheets photocatalyst was synthesized by combining the hydrothermal and photo-deposition techniques, where Ag nanoparticles as carrier transport channels significantly improve the separation efficiency of electron–hole pairs. Outstanding photocatalytic activity was observed, which indicates that the constructed Z-scheme can retain the oxidizing ability of the CdS valence band and reducing ability of the g-C3N4 conduction band. In addition, trapping experiments and ESR measurement reveal that the superoxide radical (ṖO2−) and holes (h+) are the predominant active species. This study provides a new approach to perfect the Z-scheme photocatalytic system for application in the efficient treatment of persistent pollutants in wastewater. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) CdSe exhibits relatively high photocatalytic abilities for its unique properties, but the aggregation and photocorrosion have blocked its further application. Therefore, for arriving at a solution, alkaline earth metal ions (M = Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ ) and reduced graphene oxide (rGO) are chosen to fabricated new QDs CdSe-based photocatalytic systems. In this paper, M@CdSe/rGO composites have been synthesized via a facile one-step hydrothermal approach, during which the formation of M doped CdSe crystallization and GO reduction occur simultaneously. The obtained photocatalysts demonstrates synergistically enhanced visible light photocatalytic activity and stability toward photodegrading tetracycline hydrochloride (TC-HCl) solution, especially the introduction of 6 mol% Ca 2+ and 5 wt% GO on QDs CdSe resulted in 85.6% degradation of 15 mg/L TC-HCl in 1 h with 0.5 g/L catalyst. Furthermore, the photodegradation mechanism was systematically investigated by active species trapping experiment. It revealed that h + was the major active species in the destructions process. And the possible process of charge transfer for Ca 2+ @CdSe/rGO nanocomposite was proposed based on the experimental results. [ABSTRACT FROM AUTHOR]

Recyclable flower-like MoS 2 @Fe 3 O 4 @Cu 2 O like-Z-scheme heterojunction based on magnetic assembly method exhibits efficient visible light catalytic ability. [Display omitted] • Flower-like MoS 2 @Fe 3 O 4 @Cu 2 O is obtained by magnetic self-assembly method. • The assembly of 2D into 3D structure is promoted by the mutual attraction between Fe 3 O 4. • The growth of Cu 2 O nanoparticles is limited by the flower-like structure. • Like-Z-scheme heterojunction is formed to improve the photocatalytic performance. In this work, the recyclable flower-like MoS 2 @Fe 3 O 4 @Cu 2 O like-Z-scheme heterojunction (MFC) was synthesized by magnetic assembly method, which not only exhibited excellent magnetic separation performance, but also possessed efficient visible light catalytic ability. Interestingly, the existence of Fe 3 O 4 not only endowed the material good recyclability, but also promoted the formation of like-Z-scheme heterojunction and improved the charge separation efficiency. More importantly, the assembly of MoS 2 (M) nanosheets into the flower-like structure was promoted by the mutual magnetic attraction between Fe 3 O 4 nanoparticles, and the growth of Cu 2 O nanoparticles was limited by the flower-like structure. Based on the improvement of charge separation efficiency and the formation of like-Z-scheme heterojunction, the photocatalytic efficiency of MFC was 3.5, 1.75 and 2.5 times that of MoS 2 (M), MoS 2 @Fe 3 O 4 (MF) and MoS 2 @Cu 2 O (MC), respectively. This work provided a new method for the assembly and design of highly active composite materials. [ABSTRACT FROM AUTHOR]

Fabricating 2D CN and COF based all organic van der Waals heterojunction catalyst for efficient transformation of CO 2 to hydrocarbon fuels. • 2D CN and COF based all organic heterojunction catalyst 2D CN-COF was successfully prepared. • The heterojunction arose from the interface van der Waals interaction between 2D CN and COF-TD. • The photoelectrical properties of 2D CN-COF was significantly enhanced due to the formation of heterojunction. • The CO evolution rate over 2D CN-COF is 9.2 times and 3.3 times higher than that of 2D CN and COF-TD, respectively. • The reaction was performed in the absence of any solvent and sacrificial agent. Two dimensional carbon nitride (2D CN) has attracted extensive attention due to its potential application in the field of photocatalysis. However, the poor electron-hole separation efficiency and low charge carrier migration speed confine the photocatalytic performance of 2D CN. In this work all organic van der Waals heterojunction (vdWH) catalyst (2D CN-COF) was prepared from 2D CN and triazine-based covalent organic framework (COF-TD) to efficiently enhance the catalytic activity of 2D CN. Characterization and simulation results verified the successful preparation of the catalyst. The heterojunction was originated from the intense interface van der Waals force interaction between the molecules of 2D CN and COF-TD. Furthermore, the intense π-π interaction between 2D CN and COF-TD led to the morphology transformation of COF-TD from sphere of isolated sample to elliptic sheet in 2D CN-COF. The intimate interface contact of vdWH has led to reduce bandgap, which remarkably enlarged the visible light responding region of the samples. Meanwhile, the charge carrier recombination was significantly reduced because of the formation of vdWH. The evolution rate of CO over 2D CN-COF was 9.2 times and 3.3 times higher than that of 2D CN and COF-TD, respectively. Moreover, the reaction was performed in the absence of any solvent and sacrificial agent, matching well with the idea of sustainable development. This work not only provides a new and simple strategy to fabricate 2D CN based all organic heterojunction catalyst for efficient photoreduction of CO 2 to CO and CH 4 , but also serves as a reference for other researchers to design organic heterojunction, which is based on 2D CN and COFs. [ABSTRACT FROM AUTHOR]

Synthesis of carbon nitride based catalysts containing donor-acceptor systems for photocatalytic reduction of CO 2 to CO. • Carbon nitride with donor-acceptor (D-A) systems was fabricated by C and O co-doping. • The D-A systems optimize the optical absorption and bandgap structures of carbon nitride. • The spatial separation of charge in D-A systems enhances the charge separation efficiency. • The catalyst displayed efficient CO 2 photoreduction activity and catalytic durability. Photocatalytic reduction of CO 2 to hydrocarbon fuels is an ultimate and utmost strategy to resolve the ever-increasing environmental problems and energy crisis. Our study aimed to develop a specific type of photocatalysts with increasing light utilization efficiency, reducing electron-hole recombination rate and enhancing photocatalytic activity by integrating unique donor-acceptor systems into the polymeric network of graphitic carbon nitride (g-CN). The results of the characterization showed that C and O are successfully integrated into the framework of g-CN. The O-containing and C-containing section of the as-prepared catalysts (OCCNx) play the role of donor and acceptor, respectively. The donor-acceptor systems of OCCN x offer an extra electron transfer transition mode, which dramatically extends the optical absorption range, and narrows down the bandgap of g-CN from 2.74 to 2.03 eV. Also, the donor-acceptor systems significantly improve the delocalized ability of the photoinduced charge carriers, which efficiently prolongs the lifetime of the charge carriers and reduces the electron-hole recombination rate, as all of these are all beneficial for boosting the photocatalytic activity of the catalysts. Experimental results show that OCCN 0.25 displays the best photocatalytic CO 2 reduction performance with a CO production rate of 34.97 μmol g−1 in 4 h, which is 4.3-fold higher than that obtained in the case of bulk g-CN. Moreover, the reaction is performed in water without any co-catalyst and sacrificial agent, which makes it a green and environmentally friendly reaction. Results obtained from DFT simulation agree well with the empirical results, and a possible reaction mechanism is suggested based on these calculations. [ABSTRACT FROM AUTHOR]

Exploring semiconductor-based photocatalysis toward reaching solar energy conversion was an ideal strategy. Here, Ni(OH) 2 was used an effective co-catalyst instead of noble metal to construct a novel two dimensional 2D/2D Ni(OH) 2 /Bi 4 Ti 3 O 12 composites with interfacial interaction between Ni(OH) 2 and Bi 4 Ti 3 O 12. The layer Ni(OH) 2 /Bi 4 Ti 3 O 12 composites showed higher photocatalytic activity as compared to pure samples, which was attributed to the interfacial interaction to promote the electron-holes separation. Thus, this work provided a novel insight into design 2D/2D nanocomposites and proved Ni(OH) 2 could excellently act as the effective co-catalyst instead of noble metal to enhance photocatalytic activity. • An efficient co-catalyst of Ni(OH) 2 instead of noble metal to modify Bi 4 Ti 3 O 12. • A new 2D/2D layer-like Ni(OH) 2 /Bi 4 Ti 3 O 12 composites were constructed. • The interfacial interaction and 2D coupling interfaces, promoting the electron-holes separation. [ABSTRACT FROM AUTHOR]