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A novel 2D/2D g-C3N4/BiOCl (CN/BOC) heterojunction photocatalyst was synthesized by grinding appropriate amounts of CN, Bi(NO3)3·5H2O, glacial acetic acid and KCl at room temperature. The porous CN nanosheets not only facilitate the in situ nucleation and growth of BOC to form thin nanosheets and constitute an intimate contact interface, but also introduce more oxygen vacancies (OVs) in the grinding process. The 2D/2D CN/BOC heterojunction had a good interface and generates a built-in electric field, which can improve the separation of e− and h+. The synergistic effect of the heterostructure and OVs made the photocatalyst have significantly better performance than CN and BOC alone under visible light. The most efficient CN/BOC-5 could achieve a tetracycline (TC) degradation rate of 89.8% within 2 h, which was 1.9 and 1.2 times faster than CN and BOC, respectively. It catalyzed the reduction of CO2 to CO at a rate of 2.00 μ mol h−1 g−1, 1.1 and 3.2 times faster than CN and BOC, respectively. The mechanism for the photocatalysis of CN/BOC-5 was revealed. It was confirmed that the efficiency of photo-induced carrier separation and visible-light photo-absorption were both considerably increased by the synergistic interaction between OVs and 2D/2D heterojunction. This research may open up new possibilities for the logical design of efficient photocatalysts through combining 2D/2D heterojunctions with OVs for environmental remediation. Highlights: •Grinding synthesis of 2D/2D BiOCl/g-C3N4 heterostructure with oxygen vacancies (OVs). •The synergistic effect of heterostructure and OVs enabled excellent photoactivity. •Efficient photocatalytic degradation of organic pollutants and reduction of CO2. [ABSTRACT FROM AUTHOR]

The establishment of green and environmental friendly sunlight‐driven organic reactions has received increasing attention since the 21st century. By virtue of their functional designability, micromesoporous structure, and thermal/chemical stability, porous organic polymers (POPs) have exhibited enormous promise in photocatalytic organic reactions as ideal potential alternatives to conventional small molecule and inorganic semiconductor catalysts. In particular, amorphous POPs are simplified in terms of preparation conditions and process flow. Herein, various amorphous POP materials based on polymers of intrinsic microporosity, hypercrosslinked polymers, conjugated microporous polymers, and porous aromatic frameworks are reviewed, while typical synthetic strategies are briefly introduced. It also highlights an overview of the research progress in photocatalytic oxidation, coupling, reduction, cycloaddition, and polymerization reactions at home and abroad in recent years. Finally, the challenges and prospects for future research on amorphous POPs are presented. [ABSTRACT FROM AUTHOR]

Excessive use of fossil fuels leads to energy shortages and environmental pollution, threatening human health and social development. As a clean, green, and sustainable technology, generation of renewable energy from solar light through photocatalysis has received increasing attention to cope with the impending energy and environmental crisis. The atomically thin two-dimensional (2D) semiconductors with large surface area and abundant low-coordinate surface atoms prove to exhibit enormous potential to attain efficient photocatalytic performance. These 2D ultrathin materials can shorten the transport distance of charge carriers from the interior to the surface, enhance reactants' (e.g. CO2 and H2O) adsorption and activation to lower the energy barrier, promote specific reaction processes and inhibit competitive reactions, and regulate the efficiency and selectivity of the catalytic reaction. This Feature article provides a concise overview of the preparation, catalytic mechanism, strategies for boosting the photoconversion performance, various photocatalytic applications, and characterization techniques of atomically thin 2D semiconductors. The major challenges and opportunities of the ultrathin photocatalysts are also addressed. It is hoped that this review can provide useful guidelines toward further research on 2D nanocatalysts, and inspire practical applications of these unique materials for energy conversion. [ABSTRACT FROM AUTHOR]

Effective enhancement of the separation and transfer of photogenerated electrons and holes of semiconductor photocatalysts is key to increase their photocatalytic efficiency. This study aims at improving the photocatalytic performance of visible-light-responsive, CdI 2 -type layered SnS 2 by employing good conductivity N-doped reduced graphene oxide (NRG) and polyaniline (PANI) as the receptors and transporters of photogenerated electrons and holes, respectively. PANI/SnS 2 /NRG ternary composites were prepared by a three-step method, and the optimum conditions for preparing the most efficient product were explored. The photocatalytic experiments demonstrated that the PANI/SnS 2 /NRG ternary composite prepared under the optimum conditions (PANI/SnS 2 /NRG-2%) had markedly higher photocatalytic activity than SnS 2 nanoplates, SnS 2 /PANI and SnS 2 /NRG binary composites in the reduction of aqueous Cr(VI) under the irradiation of visible-light (λ > 420 nm). Based on comparison of the photoabsorption, photoluminescence and electrochemical impedance properties of PANI/SnS 2 /NRG, SnS 2 /PANI and SnS 2 , it was thought that the coupling of SnS 2 with both PANI and NRG had synergistic effects in increasing the absorption of visible-light as well as the separation and transfer of photogenerated electrons and holes, which contributed to the exceptionally high photocatalytic activity of PANI/SnS 2 /NRG ternary composite. Moreover, it was discovered that the photocatalytic reduction of Cr(VI) over PANI/SnS 2 /NRG-2% was dominantly through the reduction by photogenerated electrons, whereas both photogenerated electron and superoxide anion radical (O 2 – ) reduction played important roles in the photocatalytic reduction of Cr(VI) over SnS 2 . Besides, the influences of photocatalytic testing conditions (including starting pH and concentration of Cr(VI) solution, and dosage of photocatalyst) on the efficiency of PANI/SnS 2 /NRG-2% in treatment of aqueous Cr(VI) were also examined. [ABSTRACT FROM AUTHOR]

This communication reports a pioneering study on the synthesis and properties of CeO 2 /SnS 2 composite. CeO 2 /SnS 2 heterojunction was synthesized via the hydrothermal reactions of SnCl 4 ·5H 2 O and thioacetamide in the presence of CeO 2 nanoparticles at 170 °C for 12 h. The composition, structure, and optical properties of the as-synthesized CeO 2 /SnS 2 heterojunction were characterized by X-ray diffraction, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectra and photoluminescence spectra. The photocatalytic properties of the as-synthesized CeO 2 /SnS 2 heterojunction were evaluated in the reduction of aqueous Cr(VI) under visible-light (λ > 420 nm) irradiation, and compared with those of SnS 2 , CeO 2 , and CeO 2 /SnS 2 nanocomposite prepared by physical mixing method (CeO 2 /SnS 2 -PM). The results demonstrated that the as-synthesized CeO 2 /SnS 2 heterojunction had exceptionally higher visible-light-driven photocatalytic activity than SnS 2 , CeO 2 , and CeO 2 /SnS 2 -PM. The possible reasons underlying the photocatalytic results were proposed. [ABSTRACT FROM AUTHOR]

This work reports the development of a new efficient visible-light-driven composite photocatalyst comprising SnS 2 nanoflakes and conjugated polymer (CPVC) from the dehydrochlorination of polyvinyl chloride (PVC). The optimum synthesis conditions were explored to obtain the most efficient SnS 2 /CPVC composite photocatalyst. The formation of SnS 2 /CPVC nanocomposites was confirmed by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, high-resolution transmission electron microscopy, and elemental mapping characterization. The photocatalytic tests demonstrated that SnS 2 /CPVC nanocomposites exhibited not only far higher visible-light-driven photocatalytic activity than SnS 2 nanoflakes, but also good photocatalytic stability and reusability in the reduction of aqueous Cr(VI) under visible-light ( λ > 420 nm) irradiation. The mechanism underlying the improved photocatalytic efficiency of SnS 2 /CPVC nanocomposites was elucidated, based on comparison between the optical, photoelectric, and electrochemical properties of SnS 2 /CPVC nanocomposites and SnS 2 nanoflakes, as well as the matched electronic band structures between SnS 2 and CPVC. [ABSTRACT FROM AUTHOR]

A novel Z-scheme CdWO 4 /ZnFe 2 O 4 photocatalyst is successfully constructed adopting isoelectric point method, and is introduced into integrated microwave-ultraviolet (MW-UV) system for the degradation of tetracycline antibiotics in aqueous solution. The influences of particle ratio (CdWO 4 : ZnFe 2 O 4), irradiation time, MW power, initial concentration, catalyst dosage and reuse times on the degradation in the CdWO 4 /ZnFe 2 O 4 /MW-UV system are examined. The possible mechanism of Z-scheme CdWO 4 /ZnFe 2 O 4 microwave-photo catalytic degradation is proposed. The results indicate the Z-scheme CdWO 4 /ZnFe 2 O 4 photocatalyst possesses superior dual responsive catalytic activity in integrated MW-UV system. In particular, the production of MW plasma promotes the isolation of the photogenerated carriers, improving the redox capability of the catalytic system. The Z-scheme CdWO 4 /ZnFe 2 O 4 at 1.0:8.0 particle ratios displays optimal dual responsive catalytic activity. Magnetic Z-scheme CdWO 4 /ZnFe 2 O 4 retains high dual responsive catalytic activity after 5 cycles. Besides, •OH plays a dominant role in the degradation of CdWO 4 /ZnFe 2 O 4 /MW-UV catalytic system. Hence, the dual responsive Z-scheme CdWO 4 /ZnFe 2 O 4 /MW-UV approach has great potential in treating those water and wastewater with various concentrations of antibiotic. [Display omitted] • Z-scheme CdWO 4 /ZnFe 2 O 4 photocatalyst is constructed using isoelectric point method. • CdWO 4 /ZnFe 2 O 4 is introduced into integrated MW-UV system for degradation. • CdWO 4 /ZnFe 2 O 4 achieves superior dual responsive catalytic activity using MW-UV. • Production of MW plasma accelerates e - transfer and separation of e - - h + pairs. • Z-scheme CdWO 4 /ZnFe 2 O 4 can be segregated from water by external magnetism. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nonmetals-modified SnO2 was synthesized by a HNO3-involved solvothermal method. [•] High specific surface area and excellent visible-light-absorbing ability. [•] High photocatalytic activity in the reduction of aqueous Cr(VI) under visible-light. [•] Photocatalyst dosage and Cr(VI) concentration affect the reduction rate of Cr(VI). [ABSTRACT FROM AUTHOR]

• Zr-SnS 2 /PANI nanocomposites were synthesized and optimized for photocatalysis. • Higher activity than SnS 2 , Zr-SnS 2 , SnS 2 /PANI, and many other photocatalysts. • Zr4+ doping and PANI coupling synergistically enhanced the photocatalysis of SnS 2. • Factors affecting the photocatalytic reduction of Cr (VI) were investigated. • Zr-SnS 2 /PANI can effectively treat the Cr (VI)-containing electroplating solution. The synergistic Zr4+ doping and PANI coupling were used to improve the photocatalytic activity of SnS 2 nanoflakes for the treatment of aqueous Cr (VI). The Zr-SnS 2 /PANI photocatalyst was prepared by a facile two-step method. The optimal Zr-SnS 2 /PANI-6% (with the Zr/Sn molar ratio of 1:8 and the PANI content of 6 wt%) exhibited dramatically higher photocatalytic activity toward Cr (VI) reduction than SnS 2 , Zr-SnS 2 , SnS 2 /PANI, and many previously reported SnS 2 -based and PANI-containing visible-light photocatalysts. Moreover, Zr-SnS 2 /PANI-6% showed outstanding performance in the photocatalytic treatment of Cr (VI)-containing electroplating solution. Based on the measured photo-electrochemical properties of the samples, the increased photocatalytic efficiency of Zr-SnS 2 /PANI-6% was mainly due to the synergistic effect induced by the smaller bandgap, higher charge transfer efficiency, and lower electron-hole recombination rate. Furthermore, the effects of coexisting cations and anions, photocatalyst amount, initial pH, Cr (VI) concentration, environmental atmosphere, and co-presence of 1,4-benzoquinone or K 2 S 2 O 8 on photocatalytic Cr (VI) reduction over Zr-SnS 2 /PANI-6% were investigated. [ABSTRACT FROM AUTHOR]

In this study, type-II heterojunction WO 3 /BaTiO 3 and Z-scheme WO 3 /SrTiO 3 or WO 3 /Ba 0.5 Sr 0.5 TiO 3 nanocomposite photocatalysts were constructed for photodegradation of organic pollutants in wastewater under visible light. The photocatalytic performance of three WO 3 /titanate systems were estimated. Some influencing factors such as molar ratio of WO 3 and titanates, light irradiation time, catalyst dose, and initial concentration of organic pollutants on the photocatalytic activity were investigated. The stability and reusability of three WO 3 /titanates systems were examined. Moreover, the production of some radicals in the three WO 3 /titanates photocatalytic systems was demonstrated, and the three WO 3 /titanates photocatalytic reaction mechanisms were compared. The results reveal that the configurations of WO 3 /titanates photocatalytic systems are transformed from type-II heterojunction WO 3 /BaTiO 3 with lower activity to Z-scheme WO 3 /SrTiO 3 and WO 3 /Ba 0.5 Sr 0.5 TiO 3 with higher activity via the change of titanates. The WO 3 /titanate nanocomposites show higher photocatalytic activity at 3.0:1.0 M ratio of WO 3 and titanates, and WO 3 /Ba 0.5 Sr 0.5 TiO 3 nanoparticles have superior photocatalytic activity. The order of photocatalytic activity is as follows: WO 3 /Ba 0.5 Sr 0.5 TiO 3 > WO 3 /SrTiO 3 > WO 3 /BaTiO 3. Several organic pollutants, such as rhodamine B, methyl parathion, direct brilliant yellow-4R, and methylene blue, can be efficiently degraded using WO 3 /Ba 0.5 Sr 0.5 TiO 3 under visible light, and the RhB has higher degradation rate. After four cycles, WO 3 /titanate nanocomposites still have relatively high stability and reusability. •OH plays a major role in three WO 3 /titanates photocatalytic degradation. It is expected that the Z-scheme WO 3 /Ba 0.5 Sr 0.5 TiO 3 photocatalytic technology creates a good foreground for disposing of dyes and pesticides in water and wastewater. [ABSTRACT FROM AUTHOR]

• CPVC/SnS 2 /TiO 2 ternary photocatalyst was synthesized and characterized. • CPVC/SnS 2 /TiO 2 had much increased visible light photocatalytic activity. • CPVC/SnS 2 /TiO 2 had certain photocatalytic stability. • The synergistic effects of the three components lead to the improved photocatalysis. Synthesis of heterojunctions is very effective in increasing the photocatalytic activity of photocatalysts. Considering conjugated polyvinyl chloride derivative (CPVC) is capable of constituting heterojunctions with both SnS 2 and TiO 2 , this study used CPVC to modify SnS 2 /TiO 2 composite to develop a new high-efficiency visible light-driven ternary photocatalyst (CPVC/SnS 2 /TiO 2). CPVC/SnS 2 /TiO 2 was synthesized by a convenient and practical method, and its composition and structure were characterized using many means. The photocatalytic tests manifested that CPVC/SnS 2 /TiO 2 not only had higher activity than TiO 2 /SnS 2 and SnS 2 in photocatalytic reduction of aqueous Cr(VI), but also was efficient in photocatalytic degradation of methylene blue under visible light irradiation. Besides, the effect of the dosage of CPVC/SnS 2 /TiO 2 on its photocatalytic reduction of Cr(VI) was investigated. Also, the photocatalytic improvement mechanism of CPVC/SnS 2 /TiO 2 was put forward, based on the results of the electrochemical impedance, transient photocurrent response and energy band structure measurements. [ABSTRACT FROM AUTHOR]

• The ZnO@ZnS@Ag heterostructures were synthesized via twice in-situ ion exchange. • NRCA was used as both a protective agent and a reducing agent. • Ag NPs were dispersed successfully on ZnO@ZnS surface with the assistance of NRCA. • The roughness of the sample surface increased due to the uniform loading with Ag0. • The ZnO@ZnS@Ag heterostructures exhibited prominent photocatalytic performance. A novel flower-like nonylresorcinol calix[4]arene (NRCA)-coated ZnO@ZnS@Ag core@shell heterostuctures were fabricated via in-situ ion exchange approach by controlling the addition order of the reagents. The synthesis of ZnO@ZnS attached with metallic Ag via twice ion exchange method combined with in-situ reduction has not been previously reported. The synthesized samples had higher absorption in the visible light region. The roughness of the surface increased due to the uniform distribution of ion exchange-synthesized silver nanoparticles on the surface of the samples. Meanwhile, the photocatalytic ability of the NRCA-coated ZnO@ZnS@Ag core@shell heterostuctures improved for the degradation of rhodamine B (RhB). Notably, the heterostucture sample containing 8.34 mol% Ag (denoted as ZA3) exhibited good stability. Improvements in the degradation performance could be ascribed to the enhanced charge separation in the type II ZnO@ZnS heterostructure with Ag0. [ABSTRACT FROM AUTHOR]

Nb5+ doped α-Fe 2 O 3 (Nb-Fe 2 O 3) nanorods with different Nb5+ contents were prepared using a low-temperature, short-time, one-pot hydrothermal method. All the prepared Nb-Fe 2 O 3 products showed better photocatalytic activities than α-Fe 2 O 3 nanorods in the reduction of aqueous Cr(VI) under visible light (wavelength > 420 nm). 4% Nb-Fe 2 O 3 had the maximum photocatalytic activity, which was 2.24 times that of α-Fe 2 O 3 nanorods and surpassed those of many newly reported visible light photocatalysts. Moreover, the photocatalytic efficiency of 4% Nb-Fe 2 O 3 can be further improved by proper increasing its dosage, decreasing the initial pH and Cr(VI) concentration of K 2 Cr 2 O 7 solution. Furthermore, 4% Nb-Fe 2 O 3 showed rather good photocatalytic stability and reusability. Besides, 4% Nb-Fe 2 O 3 was efficient in visible light-driven photocatalytic reduction of Cr(VI) in diluted black chrome plating solution. Nb5+ - doping can efficaciously enhance the abilities of α-Fe 2 O 3 in absorbing visible light and transferring and separating photogenerated carriers, thereby contributing to the elevated photocatalytic activity of Nb-Fe 2 O 3. [Display omitted] • Hydrothermal synthesis of Nb5+-doped α-Fe 2 O 3 (Nb-Fe 2 O 3) nanorods at 448 K for 2 h. • 4% Nb-Fe 2 O 3 is the optimized product with maximum photocatalytic activity. • 4% Nb-Fe 2 O 3 has a visible light photocatalytic activity 2.24 times that of α-Fe 2 O 3. • 4% Nb-Fe 2 O 3 can efficiently treat Cr(VI) in diluted black chrome plating solution. • Nb-Fe 2 O 3 has enhanced light absorption and electron-hole separation and transfer. [ABSTRACT FROM AUTHOR]

Bi 2 O 2 CO 3 (BOC)/Bi 4 O 5 Br 2 (BOB)/reduced graphene oxide (rGO) Z-scheme heterojunction with promising photocatalytic properties was synthesized via a facile one-pot room-temperature method. Ultra-thin nanosheets of BOC and BOB were grown in situ on rGO. The formed 2D/2D direct Z-scheme heterojunction of BOC/BOB with oxygen vacancies (OVs) effectively leads to lower negative electron reduction potential of BOB as well as higher positive hole oxidation potential of BOC, showing improved reduction/oxidation ability. Particularly, rGO is an acceptor of the electrons from the conduction band of BOC. Its dual roles significantly improve the transfer performance of photo-induced charge carriers and accelerate their separation. With layered nanosheet structure, rich OVs, high specific surface area, and increased utilization efficiency of visible light, the multiple synergistic effects of BOC/BOB/rGO can achieve effective generation and separation of the electron-holes, thereby generating more •O 2 − and h+. The photocatalytic reduction efficiency of CO 2 to CO (12.91 µmol/(g·hr)) is three times higher than that of BOC (4.18 µmol/(g·hr)). Moreover, it also achieved almost 100% removal of Rhodamine B and cyanobacterial cells within 2 hours. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI) was adopted to modify SnO 2 nanoparticles for developing a promising high efficiency visible light-driven photocatalyst for the treatment of Cr(VI)-polluted wastewaters. PANI modified SnO 2 nanoparticles (SnO 2 /PANI nanocomposites) were synthesized via the following procedures: (i) SnO 2 nanoparticles were synthesized by hydrothermal treatment of SnCl 4 ·5H 2 O in deionized water at 200 °C for 15 h; and (ii) adsorption of PANI in N,N-Dimethylformamide solution by SnO 2 nanoparticles, then evaporation of N,N-Dimethylformamide. The compositions, structures, optical and photoelectrochemical properties of SnO 2 /PANI nanocomposites were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, high resolution transmission electron microscopy, UV–vis diffuse reflectance spectra, photocurrents measurements and electrochemical impedance spectra. The photocatalytic tests showed that SnO 2 /PANI nanocomposites had far higher photocatalytic activity than SnO 2 nanoparticles in the reduction of aqueous Cr(VI) under visible light (λ > 420 nm) irradiation (for example, the reaction rate constant for photocatalytic reduction of Cr(VI) by the most efficient SnO 2 /PANI-3% was about 23 times that by SnO 2 ). Besides, the effects of photocatalytic experiment parameters (including dosage of photocatalyst, initial concentration and pH of Cr(VI) aqueous solution, and coexistent anions and cations) on the Cr(VI) removal rate by SnO 2 /PANI-3% were also investigated. [ABSTRACT FROM AUTHOR]

Conjugated derivative (CPVC) from thermal dehydrochlorination of polyvinyl chloride (PVC) was tried to modify SnO 2 nanoparticles for developing a high efficiency visible-light-activated photocatalyst for the treatment of Cr(VI) wastewaters. CPVC modified SnO 2 nanoparticles (SnO 2 /CPVC) were synthesized via the following procedures: (i) mixing of SnO 2 nanoparticles and PVC in tetrahydrofuran solution, then evaporation of tetrahydrofuran to produce SnO 2 /PVC nanocomposite, and (ii) thermal treatment of the SnO 2 /PVC nanocomposite at 150 °C for 2 h to transform its PVC into conjugated CPVC. The as-synthesized products were characterized using X-ray diffraction, Raman spectroscopy, high resolution transmission electron microscopy, UV–vis diffuse reflectance spectra, transient photocurrent measurement, and electrochemical impedance spectroscopy. The photocatalytic tests indicated that SnO 2 /CPVC nanocomposite had exceptionally higher (about 14 times) photocatalytic activity than SnO 2 nanoparticles in the reduction of aqueous Cr(VI) under visible-light (λ > 420 nm) irradiation. This work is the first report of SnO 2 /CPVC as photocatalyst for the reduction of Cr(VI), and also useful for developing new efficient visible-light-activated photocatalysts using low cost polyvinyl chloride. [ABSTRACT FROM AUTHOR]

Nanosheets-constructed porous flower-like hierarchical nanostructure SnS 2 (which was labeled as F-SnS 2 ) was synthesized by heating the mixture of SnCl 2 ·2H 2 O and thiourea in air at 170 °C for 2 h, in combination with a subsequent washing with water. F-SnS 2 exhibited much more adsorption and faster visible-light (wavelength >420 nm)-irradiated photocatalytic reduction of aqueous Cr(VI), as compared with SnS 2 nanoparticles, nanoplates-assembled flowerlike hierarchical structure SnS 2 synthesized by hydrothermal method, Fe, N and C tri-doped TiO 2 , and hydrothermally treated g-C 3 N 4 . The underlying reasons for the far superior performance of F-SnS 2 were proposed, based on the comparison of the microstructure, specific surface area, optical, electrochemical impedance, photocurrent, surface charge, and Cr(VI) adsorption properties of F-SnS 2 and SnS 2 nanoparticles. Besides, the photocatalytic reusability and stability of F-SnS 2 , as well as the effects of photocatalytic testing parameters (including dosage of photocatalyst, initial pH and concentration of K 2 Cr 2 O 7 aqueous solution) on the Cr(VI) removal efficiency by F-SnS 2 were also studied. This work may advance our knowledge on the scalable low temperature solid phase synthesis of SnS 2 nanomaterial, and contribute to the application of SnS 2 in treating the Cr(VI)-polluted water. [ABSTRACT FROM AUTHOR]

Highlights • In air, low temperature synthesis of pure SnS 2 nanoflakes (SnS 2 -Our) at 250 °C. • Hydrothermally prepared SnS 2 and thermally exfoliated g-C 3 N 4 are used for comparison. • SnS 2 -Our has much higher absorption of visible-light. • SnS 2 -Our has exceptionally larger photocurrent. • SnS 2 -Our has much higher visible-light photocatalytic activity in Cr(VI) reduction. Abstract This communication reports a viable low temperature method for scalable production of SnS 2 nanomaterials with promising applications in visible-light photocatalysis and photovoltaics. SnS 2 nanoflakes were synthesized via heating the mixture of NH 4 Cl, S and Sn powders in air at 250 °C for 2 h, followed by a washing process. X-ray diffraction, scanning electron microscope, and nitrogen adsorption–desorption isotherms characterization indicated the formation of pure SnS 2 nanoflakes with a specific surface area of 32.081 m2/g. Comparative synthesis experiments manifested that NH 4 Cl played an indispensable role in our low temperature synthesis of SnS 2. UV–vis absorbance spectrum demonstrated that the as-synthesized SnS 2 nanoflakes had much higher absorption of visible-light than hydrothermally synthesized SnS 2 and thermally exfoliated g-C 3 N 4. Transient photocurrent measurements and photocatalytic tests indicated that our product had not only exceptionally larger photocurrent, but also significantly higher photocatalytic activity than hydrothermally synthesized SnS 2 and thermally exfoliated g-C 3 N 4 in the reduction of Cr(VI) under visible-light (λ > 420 nm) irradiation. [ABSTRACT FROM AUTHOR]

The overuse and dissemination of antibiotics caused serious threats to the environment and public health. In this work, a molybdenum disulfide-magnetic spinel ferrite composite (MoS 2 /CdFe 2 O 4) with a low bandgap was designed and prepared by a two-step hydrothermal method. Compared with MoS 2 , CdFe 2 O 4 and other MoS 2 /CdFe 2 O 4 composites, the 60% MoS 2 /CdFe 2 O 4 composite showed best visible light induced photocatalytic activity towards tetracycline (TC) degradation reaction. More than 87% of TC (25 ppm) can be degraded under visible light till 120 min. The degradation of TC over the MoS 2 /CdFe 2 O 4 composites followed the pseudo-first-order kinetics. The 60% MoS 2 /CdFe 2 O 4 composite had largest apparent reaction rate constant of 11.36 × 10−3 min−1. Due to its magnetic property, the MoS 2 /CdFe 2 O 4 composite with saturation magnetization value of 7.0 emu g−1 can be separated easily from water and reused. Based on the band structure and active species analysis, a Z-scheme structure was formed in the MoS 2 /CdFe 2 O 4 composite, which accelerated photocatalytic oxidation. The hydroxyl radicals (˙OH) were detected under visible light irradiation and provided strong photocatalytic oxidation performance. This work may provide new ideas for designing visible light responsive and magnetic CdFe 2 O 4 photocatalysts. [Display omitted] • A Z-scheme molybdenum disulfide-spinel ferrite composite (MoS 2 /CdFe 2 O 4) was prepared. • The MoS 2 /CdFe 2 O 4 showed visible light induced photocatalytic activity to tetracycline. • The magnetic MoS 2 /CdFe 2 O 4 could be removed easily from water and reused. • The hydroxyl radical and holes were the major active species in TC degradation. [ABSTRACT FROM AUTHOR]

The heterojunction of 2D g-C 3 N 4 thin nanosheets and double-shelled ZnSnO 3 nanocubes was prepared via a reliable, convenient, and cost-effective technique to achieve efficient photocatalytic activity. The unique double-layered structure of ZnSnO 3 helps to absorb more visible light and provides a shorter diffusion path for charge carriers. The integration of some wrapped g-C 3 N 4 nanosheets to the outer layer of ZnSnO 3 increases the multiple active sites and specific surface area (S BET) to boost the photocatalytic reaction. The synergistic effect of heterojunction and oxygen vacancies effectively stimulates the generation and spatial charge separation. Furthermore, as-synthesized 2D/3D heterostructure develops an interfacial electric field that plays an efficient role in charge migration and enhances the redox ability of the material. The degradation efficiency for MB (99.5 %, within 30 mins), TC (98.2 %, within 120 mins), H 2 production rate (1799 μmol g−1 h−1) and CO evolution rate (23.6 μmol g−1 h−1) confirms the excellent performance of multifunctional photocatalyst. Additionally, DFT calculations of electronic band structure and density of states are in excellent agreement with experimental results. This work highlights the new perspective on designing suitable nanostructures for photocatalytic applications. [Display omitted] • Synthesis of ZnSnO 3 /g-C 3 N 4 heterojunction to improve the interfacial electric field. • The wrapped g-C 3 N 4 nanosheets provides multiple active sites and high surface area. • Unique double-layered structure of ZnSnO 3 helps to decrease the charge diffusion path. • This synergistic effect of 2D/3D heterojunction stimulates the spatial charge separation. • H 2 production rate is 26.8 and CO evolution rate is 23.6 times greater than pure ZnSnO 3. [ABSTRACT FROM AUTHOR]

A series of SnS 2 /Au nanocomposites were synthesized by photocatalytic deposition of Au nanoparticles on the surface of SnS 2 nanoplates at room temperature. The photocatalytic properties of the as-synthesized SnS 2 /Au nanocomposites were tested via both the reduction of Cr(VI) and degradation of MO in water under the irradiation of visible light (λ > 420 nm). SnS 2 /Au-1.0% was found to be the most photocatalytically active nanocomposite. The photocatalytic Cr(VI) reduction rate over SnS 2 /Au-1.0% was 2.1 times as that over SnS 2 under visible light irradiation. Moreover, SnS 2 /Au-1.0% was also efficient and stable in the visible light-driven photocatalytic degradation of methyl orange (MO). Based on the test results of photoabsorption, transient photocurrent response and electrochemical impedance, the best photocatalytic performance of SnS 2 /Au-1.0% was likely attributed to its most efficient separation and transfer of photo-generated electrons and holes. Besides, the mechanisms of photocatalytic Cr(VI) reduction and MO degradation by SnS 2 /Au-1.0% were also explored. [Display omitted] • SnS 2 /Au nanocomposite photocatalyst was synthesized via photocatalytic deposition. • SnS 2 /Au showed higher photocatalytic activity than SnS 2 in the reduction of Cr(VI). • SnS 2 /Au had high activity and good stability in photocatalytic degradation of MO. • Reasons for the improved photocatalytic efficiency of SnS 2 /Au were proposed. • Photocatalytic Cr(VI) reduction and MO degradation mechanisms by SnS 2 /Au were probed. [ABSTRACT FROM AUTHOR]

• Design and preparation of SnO 2 /SnS 2 /CPVC ternary composite as photocatalyst. • SnO 2 /SnS 2 /CPVC shows synergistically enhanced photoinduced charge separation. • SnO 2 /SnS 2 /CPVC has far higher visible-light photocatalytic activity. • SnO 2 /SnS 2 /CPVC shows good photocatalytic reusability and stability. • Useful for the development of new efficient ternary composite photocatalysts. A new high-efficiency ternary composite photocatalyst (SnO 2 /SnS 2 /conjugated polyvinyl chloride derivative (CPVC)) was designed based on the hypothesis that any two of its components can constitute type-II heterojunction, and its three components should have synergistic effect on the enhancement of photoinduced charge separation. SnO 2 /SnS 2 /CPVC ternary composite was prepared adopting an easy-to-implement four-step synthesis method. Photoluminescence and electrochemical impedance spectra showed that SnO 2 /SnS 2 /CPVC is more efficient than SnO 2 /SnS 2 , SnS 2 /CPVC, SnO 2 /CPVC and SnS 2 in the separation and transfer of photoinduced charges. Results from their photocatalytic reduction of Cr(VI) under visible-light irradiation indicated that SnO 2 /SnS 2 /CPVC has significantly higher visible-light photocatalytic activity than SnO 2 /SnS 2 , SnS 2 /CPVC, SnO 2 /CPVC, SnS 2 , CPVC and SnO 2. Moreover, SnO 2 /SnS 2 /CPVC also demonstrated good photocatalytic reusability and stability. This study not only has developed a new high-activity visible-light photocatalyst (SnO 2 /SnS 2 /CPVC), but is also useful for the design of other new ternary composite photocatalysts with synergistically enhanced visible-light photocatalysis. [ABSTRACT FROM AUTHOR]

The existence of excessive tetracycline hydrochloride (TCH) in the ecological environment has seriously threatened human health, so there is an urgent need to develop a high-performance photocatalyst that can efficiently and greenly remove TCH. Currently, most photocatalysts have the problems of fast recombination of photogenerated charge carriers and low degradation efficiency. Herein, S-scheme AgI/Bi 4 O 5 I 2 (AB) heterojunctions was constructed for TCH removal. Compared with the single component, the apparent kinetic constant of the 0.7AB is 5.6 and 10.2 time as high as the AgI and Bi 4 O 5 I 2 , and the photocatalytic activity only decreases by 3.0% after four recycle runs. In addition, to verify the potential practical application of the fabricated AgI/Bi 4 O 5 I 2 nanocomposite, the photocatalytic degradation of TCH was performed under different conditions by regulating the dosage of photocatalyst, the TCH concentration, pH, and the existence of various anions. Systematical characterizations are conducted to investigate the intrinsic physical and chemical properties of the constructed AgI/Bi 4 O 5 I 2 composites. Based on the synergetic characterizations by in situ X-ray photoelectron spectroscopy, band edge measurements, as well as reactive oxygen species (ROS) detections, the S-scheme photocatalytic mechanism is proved. This work provides a valuable reference for developing efficient and stable S-scheme AgI/Bi 4 O 5 I 2 photocatalyst for TCH removal. [Display omitted] • AgI/Bi 4 O 5 I 2 S-scheme heterojunction was successfully constructed. • S-scheme mechanism was verified by in-situ XPS, band edge and ROS detection. • Efficient charge carrier separation boosted the removal efficiency of AgI/Bi 4 O 5 I 2. • Degradation pathways of TCH were proposed by GC-MS and TOC experiments. [ABSTRACT FROM AUTHOR]

• pH-controlled hydrothermal synthesis of FeWO 4 nanorods with different sizes. • FeWO 4 -7 had more surface area, smaller bandgap, faster charge separation/transfer. • FeWO 4 -7 had higher activity in photo-Fenton catalytic degradation of methylene blue. • FeWO 4 -7 had higher activity in photocatalytic reduction of Cr(VI). • FeWO 4 -7 is stable in both photo-Fenton catalytic and photocatalytic applications. Different sizes of FeWO 4 nanorods were prepared employing a hydrothermal approach, solely by altering the pH of the precursor solution. The FeWO 4 nanorods prepared at pH = 7 (FeWO 4 -7) were shorter than those prepared at pH = 2 (FeWO 4 -2). Compared with FeWO 4 -2, FeWO 4 -7 had bigger specific surface area, stronger visible-light-absorbing ability (smaller bandgap), and higher photogenerated charge separation and transfer efficiencies. Accordingly, FeWO 4 -7 exhibited much superior activity than FeWO 4 -2 in both photo-Fenton catalytic degradation of methylene blue (MB) and photocatalytic reduction of Cr(VI) under visible-light (λ > 420 nm) irradiation. The photo-Fenton catalytic and photocatalytic efficiencies of FeWO 4 -7 were about 8.5 and 2.9 times those of FeWO 4 -2, respectively. Furthermore, FeWO 4 -7 was reusable and fairly stable in both the photo-Fenton catalytic and photocatalytic applications. This study would be useful for guiding the hydrothermal preparation of high-efficiency visible-light-active FeWO 4 photo-Fenton catalyst and photocatalyst, and the pH-modulated microstructural control method may be applicable to synthesize semiconductor nanomaterials with varied microstructures. [ABSTRACT FROM AUTHOR]

• Facile preparation of SnS 2 /CPAN nanocomposite as a new visible-light photocatalyst. • SnS 2 /CPAN has much superior photocatalytic activity to SnS 2 in Cr(VI) reduction. • SnS 2 /CPAN is well stable and recyclable in photocatalysis. • Mechanism for the improved photocatalytic activity of SnS 2 /CPAN has been proposed. • Instructive to exploit PAN to make new efficient visible-light photocatalysts. Tin disulfide (SnS 2) coupled with cyclized polyacrylonitrile (CPAN) was prepared via a hydrothermal synthesis-mixing in the solution-solvent evaporation-thermal cyclization method from inexpensive SnCl 4 ·5H 2 O, thioacetamide and polyacrylonitrile (PAN). The as-synthesized SnS 2 /CPAN exhibited not only a substantially increased photocatalytic activity (2.1 times that of bare SnS 2), but also a fair stability in the visible-light (λ > 420 nm)-induced reduction of aqueous Cr(VI). The modification with CPAN is capable of enlarging the specific surface area, enhancing the transfer and separation of photogenerated charge carriers, and increasing the Cr(VI)-adsorbing capacity of SnS 2 , leading to the improved photocatalytic activity of SnS 2 /CPAN. This study is instructive to exploit PAN to make SnS 2 -based and other semiconductor-based new efficient visible-light photocatalysts. Moreover, the method employed for preparing SnS 2 /CPAN nanocomposite is simple, economical, and practical for producing various semiconductor/CPAN composite materials for photocatalytic and even other applications. [ABSTRACT FROM AUTHOR]

Photocatalysis is a hopeful way to treat antibiotics-containing wastewater, but its practical application is impeded by the lack of high-performance photocatalysts for now. In the present work, a 2D/1D Bi 2 WO 6 /C 3 N 5 heterojunction photocatalyst was fabricated through a hydrothermal route, and applied to the photocatalytic degradation of tetracycline hydrochloride (TCH). The Bi 2 WO 6 /C 3 N 5 nanocomposites showed superior catalytic activity, compared with a single counterpart. The apparent TCH degradation kinetic constant achieved by the optimized Bi 2 WO 6 /C 3 N 5 nanocomposite was 7.7 times that achieved by Bi 2 WO 6 and 262 times that achieved by C 3 N 5. Moreover, the influences of the dosage of Bi 2 WO 6 /C 3 N 5 , the initial concentration and pH of TCH solution, and the presence of anions on the photocatalytic TCH degradation were investigated. In addition, the TCH degradation pathway was studied. The collaborative results of X-ray photoelectron spectra, band structure determination, active species capturing experiments, and spin-trapping electron paramagnetic resonance spectra revealed a direct Z -scheme photocatalytic mechanism of Bi 2 WO 6 /C 3 N 5. [Display omitted] • 2D/1D Bi 2 WO 6 /C 3 N 5 heterostructures were successfully fabricated for the first time. • The apparent kinetic constant of the optimized sample was greatly enhanced as compared to a single component. • Factors affecting the tetracycline hydrochloride photodegradation were investigated. • The separation of the photoinduced charge carriers was efficiently promoted. • A possible direct Z-scheme photocatalytic mechanism was proposed. [ABSTRACT FROM AUTHOR]

• Phase, shape and size-tunable hydrothermal synthesis of TiO 2 in different solutions. • The photocatalytic activities are H 2 O-TiO 2 > HAc-TiO 2 > HCl-TiO 2 > NaOH-TiO 2. • The underlying reasons for the photocatalytic activity disparity were proposed. • Helpful for future synthesis of TiO 2 -based photocatalysts by hydrothermal method. The effect of the solution acidic-basic property on the structure and photocatalytic performance of hydrothermally-synthesized TiO 2 was investigated. It was found that the solution acidic-basic property influenced the phase, morphology and size of the obtained products. Anatase TiO 2 nanoparticles, anatase TiO 2 nanoparticles, and rutile TiO 2 nanorods were synthesized in deionized water, 1.818 mol/L HAC, and 1.818 mol/L HCl aqueous solution, respectively, but phase-pure TiO 2 cannot be synthesized in 1.818 mol/L NaOH aqueous solution. For photocatalytic reduction of aqueous Cr(VI) under Xe lamp irradiation, the TiO 2 synthesized in deionized water (H 2 O-TiO 2) demonstrated the best photocatalytic activity. The smallest grain size, biggest specific surface area, most surface hydroxyl groups and highest photogenerated charge separation efficiency may be responsible for the greatest photocatalytic activity of H 2 O-TiO 2. Considering that hydrothermal method is most frequently used in synthesizing TiO 2 -based photocatalysts, our finding of pure water as the best solvent for hydrothermal synthesis of TiO 2 would have great significance and provide helpful guidance. [ABSTRACT FROM AUTHOR]

In this paper, the branched Ag-ZnO heterojunction nanostructure and the branched ZnO were synthesized successfully by a facile, green and one-pot hydrothermal method. Such branched heterojunction and the comparing branched pure ZnO were characterized by X-ray diffraction, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL) and UV–vis diffuse reflectance spectra (DRS). The photocatalytic degradation of RhB aqueous solution and acetaldehyde (CH 3 CHO) gas results both showed that the branched Ag-ZnO heterojunction possessed the enhanced photocatalytic properties in comparison to the branched ZnO and Ag-ZnO counterparts due to its special interface structures and fast separation of its photogenerated charge carriers. This method is simple, feasible and can provide an important clue for synthesis and application of other branched metal/semiconductor heterojunction nanostructures. [ABSTRACT FROM AUTHOR]

Hematite (α-Fe 2 O 3) with different morphologies were synthesized via hydrothermal treatment of ferric acetylacetonate in deionized water, simply by changing the hydrothermal temperature and time. Their photocatalytic performance was assessed based on the photocatalytic reduction of aqueous Cr(VI) under visible-light. It was found that the α-Fe 2 O 3 nanorods synthesized at 175 °C for 2 h (Fe 2 O 3 -175 °C/2 h) had better photocatalytic activity than the other products. Moreover, Fe 2 O 3 -175 °C/2 h also demonstrated good photocatalytic reusability and stability. The reasons underlying the photocatalytic activity difference of different morphologies of α-Fe 2 O 3 were proposed, by comparing their specific surface area, photoabsorption capability, and photogenerated charge transfer and separation efficiency. Various factors influencing the photocatalytic reduction of Cr(VI) by Fe 2 O 3 -175 °C/2 h were also investigated. Finally, Fe 2 O 3 -175 °C/2 h was tested for photocatalytic treatment of the diluted black chromium electroplating solution under visible-light, and a good treatment result was obtained. Hence, α-Fe 2 O 3 nanorods have great potential for photocatalytic treatment of Cr(VI) wastewater. [Display omitted] • Different morphologies of α-Fe 2 O 3 were synthesized by a simple hydrothermal method. • Their photocatalytic reduction of aqueous Cr(VI) under visibe-light was investigated. • Reasons for the highest photocatalytic activity of α-Fe 2 O 3 nanorods were explored. • Factors affecting their photocatalytic reduction of Cr(VI) were studied. • α-Fe 2 O 3 nanorods can effectively treat the diluted black chromium plating solution. [ABSTRACT FROM AUTHOR]

Possible mechanism on SrTiO 3 /MnFe 2 O 4 /MW-UV catalytic system. • Z-scheme SrTiO 3 /MnFe 2 O 4 photocatalytic system is constructed for TC degradation. • Combined MW-UV technology achieves superior SrTiO 3 /MnFe 2 O 4 catalytic performance. • Double-response SrTiO 3 /MnFe 2 O 4 utilizes MW-UV and displays high catalytic activity. • Generation of MW plasma accelerates electron transfer and separation of e −- h + pairs. • Formed Z-scheme catalytic system and generated plasma enhance redox capacity. In this work, a novel Z-scheme SrTiO 3 /MnFe 2 O 4 catalytic system with microwave-ultraviolet (MW-UV) double-response activity was constructed using MW hydrothermal method for the degradation of tetracycline in water, as a target pollutant. The effects of several parameters including mass ratio (SrTiO 3 :MnFe 2 O 4), irradiation time, MW power, and catalyst reuse cycles on the catalytic activity of SrTiO 3 /MnFe 2 O 4 under MW-UV were also investigated. The degradation mechanism on the Z-scheme SrTiO 3 /MnFe 2 O 4 /MW-UV catalytic system was proposed. The results reveal that the combination of MW-induced catalytic and UV photocatalytic oxidation technology achieves superior SrTiO 3 /MnFe 2 O 4 catalytic performance. The Z-scheme SrTiO 3 /MnFe 2 O 4 system displays high catalytic activity under MW-UV. Particularly, the generated MW plasma accelerates electron transfer and separation of e −- h + pair, which promotes the enhancement of redox capacity and the degradation of organic pollutants. At the 1.0:1.0 mass ratio, SrTiO 3 /MnFe 2 O 4 has higher catalytic activity, and TC (22.0 mg/L) can be completely degraded within 20.0 min under MW (300 W)-UV (200 W) irradiation. Moreover, the catalytic activity of SrTiO 3 /MnFe 2 O 4 remains high after five reuse cycles. During the degradation, the OH plays a major role, while the O 2 − and h+ play relatively minor roles. Therefore, SrTiO 3 /MnFe 2 O 4 /MW-UV technology demonstrates to be promising in the treatment of antibiotics at different concentrations in water and wastewater. [ABSTRACT FROM AUTHOR]