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Recently, the use of semiconductor-based photocatalytic technology as an effective way to mitigate the environmental crisis attracted considerable interest. Here, the S-scheme BiOBr/CdS heterojunction with abundant oxygen vacancies (Vo-BiOBr/CdS) was prepared by the solvothermal method using ethylene glycol as a solvent. The photocatalytic activity of the heterojunction was investigated by degrading rhodamine B (RhB) and methylene blue (MB) under 5 W light-emitting diode (LED) light. Notably, the degradation rate of RhB and MB reached 97% and 93% in 60 min, respectively, which were better than that of BiOBr, CdS, and BiOBr/CdS. It was due to the construction of the heterojunction and the introduction of Vo, which facilitated the spatial separation of carriers and enhanced the visible-light harvest. The radical trapping experiment suggested that superoxide radicals (·O2−) acted as the main active species. Based on valence balance spectra, Mott-Schottky(M-S) spectra, and DFT theoretical calculations, the photocatalytic mechanism of the S-scheme heterojunction was proposed. This research provides a novel strategy for designing efficient photocatalysts by constructing S-scheme heterojunctions and introducing oxygen vacancies for solving environmental pollution. [ABSTRACT FROM AUTHOR]

Abstract Sulfide-graphene oxide composites photocatalysts were fabricated through a simple solid-state chemical reaction method under different synthesis conditions. The resulting photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, Nitrogen adsorption-desorption specific surface areas, XPS measurements, UV–vis absorption spectroscopy, Transient photocurrent, and Photoluminescence spectra. The result suggests that ZnS and Bi 2 S 3 nanoparticles well distributed on the graphene oxide nanosheets in the sulfide-graphene oxide composites. Nitrogen adsorption-desorption results indicate that the specific surface areas of the composites increased after the graphene oxide is introduced. XPS measurements suggest that there are interactions between sulfide and graphene oxide. The photocatalytic activities of sulfide-graphene oxide composites were measured by the degradation of methyl orange under UV irradiation. Variation of the synthesis conditions allowed the sulfide-graphene oxide composites possessing different structures and photocatalytic activities as revealed by transmission electron microscopy and photocatalytic measurements. The photocatalytic results indicated that the sulfide-graphene oxide composites exhibited much higher photocatalytic activities than that of pure ZnS and Bi 2 S 3 , and nearly 97% and 90% of methyl orange were degraded over ZnS-graphene oxide and Bi 2 S 3 -graphene oxide after irradiation for 120 min, respectively. The superior photocatalytic activities can be attributed to the high specific surface areas, which is benefical for improving photocatalytic reaction. Futhermore, introducing graphene oxide can effectively reduce the photoinduced electron-hole pair recombination probability, and then improve the photocatalytic activities, which have been proved by the transient photocurrent, photoluminescence spectra, and scavengers measurements. Highlights • Sulfide-GO composites were synthesized by a simple solid-state method. • Effects of GO contents and others on activity of composites were investigated. • The composites exhibited superior activities to pure sulfides. • The superior activity is proved by transient photocurrent, PL and scavengers measurements. [ABSTRACT FROM AUTHOR]

Self-assembly has emerged as a promising method to control the structure and properties of ensembles of inorganic nanoparticles (NPs) for exploiting their collective effects. However, the rational assembly of inorganic NPs into soluble porous architectures for use as homogenized heterogeneous catalysts has been less studied. Herein, it is shown that inorganic NPs can be used for the assembly of soluble porous coordination frameworks (PCFs) by atom-scale interfacial coordination-driven assembly. Owing to their large pore size, high dispersity in solution, strong absorption in the near-infrared (NIR) range, and long-lived electron-hole pair, the obtained soluble frameworks could serve as a platform for homogenized heterogeneous photocatalysts, which exhibited excellent activity, high apparent quantum efficiency, and recyclability in the catalysis of the noble-metal-free Suzuki coupling reactions under NIR light at room temperature. Moreover, PCF catalysts can be reused more than five times without significant loss of activity, which indicates long-term stability. The present strategy to fabricate soluble porous nanostructures opens a new chemical toolbox for homogenized heterogeneous catalysts and may bring new inspiration to photocatalysis. [ABSTRACT FROM AUTHOR]

A simple solid-state method was employed for the first time to obtain ZnS/graphene nanocomposites. The chemical composition, morphology and properties of the products were characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy, nitrogen absorption-desorption and UV–vis spectroscopy. The photocatalytic performances of the products were evaluated by methyl orange. The results indicated that nanocomposites exhibited superior photocatalytic activity to pure ZnS, owing to the reduction of photoinduced electron–hole pair recombination induced by the introduction of graphene. In addition, effects of solid-state synthetic conditions on photoactivity were also investigated. It was found that the nanocomposite obtained by the reduction of NaBH 4 exhibited higher photoactivity than that of got by the direct addition of graphene, which can be attributed to the high specific surface area and the enhanced synergetic effect between ZnS and graphene. With the help of scavengers, ·O 2 - was proved to be the main reactive species during the degradation. [ABSTRACT FROM AUTHOR]

In this work, ZnS nanoparticles were successfully fabricated by a simple low-temperature solid-state method. The phase composition, morphology, pore structure and optical property of the samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen absorption–desorption specific surface area (BET) and UV–vis spectroscopy (UV). The photocatalytic activities of the as-synthesized samples were evaluated by the color removal of methyl orange (MO) under UV irradiation. The effects of surfactants and reactants on the microstructures and photocatalytic activity of the samples were investigated. The results revealed that the surfactant played an important role in the microstructures and photocatalytic activity. It was found that the as-synthesized ZnS sample assisted by sodium dodecyl sulfonate (SDS) exhibited the highest photocatalytic activity with nearly 95% of MO decomposed after irradiation for 60 min. The excellent photocatalytic activity of the sample can be ascribed to the large specific surface area and unique morphology. [ABSTRACT FROM AUTHOR]

• CdS/ZnS heterojunctions were fabricated by low-heat solid-state chemical method. • The heterojunctions exhibited superior photocatalytic activities to others. • A possible mechanism was proposed via radical trapping and theoretical calculation. Photocatalytic technology is environmentally-friendly and energy-saving for degradating organic pollutants. Highly efficient and visible light response photocatalysts are vital for the excellent degradation performance. In the work, CdS/ZnS heterojunctions were fabricated via low-heat solid-state chemical method and the photocatalytic activity was systematically studied. When the molar ratio of ZnS to CdS was 9:1, the CdS/ZnS heterojunctions exhibited the highest photocatalytic activities, and 99 % and 58 % of methyl orange were degraded under UV and visible light, respectively. Besides, 91 % and 94 % of rhodamine B and tetracycline were degraded under UV light, respectively. The outstanding photocatalytic performances of CdS/ZnS heterojunctions were attributed to the enhanced light absorption and the fast migration of carriers, which were verified by UV visible diffuse reflection absorption spectrum, surface photocurrent, and fluorescence spectrum. In addition, on the bases of free radical trapping experiment and theoretical calculation, a possible photocatalytic mechanism was put forwards. The study provides a new idea for the design of highly efficient and wide spectral responsive photocatalysts. [Display omitted] [ABSTRACT FROM AUTHOR]

Photocatalytic technology can effectively solve the problems of environmental pollution, and the core is photocatalyst. In the paper, SnS 2 /MnS 2 composites were synthesized by a mild and green low-heat solid-state approach. The composition and morphology of the samples were studied by XRD, TEM and XPS. The results showed that the samples presented flower like structure. The photocatalytic performance of the composite was investigated by photocatalytic degrading methyl orange. The results indicated that when the molar ratio of SnS 2 to MnS 2 was 5:5, the composite displayed the superior photocatalytic performance to that of other, and the degradation rates were 80 % and 70 % under UV and visible irradiation within 120 min, respectively. Photocurrent results showed that introducing MnS 2 can significantly improve the separation efficiency of carriers on SnS 2. Finally, the active species of the composite during the photocatalytic process were studied through the capture agent test, combing with first principles calculations, and a possible photocatalytic mechanism was proposed. This study provides technical guidance for the design of new and efficient SnS 2 -based photocatalysts. [Display omitted] • A simple solid-state approach was employed for synthesizing SnS 2 /MnS 2 composites. • The SnS 2 /MnS 2 composites showed superior visible photocatalytic activity to others. • Due to the fast separation of photoinduced carriers and enhanced light absorption. • A possible photocatalytic mechanism was proposed based on the DOS and band structure. [ABSTRACT FROM AUTHOR]

Herein, the combined strategy of coupling SnS 2 was adopted to modify SnO 2 nanoparticles to construct SnS 2 /SnO 2 heterostructure. The as-prepared SnS 2 /SnO 2 composites were characterized by XRD, TEM, XPS, UV–vis, transient photocurrent and photoluminescence spectra technologies. TEM results proved SnS 2 /SnO 2 composites showed flower-like structure. UV–vis spectra suggested that the introduction of SnS 2 can prolong light absorption range to visible region. The photocatalytic activity of SnS 2 /SnO 2 composites were measured by degrading methyl orange and Cr (VI). The SnS 2 /SnO 2 heterojunction exhibited excellent photodegradation activity compared with pure SnO 2 and SnS 2 , and the MO degradation rates were up to 98% and 96% after 120 min irradiation under UV and visible, and 98% and 95% of Cr (VI) were degraded by the composites in 120 min, respectively. The superior photocatalytic performance was due to the effective separation of photoinduced carriers and enhanced light absorption, which was proved by the transient photocurrent, photoluminescence, and UV–vis spectra. Photocatalytic mechanism was further studied through free radical capture experiments and theoretical calculations. Our research provides a novel design for the synthesis of SnO 2 -based composites with effective removal of environmental pollutants. [Display omitted] • SnS 2 /SnO 2 heterostructure was obtained by a simple solid-state chemical method. • SnS 2 /SnO 2 heterostructure displayed superior photocatalytic activity to SnO 2. • High activity is due to slow recombination, and enhanced light absorption. • The work provides a simple route for the synthesis of Sn-based heterostructure. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple one-step solvothermal method was employed for the synthesis of Vo-BiOBr-S. • The Vo-BiOBr-S showed superior visible photocatalytic activity to others. • The synergy of oxygen vacancies and doped sulphur facilitated the O 2 activation. • A possible photocatalytic mechanism was proposed based on the DOS and band structure. Herein, the BiOBr co-modified with oxygen vacancies (Vo) and doped by sulfur was a promising photocatalyst (Vo-BiOBr-S), which was synthesized by a one-pot solvothermal approach. The TEM showed that Vo-BiOBr-S is a sea urchin-shaped microsphere with a diameter of about 4 μm. The photocatalytic efficiency of Vo-BiOBr-S was studied by removing rhodamine B and methylene blue, which were higher than that of BiOBr, Vo-BiOBr and BiOBr-0.8S, respectively. Additionally, the photocatalyst exhibits high degradation of aqueous solutions containing both rhodamine B and methylene blue. The photocurrent and photoluminescence tests showed that the improved photocatalytic performance of Vo-BiOBr-S was due to the accelerated charge transfer and separation by the internal electric field, which extended the visible light absorption range. Furthermore, experiments free radical trapping revealed that superoxide radicals were the principal active species in this system, contributing to the superior degradation performance of Vo-BiOBr-S. The density of states of the samples was calculated via DFT to analyse the energy band structure. The effectiveness of Vo-BiOBr-S in mineralising RhB under LED light was demonstrated through total organic carbon tests. This study presents a method to design efficient photocatalysts for use in environmental preservation. [ABSTRACT FROM AUTHOR]