Preparation And Properties Of Sn/Bi Based Visible Light Catalysts With Nanograde

Heavy metals Cr（Ⅵ）and cyanide are recognized as the sources of pollution in the world,and have great toxicity.At present,the processing methods have such problems as high cost,low removal efficiency and complex process.Photocatalysis is an advanced and effective method for the removal of Cr（Ⅵ）and CN^-1.In this paper,we build two new photocatalysts,design heterostructures in situ doping,and develop magnetic recoverable materials,providing a new idea for the preparation of photocatalysts.OxygenvacantCeO₂@Bi₂WO₆hollowmagneticmicrocapsulesare controllable designed by a simple template-assisted synthesis followed by H₂reduction.The heterostructures enhance the interaction between CeO₂ and Bi₂WO₆and contain rich oxygen vacancies,leading to generate more heterojunctions.The hollow capsule of the photocatalyst improve the light efficiency significantly due to the effective multiple reflections in the cave.Therefore,the novel materials show a remarkable reduction performance for Cr（Ⅵ）and detoxification of cyanide under visible light irradiation.The initial Cr（Ⅵ）concentration was 8 mg L^-1.With the prolongation of irradiation time,the concentration of Cr（Ⅵ）decreased sharply.The Cr（Ⅵ）concentration dropped to 0.0032 mg L^-1in 60 min,and the degradation rate reached 99.6%.Meanwhile,the chromium ions can be adsorbed completely.CN^-1decreased rapidly from the original 4.78 mM L^-1to 0.08 mM L^-1at 60 min,and the removal rate was up to 98.3%.The improved photocatalytic activity of CeO₂-Bi₂WO₆ heterojunctions and oxygen vacancies can be attributed to the enhanced photoabsorption properties and effective separation of photoinduced charge carriers.Particularly,CeO₂@Bi₂WO₆ photocatalysts having an excellent magnetism are easy to be fast collected after photocatalytic reaction,displaying its great potential used in the energy and environmental science.Sn⁴⁺self-doped hollow SnS microcube is controllable designed by a simple template-assisted synthesis followed by reduction under low temperature.The in situ self-doping enhances the interaction between SnS₂ and SnS..The 3D hollow structures of the photocatalyst improve the light efficiency significantly due to effective multiple reflections in the cave.Therefore,this novel materials show a remarkable reduction performance for Cr（Ⅵ）and detoxification of cyanide under visible light irradiation.The initial Cr（Ⅵ）concentration was 8 mg L^-1.With the prolongation of irradiation time,the concentration of Cr（Ⅵ）decreased sharply.The Cr（Ⅵ）concentration dropped to 0.0032 mg L^-1in 50 min,and the degradation rate reached 99.6%.At the same time,the chromium ion can be completely adsorbed.The concentration of cyanide ions decreased sharply from 4.68 mM L^-1to 0.13 mM L^-1,and the removal rate of cyanide was as high as 97.2%.The improved photocatalytic activity of the Sn⁴⁺self-doped SnS can be attributed to the enhanced photoabsorption properties and effective separation of photoinduced charge carriers.This general strategy provides a novel route for the synthesis of hollow cubic structural materials,which can be used for photocatalysis,energy storage and wastewater purification applications.