Synthesis Of Two-dimensional Layered Sulfide And Application In Photocatalytic Water Splitting

It is promising to produce hydrogen from water via photocatalytic reaction.Compared to oxides,sulfides have smaller band-gaps,which are contributed to the absorption of visible light.Layered sulfides can form two-dimension or atomic thin structures,leading to size effects.With huge surface areas,rich edges and efficient separation of carriers,the sulfides may become excellent catalysts for hydrogen evolution.In this paper,the preparation and photocatalytic performance of various two-dimension layered sulfides are studied:(1)SnS2 nanosheets:Ultra-thin SnS2 nanosheets are synthesized by solvothermal method.Carbon quantum dots are loaded on the nanosheets by glucose splitting,with the performance increased by 10 times.In addition,Ce2S3 nanoribbons and CeO2 nanoparticles are also synthesized on SnS2 nanosheets via hydrothermal method.Thus a ternary heterojunction is formed,resulting in excellent absorption from deep UV to IR and stable hydrogen evolution.(2)WS2 nanotubes:WS2 nanotubes are synthesized from WO3 nanowires,which are prepared by CVD method.Au nanoparticles are loaded on the surface of the nanotube,and CuInS2 nanoshell is deposited on Au by a pulse current method.The direct electron transport(Z-scheme)between WS2 and CuInS2 is enhanced by the local surface plasmon resonance effect of Au nanoparticles,improving the efficiency of photocatalytic hydrogen evolution by 2 times.(3)MPS3 crystal:Layered MPS3,like FePS3 and CdPS3,are obtained by a phosphosulfurization process from metal sulfides such as FeS and CdS.The monolayered FePS3 nanosheets,below 10 mm,are obtained through the exfoliation of the bulk in the hydrazine solution.The P-CdPS3 superlattice structure can be formed by P atom intercalation via controlling the growth time.The intercalated P atom assists the formation of a local heterojunction,which promotes the absorption of light and the separation of carriers of the material.The rate of hydrogen evolution can reach 15 mmol g-1 h-1 under visible light.Atomic intercalation provides a new method for the design of high performance catalysts.