Preparation Of Core-shell Structure Transition Metal Composite And Its Photocatalytic Hydrogen Production Performance

At present,converting solar energy into chemical energy by semiconductor photocatalysts is considered to be one of the effective ways to alleviate the global energy shortage.However,the energy conversion efficiency of most semiconductor photocatalysts is not high,and its influencing factors include low electron-hole separation efficiency,narrow light absorption range,and small specific surface area.In order to improve the photocatalytic efficiency,the core/shell structure photocatalysts with special morphology have been widely studied because it can provide large specific surface area and more active sites,effectively separate electrons and holes,and increased light utilization,so resulting in more effective photocatalytic hydrogen production performance.The main contents are as follows:?1?Design and synthesis of ZnFe₂O₄@Ti O₂/Cd Se hollow core/shell nanospheres,Zn Fe₂O₄hollow nanospheres were prepared using hydrothermal and the following annealing processes.Then Ti O₂mesoporous nanolayer was coated on the surface of Zn Fe₂O₄nanospheres to obtain Zn Fe₂O₄@Ti O₂hollow core/shell nanospheres.Cd Se quantum dot were then coated on the surface of Zn Fe₂O₄@Ti O₂/Cd Se hollow core/shell nanospheres.The photocatalytic performance and mechanism of Zn Fe₂O₄@Ti O₂/Cd Se were also studied.?2?Design and synthesis of hydrogenated Pt/T O₂@Zn Fe₂O₄/Co O_xwith spatially separated cocatalyst.Hollow Zn Fe₂O₄/Co O_xnanospheres were firstly prepared using carbonaceous spheres as templates by combining with dipping method,solvothermal,and calcination processes.Then Ti O₂mesoporous nanolayer was coated on the surface of Zn Fe₂O₄/Co O_xnanospheres to obtain Ti O₂@Zn Fe₂O₄/Co O_xhollow core/shell nanospheres using dynamic coating method.The precious metal Pt is then loaded on the prepared Ti O₂@Zn Fe₂O₄/Co O_xhollow core/shell nanospheres by photodeposition method,and the following hydrogenation in H₂/Ar furnace was adopted to obtain hydrogenated Pt/TiO₂@Zn FeO₄/CoO_xhollow core/shell nanospheres.The photocatalytic performance of the prepared catalysts were also investigated to prove the structure and components advantages of the catalysts.?3?Synthesis of CdS@SnS₂/Au core/shell catalysts,Cd S nanorods were firstly prepared by hydrothermal method,and the further hydrothermal treatment was performed to obtain Cd S@Sn S₂core/shell nanomaterials.The Cd S@Sn S₂catalysts with different amount of Sn S₂were also obtained to optimize the photocatalytic performance of Cd S@Sn S₂.The precious metal Au particles are loaded on the catalyst surface by light deposition method.The obtained core-shell structure Cd S@Sn S₂/Au was subjected to a series of characterizations,and the performance of photocatalytic hydrogen productionunder visible light irradiation was also studied to prove the component and structure advantages of the catalysts.