Study On Construction And Performance Of Metallic Co-based Phosphate Modified Oxygen/Sulfide Photocatalyst

In today’s society,due to the depletion of non-renewable resources such as kerosene and the impact of greenhouse gases,a new clean energy source is necessary to replace these non-renewable resources.Photocatalytic hydrogen production technology,which uses sunlight to drive semiconductors,has naturally received a lot of attention.At present,there are hundreds of commonly used semiconductor materials in the field of photocatalytic hydrogen production research,but the high recombination of photogenerated electron-hole affects their photocatalytic activity.This problem can be effectively solved by coupling co-catalysts with the semiconductor,which can accelerate the charge separation and improve the photocatalytic efficiency of a single conventional semiconductor.The co-catalysts used in this paper are CoP and CoP/Ni₂P hybrid,and the co-catalysts are compounded with titanium dioxide（TiO₂）and cadmium zinc sulfide（CdZnS）to improve the photocatalytic activity:（1）The 0D/2D TiO₂/CoP system was prepared by phosphating and in situ synthesis using cobalt hydroxide（Co（OH）₂）as the precursor.The improved photocatalytic performance was investigated using various techniques and first density functional theory（DFT）,and it was concluded that CoP nanosheets as a co-catalyst could enhance the light absorption and provide more active sites for the water reduction reaction.In addition,the formation of ohmic junctions between 2D CoP nanosheets and 0D TiO₂nanoparticles,along with the downward bending of the TiO₂conduction band to reduce the interfacial potential barrier,is more favorable for the transfer of electrons from 0D TiO₂to 2D CoP nanosheets for the rapid separation of photogenerated carriers.（2）The 0D/1D CdZnS/CoP system was prepared by phosphating and physical stirring using cobalt hydroxide（Co（OH）₂）as the precursor.Three different morphologies of CoP were fabricated and coupled with CdZnS,and it was found that CoP nanorods showed the best cocatalytic effect to enhance the photocatalytic activity of CdZnS.The reason is the photogenerated electron transfer rate was increased after the introduction of CoP co-catalysts,thus effectively separating the photoexcited hole-electron pairs and enhancing the photocatalytic activity.（3）The 0D/3D CdZnS/Co-Ni-P system was obtained by phosphating and physical stirring using cobalt nickel hydroxide（cobalt-nickel hydrotalcite,Co Ni LDH）as the precursor.The spherical structure of the CoP/Ni₂P cocatalyst as the carrier can effectively reduce the agglomeration of CdZnS,provide more reactive sites,and accelerate the reduction efficiency of electrons.The CdZnS/Co-Ni-P composite catalyst has stronger light absorption intensity.Lactic acid consumes most of the holes in the valence band of CdZnS,and Co-Ni-P traps electrons so that they are rapidly transferred to Co-Ni-P,which separates electrons and holes spatially,thus improving the photocatalytic efficiency.