Preparation And Properties Of Composite Semiconductor Material Based On Photocatalytic Hydrogen

With the severe change of the earth’s environment,the exhaustion of traditional fuel makes the development of clean energy extremely urgent.Hydrogen as a green and sustainable energy has attracted wide attention,and photocatalysis technology can transform solar energy into chemical energy,which is an effective technical means to solve the current environmental pressure and energy crisis.The core of photocatalytic hydrogen evolution technology lies in the development and modification of photocatalysts.Traditional photocatalysts such as metal oxides and sulfides are facing many bottlenecks.The birth of new semiconductor materials provides a new direction for the study of photocatalytic agents,and black phosphorus（BP）,as a two-dimensional semiconductor material,is considered to be an excellent photocatalytic material because of its adjustable band gap.Blocky BP can be modified to obtain a variety of low-dimensional structures,such as zero-dimensional（0D）black phosphorus quantum dots（BPQDs）,two-dimensional（2D）BP nanosheets and BP nanoribbons,etc.These different morphologies of BP have been widely used in the field of photocatalytic hydrogen evolution.In addition,carbon nitride（g-C₃N₄）can be prepared into 2D nanosheets and 1D tubular structures according to different raw materials and methods,which has important application prospects in photocatalytic hydrogen evolution.Indium zinc sulfide（ZnIn₂S₄）,as a new ternary sulfide,also plays an important role in the field of photocatalytic hydrogen evolution due to its 2D ultrathin nanosheet structure.In this paper,the above semiconductor materials were prepared and combined to study their photocatalytic hydrogen evolution performance.The specific research contents are as follows:（1）Using red phosphorus（RP）as raw material,BP was prepared by hydrothermal method,solvothermal method and mineralization method,respectively,and the morphology of BP was characterized by transmission electron microscope（TEM）and scanning electron microscope（SEM）.The structure characterization and elemental analysis of the prepared BP were carried out by X-ray diffractometer（XRD）,X-ray photoelectron spectroscopy（XPS）and Raman,which confirmed that the prepared BP had high crystallinity.On this basis,BP was prepared into BPQDs by liquid exfoliation and fragmentation method,which provided a good foundation for subsequent experiments.（2）g-C₃N₄ nanotubes（TCN）were prepared by hydrothermal method and combined with black phosphorus quantum dots（BPQDs）to successfully prepare BPTCN composite semiconductor materials.The photocatalytic hydrogen evolution rate of BPTCN is 507.51μmol h^-1g^-1,which is four times higher than that of pure TCN,and the apparent quantum yield（AQY）of BPTCN at 420 nm is 2.58%.The one-dimensional（1D）tubular structure and band arrangement of BPTCN can effectively inhibit electron-hole pair recombination and improve carrier transport efficiency.（3）ZnIn₂S₄（ZIS）was successfully prepared by hydrothermal method,and ZIS（O）was obtained by doping the original ZIS with oxygen using polyvinylpyrrolidone（PVP）as an oxygen dopant while preparing ZIS,which was subjected to photocatalytic hydrogen evolution.After performance testing,it was found that the photocatalytic hydrogen evolution rate of ZIS（O）reached 187.38μmol h^-1 g^-1,which was 2.5 times that of ZIS.Finally,g-C₃N₄ nanosheets（CNnss）and ZIS（O）were composited to construct a heterojunction material,and its band gap was adjusted to improve the photocatalytic hydrogen evolution performance.A new type of heterojunction material with 2D-2D structure,ZIS（O）/CNnss,was prepared by compounding ZIS（O）and CNnss by hydrothermal method.After optimization,the photocatalytic hydrogen evolution rate of ZIS（O）/CNnss with the best ratio reaches 313.52μmol h^-1 g^-1,which is 6 times that of pure CNnss and 2 times that of pure ZIS（O）.The results show that ZIS（O）/CNnss can be used as a low-cost and efficient photocatalyst,which provides a good foundation for future research on photocatalytic hydrogen evolution.