摘要
Single photocatalysts usually exhibit unsatisfactory performance due to the serious recombination of photogenerated electron‒hole pairs.Combining two photocatalysts to construct S-scheme heterojunction could solve this problem.In S-scheme mechanism,the interfacial built-in electric field(IEF)provides a vital driving force for efficient charge separation.Modifying the IEF is a feasible strategy to further improve the photocatalytic activity.Herein,a novel idea of tuning the strength of IEF in 2D/2D graphitic carbon nitride(g-C_(3)N_(4))/MS2(M=Sn,Zr)S-scheme heterojunctions by nonmetal doping was developed by employing density functional theory calculation.Three nonmetal elements(O,P,and S)were severally introduced into g-C_(3)N_(4)/MS_(2) composites.Charge density difference suggested that O and S doping led to increased interfacial electron transfer,while P doping had minimal influence.As expected,the calculated field strength of O-and S-doped g-C_(3)N_(4)/MS_(2) composites was significantly larger than that of pristine and P-doped g-C_(3)N_(4)/MS_(2) composites.Therefore,O and S doping endowed g-C_(3)N_(4)/MS_(2) Sscheme heterojunctions with enhanced IEF and more thorough charge transfer.Correspondingly,the experimentally synthesized O-C_(3)N_(4)/ZrS_(2) composite exhibited better photocatalytic H2-production activity than g-C_(3)N_(4)/ZrS_(2) composite.This work proposed an original idea of employing proper nonmetal doping to magnify the advantage of S-scheme heterojunction in accelerating charge separation.
基金
This work was supported by the National Key Research and Development Program of China(2018YFB1502001)
the National Natural Science Foundation of China(21905219,51932007,U1905215,21871217,and U1705251)
National Postdoctoral Program for Innovative Talents(BX20180231)
China Postdoctoral Science Foundation(2020M672432)
Hubei Postdoctoral Program for Innovative Research Post
This study was also partially supported by the General Research Fund-Research Grant Council of Hong Kong Government(Project No 18301117)
Dean Research Fund 19-20,EdUHK.
