Sulfur vacancies-induced“Electron Bridge”in Ni_(4)Mo/Sv-Zn_(x)Cd_(1-x)S regulates electron transfer for efficient H_(2)-releasing photocatalysis

Despite the existence of plentiful photocatalyst heterojunctions,their separation efficiency and charge flow precision remain low on account of lacking interfacial modulation.Herein,through a defect-induced heterojunction constructing strategy,Ni4Mo alloys were in-situ grown on the unsaturated coordinated sulfur atoms of sulfur vacancies-rich ZCS(Sv-ZCS)via interfacial Ni-S covalent bonds.The experimental and theoretical results reveal that these unsaturated sulfur atoms induced by sulfur vacancies vastly facilitate to anchor more Ni-Mo nanoparticles and form abundant Ni-S covalent bonds,meanwhile,these sulfur vacancies could form dual internal electric field(IEF)and work with Ni-S covalent bonds as“Electron Bridge”to further accelerate photoelectrons transfer,as well as promote the activation of water molecules and the desorption of hydrogen proton.Accordingly,the optimized Ni_(4)Mo/Sv-ZCS composite achieves an improved photocatalytic hydrogen evolution(PHE)rate of 94.69 mmol h^(-1)g^(-1)without an evident decrease after 6 cycles of photocatalytic tests,which is 21.2 and 1.94 times higher than those of Pt/ZCS and Ni_(4)Mo/ZCS,respectively.This tactic opens a new way for optimizing Zn_(x)Cd_(1-x)S-based heterojunctions by constructing sulfur vacancies and covalent bonds as“Electron Bridge”to enhance the activity of PHE.