Transition metal phosphide of nickel and cobalt modified Zn0.5Cd0.5S for efficient photocatalytic hydrogen evolution with visible light irradiation

Transition metal phosphide (TMPs), as environmentally friendly non-noble metal cocatalyst, play a key role in promoting photocatalytic hydrogen evolution. In this work, three metal phosphating compounds (NiCoP, Ni2P, and Co2P) were synthesized by solvothermal method using red phosphorus as phosphorus source. The three kinds of co-catalysts were loaded onto Zn0.5Cd0.5S respectively by physical agitation method to form binary nanocomposites (ZnCdS/TMPs). The results showed that the three composite photocatalysts all showed excellent HER performance in Na2S/Na2SO3 sacrifice solution. Among them, the hydrogen production rate of ZnCdS/NiCoP-5% reaches 64 µmol at 5 h, which was significantly higher than that of pure Zn0.5Cd0.5S, ZnCdS/Ni2P-5%, and ZnCdS/Co2P-5%. According to the results of various characterization techniques, NiCoP nanoparticles provide more active sites for Zn0.5Cd0.5S and the composite photocatalytic materials exhibit excellent hydrogen evolution performance. Moreover, the schottky barrier between Zn0.5Cd0.5S and NiCoP nanoparticles effectively enhances the charge separation rate, thus promoting the improvement of photocatalytic hydrogen evolution. Therefore, low-cost transition metal phosphide as a cocatalyst has broad prospects in the field of photocatalysis.