Insight into Electrocatalysts as Co-catalysts in Efficient Photocatalytic Hydrogen Evolution

Recently, the implantation of non-noble-metal electrocatalysts into photocatalysts has brought dramatically improved hydrogen evolution activities; yet, the mechanistic details are still under debate, because of the poor understanding of interfacial charge carrier dynamics. Here, for the first time, we unravel that it is the electrocatalytic process that plays the critical role in these heterostructured systems. Spectroscopic characterizations, combined with theoretical calculations, give a clear physical picture that the photoexcited electrons transfer from photocatalysts to phosphides electrocatalysts, then driving H2 evolution reaction similar to electrocatalysis; and also reveal the Fermi level of electrocatalysts as a feasible descriptor for the photocatalytic activity.