Tailoring the electrochemical hydrogen evolution activity of Cu₃P through oxophilic surface modification

The hydrogen evolution reaction in alkaline medium can be promoted by the modification of platinum group metal with oxophilic metals. Herein, an earth abundant metal was first converted to copper phosphide Cu₃P and the latter was electrochemically activated by a short and simple procedure to yield an oxidized electroactive surface. Compared with the pristine Cu₃P catalyst, the electrochemical activated Cu₃P catalyst exhibits an HER overpotential of 155 mV at 10 mA/cm² (90 mV decrease from Cu₃P catalyst) in alkaline medium with a stability over 24 h). XRD, XPS and EDS reveal that the oxidation occurs only on the surface of Cu₃P which shows the presence of both copper phosphide and oxide species.