Highly efficient water electrolysis of 3-D distribution of graphene in Ni-Al intermetallic compound electrode in alkaline media

A honeycomb-like porous self-supporting Ni-Al(G) electrode was successfully prepared by low-pressure cold spraying combined with heat treatment. The main components of the electrode were Ni and NiAl. Graphene was uniformly dispersed throughout the electrode, exhibiting a 3-D distribution, which increased the active site of electrode and improved the electron exchange rate. The electrochemical properties of the Ni-Al(G) electrode were characterized using 6 M KOH. As a result, the Ni-Al(G) electrode requires only an overpotential of 130 mV to achieve a current density of 100 mA cm⁻², and a Tafel slope of 35.5 mV dec⁻¹. In addition, the electrode exhibited excellent stability. The addition of graphene and the honeycomb-like porous structure of the Ni-Al(G) electrode resulted in an excellent hydrogen evolution activity. This study provides a simple and rapid technique for building high-performance, low-cost, and industrially available electrodes for the efficient alkaline HER.