Aged Co-Mo alloy thin film catalyst for hydrogen evolution reaction in acidic solution

In this study, aged Co-Mo (3:10) alloy film has been demonstrated as an efficient and durable catalyst for hydrogen evolution reaction (HER) in acidic solution. The Co-Mo alloy films with varying Co/Mo atomic ratios have been deposited by magnetron sputtering. The catalytic activity of Mo film is outperformed by the Co-Mo alloys, among which the Co-Mo (3:10) alloy exhibits the highest HER activity with an overpotential of 310 mV at 10 mA cm(-2) current density, exchange current density of 1.74 x 10(-4) A cm(-2) and a Tafel slope of 61 mV dec(-1). Combined with the good stability provided by the surface oxide layer, the aged Co-Mo (3:10) alloy is a promising catalyst for HER in acidic solutions.