Ordered Ag composite electrode for an efficient alkaline hydrogen evolution reaction

Developing active, durable, and cost-controllable catalytic electrodes is the key of efficiently convert and store sustainable energy of hydrogen, but still a great challenge. Herein, we prepared a new Ag-based composite electrode of NiO/Ag and CuO/Ag by a facile method, which had a special through-hole-ordered structure for high-efficiency hydrogen evolution reaction (HER) in alkaline media. Of them, the NiO/Ag electrode showed excellent electrocatalytic performance, with an extremely low overpotential of 23 mV at a current density of 10 mA cm(-2), as well a small Tafel slope of 73.2 mV dec(-1), which exhibited comparable or better performance than the other state-of-the-art Ag-based electrodes for HER. The composite electrodes were characterized and the reaction mechanism was discussed. It is proposed that the heterojunction on the interface of NiO with Ag decreased the binding energy and charge density of Ag. Particularly, the through-hole-ordered structure provided more reactive sites and accelerated species transfer and water decomposition reaction.