Improved Bifunctional Catalytic Performance of FeNiMoB Ribbons in Alkaline Electrolyte by Dealloying

Abstract

Designing low-cost and efficient bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media remains challenging. In this paper, we fabricated electrocatalyst with nanoporous structures by means of dealloying. The treatment process generates a large number of nanopores on the surface of the alloy, which allows the electrocatalyst with this structure to have high electrocatalytic activity. The electrocatalyst, prepared by dealloying at 30 °C for 2 h, can reach a current density of 10 mA cm−2 with small HER and OER overpotentials of only 144 mV and 260 mV in 1 M KOH solution, respectively. Both HER and OER can be maintained for 20 h at a current density of 10 mA·cm−2. When the 30 °C–2 h FeNiMoB ribbons were used as both anode and cathode in a two-electrode water electrolysis system, the electrodes showed a low cell voltage of 1.68 V at 10 mA·cm−2 and excellent stability for 70 h. This work provides ideas for the application of transition metal borides (TMBs) in bifunctional electrocatalysis.