Multifunctional electrocatalysts of nickel boride nanoparticles for superior hydrogen oxidation and water splitting

Abstract The development of active, durable, and earth-abundant multifunctional electrocatalysts is of importance for hydrogen energy conversion and storage. Here, we report a facile strategy to synthesize earth-abundant nickel boride nanoparticles supported on reduced graphene oxide (Ni 3 B/rGO) as multifunctional electrocatalysts for both hydrogen oxidation reaction and overall water splitting. The Ni 3B/rGO catalysts produce a hydrogen oxidation reaction current density of 2.39 mA cm−2 at an overpotential of 100 mV vs. reversible hydrogen electrode, being comparable to commercial Pt/C (2.95 mA cm−2) and 60 times as high as bare Ni/rGO (0.04 mA cm−2). In addition, the Ni3B/rGO-based alkali electrolyzer affords 100 mA cm−2 at a cell voltage input of 1.85 V for electrocatalytic overall water splitting. Density functional theory calculations further demonstrate that the Ni3B/rGO catalysts possess optimal adsorption energies of both H∗ and OH∗ intermediates, which are favorable to electrocatalytic hydrogen electrochemistry in an alkaline medium. This work opens a new avenue toward the rational design of high-performance platinum group metal-free multifunctional electrocatalysts for the hydrogen economy.