High-performance diluted nickel nanoclusters decorating ruthenium nanowires for pH-universal overall water splitting

Abstract

Developing a versatile electrocatalyst with remarkable performance viable for pH-universal overall water splitting is increasingly important for the industrial production of renewable energy conversion. Herein, our theoretical calculations predicate that the limitations in the mean-field behavior from the traditional catalyst designing strategy can be largely overcome by introducing diluted metal nanoclusters, which can give an optimal thermodynamic effect for enhancing electron-transfer capability, and in turn promote the activation of initial water-dissociation for both the hydrogen evolution reaction and oxygen evolution reaction. As a proof of concept, a unique catalyst, namely diluted nickel nanocluster-decorated ruthenium nanowires, was explored as a high-performance electrocatalyst for overall water splitting. The optimized catalyst delivered record activity for overall water splitting in a wide pH range from 0 to 14 with all the potentials lower than 1.454 V to achieve the current density of 10 mA cm⁻², largely outperforming the Pt/C–Ir/C integrated couple. It also readily reaches a high current density, of up to 100 mA cm⁻², with a low voltage of only 1.55 V applied. It is further demonstrated that the diluted nickel nanoclusters can strongly anchor on the ruthenium nanowires, contributing to the enhanced stability after the long-term tests. The diluted metal nanocluster-enhanced strategy highlights a general pathway for the rational design of catalysts with unprecedented performance for electrocatalysis and beyond.