Ultrafast synthesis of NiCo alloy catalysts by Joule heating for the electrocatalytic hydrogen evolution reaction

Abstract

Identifying effective synthesis strategies that can obtain high-performance electrocatalysts is pivotal to realizing a hydrogen economy. Nickel–cobalt (NiCo) alloy electrocatalysts are promising candidates for the hydrogen evolution reaction (HER), but the traditional approach for synthesizing NiCo alloy electrocatalysts is generally time-consuming, and the physiochemical features of the resulting NiCo are unsatisfactory. Herein, we report the ultrafast synthesis of NiCo alloy nanocatalysts with a Joule heating (JH) approach. We show that ultrasmall NiCo alloy nanoparticles that are uniformly and intimately distributed on carbon cloth can be obtained in just 0.6 seconds using the JH approach, while the NiCo catalysts prepared by traditional thermal treatment exhibit agglomerated and large particles. The as-prepared NiCo alloy electrocatalyst with JH shows favorable activity for the HER with low overpotentials of 83 and 220 mV to achieve current densities of 10 and 100 mA cm⁻², respectively, outperforming the NiCo alloy electrocatalysts prepared using traditional approaches. Moreover, the NiCo alloy electrocatalyst maintains excellent stability during the long-term reaction for 200 h, demonstrating its potential for large-scale deployment.