Anchoring Ni single atoms on Co3O4 nanocubes as efficient electrocatalysts for enhanced hydrogen evolution reaction (HER)

Abstract

Hydrogen evolution from water splitting is a sustainable route for clean fuel generation, yet efficient and durable non-precious electrocatalysts are urgently needed. In this work, Ni single atoms were successfully anchored on Co₃O₄ nanocubes via a simple ion adsorption–reduction method. TEM, SAED, and elemental mapping confirm the uniform cubic morphology and atomic dispersion of Ni on the Co₃O₄ surface. XRD and XAFS analyses reveal that Ni exists as a mixture of Ni⁰ and Ni²⁺ species, strongly stabilized by Co₃O₄. Electrochemical tests demonstrate that the optimized Co₃O₄/Ni-2 catalyst achieves a low overpotential of 93 mV at 10 mA cm⁻² with a Tafel slope of 62.6 mV dec⁻¹, outperforming pristine Co₃O₄. EIS and C_dl measurements indicate enhanced charge transfer and enlarged active surface area, while 5000-cycle stability tests confirm excellent durability. These findings highlight Ni single-atom anchoring as an effective strategy to boost Co₃O₄-based electrocatalysts for hydrogen production.