Nanoporous Ni/NiO catalyst for efficient hydrogen evolution reaction prepared by partial electro-oxidation after dealloying

Abstract

The electrocatalytic hydrogen evolution reaction (HER) is an alternative eco-friendly strategy to obtain sustainable hydrogen energy. However, the HER in alkaline medium exhibits sluggish kinetics because of the difficulty of hydrogen adsorption and hydrolysis. Herein, a hierarchical nanoporous Ni/NiO catalyst with self-supported structures is prepared through dealloying followed by partial electro-oxidation. The catalytic activity for HER in alkaline medium is significantly enhanced by very short time electro-oxidation. The Ni/NiO-3 s sample (subjectied to 3 s of electro-oxidation) exhibits the outstanding catalytic performance with an overpotential of 25 mV at the current density of 10 mA cm⁻². The synergic effect of NiO and Ni improves the kinetics of Volmer and Heyrosky steps. The nanoporous structure provides more active sites and facilities for the transfer of substances and charges. The self-supporting structure ensures long-term stability. This work offers an effective strategy to design metal/metal oxide catalysts for efficient hydrogen evolution reactions.