Synergistic regulation of hydrogen adsorption/desorption via dual interfaces of Cu/Ni/Ni(OH)2 toward efficient hydrogen evolution reaction

Abstract

Nickel-based catalysts have attracted tremendous attention as alternatives to precious metal-based catalysts for electrocatalytic hydrogen evolution reaction (HER) in virtue of their conspicuous advantages such as abundant reserves and high electrochemical activity. Nevertheless, a great challenge for Ni-based electrocatalyst is that nickel sites possess too strong adsorption for key intermediates H∗, which severely suppresses the hydrogen-production activities. Herein, we report a hierarchical architecture Cu/Ni/Ni(OH) 2 consisting of dual interfaces as a high-efficient electrocatalyst for HER. The Cu nanowire backbone could provide geometric spaces for loading plenty of Ni sites and the formed Ni/Cu interface could effectively weakened the adsorption intensity of H∗ intermediates on the catalyst surface. Moreover, the H∗ adsorption could be further controlled to appropriate states by in-situ formed Ni(OH) 2 /Ni interface, which simultaneously promotes water adsorption and activation, thus both Heyrovsky and Volmer steps in HER could be obviously accelerated. Experimental and theoretical results confirm that this interface structure can promote water dissociation and optimize H∗ adsorption. Consequently, the Cu/Ni/Ni(OH) 2 electrocatalyst exhibits a low overpotential of 20 mV at 10 mA cm −2 and an ultralow Tafel slope of 30 mV dec −1 in 1.0 M KOH, surpassing those of reported transition-metal-based electrocatalysts and even the prevailing commercial Pt/C. • The hierarchical architecture of Cu/Ni/Ni(OH) 2 nanoarray containing dual significant interfaces was fabricated. • The prepared Cu/Ni/Ni(OH) 2 delivered remarkable hydrogen evolution reaction activity surpassing the commercial Pt/C. • The adsorption intensity toward key intermediates was directionally regulated. • The catalytic mechanism of the interfacial structure was distinctly unveiled by theoretical simulations.