Reversible hydrogen spillover enhances hydrogen evolution reaction on electrodeposited MoNi4/Ni17W3 with amorphous/crystalline heterostructure

Abstract

Hydrogen spillover phenomena have recently created a new opportunity for ehancing the surface adsorption/desorption kinetics of reactants and intermediates, thereby effectively improving electrocatalytic activity. In this work, Mo elements are introduced into an electrolyte containing Ni, W, and Co, inducing the in-situ formation of an amorphous MoNi₄ phase during electrodeposition. Consequently, a coral-like porous MoNi₄/Ni₁₇W₃ heterostructure is constructed on a stainless steel mesh substrate. The MoNi₄/Ni₁₇W₃ heterogeneous structure features abundant defect sites and oxygen vacancies, which promote enhanced interfacial charge transfer. This configuration optimizes the H∗ adsorption, transfer, and desorption processes by facilitating a reversible hydrogen spillover effect between MoNi₄ and Ni₁₇W₃, as suggested by both experimental results and DFT calculations. These advancements notably improve the kinetics of the electrocatalytic hydrogen evolution reaction (HER), highlighting its promising potential for efficient hydrogen production. In a 1 M KOH solution, the MoNi₄/Ni₁₇W₃ electrode affords the overpotentials of only 26 mV and 98 mV at current densities of 10 mA cm⁻² and 100 mA cm⁻², respectively. Moreover, the electrode maintain almost unchanged HER performance during a 48-h stability test at a current density of 100 mA cm⁻². This work provides a new approach for designing and constructing high-performance non-noble-metal-based heterostructured electrocatalysts.