Construction of hierarchical NiCu-based bimetallic electrocatalysts for promoting the electrooxidation of biomass derivatives

Abstract

Replacing the oxygen evolution reaction (OER) which is limited by intrinsic sluggish kinetics with the more thermodynamically favorable 5-hydroxymethylfurfural electrooxidation reaction (HMFEOR) to couple with the hydrogen evolution reaction (HER) is of significant importance to produce sustainable value-added products and green hydrogen. Herein, we report a Ni–Cu-based hierarchical electrocatalyst, fabricated via a facile one-pot sequential deposition hydrothermal process. For the HMFEOR, a high current density of 400 mA cm⁻² is achieved with a low overpotential of 222 mV. The catalyst exhibits a high faradaic efficiency of over 98% for FDCA and excellent long-term stability. The enhanced HMFEOR activity and the good cycling durability of the catalyst are ascribed to the hierarchical heterogeneous structure. The crystalline Cu₂O doped amorphous Ni(OH)₂ heterogeneous structure provides increased active sites for the HMFEOR without sacrificing conductivity, and the layered hierarchical structure provides high activities for both the aldehyde group and alcohol group.