Tailoring the electron structure and substrate adsorption energy of Ni hydroxide via Co doping to enhance the electrooxidation of biomass-derived chemicals

Electrooxidation of the biorefinery product 5-hydroxymethylfurfural (HMF) is a viable green strategy for acquiring vital industrial feedstock. However, a thorough examination of the electrocatalytic character of HMF has not been conducted because of the intricacy of the HMF electrooxidation reaction (HMFOR), which relates to the adsorption and coupling of substrates and OHad−. Herein, we propose a Co modification strategy to elucidate the electrocatalytic mechanism in the HMFOR. Experimental and theoretical calculations demonstrate that 10% Co doping effectively contributes to forming the active species Ni3+–O and increases the adsorption energy for HMF and OHad−. HMF performs spontaneous proton-coupled electron transfer on the electrogenerated Ni3+-O. In addition, the oxidation of–CHO is a priority to the –OH, and β-Co0.1Ni0.9(OH)2 facilitates the rate-determining step in the HMFOR process. This work reveals the doping effects of the transition metal on the electrocatalytic performance of HMFOR over Ni-based catalysts.