Synergistically enhanced co-adsorption of HMF and hydroxyl on selenium and oxygen dual vacancies in CeO2-CuNiSe2/NF for high-efficiency HMF electrooxidation

Abstract

Electrocatalytic conversion of biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA) represents a sustainable route for value-added chemical production. However, the sluggish reaction kinetics, caused by inadequate adsorption of HMF and OH⁻ on catalyst surfaces, remains a major challenge. Herein, we construct a CeO₂-CuNiSe₂/NF catalyst with oxygen and selenium vacancies by triggering a charge compensation mechanism via Cu²⁺ modification of NiSe₂ and introducing CeO₂. The optimized CeO₂-CuNiSe₂/NF catalyst delivered an exceptional current density of 1.23 A cm⁻² at 1.5 V, outperforming its unmodified counterparts with approximately 3.15-fold, 2.16-fold, and 1.82-fold enhancements over NiSe₂/NF, CuNiSe₂/NF, and CeO₂-NiSe₂/NF, respectively. Notably, the catalyst maintains HMF conversion and FDCA selectivity above 95% over 10 consecutive cycles, demonstrating outstanding operational stability. In situ electrochemical impedance spectroscopy (EIS) confirmed that the engineered dual vacancies (Se and O vacancies) effectively reduced the interfacial resistance and significantly enhanced the interfacial reaction kinetics of the catalyst. Theoretical calculations confirm that the Se and O vacancies promote HMF adsorption and OH⁻ capture, collectively reducing the reaction energy barrier of the rate-determining step (FFCA* to FDCA*). This study establishes a novel strategy for designing highly efficient HMFOR catalysts that enhance co-adsorption performance through the construction of dual vacancies.