High‐Entropy Environments Enable Metal Surface‐Catalyzed Nucleophilic Electrooxidation

Abstract Electrochemical biomass conversion offers a sustainable route to diverse products, minimizing environmental impact. However, conventional 5‐hydroxymethylfurfural electrooxidation (HMFOR) catalysts such as Ni(OH)₂ and NiS suffer from low conductivity, poor stability, and limited active sites. This work introduces a CoNiMnMoPd high entropy alloy (HEA) to address these limitations by simultaneously maintaining high conductivity, stability, and a high Ni oxidation state, enabling nucleophilic dehydrogenation. The HEA catalyst achieved a 92.5% 2,5‐furandicarboxylic acid (FDCA) Faradaic efficiency, 89.5% HMF conversion, and 95.8% FDCA selectivity, maintaining performance for over 100 h. Experimental and theoretical investigations revealed that the multielement composition of the HEA enabled Ni sites to maintain a high‐valence state, serving as the primary adsorption sites for HMF, and the dehydrogenation reaction occurs preferentially at non‐Ni sites within the HEA. Compared to monometallic Ni, the d‐band center shift and reduced antibonding filling contributed to a decrease in the energy barrier for the rate‐determining step (RDS) in the HMF‐to‐FDCA conversion, from 0.770 to 0.567 eV. This work offers novel insights for the development of Ni‐based HEA catalysts for biomass valorization.