CoSe2@NiSe‐CoSe2 Heterojunction for Enhanced Electrocatalytic 5‐Hydroxymethylfurfural Oxidation Coupled with Hydrogen Evolution

Abstract Electrochemical 5‐hydroxymethylfurfural oxidation reaction (HMFOR) offers a promising approach to producing valuable chemicals and facilitating coupled H 2 production. A significant challenge in the HMFOR lies in elucidating the interaction mechanisms between the active sites and 5‐hydroxymethylfurfural (HMF). However, the unpredictable reconstruction of active sites during the catalytic process complicates the understanding of these mechanisms. In this study, a novel heterojunction (CoSe 2 @NiSe‐CoSe 2 /NF) is synthesized using a straightforward hydrothermal method combined with classical selenization. This heterojunction demonstrates exceptional electrocatalytic performance for direct HMF oxidation, achieving a Faradaic efficiency of 2,5‐furanedicarboxylic acid (FDCA) up to 97.9%. Notably, it requires only 1.29 V versus RHE to achieve a current density of 10 mA cm −2 for the HMFOR‐assisted hydrogen evolution reaction (HER). The high activity of the heterojunction primarily arises from interfacial electron redistribution. Specifically, Co modulates the band structure of Ni, with Se serving as the intermediary. This modulation increases the adsorption energy of HMF and reduces the energy barrier of the rate‐determining step in HMFOR. This research not only achieves the selective synthesis of high‐value chemicals but also provides a comprehensive analysis of the structure‐performance relationship of the catalyst, offering a new pathway for the development of efficient heterogeneous catalysts.