Boosting the Electrochemical 5‐Hydroxymethylfurfural Oxidation by Balancing the Competitive Adsorption of Organic and OH− over Controllable Reconstructed Ni3S2/NiOx

Abstract The electrocatalytic oxidation of 5‐hydroxymethylfurfural (HMF) is a promising method for the efficient production of biomass‐derived high‐value‐added chemicals. However, its practical application is limited by: 1) the low activity and selectivity caused by the competitive adsorption of HMF and OH − and 2) the low operational stability caused by the uncontrollable reconstruction of the catalyst. To overcome these limitations, a series of Ni 3 S 2 /NiO x ‐ n catalysts with controllable compositions and well‐defined structures are synthesized using a novel in situ controlled surface reconstruction strategy. The adsorption behavior of HMF and OH − can be continuously adjusted by varying the ratio of NiO x to Ni 3 S 2 on the catalysts surface, as indicated by in situ characterizations, contact angle analysis, and theoretical simulations. Owing to the balanced competitive adsorption of HMF and OH − , the optimized Ni 3 S 2 /NiO x ‐15 catalyst exhibited remarkable HMF electrocatalytic oxidation performance, with the current density reaching 366 mA cm −2 at 1.5 V RHE and the Faradaic efficiency of the product, 2,5‐furanedicarboxylic acid, reaching 98%. Moreover, Ni 3 S 2 /NiO x ‐15 exhibits excellent durability, with its activity and structure remaining stable for over 100 h of operation. This study provides a new route for the design and construction of catalysts for value‐added biomass conversion and offers new insights into enhancing catalytic performance by balancing competitive adsorption.