Chainmail CuNi Lattice‐Distorted Nanoalloys on Monolithic Woody Carbon for High‐Performance Electrocatalytic 5‐HMF Hydrogenation

ABSTRACT Electrocatalytic hydrogenation (ECH) of biomass‐derived 5‐hydroxymethylfurfural (5‐HMF) offers a promising route for sustainable chemical production from renewable carbon resource. However, conventional powder catalysts often suffer from poor stability and weak adhesion to substrates under practical conditions. In this work, we develop a robust, self‐supporting chainmail electrocatalyst (CuNi@NC/CW) by in situ encapsulating CuNi nanoalloys within nitrogen‐doped carbon shells on a monolithic carbonized wood. The hierarchical three‐dimensional (3D) microchannel architecture promotes efficient electron and mass transport while ensuring strong catalyst–substrate integration and excellent corrosion resistance. Alloying‐induced lattice distortion in the CuNi nanoalloy facilitates the surface charge redistribution, which enhances adsorbed hydrogen species ( * H) coverage, optimizes 5‐HMF adsorption, and selectively suppresses undesirable ketyl radical coupling. As a result, the CuNi@NC/CW achieves a remarkable 2,5‐dihydroxymethylfuran (DHMF) selectivity of 96.4% at −0.6 V vs. reversible hydrogen electrode (RHE) and maintains over 90% selectivity after 20 consecutive cycles. Combined experimental and Density Functional Theory (DFT) analyses reveal that CuNi nanoalloys enhance * H generation and reduce the energy barrier for HMF hydrogenation. The design of biomass‐derived chainmail catalyst provides a promising way to fabricate robust electrocatalysts for the production of value‐added chemicals from renewable carbon resources.