Interfacial Proton‐Coupled Electron Transfer Reverses Water Inhibition for Selective 5‐hydroxymethylfurfural Hydrogenation

ABSTRACT The selective aqueous hydrogenation of 5‐hydroxymethylfurfural (HMF) to 2,5‐bis(hydroxymethyl)furan (BHMF) is pivotal for biomass valorization. While nanoscale zero‐valent iron (nZVI) offers a sustainable H 2 ‐free alternative, its efficiency is severely suppressed by a rigid interfacial water layer that impedes substrate access and drives non‐selective pathways. Herein, we surmount this limitation by engineering atomically dispersed Ni sites on nZVI to orchestrate a surface proton‐coupled electron transfer (PCET). Mechanistically, single Ni atoms in the electron‐deficient state (Ni δ+ ) function as “electron pumps”, establishing a direct longitudinal inner‐sphere channel for electron delivery towards the −CHO group of HMF. Concurrently, the Ni δ+ sites facilitate prompt proton release by weakening hydrogen binding on adjacent lattice oxygen. Ni δ+ ‐induced electronic modulation transforms proximal lattice Fe into strong Lewis acids to polarize bulk water, creating a continuous lateral proton shuttle to the adsorbed HMF. This orthogonal PCET system drastically boosts electron selectivity from 10.6% (pristine nZVI) to 81.6%, achieving >95% HMF conversion (20–150 mM) with >95% BHMF selectivity under ambient conditions, outperforming pristine nZVI (<10% conversion) by orders of magnitude. This work demonstrates that engineering interfacial PCET pathways can reverse classical solvent inhibition, opening a general route for efficient aqueous hydrogenation.