Balancing the Activity‐Adsorption Trade‐Off in Biomass Valorization via Electron‐Reconstructed High‐Entropy Oxides

ABSTRACT The directional anchoring of heteroatoms into a high‐entropy oxides (HEOs) platform offers substantial scientific and technological promise, yet achieving atomic‐level control over such doping remains challenging and rarely demonstrated. Here, we precisely anchor B atoms into an HEO framework (BS‐HEO), possessing a distinct O‐Mn‐B coordination unit in which Mn acts as an electronic hub that triggers an electron‐siphoning effect, thereby redistributing the interfacial electron configuration. Theory and experiments confirm that the electron‐reconstructed surface enables the optimization of the balance between intrinsic activity and adsorption toward 5‐hydroxymethylfurfural (5‐HMF) within the potential window (1.40–1.45 V vs. RHE), consequently enhancing interfacial mass transport efficiency. As a result, when the carbon balance is taken into consideration, the BS‐HEO catalyst delivers impressive HMFOR performance at 1.42 V versus RHE, achieving 96.0% selectivity for 2,5‐furandicarboxylic acid (FDCA) and 99.1% faradaic efficiency (F.E.), which surpasses most previously reported benchmarks. This work not only demonstrates precise B anchoring into a HEO but also introduces a new strategy for tailoring and identifying active sites in high‐entropy materials for high‐performance electrosynthesis.