Balancing the Activity and Stability of Iron‐Based Catalysts via Mixed Oxide Species Formation for Electrocatalytic Biomass Hydrogenation

Abstract Electrochemical biomass conversion offers a promising approach for organic synthesis and biomass upgrading. Iron‐based catalyst hold considerable promise in this domain, however, challenges related to stability under electrocatalytic conditions limit their broader application. In this work, an iron‐based integrated foam (FeO x /Fe‐IF) electrode fabricated via thermal treatment process is presented, which generates highly active and stable mixed oxide species in situ. The structural composition enables FeO x /Fe‐IF to exhibit outstanding activity in 5‐hydroxymethylfurfural (5‐HMF) electroreduction, achieving near‐complete conversion with high selectivity toward 2,5‐dihydroxymethylfuran (DHMF). Remarkably, FeO x /Fe‐IF maintains high stability and durability with 5‐HMF conversion approaching 100% and DHMF selectivity around 92% over ten successive cycles. In situ spectroscopic analyses reveal that Fe 2 O 3 species effectively stabilize Fe 3 O 4 active sites, ensuring sustained catalytic performance. Electrochemical and kinetic isotope studies suggest an electrochemical hydrogenation (ECH) mechanism, where adsorbed hydrogen (*H) and 5‐HMF (*HMF) interact to produce DHMF. Additionally, the catalyst demonstrates adaptability across a broad pH range (7–14), high efficiency in continuous flow‐cell synthesis, and great catalytic activity in hydrogenating other biomass‐derived chemicals, underscoring the versatility of FeO x /Fe‐IF. This work provides valuable insights for designing stable and efficient iron‐based electrocatalysts for biomass conversion.