Lewis Acid–Base Interactions in Ru-Stabilized NiFe (Oxy)Hydroxide Promoting Biomass Upgrading at Industrial Currents
Minyuan Tan, Tong Liu, Yuanhua Sun, Dan Wu, Xiao‐Kang Liu, Xue Zhang, Ming Ni, Qiquan Luo, Haiwei Du, Linlin Cao, Tao Yao
Abstract
Achieving the continuous conversion of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) at industrial current densities holds great promise for plastic manufacturing but poses significant challenges in maintaining long-term stability. Herein, we introduce single-atom Ru sites exhibiting Lewis acidic properties stabilized on nickel–iron-layered double hydroxide (Ru@NiFe) through defect-mediated anchoring and strong covalent metal–support interactions, specifically designed for efficient biomass upgrading. In a practical electrolyzer, Ru@NiFe achieves a robust FDCA conversion rate of 159.3 mg cm –2 h –1 with 90% Faradaic efficiency, maintaining stable operation for over 500 h at an industrial density close to 270 mA cm –2 without significant activity loss. Operando spectroscopies and theoretical investigations reveal that electrophilic single-atom Ru sites establish strong Lewis acid–base interactions, promoting the formation of active Ni 3+δ (0 < δ < 1) species and enhancing adsorption toward HMF. This promotion enables an enhanced dynamic oscillation between Ni 2+ and Ni 3+δ during the electrooxidation–reduction of HMF, effectively preventing overoxidation of Ni 3+δ by preferentially capturing released protons, thus ensuring long-term operation.