Asymmetric oxygen vacancies <b>‐</b> rich layered double hydroxides couple biomass refining with nitrate reduction

Abstract Electrochemical coupling of biomass valorization with nitrate (NO 3 − ) conversion provides a promising approach to generating value‐added chemicals. Herein, we synthesized a CoFe‐layered double hydroxides with abundant asymmetric oxygen vacancies (A‐Ov‐LDHs), which serve as a robust electrocatalyst for 5‐hydroxymethylfurfural (HMF) oxidation reaction (HMFOR) to 2,5‐furandicarboxylic acid (FDCA) and NO 3 − reduction reaction (NO 3 RR) to ammonia (NH 3 ). A‐Ov‐LDHs possess a higher Ov content (4.21 × 10 15 spin mg −1 , 1.5 times that of LDHs). In HMFOR, A‐Ov‐LDHs achieved 82.1% FDCA yield, a 22.2% enhancement over LDHs (59.9%). Theoretical calculations revealed that A‐Ov increased HMF adsorption energy by 50.3%, and lowered the activation barrier by 0.28 eV. For NO 3 RR, A‐Ov‐LDHs delivered 99.8% NH 3 Faradaic efficiency and 2.1 mmol h −1 cm −2 yield. In a coupled HMFOR||NO 3 RR system, A‐Ov‐LDHs exhibited ≥90.2% NH 3 Faradaic efficiency and ≥92.5% FDCA yield over 100 h. This study provides valuable insights into efficient bifunctional catalysts with asymmetric oxygen vacancies for synthesizing value‐added chemicals.