Interfacial Electronic Modulation Redirects Anodic Radical Chemistry for Selective C─C Bond Cleavage in Electro‐Oxidative Lignin Depolymerization

Abstract

ABSTRACT Electro‐oxidative lignin depolymerization is considered a promising route to renewable aromatics; however, its selectivity is often limited by competition with oxygen evolution and uncontrolled overoxidation at the anode. A CuO/Cu 0.92 Co 2.08 O 4 hetero structured catalyst was developed, with which 88% conversion of 2‐phenoxy‐1‐phenylethanol was achieved, affording benzaldehyde and phenol in 53% and 27% yields, respectively. By means of time‐resolved analysis and intermediate‐feeding experiments, a tandem pathway involving benzylic oxidation to 2‐phenoxyacetophenone followed by C α ‐C β scission was identified. In situ Raman and FTIR spectroscopy, together with EPR, revealed that the Cu─Co interface suppresses the accumulation of OER‐type CoOOH species while promoting oxygen‐centered radical chemistry under reaction conditions. Through density functional theory, it was further shown that interfacial electronic modulation strengthens substrate adsorption and lowers the barrier for bond cleavage. The same mechanistic logic was extended from the model substrate to enzymatic hydrolysis lignin, for which characteristic interunit linkages are weakened while aromatic products are retained. These findings establish interfacial control of anodic radical chemistry as a strategy for selective lignin bond editing under electrochemical conditions.