Interfacial Electronic Modulation of Co ₃ O ₄ /CeO ₂ Heterojunction for Optimizing C–C Bond Cleavage and Intermediate Adsorption in Glycerol Oxidation to Glycolic Acid

The selective electrocatalytic oxidation of glycerol to high-value C2-C3 chemicals offers a promising approach to glycerol overproduction, while it struggles with precise C-C cleavage and limited selectivity from multiple pathways. Regulating the adsorption capacity of glycerol oxidation intermediates and the degree of C-C bond cleavage through the interfacial electronic structure of electrocatalysts is crucial for controlling C2-C3 selectivity. Herein, a self-supported p-n heterojunction catalyst (Co₃O₄/CeO₂) is developed for the efficient electrocatalytic oxidation of glycerol to C2 chemicals, achieving a glycolic acid selectivity of 42%, with a yield of 19.6 μmol cm^-2 h^-1. The built-in electric field enables rapid interfacial charge transfer from CeO₂ to Co₃O₄, which leads to the upshifted d-band center of active Co₃O₄. Electrochemical characterization and theoretical calculations demonstrate that the heterojunction promotes the adsorption of hydroxyl species and glycerol, thereby enhancing the activity of the glycerol oxidation reaction (GOR). Concurrently, the optimized electron cloud distribution of Co₃O₄ active sites strengthens the adsorption of oxygen-containing intermediates while weakening the adsorption of glycolic acid and suppresses the further cleavage of C-C bonds, thus increasing glycolic acid selectivity. This study clarifies the redox kinetic adsorption regulation mechanism of the Co₃O₄/CeO₂ heterojunction catalyst and provides a highly promising electrocatalyst design strategy for the production of high-value-added C2 products via glycerol oxidation.