Tuning the Adsorption Sites of OH in Glycerol Electro-Oxidation via Oxygen Vacancies on Cobalt (II) Oxide to Promote Electrocatalytic Performance.

The electrocatalytic oxidation of biomass-derived polyols (e.g., glycerol, GLY) represents a sustainable route to simultaneously produce value-added chemicals and green hydrogen under renewable energy-driven conditions. However, the intricate interplay between defect-rich metal oxides, organic intermediates, and hydroxyl species during the glycerol electro-oxidation reaction (GOR) remains poorly understood, limiting rational catalyst design. Herein, it is demonstrated that oxygen-deficient CoO nanosheets (Vo-CoO) serve as an efficient catalyst for the GOR, affording remarkable C1 product selectivity toward formic acid (FA). Synergistic experimental and theoretical investigations unravel that oxygen vacancies act as preferential adsorption sites for hydroxyl ions (OH), which dynamically reconstruct into lattice-bound hydroxyl species (*OH). This unique configuration accelerates nucleophilic attack on adsorbed glycerol intermediates, lowers the energy barrier for C─C bond cleavage, and directs the reaction pathway toward FA generation. When implemented in a flow electrolytic cell, the Vo-CoO catalyst enables continuous co-production of FA (2.75 mmol cm  h) and H (3.64 mmol cm  h) over 120-h. This work provides atomic-level insights into defect-mediated reaction mechanisms and establishes a paradigm for dual-pathway valorization of biomass derivatives and green hydrogen production.