Oxygen Vacancy Enhanced <i>p</i> – <i>d</i> Orbital Hybridization in Defect-Rich Vo-MnO ₂ for Efficient Electrooxidation of Glycerol to Formic Acid

Electrocatalytic glycerol oxidation reaction (GOR) coupled with hydrogen production offers a sustainable route to valorize biodiesel byproducts into high-value chemicals, yet simultaneously achieving high current density and superior formic acid (FA) selectivity remains challenging. Herein, an oxygen defect-rich Vo-MnO 2 electrocatalyst is fabricated via hydrothermal synthesis followed by high-temperature hydrogen reduction. Systematic studies reveal that oxygen vacancies significantly enhance the p – d hybridization between Mn e g and O 2 p orbitals in Vo-MnO 2, which facilitates catalyst surface reconstruction to produce the highly active α -MnOOH during GOR. Consequently, Vo-MnO 2 achieves 95.2% FA selectivity with 83.0% Faradaic efficiency at 1.4 V RHE and delivers industrial current densities of 400 mA cm –2 at 1.32 V RHE and 840 mA cm –2 at 1.4 V RHE, outperforming most state-of-the-art electrocatalysts. Comprehensive experiments and DFT calculations demonstrate that the presence of oxygen vacancy defects accelerates the charge transfer kinetics. Simultaneously, the reconstructed α -MnOOH efficiently promotes substrate adsorption and lowers the C–C bond cleavage barrier, accounting for the excellent activity and selectivity for GOR. This work establishes a deep structure–performance relationship between oxygen vacancy-induced p – d orbital hybridization and electrocatalytic GOR performance, offering a new avenue to design advanced electrocatalysts via defect engineering.