Glycerol electrooxidation (GOR), as a typical nucleophilic biomass oxidation reaction, provides a promising anodic alternative for coupling green hydrogen generation at the cathode. However, the challenges of identifying active sites and elucidating reaction mechanisms greatly limit the design of high-performance catalysts. Herein, we use NiO and Ni/NiO as model catalysts to investigate glycerol oxidation. Electrochemical measurements and