Lattice-S Regulation of CoOOH Spin State and Surface Microenvironment Enables High-Activity, High-Selectivity,...

Electrocatalytic upgrading of biomass-derived glycerol into high value-added formate presents significant energy and chemical application potential. Herein, an anion-S modification strategy was employed to precisely modulate the electronic structure and surface chemistry of CoOOH, enabling highly efficient glycerol-to-formate (GOR) conversion. The resulting CoOOH-S catalyst requires only 1.25 and 1.31 V (vs. RHE) to achieve 100 and 500 mA cm^-2, respectively. Moreover, it delivers a formate selectivity and Faradaic efficiency of 96% and 95% at 1.4 V, surpassing most systems reported so far. Notably, under flow-electrolysis conditions, the CoOOH-S achieves industrial-level current densities of 1.0 and 1.5 A cm^-2 at merely 2.14 and 2.27 V, and maintains stable operation for over 500 h at  > 500 mA cm^-2. Such GOR activity can be attributed to the modification of S, which disrupts the original octahedral symmetry of CoOOH, induces elongation of the Co─O bond and lattice distortion, and promotes electron redistribution and the presence of unpaired electrons, thereby enhancing electron transport and intrinsic activity. Meanwhile, the lower electronegativity of S strengthens the cooperative adsorption of OH^- and glycerol, accelerating dehydrogenation and formate dissociation. This study elucidates the synergistic role of anion doping in regulating proton deintercalation and substrate adsorption on Co-based catalysts.