Lattice Oxygen Mediated C(OH)-C(OH) Bond Cleavage to Promote Alcohols Electrooxidation.

Selective cleavage of C(OH)-C(OH) bond is crucial for valorization of biomass, waste plastics and other organic compounds, while facing thermodynamic and kinetic barriers. Utilizing active oxygen species (e.g., active hydroxyl (OH*) or lattice oxygen) generated at the anode during water electrolysis provides a sustainable solution to achieve electrochemical activation of the C(OH)-C(OH) bond. However, elucidating the mechanisms of active oxygen species and their roles in enhancing product selectivity remains a challenge. Herein, we report a strategy to unravel the contribution of active oxygen species for C(OH)-C(OH) bond cleavage during alcohols electrooxidation, revealing that lattice oxygen promotes C(OH)-C(OH) bond cleavage and enhances product selectivity. We constructed NiAl-LDH and Ni(Al)-LDH as model catalysts, the latter derived through a "nano-tailoring" Al-leaching strategy. As a result, Ni(Al)-LDH facilitates lattice oxygen formation more readily, which acts as the primary active species for C(OH)-C(OH) bond cleavage and achieves ∼90% selectivity for formic acid production in ethylene glycol oxidation reaction (EGOR). The intrinsic mechanism involves that lattice oxygen participates in EGOR via the Mars-van-Krevelen mechanism and specifically induces C(OH)-C(OH) bond cleavage through an indirect pathway. This mechanistic insight into C(OH)-C(OH) bond cleavage mediated by lattice oxygen provides a valuable reference for designing selective catalysts in alcohols electrooxidation.