Lattice oxygen-mediated electrosynthesis of carboxylic acids via high-valence cobalt oxide catalysts

Electrocatalytic oxidation of biomass-derived alcohols offers a sustainable pathway for the synthesis of high value-added chemicals from renewable carbon sources. However, multi-step electron transfer and intermediates-diversity in alcohol oxidation reactions (AOR) often result in low reactivity efficiency and poor product selectivity. Therefore, it is still highly desirable yet challenging to develop efficient catalysts for the electrosynthesis of carboxylic acids via AOR. Herein, taking AOR as the proof-of-concept reaction, earth-abundant NiCoO x nanosheets prepared by O 2 -plasma treatment demonstrate impressively high Faradaic efficiencies of 78.7–96.8 % for carboxylic acids electrosynthesis as well as low overpotentials (E 10 = 1.08–1.23 V vs. RHE at 10 mA cm −2 ). In situ spectroscopy and electrochemical measurements reveal that both Co 3+ and Co 4+ species formed on surface reconstructed (oxy)hydroxides are AOR active sites. Empirical evidence from isotope labeling and theoretical calculation demonstrate that lattice oxygen is activated and mediates in the oxygenation process of AOR, owing to the enhanced covalency of metal-oxygen bond and elevation of O 2p band center. This work has substantiated the direct participation of lattice oxygen in alcohol electrooxidation through compelling experimental and theoretical evidence, thereby offering valuable mechanistic insights into the biomass-derived chemical synthesis.