Abstract
Selective oxidation of low-molecular-weight aliphatic alcohols like methanol and ethanol into carboxylates in acid/base hybrid electrolytic cells offers reduced process operating costs for the generation of fuels and value-added chemicals, which is environmentally and economically more desirable than their full oxidation to CO
2
. Herein, we report the in-situ fabrication of oxygen-vacancies-rich CuO nanosheets on a copper foam (CF) via a simple ultrasonication-assisted acid-etching method. The CuO/CF monolith electrode enables efficient and selective electrooxidation of ethanol and methanol into value-added acetate and formate with ~100% selectivity. First principles calculations reveal that oxygen vacancies in CuO nanosheets efficiently regulate the surface chemistry and electronic structure, provide abundant active sites, and enhance charge transfer that facilitates the adsorption of reactant molecules on the catalyst surface. The as-prepared CuO/CF monolith electrode shows excellent stability for alcohol oxidation at current densities >200 mA·cm
2
for 24 h. Moreover, the abundant oxygen vacancies significantly enhance the intrinsic indicators of the catalyst in terms of specific activity and outstanding turnover frequencies of 5.8k s
−1
and 6k s
−1
for acetate and formate normalized by their respective faradaic efficiencies at an applied potential of 1.82 V vs. RHE.
Converting low-molecular-weight aliphatic alcohols like methanol and ethanol into value-added chemicals such as carboxylates in electrolytic cells offers low operating costs, but non-noble-metal catalysts often bring about low selectivities and overoxidation to CO
2
. Here, the authors report the efficient and selective electrooxidation of ethanol and methanol into acetate and formate on in-situ generated oxygen-vacancies-rich CuO nanosheets on a copper foam via ultrasonication-assisted acid-etching.