Boron-Induced Cationic Vacancy on Copper Cobalt Oxide toward Formate Selectivity: New Insights into Methanol Oxidation Reaction

In noble metal-based fuel cells, adsorbed carbon monoxide plays a vital role in hindering their efficiency. To alleviate this problem, constructing non-noble metals, particularly selective toward formate formation, will be an ideal solution. Further, to improve the electrochemical properties, we deliberately introduced point defects, namely, cationic vacancies. Herein, we have chosen boron as a dopant that introduces the cationic vacancy in copper cobalt oxide (B/CuCo2O4) and improves the methanol absorption capability. Our synthesized B/CuCo2O4 electrocatalyst showed 91 mA cm–2 (∼4-fold) higher current density than the pristine electrocatalyst. Most importantly, unlike noble metals, our synthesized electrocatalyst was selective toward formate formation and obtained a faradic efficiency of 43% as demonstrated by NMR, and the reaction pathway was predicted by density calculation theory.