A Density Functional Theory Analysis of Electrochemical Oxidation of Methane to Alcohol over High-Entropy Oxide (CoCrFeMnNi)₃O₄ Catalysts

The direct conversion of methane into alcohol is a promising approach for achieving a low-carbon future, yet it remains a major challenge. In this study, we utilize density functional theory to explore the potential of the (CoCrFeMnNi)₃O₄ (CCFMNO) high entropy oxide (HEO) for electrochemical oxidation of methane to methanol and ethanol, alongside their competition with CO₂ production. Our primary focus in this study is on thermodynamics, enabling a prompt analysis of the catalyst‘s potential, with the calculation of electrochemical barriers falling beyond our scope. Among all potential active sites within CCFMNO HEO, we identify Co as the most active site for methane activation when using carbonate ions as oxidants. This results in methanol production with a limiting potential of 1.4 V_CHE, and ethanol and CO₂ productions with a limiting potential of 1.2 V_CHE. Additionally, our findings suggest that the occupied p-band center of O* on CCFMNO HEO is a potential descriptor for identifying the most active site within CCFMNO HEO. Overall, our results indicate that CCFMNO HEO holds promise as catalysts for methane oxidation to alcohols, employing carbonate ions as oxidants.