High-Efficiency CO2 Electroreduction on Molybdenene: A Comparative Study Using Fixed-Charge and Fixed-Potential Methods

The electrochemical conversion of renewable energy into fuels and chemicals addresses the energy crisis and environmental pollution. Current CO2 reduction reaction (CO2RR) catalysts face challenges like high overpotentials and poor selectivity. Metallenes, with structural advantages and abundant active sites, offer high performance. Notably, molybdenene has excelled in nitrogen reduction reaction electrocatalysis. Herein, employing three methods, the fixed-charge method (FCM) without and with solvent effect and the fixed-potential method (FPM), to evaluate molybdenene for CO2RR. This material inherently captures and activates CO2 due to its surplus surface electrons, demonstrating high activity and selectivity, favoring CH4 production. The optimal pathway, *CO2 → *OCHO → *OCH2O → *OCH2OH → *OCH2 → *OCH3 → *O → *OH → *H2O, exhibits low overpotentials (0.68 V), lower than Cu(211). Despite identical overpotentials from FCM with solvent effect and FPM, varying the potential-determining step emphasizes constant potential conditions. These findings underscore potential of this emerging materials as a high-efficiency CO2RR electrocatalyst, broadening its application prospects and encouraging further theoretical and practical exploration.