Synergistic copper-manganese oxide electrocatalysts for CO2 conversion to CO

CO is a key product of CO 2 electroreduction (CO 2 ER) and an important feedstock for the production of hydrocarbons and alcohols. Herein, we synthesized electrocatalysts by growing Cu nanocluster on manganese oxide (Cu n -Mn 3 O 4 ) for CO 2 ER. In 0.5 M KHCO 3 electrolyte using an H-cell, the optimized Cu 0.4 -Mn 3 O 4 achieved a Faradaic efficiency for CO (FE CO ) of 88.5 ± 2.3% and a current density of 14.3 ± 0.2 mA cm −2 at − 0.6 V vs. RHE, while substantially suppressing the hydrogen evolution reaction (HER). The better performance was due to the electrons transferred from Mn to CO 2 by Cu as a shuttle and anchored Cu nanoclusters shifted the d-band center toward the Fermi level, which was more conducive to the intermediate formation. In situ electrochemical attenuated total internal reflectance (EC-ATR) spectroscopy and density functional theory (DFT) calculations revealed the *COOH intermediate (1399 cm⁻ 1 ) along the CO 2  → *COOH → *CO → CO pathway. Moreover, the DFT calculations further demonstrated the Gibbs free energy barrier (ΔG) of the key steps in the CO 2 ER pathway and the corresponding intermediate configurations, which were used to reveal the relationship between the catalyst structure and CO 2 ER performance. The design of the metal/metal oxide electrocatalyst in this study provides a new perspective for the highly selective reduction of CO 2 to CO. Graphical