MOF-derived Cu@Cu2O heterogeneous electrocatalyst with moderate intermediates adsorption for highly selective reduction of CO2 to methanol

To improve Faradaic efficiency (FE) of CO2 reduction reaction (CO2RR) to methanol over Cu-based complex electrocatalysts, a novel MOF-derived [email protected]2O heterogeneous electrocatalyst with moderate intermediates adsorption was proposed for highly selective reduction of CO2 to methanol. XRD and HRTEM confirmed the presence of a distinct heterogeneous interface between Cu and Cu2O, while XPS verified the existence of Cu0/Cu+ and OH on catalyst surfaces. Cu0/Cu+ with a moderate CO* binding energy and OH which favored H* adsorption were conducive to hydrogenation reduction of CO2 to methanol. The intermediate products CO*, COOH*, and CHO* were detected on in-situ electrochemical ATR-FTIR spectroscopy. The most favorable reduction route of CO2 to methanol was as follows: CO2 → COOH* → CO*+H2O → CHO* → CH2O* → CH2OH* → CH3OH. The FE of electrochemical CO2 reduction to methanol over [email protected]2O-400 °C electrocatalyst was ≥35% at −0.6 ∼ −1.0 V (vs. RHE). The [email protected]2O-400 °C electrocatalyst exhibited a peak FECH3OH of 45% at −0.7 V, which was attributed to synergistic effect between Cu0 and Cu+ active sites.