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 Cu@Cu2O 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 Cu-0/Cu+ and OH on catalyst surfaces. Cu-0/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 Cu@Cu2O-400 degrees C electrocatalyst was >= 35% at-0.6 similar to-1.0 V (vs. RHE). The Cu@Cu2O-400 degrees C electrocatalyst exhibited a peak FECH3OH of 45% at-0.7 V, which was attributed to synergistic effect between Cu-0 and Cu+ active sites.