02213nas a2200313 4500008004100000022001400041245014500055210006900200260000800269300001600277490000700293520116000300653001701460653003401477653001901511653002801530653002301558653001901581100002801600700001301628700001701641700001901658700001901677700002501696700002001721700001801741700001401759856012601773 2022 eng d a2155-543500aBoosting electrochemical CO2 reduction to methane via tuning oxygen vacancy concentration and surface termination on a copper/ceria catalyst0 aBoosting electrochemical CO2 reduction to methane via tuning oxy cSEP a10973-109830 v123 a

Metal oxides are a promising material for designing highly active and selective catalysts for the electrochemical reduction of carbon dioxide (CO2RR). Here, we designed a Cu/ceria catalyst with high selectivity of methane production at single-atomic Cu active sites. Using this, we report favorable design concepts that push the product selectivity of methane formation by combining detailed structural analysis, density functional theory (DFT), in situ Raman spectroscopy, and electrochemical measurements. We demonstrate that a higher concentration of oxygen vacancies on the catalyst surface, resulting from more available Cu+ sites, enables high selectivity for methane formation during CO2RR and can be controlled by the calcination temperature. The DFT calculation and in situ Raman studies indicate that pH controls the surface termination; a more alkaline pH generates hydroxylated surface motifs with more active sites for the hydrogen evolution reaction. These findings provide insights into designing an efficient metal oxide electrocatalyst by controlling the atomic structure via the reaction environment and synthesis conditions.

10acopper-ceria10aelectrochemical CO2 reduction10aelectrolyte pH10agas diffusion electrode10amethane production10aOxygen vacancy1 aPatra, Kshirodra, Kumar1 aLiu, Zhu1 aLee, Hojeong1 aHong, Seungwon1 aSong, Hakhyeon1 aAbbas, Hafiz, Ghulam1 aKwon, Youngkook1 aRinge, Stefan1 aOh, Jihun uhttps://library.ncl.res.in/content/boosting-electrochemical-co2-reduction-methane-tuning-oxygen-vacancy-concentration-and