Enhanced Stability and CO/Formate Selectivity of Plasma-Treated SnO x /AgO x Catalysts during CO 2 Electroreduction

• Published in: Journal of the American Chemical Society Vol. 141; no. 13; pp. 5261 - 5266
• Main Authors: Choi, Yong-Wook, Scholten, Fabian, Sinev, Ilya, Roldan Cuenya, Beatriz
• Format: Journal Article
• Language: English
• Published: United States 03.04.2019
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.8b12766

CO electroreduction into useful chemicals and fuels is a promising technology that might be used to minimize the impact that the increasing industrial CO emissions are having on the environment. Although plasma-oxidized silver surfaces were found to display a considerably decreased overpotential for the production of CO, the hydrogen evolution reaction (HER), a competing reaction against CO reduction, was found to increase over time. More stable and C1-product-selective SnO /AgO catalysts were obtained by electrodepositing Sn on O -plasma-pretreated Ag surfaces. In particular, a strong suppression of HER (below 5% Faradaic efficiency (FE) at -0.8 V vs the reversible hydrogen electrode, RHE) during 20 h was observed. Ex situ scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS), quasi in situ X-ray photoelectron spectroscopy (XPS), and operando X-ray absorption near-edge structure spectroscopy (XANES) measurements showed that our synthesis led to a highly roughened surface containing stable Sn /Sn species that were found to be key in the enhanced activity and stable CO/formate (HCOO ) selectivity. Our study highlights the importance of roughness, composition, and chemical state effects in CO electrocatalysis.