Selective reduction of CO to acetaldehyde with CuAg electrocatalysts

Abstract

Electrochemical CO reduction can serve as a sequential step in the transformation of CO2into multicarbon fuels and chemicals. In this study, we provide insights on how to steer selectivity for CO reduction almost exclusively toward a single multicarbon oxygenate by carefully controlling the catalyst composition and its surrounding reaction conditions. Under alkaline reaction conditions, we demonstrate that planar CuAg electrodes can reduce CO to acetaldehyde with over 50% Faradaic efficiency and over 90% selectivity on a carbon basis at a modest electrode potential of −0.536 V vs. the reversible hydrogen electrode. The Faradaic efficiency to acetaldehyde was further enhanced to 70% by increasing the roughness factor of the CuAg electrode. Density functional theory calculations indicate that Ag ad-atoms on Cu weaken the binding energy of the reduced acetaldehyde intermediate and inhibit its further reduction to ethanol, demonstrating that the improved selectivity to acetaldehyde is due to the electronic effect from Ag incorporation. These findings will aid in the design of catalysts that are able to guide complex reaction networks and achieve high selectivity for the desired product.

Operando Investigation of Ag‐Decorated Cu2O Nanocube Catalysts with Enhanced CO2 Electroreduction toward Liquid Products

“…DFT calculations of our previous study showed that an expanded Cu lattice increases the binding energies for the intermediates of CO 2 RR (e.g., *CO on Cu) [9c] . Additionally, Ag incorporation in Cu weakens the binding energies of the reduced aldehyde intermediates and inhibits their further reduction to ethanol and 1‐propanol as demonstrated in a recent DFT study [22] . However, the structural analysis of the catalysts showed that the surface partially consists of Cu/Ag areas, which also leads to the formation of ethanol and 1‐propanol at the Cu sites, since they are expected to have higher binding energies for the oxygenated intermediates as compared to the Ag–Cu mixed regions.…”

Efficient electroreduction of CO2to C2+products on CeO2modified CuO

“…Generally, CO 2 can be rst reduced into CO through the *COOH pathway, 28 and the adsorbed CO is regarded as the common intermediate for the C 2+ products in CO 2 RR. 66 In this condition, four potential reaction pathways are taken into account in the C-C coupling step and all of them are generated from the vital intermediate *CO (Fig. S28-S33 †).…”

Operando‐Untersuchung von Ag‐dekorierten Cu2O‐Nanowürfel‐Katalysatoren mit verbesserter CO2‐Elektroreduktion zu Flüssigprodukten

“…*CO auf Cu) erhöht [9c] . Außerdem schwächt die Einführung von Ag in Cu die Bindungsenergien der reduzierten Aldehyd‐Intermediate und hemmt deren weitere Reduktion zu Ethanol und 1‐Propanol, wie eine neuen DFT‐Studie dargelegte [22] . Trotzdem zeigte die genaue strukturelle Analyse der Katalysatoren, dass die Oberfläche teilweise auch aus Cu/Ag‐Flächen besteht.…”