title: Monodisperse Au nanoparticles for selective electrocatalytic reduction of CO2 to CO.
abstract: We report selective electrocatalytic reduction of carbon dioxide to carbon monoxide on gold nanoparticles (NPs) in 0.5 M KHCO3 at 25 °C. Among monodisperse 4, 6, 8, and 10 nm NPs tested, the 8 nm Au NPs show the maximum Faradaic efficiency (FE) (up to 90% at -0.67 V vs reversible hydrogen electrode, RHE). Density functional theory calculations suggest that more edge sites (active for CO evolution) than corner sites (active for the competitive H2 evolution reaction) on the Au NP surface facilitates the stabilization of the reduction intermediates, such as COOH*, and the formation of CO. This mechanism is further supported by the fact that Au NPs embedded in a matrix of butyl-3-methylimidazolium hexafluorophosphate for more efficient COOH* stabilization exhibit even higher reaction activity (3 A/g mass activity) and selectivity (97% FE) at -0.52 V (vs RHE). The work demonstrates the great potentials of using monodisperse Au NPs to optimize the available reaction intermediate binding sites for efficient and selective electrocatalytic reduction of CO2 to CO.
authors.affiliation: Department of Chemistry and ‡School of Engineering, Brown University , Providence, Rhode Island 02912, United States.
authors.forename: Wenlei
authors.initials: W
authors.lastname: Zhu
authors.forename: Ronald
authors.initials: R
authors.lastname: Michalsky
authors.forename: Önder
authors.initials: Ö
authors.lastname: Metin
authors.forename: Haifeng
authors.initials: H
authors.lastname: Lv
authors.forename: Shaojun
authors.initials: S
authors.lastname: Guo
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Wright
authors.forename: Xiaolian
authors.initials: X
authors.lastname: Sun
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Peterson
authors.forename: Shouheng
authors.initials: S
authors.lastname: Sun