Hydronium-Induced Switching between CO Electroreduction Pathways.
Over a broad range of operating conditions, many CO electroreduction catalysts can maintain selectivity toward certain reduction products, leading to materials and surfaces being categorized according to their products; here we ask, is product selectivity truly a property of the catalyst? Silver is...
| Publicado en: | Journal of the American Chemical Society Vol. 140; no. 11; pp. 3833 - 3838 |
|---|---|
| Autores principales: | , , , , , , , , , |
| Formato: | Artículo |
| Publicado: |
American Chemical Society
3/21/2018
|
| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=128662222&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 128662222 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 3/21/2018 vid: 140 iid: 11 pid: 997 pub: American Chemical Society artinfo: ui: 128662222 10.1021/jacs.7b13542 ppf: 3833 ppct: 5 formats: tig: atl: Hydronium-Induced Switching between CO Electroreduction Pathways. aug: au: Seifitokaldani, Ali Dinh, Cao-Thang Kibria, Md Golam Sargent, Edward H. Bushuyev, Oleksandr S. Gabardo, Christine M. Burdyny, Thomas Edwards, Jonathan P. Sinton, David Kelley, Shana O. affil: Department of Electrical and Computer Engineering, University of Toronto, 35 St. George Street, Toronto, Ontario M5S 1A4, Canada Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3G4, Canada Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario M5S 3G8, Canada Department of Pharmaceutical Sciences, University of Toronto, Leslie Dan Faculty of Pharmacy, 144 College Street, Toronto, Ontario M5S 3M2, Canada su: Oxonium ions Electrolytic reduction Density functional theory Hydrogenation Potassium hydroxide Carbon dioxide sug: subj: Oxonium ions Electrolytic reduction Density functional theory Hydrogenation Potassium hydroxide Carbon dioxide ab: Over a broad range of operating conditions, many CO electroreduction catalysts can maintain selectivity toward certain reduction products, leading to materials and surfaces being categorized according to their products; here we ask, is product selectivity truly a property of the catalyst? Silver is among the best electrocatalysts for CO in aqueous electrolytes, where it reaches near-unity selectivity. We consider the hydrogenations of the oxygen and carbon atoms via the two proton-coupled-electron-transfer processes as chief determinants of product selectivity; and find using density functional theory (DFT) that the hydronium (HO) intermediate plays a key role in the first oxygen hydrogenation step and lowers the activation energy barrier for CO formation. When this hydronium influence is removed, the activation energy barrier for oxygen hydrogenation increases significantly, and the barrier for carbon hydrogenation is reduced. These effects make the formate reaction pathway more favorable than CO. Experimentally, we then carry out CO reduction in highly concentrated potassium hydroxide (KOH), limiting the hydronium concentration in the aqueous electrolyte. The product selectivity of a silver catalyst switches from entirely CO under neutral conditions to over 50% formate in the alkaline environment. The simulated and experimentally observed selectivity shift provides new insights into the role of hydronium on CO electroreduction processes and the ability for electrolyte manipulation to directly influence transition state (TS) kinetics, altering favored CO reaction pathways. We argue that selectivity should be considered less of an intrinsic catalyst property, and rather a combined product of the catalyst and reaction environment. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2018 holdings: @attributes: islocal: N |
|---|