Structure- and Potential-Dependent Cation Effects on CO Reduction at Copper Single-Crystal Electrodes.
The complexity of the electrocatalytic reduction of CO to CH and CH on copper electrodes prevents a straightforward elucidation of the reaction mechanism and the design of new and better catalysts. Although structural and electrolyte effects have been separately studied, there are no reports on stru...
| Published in: | Journal of the American Chemical Society Vol. 139; no. 45; pp. 16412 - 16420 |
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| Main Authors: | , , , , |
| Format: | Article |
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American Chemical Society
11/15/2017
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| Subjects: | |
| Online Access: | View this record in EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=126380020&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 126380020 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: 11/15/2017 vid: 139 iid: 45 pid: 997 pub: American Chemical Society artinfo: ui: 126380020 10.1021/jacs.7b10142 ppf: 16412 ppct: 8 formats: tig: atl: Structure- and Potential-Dependent Cation Effects on CO Reduction at Copper Single-Crystal Electrodes. aug: au: Pérez-Gallent, Elena Marcandalli, Giulia Figueiredo, Marta Costa Calle-Vallejo, Federico Koper, Marc T. M. affil: Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands Departament de Ciència de Materials i Química Fisica & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, Martí i Franqués 1, 08028 Barcelona, Spain su: Cation analysis Carbon monoxide Chemical reduction Electrodes Copper crystals Density functionals sug: subj: Cation analysis Carbon monoxide Chemical reduction Electrodes Copper crystals Density functionals ab: The complexity of the electrocatalytic reduction of CO to CH and CH on copper electrodes prevents a straightforward elucidation of the reaction mechanism and the design of new and better catalysts. Although structural and electrolyte effects have been separately studied, there are no reports on structure-sensitive cation effects on the catalyst's selectivity over a wide potential range. Therefore, we investigated CO reduction on Cu(100), Cu(111), and Cu-(polycrystalline) electrodes in 0.1 M alkaline hydroxide electrolytes (LiOH, NaOH, KOH, RbOH, CsOH) between 0 and -1.5 V vs RHE. We used online electrochemical mass spectrometry and high-performance liquid chromatography to determine the product distribution as a function of electrode structure, cation size, and applied potential. First, cation effects are potential dependent, as larger cations increase the selectivity of all electrodes toward ethylene at E > -0.45 V vs RHE, but methane is favored at more negative potentials. Second, cation effects are structure-sensitive, as the onset potential for CH formation depends on the electrode structure and cation size, whereas that for CH does not. Fourier Transform infrared spectroscopy (FTIR) and density functional theory help to understand how cations favor ethylene over methane at low overpotentials on Cu(100). The rate-determining step to methane and ethylene formation is CO hydrogenation, which is considerably easier in the presence of alkaline cations for a CO dimer compared to a CO monomer. For Li and Na, the stabilization is such that hydrogenated dimers are observable with FTIR at low overpotentials. Thus, potential-dependent, structure-sensitive cation effects help steer the selectivity toward specific products. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2017 holdings: @attributes: islocal: N |
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