التفاصيل البيبلوغرافية
| العنوان: |
Methanol Dehydrogenation on Pt Electrodes: Active Sites and Role of Adsorbed Spectators Revealed through Time-Resolved ATR-SEIRAS |
| المؤلفون: |
Laura Pérez-Martínez (11596727), Laura M. Machado de los Toyos (11596730), Jani J. T. Shibuya (11596733), Angel Cuesta (1271742) |
| سنة النشر: |
2021 |
| المجموعة: |
Smithsonian Institution: Digital Repository |
| مصطلحات موضوعية: |
Biophysics, Biochemistry, Medicine, Cell Biology, Neuroscience, Biotechnology, Ecology, Chemical Sciences not elsewhere classified, reversible hydrogen electrode, occurs nearly exclusively, initially remains constant, hydrogen underpotential adsorption, direct spectroscopic determination, 06 v ), l , ad , ), tafel plots revealing, low methanol concentration, important role played, experiments also allow, linearly bonded co, → 0 ), co , sufficiently negative potential, adsorbed spectators revealed, , adsorbed spectators, bonded co, versus < |
| الوصف: |
The dynamics of methanol dehydrogenation to adsorbed CO (CO ad ) on polycrystalline Pt in the hydrogen underpotential adsorption (H upd ) region has been investigated under potentiostatic conditions using time-resolved surface-enhanced infrared absorption spectroscopy in the attenuated total reflection mode (ATR-SEIRAS) after a potential step. Our experiments reveal that the electrooxidation of methanol to CO ad is possible at potentials at least as negative as 0.01 V versus reversible hydrogen electrode and occurs nearly exclusively at (111)- and (100)-oriented defect sites, whereby (111)-oriented defects show higher activity unless blocked by spectator species. Under conditions in which, due to a combination of low methanol concentration and sufficiently negative potential, the formation of CO ad is very slow, we have been able to determine the singleton frequency of linearly bonded CO ad (CO L ) on Pt (2002 cm –1 ± 2 between 0.01 and 0.06 V). Under these conditions, the slow increase in the coverage of CO ad (θ CO ), as revealed by the increase of the integrated intensity of the bands corresponding to CO L and bridge or multiple-bonded CO ad (CO B /CO M ), is not accompanied by an increase in the CO L stretching frequency (ν COL ), which initially remains constant and then increases sharply, an effect that repeats itself several times, giving rise to a staircase-like increase of ν CO L before it starts to increase monotonously in parallel with θ CO . We attribute this behavior to the progressive population of terraces by CO ad diffusing from the defect sites where it has been formed. We also detected under these conditions a band at 1677 cm –1 , which we attribute to adsorbed formyl (HCO ad ) and which we suggest is the last intermediate in the oxidation leading from methanol to CO ad . Our experiments also allow the direct spectroscopic determination of the rate of formation of CO ad at the limit of zero coverage (θ CO → 0), from which Tafel plots revealing the potential dependence of the reaction rate when ... |
| نوع الوثيقة: |
article in journal/newspaper |
| اللغة: |
unknown |
| Relation: |
https://figshare.com/articles/journal_contribution/Methanol_Dehydrogenation_on_Pt_Electrodes_Active_Sites_and_Role_of_Adsorbed_Spectators_Revealed_through_Time-Resolved_ATR-SEIRAS/16860524 |
| DOI: |
10.1021/acscatal.1c03870.s001 |
| الاتاحة: |
https://doi.org/10.1021/acscatal.1c03870.s001 |
| Rights: |
CC BY-NC 4.0 |
| رقم الانضمام: |
edsbas.9F43A4C1 |
| قاعدة البيانات: |
BASE |