Lateral Adsorbate Interactions Inhibit HCOO − while Promoting CO Selectivity for CO 2 Electrocatalysis on Silver
Ag is a promising catalyst for the production of carbon monoxide (CO) via the electrochemical reduction of carbon dioxide (CO 2 ER). Herein, we study the role of the formate (HCOO − ) intermediate *OCHO, aiming to resolve the discrepancy between the theoretical understanding and experimental performance of Ag. We show that the first coupled proton-electron transfer (CPET) step in the CO pathway competes with the Volmer step for formation of *H, whereas this Volmer step is a prerequisite for the formation of *OCHO. We show that *OCHO should form readily on the Ag surface owing to solvation and favorable binding strength. In situ surface-enhanced Raman spectroscopy (SERS) experiments give preliminary evidence of the presence of O-bound bidentate species on polycrystalline Ag during CO 2 ER which we attribute to *OCHO. Lateral adsorbate interactions in the presence of *OCHO have a significant influence on the surface coverage of *H, resulting in the inhibition of HCOO − and H 2 production and a higher selectivity towards CO.
| Main Authors: | , , , , , |
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| Format: | Article/Letter to editor biblioteca |
| Language: | English |
| Subjects: | DFT, Raman spectroscopy, adsorbate-adsorbate interactions, electrocatalysis, in situ studies, |
| Online Access: | https://research.wur.nl/en/publications/lateral-adsorbate-interactions-inhibit-hcoo-supsup-while-promotin |
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| Summary: | Ag is a promising catalyst for the production of carbon monoxide (CO) via the electrochemical reduction of carbon dioxide (CO 2 ER). Herein, we study the role of the formate (HCOO − ) intermediate *OCHO, aiming to resolve the discrepancy between the theoretical understanding and experimental performance of Ag. We show that the first coupled proton-electron transfer (CPET) step in the CO pathway competes with the Volmer step for formation of *H, whereas this Volmer step is a prerequisite for the formation of *OCHO. We show that *OCHO should form readily on the Ag surface owing to solvation and favorable binding strength. In situ surface-enhanced Raman spectroscopy (SERS) experiments give preliminary evidence of the presence of O-bound bidentate species on polycrystalline Ag during CO 2 ER which we attribute to *OCHO. Lateral adsorbate interactions in the presence of *OCHO have a significant influence on the surface coverage of *H, resulting in the inhibition of HCOO − and H 2 production and a higher selectivity towards CO. |
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