On the relationship between potential of zero charge and solvent dynamics in the reversible hydrogen electrode
| Autor: | Suihao Zhang, Zhenhua Zeng, Huiqiu Deng, Joshua Snyder, Luis Rebollar, Saad Intikhab, Maureen H. Tang |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Hydrogen
010405 organic chemistry Kinetics chemistry.chemical_element Electrolyte 010402 general chemistry Electrochemistry Electrocatalyst 01 natural sciences Catalysis 0104 chemical sciences Chemical kinetics chemistry Chemical physics Kinetic isotope effect Reversible hydrogen electrode Physical and Theoretical Chemistry |
| Zdroj: | Journal of Catalysis. 398:161-170 |
| ISSN: | 0021-9517 |
| DOI: | 10.1016/j.jcat.2021.04.008 |
| Popis: | The impact of interfacial electric fields on electrochemical reaction kinetics is assessed in the context of hydrogen electrocatalysis. Recent efforts have proposed that interfacial electric field strength, as described by the electrode’s potential of zero free charge (pzfc), contributes to the slow kinetics of the alkaline hydrogen evolution and oxidation reactions (HER/HOR) by hindering solvent reorganization. In this work, we examine through single-crystal voltammetry the importance of the interfacial electric field strength on hydrogen reaction kinetics using three complementary approaches: (1) correlating the pzfc with reaction kinetics using caffeinated Pt as a model surface; (2) varying the electrolyte ionic strength at constant pH; and (3) probing solvent dynamics via caffeinated kinetic isotope effects (KIEs). Our results show that pzfc seems to correlate with HER/HOR kinetics, but also suggest that the effect more likely originates from activation barriers to the reaction elementary steps than from electric field effects on solvent dynamics. Although the importance of interfacial phenomena such as the electrode’s pzfc and water reorganization energy are well established, the pzfc may not be a mechanistic descriptor of the alkaline hydrogen reaction kinetics. Surface additives such as caffeine may help elucidate the origin behind the slow alkaline HER/HOR kinetics and ways to manipulate it. |
| Databáze: | OpenAIRE |
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