Role of H2O in CO2 Electrochemical Reduction As Studied in a Water-in-Salt System
| Autor: | Da He, Qi Dong, Xizi Zhang, Chaochao Lang, Dunwei Wang |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
010405 organic chemistry
Chemistry General Chemical Engineering Solvation General Chemistry Electrolyte 010402 general chemistry Electrochemistry 01 natural sciences 0104 chemical sciences Catalysis Reaction rate Electron transfer Electrokinetic phenomena Chemical physics Electrode QD1-999 Research Article |
| Zdroj: | ACS Central Science ACS Central Science, Vol 5, Iss 8, Pp 1461-1467 (2019) |
| ISSN: | 2374-7951 2374-7943 |
| Popis: | CO2 electrochemical reduction is of great interest not only for its technological implications but also for the scientific challenges it represents. How to suppress the kinetically favored hydrogen evolution in the presence of H2O, for instance, has attracted significant attention. Here we report a new way of achieving such a goal. Our strategy involves a unique water-in-salt electrolyte system, where the H2O concentration can be greatly suppressed due to the strong solvation of the high-concentration salt. More importantly, the water-in-salt electrolyte offers an opportunity to tune the H2O concentration for electrokinetic studies of CO2 reduction, a parameter of critical importance to the understanding of the detailed mechanisms but difficult to vary previously. Using Au as a model catalyst platform, we observed a zeroth-order dependence of the reaction rate on the H2O concentration, strongly suggesting that electron transfer, rather than concerted proton electron transfer, from the electrode to the adsorbed CO2 is the rate-determining step. The results shed new light on the mechanistic understanding of CO2 electrochemical reduction. Our approach is expected to be applicable to other catalyst systems, as well, which will offer a new dimension to mechanistic studies by tuning H2O concentrations. A water-in-salt system was used to understand the role of H2O in CO2 electrochemical reduction. Improved CO selectivity was achieved owing to the suppressed hydrogen evolution reaction. |
| Databáze: | OpenAIRE |
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