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For the conversion of CO 2 into fuels and chemical feedstocks, hybrid gas/liquid-fed electrochemical flow reactors provide advantages in selectivity and production rates over traditional liquid phase reactors. However, fundamental questions remain about how to optimize conditions to produce desired products. Using an alkaline electrolyte to suppress hydrogen formation and a gas diffusion electrode catalyst composed of copper nanoparticles on carbon nanospikes, we investigate how hydrocarbon product selectivity in the CO 2 reduction reaction in hybrid reactors depends on three experimentally controllable parameters: (1) supply of dry or humidified CO 2 gas, (2) applied potential, and (3) electrolyte temperature. Changing from dry to humidified CO 2 dramatically alters product selectivity from C 2 products ethanol and acetic acid to ethylene and C 1 products formic acid and methane. Water vapor evidently influences product selectivity of reactions that occur on the gas-facing side of the catalyst by adding a source of protons that alters reaction pathways and intermediates.
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Acid–Base Interaction Enhancing Oxygen Tolerance in Electrocatalytic Carbon Dioxide Reduction
Abstract Hybrid electrodes with improved O2tolerance and capability of CO2conversion into liquid products in the presence of O2are presented. Aniline molecules are introduced into the pore structure of a polymer of intrinsic microporosity to expand its gas separation functionality beyond pure physical sieving. The chemical interaction between the acidic CO2molecule and the basic amino group of aniline renders enhanced CO2separation from O2. Loaded with a cobalt phthalocyanine‐based cathode catalyst, the hybrid electrode achieves a CO Faradaic efficiency of 71 % with 10 % O2in the CO2feed gas. The electrode can still produce CO at an O2/CO2ratio as high as 9:1. Switching to a Sn‐based catalyst, for the first time O2‐tolerant CO2electroreduction to liquid products is realized, generating formate with nearly 100 % selectivity and a current density of 56.7 mA cm−2in the presence of 5 % O2.
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- Award ID(s):
- 1651717
- PAR ID:
- 10145561
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 59
- Issue:
- 27
- ISSN:
- 1433-7851
- Page Range / eLocation ID:
- p. 10918-10923
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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