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Favoring CO Intermediate Stabilization and Protonation by Crown Ether for CO2 Electromethanation in Acidic Media |
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| Authors: | Keqiang Xu Jinhan Li Fangming Liu Xijie Chen Tete Zhao Fangyi Cheng |
| Affiliation: | 1. Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Engineering Research Center on High-Efficiency Energy Storage (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry, Nankai University, Tianjin, 300071 China Contribution: Data curation (lead), Formal analysis (lead), Investigation (lead), Methodology (lead), Visualization (lead), Writing - original draft (equal);2. Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Engineering Research Center on High-Efficiency Energy Storage (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry, Nankai University, Tianjin, 300071 China Contribution: Data curation (supporting), Formal analysis (equal), Investigation (supporting), Methodology (equal), Software (equal), Validation (equal);3. Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Engineering Research Center on High-Efficiency Energy Storage (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry, Nankai University, Tianjin, 300071 China;4. Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Engineering Research Center on High-Efficiency Energy Storage (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry, Nankai University, Tianjin, 300071 China Contribution: Data curation (supporting), Formal analysis (supporting), Investigation (supporting), Methodology (supporting), Validation (supporting);5. Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Engineering Research Center on High-Efficiency Energy Storage (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry, Nankai University, Tianjin, 300071 China Contribution: Data curation (supporting), Formal analysis (supporting), Investigation (supporting), Visualization (supporting) |
| Abstract: | The large-scale deployment of CO2 electroreduction is hampered by deficient carbon utilization in neutral and alkaline electrolytes due to CO2 loss into (bi)carbonates. Switching to acidic media mitigates carbonation, but suffers from low product selectivity because of hydrogen evolution. Here we report a crown ether decoration strategy on a Cu catalyst to enhance carbon utilization and selectivity of CO2 methanation under acidic conditions. Macrocyclic 18-Crown-6 is found to enrich potassium cations near the Cu electrode surface, simultaneously enhancing the interfacial electric field to stabilize the *CO intermediate and accelerate water dissociation to boost *CO protonation. Remarkably, the mixture of 18-Crown-6 and Cu nanoparticles affords a CH4 Faradaic efficiency of 51.2 % and a single pass carbon efficiency of 43.0 % toward CO2 electroreduction in electrolyte with pH=2. This study provides a facile strategy to promote CH4 selectivity and carbon utilization by modifying Cu catalysts with supramolecules. |
| Keywords: | CO2 Electroreduction Copper Catalyst Crown Ether Methanation Protonation |