Enhancing CO2 Electroreduction to Ethanol on Copper–Silver Composites by Opening an Alternative Catalytic Pathway
| Autor: | Oriol Piqué, Mohammad Tanhaei, Si Ying Lim, Federico Calle-Vallejo, Louisa Rui Lin Ting, Boon Siang Yeo |
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| Rok vydání: | 2020 |
| Předmět: |
Reaction mechanism
Ethanol 010405 organic chemistry Chemistry chemistry.chemical_element General Chemistry 010402 general chemistry Electrocatalyst Electrochemistry 01 natural sciences Redox Combinatorial chemistry Copper Catalysis 0104 chemical sciences copper−silver chemistry.chemical_compound electrocatalysis ethanol reaction mechanism Selectivity electrochemical CO2 reduction |
| Zdroj: | ACS Catalysis. 10:4059-4069 |
| ISSN: | 2155-5435 |
| DOI: | 10.1021/acscatal.9b05319 |
| Popis: | A fundamental question in the electrochemical CO2 reduction reaction (CO2RR) is how to rationally control the catalytic selectivity. For instance, adding a CO-producing metal like Ag to Cu shifts the latter’s CO2RR selectivity towards C2 products, but the underlying cause of the change is unclear. Herein, we show that CuAg boundaries facilitate the coupling of carbon-containing species to give ethanol, through an otherwise closed pathway. Oxide-derived Cu nanowires mixed with 20 nm Ag particles (Cu:Ag mole ratio of 1:20) reduce CO2 to ethanol with a current density of -4.1 mA/cm2 at -1.1 V vs. RHE and ethanol/ethylene Faradaic efficiency ratio of 1.1. These figures of merit are respectively 5 and 3 times higher than those for pure oxide-derived Cu nanowires. CO2RR using different Ag:Cu ratios and Ag particle sizes reveals that ethanol production scales with CO production on the Ag sites and the abundance of CuAg boundaries, and, very interestingly, without significant modifications to ethylene formation. Computational modelling shows selective ethanol evolution via Langmuir-Hinshelwood *CO + *CHx (x = 1, 2) coupling at CuAg boundaries, and that the formation of energy-intensive CO dimers is circumvented. This work is supported by an academic research fund (R-143-000-683-112) from the Ministry of Education, Singapore and the National University of Singapore Flagship Green Energy Program (R-143-000-A55-646 and R-143-000-A55-733). F.C.-V acknowledges funding from Spanish MICIUN RTI2018-095460–B-I00 and María de Maeztu MDM-2017-0767 grants and, in part, by Generalitat de Catalunya 2017SGR13. O.P. thanks the Spanish MICIUN for a PhD grant (PRE2018-083811). We thank Red Española de Supercomputación (RES) for supercomputing time at SCAYLE (projects QS-2019-3-0018, QS-2019-2-0023 and QCM-2019-1-0034). The use of supercomputing facilities at SURFsara was sponsored by NWO Physical Sciences, with financial support by NWO. We also thank Cheryldine Lim from the SERIS for assisting with SEM and EDX mapping experiments, and Futian You and Ka Yau Lee from the NUS for assisting with TEM imaging. |
| Databáze: | OpenAIRE |
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