Surface hydroxide promotes CO<sub>2</sub> electrolysis to ethylene in acidic conditions.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37185342.
- Also identified by DOI 10.1038/s41467-023-37898-8 and PMC identifier 10130127.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Performing CO<sub>2</sub> reduction in acidic conditions enables high single-pass CO<sub>2</sub> conversion efficiency. However, a faster kinetics of the hydrogen evolution reaction compared to CO<sub>2</sub> reduction limits the selectivity toward multicarbon products. Prior studies have shown that adsorbed hydroxide on the Cu surface promotes CO<sub>2</sub> reduction in neutral and alkaline conditions. We posited that limited adsorbed hydroxide species in acidic CO<sub>2</sub> reduction could contribute to a low selectivity to multicarbon products. Here we report an electrodeposited Cu catalyst that suppresses hydrogen formation and promotes selective CO<sub>2</sub> reduction in acidic conditions. Using in situ time-resolved Raman spectroscopy, we show that a high concentration of CO and OH on the catalyst surface promotes C-C coupling, a finding that we correlate with evidence of increased CO residence time. The optimized electrodeposited Cu catalyst achieves a 60% faradaic efficiency for ethylene and 90% for multicarbon products. When deployed in a slim flow cell, the catalyst attains a 20% energy efficiency to ethylene, and 30% to multicarbon products.