High-Pressure CO Electroreduction at Silver Produces Ethanol and Propanol

Reducing CO₂ to long-chain carbon products is attractive considering such products are typically more valuable than shorter ones. However, the best electrocatalyst for making such products from CO₂ , copper, lacks selectivity. By studying alternate C₂₊ producing catalysts we can increase our mechanistic understanding, which is beneficial for improving catalyst performance. Therefore, we investigate CO reduction on silver, as density functional theory (DFT) results predict it to be good at forming ethanol. To address the current disagreement between DFT and experimental results (ethanol vs. no ethanol), we investigated CO reduction at higher surface coverage (by increasing pressure) to ascertain if desorption effects can explain the discrepancy. In terms of product trends, our results agree with the DFT-proposed acetaldehyde-like intermediate, yielding ethanol and propanol as C₂₊ products-making the CO₂ electrochemistry of silver very similar to that of copper at sufficiently high coverage.