Formation of 1-Butanol from CO₂ without *CO Dimerization on a Phosphorus-Rich Copper Cathode

In this paper we first report the generation of 1-butanol from carbon dioxide (CO2) on a phosphorus-rich copper cathode, based on a combination of faradaic and autonomous nonfaradaic reactions. Experimental observations via in situ surface-enhanced infrared absorption spectroscopy show depletion of the CO adsorption peak. However, the faradaic efficiency of the obtained formate and acetaldehyde intermediates led us to propose a mechanism for the formation of 1-butanol that does not include a *CO dimerization step. All compounds were confirmed by nuclear magnetic resonance spectroscopy and headspace gas chromatography–mass spectrometry. In addition, 13CO2 labeling experiments confirmed that the origin of each product was from dissolved CO2. Results indicated remarkable faradaic efficiency for 1-butanol formation of 3.868%. This study provides a perspective on the C–C coupling reaction on Cu-based electrocatalysts for the electroreduction of CO2 into high-value multicarbon products.