Unique properties of fine bubbles in the electrochemical reduction of carbon dioxide using boron-doped diamond electrodes

The electrochemical CO2 reduction on boron-doped diamond (BDD) electrodes in an aqueous solution with fine bubbles was studied. The overpotential decreased and the production of carbon monoxide was promoted in the CO2 reduction with fine bubbles compared to that without fine bubbles. It is suggested that fine bubbles in solution could facilitate the mass transport and also act as the catalyst for producing carbon monoxide. Potential-dependent in-situ attenuated total reflectance-infrared (ATR-IR) measurements confirmed the catalytic activity, showing that in solutions with CO2 fine bubbles the CO2 center dot- intermediate or the CO2 molecules themselves become stabilized near the electrode and these can be adsorbed on the electrode surface more easily compared to using solutions without CO2 fine bubbles. The reported work is a first step in understanding the effects of fine bubbles in CO2 reduction reactions. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The electrochemical CO2 reduction on boron-doped diamond electrodes in an aqueous solution with fine bubbles showed decreased overpotential and promoted production of carbon monoxide compared to the solution without fine bubbles. Fine bubbles in the solution facilitated mass transport and also acted as a catalyst for producing carbon monoxide. Potential-dependent in-situ ATR-IR measurements confirmed the catalytic activity, indicating that CO2 intermediates or molecules themselves can be stabilized near the electrode in solutions with fine bubbles, making it easier for them to be adsorbed on the electrode surface.