Efficient reduction of CO2 to CO over grain boundary rich gold film reconstructed by O2 plasma treatment

Electrochemical carbon dioxide reduction offers a potential way to simultaneously mitigate carbon emission and produce value-added carbonaceous fuels and feedstock. This work proposes a facile method of O-2 plasma bombardment to obtain efficient Au electrodes for selectively CO2 reduction. A sustainable setup assisted by solar energy is used to realize green utilization of CO2, with Fe2O3 photoanode for voltage compensation and Si solar cell for external bias. The O-2 plasma treatment of Au results in formation of grain boundaries via fast surface reconstruction. The Au film with higher density of grain boundary possesses higher electrochemical active surface area, lower surface work function, and faster charge transfer through Au/electrolyte interface, which can facilitate the CO2 reduction. Compared with the as-deposited Au film, the O-2 plasma treated Au film displays a lower overpotential and enhanced CO2-to-CO conversion performance. Faradic efficiency of 88.7% towards CO is achieved over plasma treated Au film.

Automated summary

Electrochemical carbon dioxide reduction using O-2 plasma treated Au electrodes showed enhanced CO2 reduction performance with higher Faradic efficiency of 88.7% towards CO. The sustainable setup assisted by solar energy demonstrated efficient green utilization of CO2, utilizing Fe2O3 photoanode for voltage compensation and Si solar cell for external bias. The formation of grain boundaries on Au film through O-2 plasma treatment led to higher electrochemical active surface area, lower surface work function, and faster charge transfer, facilitating the CO2 reduction process.