Electrochemical Plasma-Activated CO₂ Reduction at a Plasma-Water Interface

The development of technologies and processes to decarbonize chemical and fuel production is key to reducing global anthropogenic greenhouse gas emissions. Electrochemical carbon dioxide reduction enables a sustainable pathway to circularize carbon-based chemical products by upgrading recovered carbon dioxide using renewable energy sources. Electrochemical CO 2 reduction has successfully been employed to produce chemicals such as methanol and ethylene, but it has been hindered by dependence on elevated temperature to achieve high yields and limited ability to generate higher order carbon products. Non-thermal carbon dioxide plasma can be generated at ambient temperature and pressure and contains energetically excited oxygen and carbon species. When introduced to an electrocatalyst, these reactive species could more readily participate in reaction pathways with higher activation barriers towards forming higher order carbon species compared to electrochemical reactions involving ground-state reactants. Further, plasma discharges over water in an electrochemical cell generate plasma-activated water, introducing solvated electrons and secondary reactive oxygen species. In this work, we investigate how the use of plasma-activated carbon dioxide and a plasma-water interface impacts electrochemical product generation. We design a novel non-thermal plasma electrode to discharge carbon dioxide plasma into water in an electrochemical cell with a Cu nanoparticle electrocatalyst. Results suggest the potential for a plasma-water electrochemical system to generate value-added products that are less commonly generated in electrochemical processes at ambient pressure and temperature.