Plasma-catalytic CO2 hydrogenation to ethane in a dielectric barrier discharge reactor

Abstract

Anthropogenic greenhouse gas emissions have caused changes to the Earth’s climate, resulting in catastrophic weather events that are becoming more frequent and intense. Developing carbon-neutral processes for CO2 conversion powered by renewable energy is one way of attaining a circular economy, as waste CO2 is converted to a new carbon-containing product, without also being created as a by-product during the process. Plasma-catalysis is gaining increasing interest for CO2 conversion and utilisation under mild conditions, particularly CO2 conversion to green chemicals and fuels using renewable hydrogen, as this electrified process can easily be combined with clean and renewable energy to ensure a carbon-neutral process. Previous studies have mainly focussed on the production of methane from CO2 and H2; however, ethane (C2H6) is a much more valuable product. In this work, we report a non-thermal plasma-catalytic process for the conversion of CO2 into C2H6 in a dielectric barrier discharge (DBD) reactor. The influence of a variety of alumina-supported metal catalysts (Ru, Cu, Ni and Fe) on the plasma-catalytic CO2 hydrogenation to C2H6 was evaluated. The Ru catalyst attained the highest selectivity towards C2H6, at almost 40%. The Ru catalyst also increased the energy efficiency of the process to around 18%, in comparison to the plasma reaction using pure alumina (12%). The Ru catalyst also achieved the highest H2 conversion at 29%. Plasma-assisted production of C2H6 is a new promising process for the utilisation of CO2 via carbon-neutral electrified gas conversion.