Efficient reduction of CO2 to C2 hydrocarbons by tandem nonthermal plasma and photocatalysis

Abstract

CO2 photoreduction to hydrocarbons is a carbon-neutral technology for renewable energy. However, this strategy is challenged by the thermodynamic stability of CO2 and the low efficiency of multi-photoelectron utilization. In this paper, tandem nonthermal plasma and photocatalysis were used to effectively improve the efficiency of CO2 reduction to C2. We first activated CO2 by nonthermal plasma technology (NTP) and then converted the activated CO2 into C2 products by Cd0.8Zn0.2S/In2O3 photocatalyst with a special nanostructure. Without the addition of any sacrificial agent, the C2 yield of the catalyst reached 0.382 μmol h−1, which is one of the highest performances to date. In situ experimental and computational studies show that CO2+ activated by NTP has higher π orbital and HUMO levels of lone pair electrons and promotes the reduction of CO2+ by injecting electrons into the vacant orbital of the active site of Zn. At the same time, the unique structure of Cd0.8Zn0.2S/In2O3 photocatalyst can extend the life of charge through the optical field enhancement effect, and then react with the CO2+ intermediates generated by NTP technology to promote the coupling of C-C bonds, and finally promote the photocatalytic multi-electron reaction to produce C2 hydrocarbons.