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

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 Cd_0.8Zn_0.2S/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 Cd_0.8Zn_0.2S/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.