By discharging nanosecond high-voltage pulses in CO₂-saturated water, we observe CO₂ reduction to higher-order hydrocarbons, including acetic acid, formic acid, and oxalate. Here, the plasma emission spectra exhibit Swan bands, which correspond to C₂ species, indicating that in addition to reducing CO₂, C₂-species are formed, which presents the possibility of converting a notorious greenhouse gas into liquid (i.e., dense) hydrocarbon fuels. In order to characterize various hydrocarbon products formed in this process, cryogenic NMR spectroscopy and liquid ion chromatography are performed ex situ. Here, we observe clear peaks corresponding to formic acid (CH₂O₂) and acetic acid (CH₃COOH). We have also observed the presence of formate (HCO₂^–), acetate (C₂H₃O₂^–), and oxalate (C₂O₄^2–) using liquid ion chromatography. Plasma emission spectroscopy exhibits spectral signatures associated with atomic hydrogen and atomic oxygen due to the plasma discharge in water, which facilitate (and compete with) the CO₂-to-hydrocarbon conversion.

中文翻译：

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在碳酸水中通过等离子体放电将 CO2 还原为高级碳氢化合物

通过在 CO ₂饱和水中放电纳秒高压脉冲，我们观察到 CO ₂还原为高级烃，包括乙酸、甲酸和草酸盐。在这里，等离子体发射光谱表现出对应于 C ₂物种的斯旺带，表明除了减少 CO _{2 外}，还形成了C ₂物种，这提供了将臭名昭著的温室气体转化为液体（即致密）的可能性碳氢燃料。为了表征在该过程中形成的各种烃产物，低温核磁共振光谱和液相离子色谱在异位进行。在这里，我们观察到与甲酸（CH₂ O ₂ ) 和乙酸 (CH ₃ COOH)。我们还使用液体离子色谱法观察到甲酸盐 (HCO ₂ ^– )、乙酸盐 (C ₂ H ₃ O ₂ ^– ) 和草酸盐 (C ₂ O ₄ ^2– ) 的存在。由于水中的等离子体放电，等离子体发射光谱表现出与原子氢和原子氧相关的光谱特征，这促进（并与之竞争）CO ₂到烃的转化。