A hybrid electro-thermochemical device for methane production from the air.

Huang, Yaowei; Xu, Da; Deng, Shuai; Lin, Meng · Nat Commun · 2024

basic_science · Level V

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Abstract

Coupling direct air capture (DAC) with methane (CH<sub>4</sub>) production is a potential strategy for fuel production from the air. Here, we report a hybrid electro-thermochemical device for direct CH<sub>4</sub> production from air. The proposed device features the cogeneration of carbon dioxide (CO<sub>2</sub>) and hydrogen (H<sub>2</sub>) in a single compartment via a bipolar membrane electrodialysis module, avoiding a separate water electrolyzer, followed by a thermochemical methanation reaction to produce CH<sub>4</sub>. H<sub>2</sub>-induced disturbances lead to efficient CO<sub>2</sub> extraction without pumping requirement. The energy consumption and techno-economic analysis predict an energy reduction of 37.8% for DAC and a cost reduction of 36.6% compared with the decoupled route, respectively. Accordingly, CH<sub>4</sub> cost is reduced by 12.6%. Our proof-of-concept experiments show that the energy consumption for CO<sub>2</sub> release and H<sub>2</sub> production is 704.0 kJ mol<sup>-1</sup> and 967.4 kJ mol<sup>-1</sup>, respectively with subsequent methanation achieving a 97.3% conversion of CO<sub>2</sub> and a CH<sub>4</sub> production energy of 5206.4 kJ mol<sup>-1</sup> showing a promising pathway for fuel processing from the air.