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

Coupling direct air capture (DAC) with methane (CH ₄ ) production is a potential strategy for fuel production from the air. Here, we report a hybrid electro-thermochemical device for direct CH ₄ production from air. The proposed device features the cogeneration of carbon dioxide (CO ₂ ) and hydrogen (H ₂ ) in a single compartment via a bipolar membrane electrodialysis module, avoiding a separate water electrolyzer, followed by a thermochemical methanation reaction to produce CH ₄ . H ₂ -induced disturbances lead to efficient CO ₂ 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 ₄ cost is reduced by 12.6%. Our proof-of-concept experiments show that the energy consumption for CO ₂ release and H ₂ production is 704.0 kJ mol ^-1 and 967.4 kJ mol ^-1 , respectively with subsequent methanation achieving a 97.3% conversion of CO ₂ and a CH ₄ production energy of 5206.4 kJ mol ^-1 showing a promising pathway for fuel processing from the air.
(© 2024. The Author(s).)