Abstract
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.