Feasibility of switchable dual function materials as a flexible technology for CO capture and utilisation and evidence of passive direct air capture.

The feasibility of a Dual Function Material (DFM) with a versatile catalyst offering switchable chemical synthesis from carbon dioxide (CO) was demonstrated for the first time, showing evidence of the ability of these DFMs to passively capture CO directly from the air as well. These DFMs open up possibilities in flexible chemical production from dilute sources of CO, through a combination of CO adsorption and subsequent chemical transformation (methanation, reverse water gas shift or dry reforming of methane). Combinations of Ni Ru bimetallic catalyst with NaO, KO or CaO adsorbent were supported on CeO-AlO to develop flexible DFMs. The designed multicomponent materials were shown to reversibly adsorb CO between the 350 and 650 °C temperature range and were easily regenerated by an inert gas purge stream. The components of the flexible DFMs showed a high degree of interaction with each other, which evidently enhanced their CO capture performance ranging from 0.14 to 0.49 mol kg. It was shown that captured CO could be converted into useful products through either CO methanation, reverse water-gas shift (RWGS) or dry reforming of methane (DRM), which provides flexibility in terms of co-reactant (hydrogen . methane) and end product (synthetic natural gas, syngas or CO) by adjusting reaction conditions. The best DFM was the one containing CaO, producing 104 μmol of CH per kg in CO methanation, 58 μmol of CO per kg in RWGS and 338 μmol of CO per kg in DRM.