Abstract
This study reports a dual function material (DFM) composed entirely of non-precious metals for methanol production (13.8 μmol/g material) at ambient pressure from passively captured CO2 from the air. While state of the art carbon capture and utilisation (CCU) processes rely on expensive CO2 capture systems and a high-pressure catalytic reactor for methanol synthesis, this Ni-Ga-Ca DFM can be an enabler for significant energy efficiency gains in methanol synthesis from CO2 through the direct utilisation of dilute emissions and substantially lower operating pressures. Using operando DRIFT spectroscopy coupled with density functional theory, XAFS, XRD, and TEM-HAADF, a combination of Ni-Ga intermetallic species and their oxides are identified as the active sites. During cyclic operation a shift in selectivity towards methane is observed, which is associated with dynamic restructuring of the DFM. Guided by mechanistic and structural understanding, a synthesis strategy is developed to enhance cyclic stability by mitigating dealloying and Ni particle agglomeration. It is indicated that cyclic stability can be achieved by strengthening the Ni-Ga-Ca interaction, however, there remains a gradual shift in selectivity towards methane which highlights the need for further material optimisation.
