(533f) Feasibility Study of Alkaline Metal Oxide Modified Cu-ZnO-Al2O3 for Reactive Capture of CO2 to Methanol

Rising global temperatures associated with increased anthropogenic emissions of CO₂ to the atmosphere have put CO₂ capture, utilization, and storage (CCUS) technologies at the forefront of all the scenarios for climate change mitigation. Reactive carbon capture (RCC) technologies, in which capture and conversion of CO₂ occur in a single reactor, are particularly energetically and economically attractive by avoiding the need to purify, compress, and transport the captured CO₂. To this end, the dual function materials (DFM) have been developed to enable CO₂ capture and subsequent conversion to methane. Dual function materials (DFMs) have recently been developed as a promising technology for RCC.

DFMs are comprised of basic CO₂ adsorption sites co-located with catalytic hydrogenation sites on the same high surface area carrier. They have demonstrated stable performance over simulated realistic direct air capture (DAC) and post-combustion capture conditions with subsequent production of methane upon exposure with renewably sourced H₂. While renewable CH₄ would be an excellent transition fuel, it is economically noncompetitive compared to fossil methane and minimally adaptative as a platform molecule for upgrading to higher C-containing compounds. This requires design and investigation of DFMs that enable CO₂ capture and conversion to more valuable and more useful C1 products like methanol. Herein, we propose a DFM consisting of an alkali-modified Cu-ZnO-Al₂O₃ (CZA), the state-of-the-art commercial methanol synthesis catalyst, for CO₂ capture from a CO₂-rich waste gas stream and in-situ conversion to methanol (Figure 1). We explore the hydrogenation activities of alkali modified CZA over a variety of temperatures (150-300°C) and pressures (0.6-4 MPa) at stoichiometric 3:1 H₂:CO₂ ratio. The DFMs are characterized via CO₂ TPD, CO₂ chemisorption, and DRIFTS. Proof of concept of cyclic CO₂ capture and hydrogenation to methanol at the selected temperature and pressure conditions is also presented.