Integration of CO2 Adsorbent with Ni-Al2O3 Catalysts for Enhanced Methane Production in Carbon Capture and Methanation: Cooperative Interaction of CO2 Spillover and Heat Exchange

In this study, we conducted a comparative analysis of the catalytic behavior of Ni-CaO-Al2O3 dual functional material (DFM) and a physical mixture of Ni-Al2O3 and CaO-Al2O3 in the integrated carbon capture methanation (ICCM) process for promoted methane production. H2-temperature-programmed surface reaction (H2-TPSR) analysis revealed that in Ni-CaO-Al2O3 DFM, CO2 adsorbed on the CaO surface can spillover to metallic Ni surface, enabling direct hydrogenation without desorption of CO2. Ni-CaO-Al2O3 DFM exhibited a rapid initial methanation rate due to CO2 spillover. The Ni-CaO-Al2O3 DFM, with Ni and CO2 adsorption sites in close distance, allows efficient utilization of the heat generated by methanation to desorb strongly adsorbed CO2, leading to enhanced methane production. Consequently, Ni-CaO-Al2O3 DFM produced 1.3 mmol/gNi of methane at 300 °C, converting 35% of the adsorbed CO2 to methane.