Integration of CO[sub.2] Adsorbent with Ni-Al[sub.2]O[sub.3] Catalysts for Enhanced Methane Production in Carbon Capture and Methanation: Cooperative Interaction of CO[sub.2] Spillover and Heat Exchange

In this study, we conducted a comparative analysis of the catalytic behavior of Ni-CaO-Al[sub.2]O[sub.3] dual functional material (DFM) and a physical mixture of Ni-Al[sub.2]O[sub.3] and CaO-Al[sub.2]O[sub.3] in the integrated carbon capture methanation (ICCM) process for promoted methane production. H[sub.2]-temperature-programmed surface reaction (H[sub.2]-TPSR) analysis revealed that in Ni-CaO-Al[sub.2]O[sub.3] DFM, CO[sub.2] adsorbed on the CaO surface can spillover to metallic Ni surface, enabling direct hydrogenation without desorption of CO[sub.2]. Ni-CaO-Al[sub.2]O[sub.3] DFM exhibited a rapid initial methanation rate due to CO[sub.2] spillover. The Ni-CaO-Al[sub.2]O[sub.3] DFM, with Ni and CO[sub.2] adsorption sites in close distance, allows efficient utilization of the heat generated by methanation to desorb strongly adsorbed CO[sub.2], leading to enhanced methane production. Consequently, Ni-CaO-Al[sub.2]O[sub.3] DFM produced 1.3 mmol/g[sub.Ni] of methane at 300 °C, converting 35% of the adsorbed CO[sub.2] to methane.