Optimizing alkali metal Salt-Induced structural assembly of Ni-MgO dual function materials for enhanced CO2 capture and methanation performance

Abstract

Alkali metal salts (AMS) promoted Ni-MgO dual function materials (DFMs) show exhibit potential in integrated CO2 capture and methanation. However, the CO2 adsorption and methanation efficiency of these materials is contingent upon their adsorptive and catalytic sites, which are significantly susceptible to the incorporated AMS. Herein, we investigate the effect of assemble configuration of AMS and Ni on the structural properties and integrated CO2 capture and methanation performance of the AMS-promoted Ni-MgO DFMs. By preferentially incorporating AMS to form the Ni-AMS-MgO configuration, AMS is allocated throughout both the internal core and external layer of MgO particles. Given AMS's preferential occupation of specific pore structures, Ni is evenly distributed as smaller particles on the MgO surface, minimally influenced by the carbonate formed during adsorption. The Ni-AMS-MgO configuration demonstrates superior integrated CO2 capture and methanation performance, featuring high CO2 uptake (1.86 mmol/g) and CH4 yield (1.37 mmol/g).