A bifunctional material for sorption-enhanced steam methane reforming (SE-SMR) was synthesized via the sol-gel method, combining a Ni-based catalyst with a CaO-based sorbent promoted by MgO as a structural stabilizer. The material was characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy (TEM), N2 physisorption, and temperature-programmed reduction (TPR). In fluidized bed reactor tests, with an operating temperature condition of 650 oC and a steam to carbon ratio of 3, both Ni/CaO and Ni/CaO-MgO were able to surpass the thermodynamic equilibrium limits in CH4 conversion while maintaining extremely low CO2 concentrations in the outlet stream. The tests also revealed that Ni/CaO exhibited moderately faster reaction rates than Ni/CaO-MgO. However, cyclic performance tests demonstrated that MgO addition (CaO:MgO = 2:1) significantly enhanced long-term CO2 adsorption stability. Over 10 cycles, the bifunctional material is stable with the final CO2 capture capacity of 8.4 moles of CO2/kg of material, about 44% higher than the Ni/CaO bifunctional material. These results highlight the critical role of adding MgO to improve the stability of the bifunctional material for SE-SMR without substantially compromising the overall process efficiency.
