Impact of double-solvent impregnation on the Ni dispersion of Ni/SBA-15 catalysts and catalytic performance for the syngas methanation reaction

Several nickel-based SBA-15 catalysts with Ni content in range of 3 wt% to 10 wt% were prepared by the double-solvent impregnation method and investigated for synthetic natural gas (SNG) production in a continuous flow fixed-bed reactor. Using a double-solvent impregnation method could improve the dispersion of nickel particles, which significantly improved the catalytic activity of the Ni-based catalysts in the syngas methanation reaction. The 10% Ni/SBA-15(D) catalyst achieved the best activity with 100% CO conversion and about 99% CH4 yield at 400 degrees C, 0.3 MPa and 15 000 mL g(-1) h(-1). The catalysts were characterized by N-2 adsorption-desorption, X-ray diffraction (XRD), transmission electron microscope (TEM), H-2-temperature-programmed reduction (H-2-TPR), H-2 pulse chemisorption, CO-temperature-programmed desorption (CO-TPD) and thermogravimetric (TG). It could be speculated that using the double-solvent impregnation method strengthened the interactions between NiO and the support based on the TPR results. The results of XRD and TG analysis showed that catalyst sintering rather than carbon deposition led to catalyst deactivation in the heat-resistant performance and 100 h stability test.