Effect of impregnation solvent on Ni dispersion and catalytic properties of Ni/SBA-15 for CO methanation reaction

Abstract

A series of SBA-15-supported Ni catalysts were prepared by incipient-wetness impregnation with different nickel nitrate solutions and applied in the CO methanation reaction for the production of synthetic natural gas (SNG). The catalysts were also characterized using X-ray diffraction (XRD), N2 physisorption measurements, hydrogen temperature-programmed reduction (H2-TPR), CO chemisorption, CO temperature-programmed desorption (CO-TPD) and transmission electron microscope (TEM). The results showed that the impregnation solvent influenced the catalytic activity in the CO methanation. The catalyst 20%Ni/SBA-15(ET) prepared from ethanol solution exhibited the highest activity with 100% CO conversion and 95% CH4 yield at 300°C under 0.3MPa. The effect of impregnation solvents could be related to the polarities of solvents and the solubility of nickel nitrate. The decreased polarity of the solvent caused an increase in the interaction between the nickel complex and silica surface, which would promote the fixation of the precursor onto the silica support and increase the nickel dispersion. As a result, the activity of the catalysts was improved effectively. The lifetime test also indicated that Ni based SBA-15 catalysts had a good catalytic stability. This was because of the stronger interaction between Ni and support.