Tin Modification on Ni/Al2O3: Designing Potent Coke-Resistant Catalysts for the Dry Reforming of Methane



Sn-modified Ni/Al2O3 catalysts for CH4 dry reforming were prepared by co-impregnation and two-step impregnation methods and characterized by thermogravimetric analysis with differential scanning calorimetry, SEM, TEM, high-angle annular dark-field scanning transmission electron microscopy mapping, XRD, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction, and CO2 temperature-programmed desorption. After reduction, surface Ni-Sn alloys were formed on the Ni particles, which changed the inherent activity of Ni sites and suppressed coking effectively with a mild loss of the activity. The catalysts with different amounts of surface Ni-Sn alloys also provided strong evidence to prove that the coking rate and activity change tendency correlate well with the amount of the surface alloys. These results are of help to develop catalysts with potent resistance to coking for industrial use.