Effect of the Nickel Source on the Structure, Performance, and Carbon Deposition of the Ni/Al2O3 Catalyst for CO2-CH4 Reforming.

Ni/Al2O3 catalysts were prepared with Ni(NO3)2·6H2O, NiSO4·6H2O, NiCl2·6H2O, and NiC4H6O4·4H2O as nickel sources by the solution combustion method. The catalysts were characterized by X-ray diffraction, H2 temperature-programmed hydrogenation, TG-DTG, TPH, and transmission electron microscopy methods, and the effect of the nickel source on performance of the Ni/Al2O3 catalyst was investigated via the CO2-CH4 reforming experiment. Results showed that Ni dispersion, Ni size, and the metal-support interaction between active component Ni and the support were influenced significantly by anion in nickel sources, resulting in that the performance of each catalyst was different. Highly dispersed Ni species, small Ni crystallite size, and strong metal-support interaction were presented in the Ni/Al2O3 catalysts with Ni(NO3)2·6H2O and NiSO4·6H2O as nickel sources. Evaluation results showed that the catalyst prepared with Ni(NO3)2·6H2O exhibited higher activity and stability, with CH4 and CO2 conversions of 31.21 and 48.97%. Carbon deposition analysis demonstrated that the catalyst prepared with NiSO4·6H2O contained more graphite carbon.