Syngas methanation over Ni/SiO2 catalyst prepared by ammonia-assisted impregnation

Ni/SiO2 catalyst was prepared via ammonia-assisted impregnation using amorphous porous SiO2 as support. The process of the ammonia-assisted impregnation was analyzed and the catalyst was attempted for syngas methanation. X-ray diffraction, infrared radiation and UV-vis analysis demonstrated two kinds of Ni species with less water formed after dried: the formation of Ni-containing phyllosilicates (PS) and the anchored Ni2+ on the surface of SiO2 derived from adsorption of [Ni(NH3)6]2+. X-ray diffraction and temperature programmed reduction together with X-ray photoelectron spectroscopy verified the above two Ni species induced the formation of Ni-containing PS and highly dispersed NiO strongly interacting with SiO2 after calcination. NiO aggregation in the process of calcination and metal Ni sintering during further reduction were effectively suppressed. The as-prepared Ni/SiO2 catalyst with high nickel dispersion and strong metal-support interaction showed improved activity and better stability in syngas methanation.