Abstract:
Spherical silica derived nickel phyllosilicate catalysts were prepared via a one-step modified spherical silica synthesis under room temperature. For 10wt% Ni loading, the loading sequence of Ni and Si sources during spherical silica synthesis was found to affect the characteristics and catalytic properties in CO2 methanation. The stronger interaction between Ni and silica in the form of nickel phyllosilicate revealed the better catalytic performances than the impregnation method. The highest CO2 methanation activity and methane selectivity were obtained over the catalyst prepared by alternate loading between Ni and Si (Ni_Alt_Si) due to high electron density of nickel on the surface, high metal dispersion, and high CO2 adsorption ability. Furthermore, one step synthesis by alternate addition of Ni and Si precursor (Ni_Si) with different Ni loadings in the range of 2-30 wt% were evaluated in the selective hydrogenation of furfural to furfuryl alcohol. The unique properties of the remaining nickel phyllosilicate after reduction could act as a good support for metallic nickel, yielding high dispersion of small nickel particles and stable catalytic performances for multiple recycle runs. Furfural conversion over the Ni_PS catalysts increased monotonically with increasing Ni loading without FA selectivity drop. It is suggested that the presence of both metallic Ni0 and Niphyllosilicate also produced a synergistic promotional effect for FA formation.
