Dispersion Control of Ni Particles in Porous Silica by Solution Exchange of Wet Silica Gel

Abstract

Particle size of NiO in silica with well defined mesoporous structure can be controlled from 3.5 to 10 nm regardless of NiO content up to 30 wt% by solution exchange of wet silica gel derived from sol-gel process. Ni surface area of samples reduced at 500 °C can be enlarged by decreasing the NiO particle size, resulting in 30 m2g−1 at 30 wt% loading. The catalysts showed superior activities for gas-phase hydrogenation of benzene.

Ni/SiO2 catalyst with hierarchical pore structure prepared by phase separation in sol–gel process

“…Recently, we have reported the preparation of by solution exchange of wet silica gel. 15 The Ni/SiO 2 Ni/SiO 2 showed a high dispersion of Ni particles and superior activities for gas-phase hydrogenation of benzene when citric acid was used as an additive in the solution exchange.…”

Addition of zirconia in Ni/SiO2 catalyst for improvement of steam resistance

“…We have also prepared Ni/SiO 2 by modifying the sol-gel method, and proposed methodologies to control their structural properties. High dispersion of Ni was achieved by using a complex reagent such as citric acid in the preparation [13][14][15][16]. Nickel citrate formed in the solution does not aggregate by crystallization of salts during drying, and the following calcination under mild condition disturbs the growth of NiO particles.…”

Measurement of the diffusion coefficient of nickel nitrate in wet silica gel using UV/VIS spectroscope equipped with a flow cell

“…Recently, we have proposed a new method to prepare with superior catalytic activity by utilizing Ni/SiO 2 solution exchange method. 5 In the process, knowledge of the transport kinetics of Ni solution in wet silica gel is also required to estimate the time necessary for immersing the wet gel in aqueous solution and to understand a forma-Ni(NO 3…”