Mesoporous nickel (or cobolt)-doped silica-pillared clay: Synthesis and characterization studies

The metals-doped silica-pillared clay (SPC) materials with ordered pore structure in the gallery were obtained by a surfactant-directed assembly of silica species in the interlayer space of natural montmorillonite (MMT). The novel method afforded SPC derivatives with basal spacings of 4.4–4.5 nm, BET specific surface areas of 382.4–472.6 m2/g, pore volumes of 0.64–0.71 cm3 g−1 and uniform pores (3.6 nm) between the layers. The main nickel and cobalt species was tetrahedrally coordinated Ni2+ or Co2+ in the gallery silica framework. Our results indicate that surfactant plays a decisive role in pore formation, because in acts as a micelle-like template during the hydrolysis of TEOS. In particular, the formation of metal–ammonia complex and rapid adsorption by surfactant in galleries controls metal species outflow from interlayers and contributes to the formation of metal species containing firm silica-pillars.