Chemical coating of the metal oxides onto mesoporous silicas

Mesoporous silicas have been widely used to support transition metal oxides for catalytic applications because these supports are attractive for their high surface area (1000 m²/g), tuneable pore size (1.0-30.0 nm) and promotion of well-dispersed active metal sites (Kresge et al., 1992; Zhao et al., 1998). Because the nanochannels of the calcined mesoporous silicas can absorb a huge amount of water from atmosphere, which inhibits metal oxides grafting, a non-polar solvent (such as, toluene) and moisture-free reaction condition were needed to prevent the facile and fast hydrolysis/condensation reactions of the water-sensitive metal alkoxides in many typical metal-oxides grafting cases. Thus, a simple and versatile process for grafting high-content metal oxides onto mesoporous silicas is still desirable.