A high-stability silica–clay composite: Synthesis, characterization and combination with TiO 2 as a novel photocatalyst for Azo dye

Abstract

A novel micro-mesopores composite material has successfully been synthesized at basic hydrothermal conditions using natural mineral montmorillonite (MMT) and tetraethoxysilane (TEOS). Two surfactants, cetyltrimethyl ammonium bromide (CTAB) and polyethylene glycol (PEG), have been employed in order to shape the pores in the composite. The resultant silica–clay has large surface area (472 m 2/g) and high hydrothermal stability, which makes it a potentially host-material for catalyst. The molecular size of different surfactant leads to the multi-peak distribution of pore size, and the surfactant of larger size (PEG) corresponds to the formation of larger pores. Moreover, the photocatalytic results show that, comparing with pure TiO 2 particles, the loaded TiO 2 on such silica–clay shows higher photodegradation rate of methyl orange (MO) in aqueous. And another porous aluminosilicate host, zeolite, was also discussed for comparison.