Preparation of ordered mesoporous TiO 2 /activated carbon with high thermal stability and hole-hole synergistic photocatalytic property

By surfactant template technique with the aid of ultrasound systerm, the ordered mesoporous titania (OMPT) and OMPT/activated carbon (OMPTA) were prepared using cetyl trimethyl ammonium bromide (CTAB) surfactant and tetrabutyl titanate as creating-pore template and titanium source, respectively. To explore the relationship between structure and properties OMPTA, ultrasound-sol-gel technique was applied to synthesize nonporous titania dioxide/activated carbon (noporous TiO 2 /AC, NPTA). The obtained material structure was characterized by thermogravimetric-differential thermal (TG-DTA), X-ray diffraction (XRD), nitrogen adsorption- desorption, transmission electron microscopy (TEM) and UV diffuse reflectance (DRS). OMPTA photocatalytic performance and service life were evaluated by means of acid red B (ARB) as a probe photocatalytic degradation experiments. The hole-hole synergistic amplification mechanism of photocatalytsis was proposed and the effects of catalytic conditions (dye concentration and catalyst concentration) on synergistic amplification were explored. The results show that: compared to pure OMPT, OMPTA has grain growth with high activation energy, the smaller particle size and mesoporous structure for high thermal stability, because the activated carbon adsorption and amorphous phases hinder the crystalline grain growth. Due to hore-hole synergistic amplification effect of photocatalytsis, OMPTA has the highest catalytic activity among NPTA, OMPT, P25, OMPT-AC mixture and NPT. The heat treatment temperature is strongly affected OMPTA photocatalytic activity, and OMPT-500 has the highest photocatalytic activity. It is attributed to the fact that it has perfect crystallinity, a relatively high concentration of hydroxyl and Ti 3+ ions. Meanwhile, OMPTA-500 also shows high photocatalytic properties in the repeated usage. When ARB is degraded by OMPTA-500, the optimum catalytic conditions are catalyst concentration of 1 g/L with ARB concentration of 15 mg/L and pH 5.