Hydrothermal synthesis of mesoporous TiO2 using ?-diketonate stabilizing agents for photocatalytic degradation of methyl violet 2B under visible light

Mesoporous TiO2 (m-TiO2) has gained much attention in various industrial fields because of its good photo-sensitivity and nontoxicity. In this study, we investigated the effect of stabilizing agents on the surface area and porosity of m-TiO2. m-TiO2 was synthesized via a soft-template-assisted hydrothermal method using four different beta-diketonate stabilizers. With the electron-donating group in beta-diketones, the particle size of m-TiO2 decreased and its surface area increased because of increased substitutions with alkoxyl or alkyl groups. Among the m-TiO2 spheres prepared using the four stabilizers, m-TiO2(3MP), which had the highest pKa value of 3MP, exhibited the most uniform and smallest particle size because of the greater number of electrons in its C--O bonds for bonding with Ti cations. The prepared m-TiO2 catalysts were evaluated for the photocatalytic degradation of methyl violet 2B (MV) under UV and visible light. m-TiO2(3MP) resulted in the highest degra-dation and reaction rates, 0.0189 min-1 (UV) and 0.0232 min-1 (visible), which was superior activity than commercial TiO2 (P25). These results indicate that the stabilizing agents affect the formation of m-TiO2 and the largest surface area leads to the highest photocatalytic activity.

Automated summary

This study investigated the effect of stabilizing agents on the surface area and porosity of m-TiO2. The results showed that the electron-donating group in the stabilizers could decrease the particle size of m-TiO2 and increase its surface area. Among the stabilizers, m-TiO2(3MP) with the highest pKa value exhibited the most uniform and smallest particle size, leading to the highest photocatalytic activity.