Facile postsynthesis of visible-light-sensitive titanium dioxide/mesoporous SBA-15

Visible-light-sensitive titanium dioxide/mesoporous SBA-15 (TiO2/SBA-15) composites were synthesized through a postsynthetic approach with the assistance of ethylenediamine. The as-prepared nanocomposites were characterized by XRD, nitrogen adsorption, SEM, HRTEM/EDS, FT-IR, DR UV-vis, and XPS. TiO2 nanoparticles are homogenously dispersed on the silica SBA-15. XPS analyses indicate that the oxygen atoms of TiO2 were partially substituted by nitrogen atoms, resulting in good response to the visible-light absorption. Ethylenediamine plays a double role: (1) etching the surface of silica SBA-15 and directing its regeneration and (2) introducing nitrogen atoms to the lattice of TiO2. The excellent photocatalytic activity of the composites is evaluated via the photodecomposition of phenol in the liquid phase under visible- and ultraviolet-light illumination. The conversion of phenol varies with the content of TiO2 in the composites, and the optimal value is up to 46.2% under illumination in the visible region.