Abstract
The micro-mesoporous TiO2 materials obtained from hydrothermal crystallization of polyols (xylitol, glucose and sorbitol)/TiCl4/acetylacetone/H2(O) systems were characterized; and compared with VOx/TiO2, by N-2-sorption, TG/DTA, X-ray diffraction, IR and scanning electron microscope. Through comparison of the results, it was found that glucose assembled TiO2 (T-G) calcinations at 623 K exhibited the formation of rutile-anatase nanoparticles (15 nm) as irregular shapes with disordered holes on particles surfaces, gyroidal structure (25 nm) following calcining at 773 K and cotton fibrils structure (10 nm) following vanadium incorporation (T-G/V). Increasing the concentration of xylitol (T-XY/C) significantly enhanced microporosites but decreases the specific surface area (309 m(2)/g) and wall thickness (0.609 nm); as compared to T-XY (356 m(2)/g, 0.929 nm). T-G presented remarkable increase in wall thickness (2.142 nm) that was principally responsible for enhancing the durability as well as the activity of this material towards photocatalytic reduction of Hg2+ (giving 100% reduction activity at 80 min reaction time) in aqueous medium. Additionally, this material offered low acid content compared with other polyols assembled TiO2 but in contrast confirmed high accessibility of their basic sites. (c) 2007 Elsevier Inc. All rights reserved.