First Synthesis of Highly Crystalline, Hexagonally Ordered, Uniformly Mesoporous TiO2-B and Its Optical and Photocatalytic Properties

Out of the 11 different phases of titanium dioxide, TiO2-B is unique in that it contains crystalline voids, which can readily intercalate small cations. Because of this property, TiO2-B is receiving great attention as an electrode material for energy storage devices, dye sensitized solar cells, and supercapacitors as well as a photocatalyst for hydrogen production and dye decomposition. Applications in the above arenas are expected to increase significantly if this substance can be prepared in the form of ordered, uniformly mesoporous TiO2-B. In the current study, we developed the first method for synthesis of hexagonally ordered, uniformly mesoporous TiO2-B (houm-TiO2-B) with a high degree of purity on a large scale (>10 g). The results show that the band gap energy of houm-TiO2-B is 0.36 eV less than that of the corresponding nanoparticle. Importantly, houm-TiO2-B displays a higher performance than the corresponding nanoparticles as a photocatalyst in hydrogen production from aqueous methanol and in the photodecomposition of 4-chlorophenol and methylene blue.