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A novel N H TiO 2 photocatalyst was prepared via hydrothermal synthesis followed by a thermal treatment in NH 3 and H 2 atmospheres. The results showed that benzene with the initial concentration of 150 ppm (±5 ppm) could be thoroughly removed by N H TiO 2 under visible light irradiation. The influences of doping and hydrogenation on properties of TiO 2 samples were investigated. It is suggested that the disordered surface layer introduced by hydrogenation contributes to the excellent photocatalytic activity of N H TiO 2 . The synergistic effect of N doping and surface oxygen vacancies was also confirmed by ultraviolet–visible diffuse reflectance spectra and photoluminescence. Moreover, the diverse role of oxygen vacancies in different positions of TiO 2 has been focused on. [ABSTRACT FROM AUTHOR]

Highlights: [•] A thermally stable mesoporous ZrO2–CeO2–TiO2 was prepared. [•] The ZrO2–CeO2–TiO2 had a high surface area due to the enhanced thermal stability. [•] The ZrO2–CeO2–TiO2 had a good optical absorption capacity in the visible range. [•] The ZrO2–CeO2–TiO2 was effective for the degradation of Rhodamine B. [ABSTRACT FROM AUTHOR]

Nitrogen-doped TiO 2 nanomaterial attracts enormous attention due to its excellent visible photocatalytic activity. A simple annealing method assisted by adjusting gas composition to control the positions of nitrogen dopants in TiO 2 lattice is presented. The nitrogen doping sites are confirmed by XPS. The photo-degradation results of gaseous benzene under visible light illumination reveal that photocatalytic activity in as-prepared samples containing the substitutional nitrogen species is higher than that in samples containing interstitial nitrogen species. The improvement of photocatalytic performance is ascribed to the increased amounts of surface hydroxyl group in N-TiO 2 samples. The efficient separation of electron-hole pairs was also responsible for the enhanced photocatalytic activity. In addition, an important conclusion is pointed out: the presence of oxygen during annealing process has an important effect on the formation of interstitial nitrogen dopants. The present work is believed to have guiding significance for preparing nitrogen-doped TiO 2 with high photocatalytic activity. [ABSTRACT FROM AUTHOR]

Highlights: [•] A high catalytic activity modified TiO2 was prepared by a simple annealing method. [•] Hydrogenated TiO2 decomposed formaldehyde without light illumination at room temperature. [•] The mechanism was attributed to the existence of oxygen vacancies and surface hydroxyl groups. [•] The concentration of oxygen vacancy played an important role in the degradation process. [Copyright &y& Elsevier]

Abstract: Titanium dioxide (TiO2) doped with phosphorus (P) was synthesized by anodization of Ti in the mixed acid electrolyte of H3PO4 and HF and characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–vis spectrum. The morphology greatly depends on the applied voltage. The as-formed nanotubes under the optimized condition, at 20V for 2h, are highly ordered with ~200nm in length and the average tube diameter is about 100nm. By annealing the initial samples at different temperatures, the importance of the crystalline nature is confirmed. Significantly, the peak positions of anatase in XRD patterns shifts to lower diffraction angles with an increase in the amount of H3PO4 ion. A remarkable red shift of the absorption edge has been observed for the sample formed in the electrolyte of HF and H3PO4, which is related to the introduction of P5+ into TiO2 crystallization and the possible impurity energy level formed in the TiO2 band gap. The presence of P 2p state in XPS spectrum can further confirm the P5+ which can replace a part of Ti4+ has been introduced into TiO2 crystallization. The present convenient synthesis technique can be considered to the composition of other doped oxide materials. [Copyright &y& Elsevier]

Abstract: TiO2/CoFe2O4 composite nanoparticles with a core–shell structure have been obtained. The core CoFe2O4 nanoparticles were synthesized via co-precipitation method, and the shell TiO2 nanocrystals were derived via sol–gel technology followed by heat-treatment at 450 °C. The morphology and the crystalline structure of composite nanoparticles were characterized by transmission electron microscopy (TEM) and X-ray diffraction, respectively. The as-prepared composite particles can be utilized as a magnetic photocatalyst, which can be fluidized and recovered by an applied magnetic field enhancing both the separation and mixing efficiency for recyclable fluids. Magnetic properties and photocatalytic activities of these powders have been evaluated. [Copyright &y& Elsevier]