The prototypical photocatalyst TiO2 exists in different polymorphs, the most common forms are the anatase- and rutile-crystal structures. Generally, anatase is more active than rutile, but no consensus exists to explain this difference. Here we demonstrate that it is the bulk transport of excitons to the surface that contributes to the difference. Utilizing high -quality epitaxial TiO2 films of...

A synergistic effect between anatase and rutile TiO2 is known, in which the addition of rutile can remarkably enhance the photocatalytic activity of anatase in the degradation of organic contaminants. In this study, mixed-phase TiO2 nanocomposites consisting of anatase and rutile nanoparticles (NPs) were prepared for use as photoanodes in dye-sensitized solar cells (DSSCs) and were characterize...

Detailed EPR investigations on as-grown and annealed TiO2 nanoparticles in the anatase and rutile phases were carried out at X-band (9.6 GHz) at 77, 120-300 K and at 236 GHz at 292 K. The analysis of EPR data for as-grown and annealed anatase and rutile samples revealed the presence of several paramagnetic centers: Ti3+, O-, adsorbed oxygen (O2-) and oxygen vacancies. On the other hand, in as-g...

In this study, the cytotoxicity of two different crystal phases of TiO2 nanoparticles, with surface modification by humic acid (HA), to Escherichia coli, was assessed. The physicochemical properties of TiO2 nanoparticles were thoroughly characterized. Three different initial concentrations, namely 50, 100, and 200 ppm, of HA were used for synthesis of HA coated TiO2 nanoparticles (denoted as A/...

In this study, we focused on the origin on the selective deposition of rutile and anatase TiO2 thin films during the sputtering process. The observation on microstructural evolution of the TiO2 films by transmission electron microscopy revealed the coexistence of rutile and anatase TiO2 phases in the initial stage under the preferential growth conditions for the anatase TiO2; the observations f...

In this study, the commercial TiO2 nanopowder and micropowder of anatase phase and rutile phase have been characterized by x-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD patterns of nano-TiO2 in rutile and anatase phases exhibit broad peaks whereas both phases of micro-TiO2 demonstrate very sharp peaks. TEM images show that the grain size of TiO2 micropowders and TiO2 n...

A comparison has been drawn in pure anatase and rutile forms of TiO2 films with their respective nano crystalline forms as photoanodes in dye-sensitized solar cells. All the films have been synthesized by using sol-gel method. Crystalline nature of the films has been investigated by x-ray diffraction (XRD) and morphologies have been studied by scanning electron microscopy (SEM). The short-circu...

Titania is the most widely studied photocatalyst. In its mixed-phase configuration ( anatase–rutile form) – as manifested in the commercially available P25 Degussa material – titania was previously found to exhibit the best photocatalytic properties reported for the pure system. A great deal of published research by various workers in the field has not fully explained the underlying mechanism f...

Absorption spectra of anatase and rutile TiO2 in the 150-300 nm region before and after the deposition of Pt nanoparticles were measured. For anatase TiO2, the spectral intensity in the longer wavelength region decreased (>∼210 nm), while that in the shorter wavelength region increased (<∼210 nm). In particular, spectral band intensity in the far-ultraviolet (FUV) region (∼160 nm) was increased...