@article { ISI:000263073800048, title = {Template free synthesis of mesoporous TiO2 with high wall thickness and nanocrystalline framework}, journal = {Journal of Nanoscience and Nanotechnology}, volume = {9}, number = {1, SI}, year = {2009}, month = {JAN}, pages = {371-377}, publisher = {AMER SCIENTIFIC PUBLISHERS}, address = {26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA}, abstract = {

A simple procedure to prepare nanocrystalline mesoporous titania (meso-TiO2) is reported without any templating agent and it possesses a high BET surface area and a large pore wall thickness (11.3 nm) than that of meso-TiO2 prepared by other methods. Nanocrystalline meso-TiO2 also has been synthesized with hexadecylamine template for comparison through known procedure. The meso-TiO2 materials were characterized by X-ray diffraction, FT-IR, UV-Vis absorbance spectra, thermal analysis, SEM, HRTEM and textural properties through N-2 adsorption-desorption isotherms. Spherical shape particles in a range of few hundred nanometers are obtained in the template free method. Above systematic characterization provides direct indications toward the mechanism of formation of meso-TiO2 in the template free method. A comparison of the physical and textural properties indicates a possibility of coarse-tuning of the textural characteristics of mesoporous TiO2 by adopting different preparation methods.

}, keywords = {Mesopore, Mesopore Formation, Template-Free, Thick Wall, titania}, issn = {1533-4880}, doi = {10.1166/jnn.2009.J019}, author = {Kulkarni, Dhanashree G. and Murugan, A. Vadivel and Viswanath, Annamraju Kasi and Gopinath, Chinnakonda S.} } @article { ISI:000341405600003, title = {Ambient oxidation of benzene to phenol by photocatalysis on Au/Ti0.98V0.02O2: role of holes}, journal = {ACS Catalysis}, volume = {4}, number = {9}, year = {2014}, month = {SEP}, pages = {2844-2853}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A potential photocatalyst with 2 atom \% vanadium incorporated into the 1 lattice of disordered mesoporous titania, Ti0.98V0.02O2, (TV2) was synthesized. Au was deposited on TV2 (Au/TV2) through a photodeposition method. Structural, microscopy, and spectroscopy techniques support the incorporation of vanadium into the TiO2 lattice, and Au was deposited on the surfaces of TV2. Photocatalytic oxidation of benzene was conducted at ambient temperature under UV and/or visible light to demonstrate the catalytic activity of the Au/TV2 catalyst. The TV2 lattice exhibits a quantum jump in benzene to phenol oxidation compared to that of TiO2, highlighting the importance of V for oxidation. Introduction of Au onto TV2 further increases the benzene to phenol oxidation and phenol yield by a factor of 2 under UV light compared to those of bare TV2. No significant phenol production was observed in visible light with or without gold, indicating the role of gold is indirect toward charge separation and electron storage. Nano gold clusters on TV2 selectively store photoexcited electrons and in turn maximize holes utilization on TiO2. The high photocatalytic activity of Au/TV2 is mainly attributed to the presence of Schottky junctions, disordered mesoporosity, and short diffusion lengths for charge carriers.

}, keywords = {nano gold, phenol, Photocatalysis, Schottky junction, titania, Vanadium}, issn = {2155-5435}, doi = {10.1021/cs500724z}, author = {Devaraji, Perumal and Sathu, Naveen K. and Gopinath, Chinnakonda S.} } @article {44194, title = {Marginally hydrogenated triphasic titania nanotubes for effective visible-light photocatalytic hydrogen generation}, journal = {Energy Technology}, volume = {6}, year = {2018}, month = {FEB}, pages = {280-288}, type = {Article}, abstract = {

We report the first demonstration of hydrogen-annealed triphase TiO nanotubes (anatase-rutile-brookite) (T-ARB) as a visible-light-active photocatalyst for water splitting with high quantum efficiency. As-synthesized T-ARB was annealed under hydrogen atmosphere at 250 and 4508 degrees C for 2 h. We found that the tubular structures were retained in the hydrogenated TiO2 samples. It was observed that the concentrations of Ti3+ and the oxygen vacancies and their distribution significantly increased with respect to the hydrogen annealing temperature. Such changes in defects were found to be critical in enhancing the photocatalytic activity of the hydrogen-annealed triphase TiO2 nanotubes. The triphase TiO2 nanotubes hydrogen annealed at 450 degrees C were 16 times more efficient than pristine TiO2. Such an increase in the photocatalytic activity was explained by a triphase band diagram with defect states below the conduction band of each phase, which facilitated visible-light activity and easy transfer of charge carriers from one phase to another. Our study showed that the well-designed multiphase construction with oxygen vacancies enhanced the photocatalytic activity tremendously owing to the presence of a higher number of phase junctions.

}, keywords = {charge transfer, Defects, Hydrogenation, titania, water splitting}, issn = {2194-4288}, doi = {10.1002/ente.201700406}, author = {Preethi, Laguduva K. and Mathews, Tom and Walczak, Lukasz and Gopinath, Chinnakonda S.} }