N-TiO2 Photocatalysts highly active under visible irradiation for NOX abatement and 2-propanol oxidation

N-doped TiO2 powders were prepared by two different sol–gel methods. Samples were characterised by X-ray diffraction (XRD), BET specific surface area measurements (SSA), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Electron Paramagnetic Resonance (EPR). XPS measurements revealed a signal at 400 eV assignable to nitrogen in the form of Ti N O. EPR signals are attributed to molecular NO trapped with cavities/defects possibly interacting with oxygen vacancies. The photocatalytic activity under UV and visible light was determined following the abatement of NOx and the photodegradation of 2-propanol in gas–solid systems. N-doped TiO2 showed a higher activity compared with the pristine commercial and home prepared samples under visible light irradiation. A good photoactivity in the abatement of both NOx and 2-propanol is also observed for mechanical dispersions of N-TiO2 in CaCO3 serving as a model in view of perspective application in photocatalytically active construction and architectural materials

Keggin heteropolyacid H3PW12O40 supported on different oxides for catalytic and catalytic photo-assisted propene hydration

Catalytic and catalytic photo-assisted hydration of propene to form 2-propanol in gas–solid regime at atmospheric pressure and 85 1C were carried out by using a heteropolyacid (POM) supported on different oxides. Binary materials were prepared by impregnation of H3PW12O40 on different commercial and home prepared supports (TiO2, SiO2, WO3, ZrO2, ZnO, Al2O3). Some of the composites were active both for catalytic and catalytic photo-assisted reactions. The Keggin type POM was completely and partially degraded, when supported on ZnO and Al2O3, respectively, and these binary solids always resulted as inactive for both catalytic and catalytic photo-assisted reactions. The supported Keggin POM species played a key role both for the catalytic and the photo-assisted catalytic reactions, due to their strong acidity and ability to form strong oxidant species under UV irradiation, respectively. The contemporary presence of heat and UV light improved the activity of almost all POM supported materials. All materials were characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM), diffuse reflectance spectroscopy (DRS), determination of the conduction and valence band energy by photovoltage measurements, Fourier transform infrared spectroscopy (FTIR), NH3-TPD experiments and time resolved microwave conductivity (TRMC). Introduction Propene hydration to obtain 2-propanol is a reaction carried out at moderate temperatures (ca. 150–200 1C) and pressure (2MPa) in the presence of an acid catalyst;1 however the realization of this reaction at ambient conditions is of great interest. The us

Photocatalytic H2production over inverse opal TiO2catalysts

The influence of BiVO4and CuO on the chemico-physical properties of TiO2-based systems is reported. The performances of these systems were investigated in the photocatalytic H2production both under UV and solar light irradiation. The characterization data pointed out that the obtained TiO2samples have highly porous inverse opal structures with interconnected macropores. Inverse opal TiO2exhibited higher activity in the H2production than the commercial TiO2due to the peculiar porosity that allows photons to enter inside the photocatalyst. A further improvement in terms of photoactivity was verified by addition of increasing amounts of BiVO4. On the contrary a small CuO content was found to be the optimal one for the inverse opal TiO2-CuO composites. In fact, due to surface segregation effects, a higher amount of CuO can partially keep the light radiation away from the TiO2surface active sites, thus decreasing drastically the absorption of photons. The combination of the benefits of the highly ordered porous TiO2structure and the presence of BiVO4or small amounts of CuO can represent a promising strategy towards efficient photocatalytic H2production

TiO2 Photocatalytic glucose conversion to H2 and high value chemicals

In this work it is reported the conversion of glucose in aqueous dispersion of various TiO2 based photocatalysts. Aerobic and anaerobic conditions were used to study the distribution of the products both in the liquid (arabinose, gluconic acid, fructose and formic acid) and gas (H2 and CO2) phases. Commercial and home prepared bare and Pt-supported TiO2 samples were used as the photocatalysts

Photocatalytic glucose conversion to produce hydrogen in the presence of TiO2 based materials.

In the present research commercial anatase (BDH) and anatase/rutile (P25) and home prepared anatase (HPA), rutile (HPR) and brookite (HPB) TiO2 polymorphs and have been used as supports for the deposition of metallic Pt. The Pt-TiO2 samples have been tested in the glucose conversion under anaerobic conditions. The presence of Pt resulted essential for the production of H2 and the home prepared samples resulted more active than the commercial ones

H2 and value added chemicals from photocatalytic conversion of glucose

Commercial and home prepared bare and Pt-supported TiO2 samples were used as the photocatalysts for the aqueous aerobic and anaerobic photo-conversion of glucose at ambient pressure and temperature. H2 and valuable chemicals were the obtained products. The home prepared samples resulted more active than the commercial one

Sintesi di TiO2 anatasio in presenza di HF: studio delle proprietà strutturali e fotocatalitiche

In questo lavoro viene riportata la sintesi di TiO2 anatasio in presenza di soluzioni contenenti quantità diverse di HF allo scopo di ottenere campioni con proprietà strutturali diverse e la valutazione dell’attività fotocatalitica in reazioni liquido-solido e gas-solido