6533b821fe1ef96bd127b9c5

RESEARCH PRODUCT

Nanostructured anatase TiO2 densified at high pressure as advanced visible light photocatalysts

Ilaria CitroAntonino BartolottaGiovanni PalmisanoGabriele ScanduraGaetano Di MarcoFrancesco ParrinoGiovanni CariniGiuseppe Calogero

subject

Settore ING-IND/24 - Principi Di Ingegneria ChimicaAnataseMaterials scienceMineralogysymbols.namesakechemistry.chemical_compoundchemistryChemical engineeringTitanium dioxidePhotocatalysissymbolsPhotocatalysis Anatase Densified TiO2IrradiationPartial oxidationPhotocatalysisPhysical and Theoretical ChemistryAbsorption (electromagnetic radiation)Raman spectroscopyVisible spectrum

description

This study reports on characterization and photoactivity of nanostructured TiO2 samples, which have been permanently densified under high pressures, up to 2.1 GPa. Commercial Mirkat 211 anatase has been used as a benchmark sample, in order to investigate the effect of unidirectional high pressure on structural, optical and photocatalytic properties of TiO2. Vibrational Raman spectroscopy shows that the treatment does not cause transitions among the different crystalline phases of titanium dioxide. UV-vis diffuse reflectance spectra reveal that increasing pressure gives rise to a shift of the absorption onset towards higher wavelength enhancing the photoactivity under visible radiation. Samples are also photo-electrochemically characterized and tested in the gas phase with partial oxidation of ethanol to acetaldehyde under visible irradiation. Compaction up to 0.8 GPa depresses both the alcohol conversion and the aldehyde yield, while samples treated under higher pressures show enhanced characteristics of conversion compared to the pristine material. Moreover, promising results in the reduction of CO2 are also obtained under UV-visible radiation.

https://doi.org/10.1039/c5pp00149h