Observation of carbon-containing nanostructured mixed titania phases for visible-light photocatalysts

This research analyzed a visible-light-responsive carbon-containing titania photocatalysts prepared by sol-gel method using confocal Raman spectral mapping, transmission electron microscopy, and UV/visible spectroscopy. The incorporation of carbons in the initial titania powder of anatase and amorphous phases was found to facilitate the formation of rutile or brookite phases from the amorphous phase in the 150-250 degrees C temperature range, resulting in nanostructured mixed titania phases which create interface states and effectively shift the band gap to similar to 2.7 eV. The further shift in the absorption tails up to 800 nm was attributed to carbon species-covered and/or defected titania powders. (c) 2006 American Institute of Physics.