SILAR BiOI‐Sensitized TiO₂ Films for Visible‐Light Photocatalytic Degradation of Rhodamine B and 4‐Chlorophenol

Abstract

BiOI nanoplates were deposited upon a film of TiO nanoparticles derived from a commercial source using a simple room temperature sequential ionic layer adsorption and reaction (SILAR) method. X-ray diffraction, X-ray photoelectron spectroscopy and electron microscopies have been used to confirm the crystal phase, chemical states of key elements and morphology of the BiOI nanoplate-TiO composites. Using both valence band X-ray photoelectron spectroscopy and UV/Vis diffuse reflectance measurements the band structure of the composites is determined to be that of a type II heterojunction. Through initial screening of the photocatalytic activity of the SILAR-modified films it was determined that five SILAR cycles are optimal in the photocatalytic degradation of rhodamine B. The visible-light sensitisation effect of BiOI was then proven by examination of the photocatalytic degradation of the colourless organic pollutant 4-chlorophenol, showing a large enhancement over an equivalent TiO film.

Improving Carbon‐Coated TiO2 Films with a TiCl4 Treatment for Photocatalytic Water Purification

“…Upon thermal treatment under N 2 the films were found to turn from the characteristic yellow colour of the surface complex to a light brown, indicating the decomposition of the organic catechol to carbon. The general synthetic procedure is given in Figure , in which the initial TiO 2 film is formed by a doctor blading method (see the Experimental Section) giving a film, which has previously been found to be 10–12 microns thick . Hydrolysis of TiCl 4 to give TiO 2 is typically followed up with a thermal treatment step in air to give complete conversion to crystalline TiO 2 .…”

Photocatalytic Degradation of Dyes: An Overview

“…The kinetics of photocatalytic degradation of organic pollutants and dyes by semiconductors have been most often treated as first order kinetics. This is most common in literature, and as an example one of the recent references [15,54,55 and many other references] is provided. In Table.4.…”

“…The majority of the studies reported in literature deal with the effect on degradation activity on variables like the amount of the catalyst, the concentration of the dye employed, pH, effect of the radiation source and time of irradiation and also the effect of dissolved oxygen and others. The kinetics of degradation of dyes on most of the catalyst systems studied follows first order [15].…”

Field testing of low-cost titania-based photocatalysts for enhanced solar disinfection (SODIS) in rural India

“…In previous studies, we have developed successful photocatalysts based on TiO 2 , including C-TiCl 4 -TiO 2 , 21 BiVO 4 -TiO 2 , 22 BiOI-TiO 2 23 and Bi 4 Ti 3 O 12 -TiO 2 . 24,25 These offer enhanced photocatalytic activity over un-modified titania and, thus far, the most promising of these under laboratory conditions is the Bi 4 Ti 3 O 12 -TiO 2 co-catalyst system (BTO-TiO 2 ), attributed to its good stability and the presence of the heterojunction band architecture, which can reduce the extent of charge recombination.…”