Enhanced Photocatalytic Degradation of Dye Pollutants under Visible Irradiation on Al(III)-Modified TiO2: Structure, Interaction, and Interfacial Electron Transfer
- 27 November 2007
- journal article
- research article
- Published by American Chemical Society (ACS) in Environmental Science & Technology
- Vol. 42 (1), 308-314
- https://doi.org/10.1021/es071770e
Abstract
Aluminum(III)-modified TiO2 was prepared by sol–gel process via a sudden gelating method. The structure of the modified material and the local environment of aluminum were investigated using X-ray diffraction, HRTEM, XPS, 27Al MAS NMR, and ξ-potential measurements. The effect of the aluminum modification on interaction between the dye and photocatalyst, the interfacial electron transfer process, and thereby the degradation of dye pollutants under visible irradiation were also examined by FTIR spectra and UV–vis diffuse reflectance spectra. It was found that, rather than incorporating into the crystal lattice of TiO2, the aluminum forms an overlayer of Al2O3 on the surface of TiO2, interfaced with Ti−O−Al bonds. It is interesting that the carboxylate-containing dyes such as Rhodamine B (RhB) adsorb preferentially on the Al2O3, rather than the Ti(IV) sites on the surface of TiO2. The photodegradation rate observed for RhB is nearly 5-fold faster than that obtained in the pristine TiO2 system. The photodegradation of dyes on the aluminum(III)-modified photocatalyst is of great dependence on the structure and anchoring group of the dyes. Structure with carboxylate as anchoring group and amino group as electron donor is favorable for degradation. The mechanistic details are discussed on the basis of experimental results.Keywords
This publication has 43 references indexed in Scilit:
- Simultaneous and Synergistic Conversion of Dyes and Heavy Metal Ions in Aqueous TiO2 Suspensions under Visible-Light IlluminationEnvironmental Science & Technology, 2005
- Enhancement of photocatalytic activity of TiO2 by adsorbed aluminium(III)Applied Catalysis B: Environment and Energy, 2005
- Al-doped TiO2 pigments: influence of doping on the photocatalytic degradation of alkyd resinsJournal of Photochemistry and Photobiology A: Chemistry, 2001
- Photoassisted Degradation of Dye Pollutants. 8. Irreversible Degradation of Alizarin Red under Visible Light Radiation in Air-Equilibrated Aqueous TiO2 DispersionsEnvironmental Science & Technology, 1999
- Photoassisted Degradation of Dye Pollutants. 3. Degradation of the Cationic Dye Rhodamine B in Aqueous Anionic Surfactant/TiO2 Dispersions under Visible Light Irradiation: Evidence for the Need of Substrate Adsorption on TiO2 ParticlesEnvironmental Science & Technology, 1998
- Photoassisted Degradation of Dye Pollutants. V. Self-Photosensitized Oxidative Transformation of Rhodamine B under Visible Light Irradiation in Aqueous TiO2 DispersionsThe Journal of Physical Chemistry B, 1998
- TiO2-assisted photodegradation of dye pollutants II. Adsorption and degradation kinetics of eosin in TiO2 dispersions under visible light irradiationApplied Catalysis B: Environment and Energy, 1998
- Environmental Photochemistry on Semiconductor Surfaces: Photosensitized Degradation of a Textile Azo Dye, Acid Orange 7, on TiO2 Particles Using Visible LightEnvironmental Science & Technology, 1996
- Chemical- and Sediment-Mediated Reduction of the Azo Dye Disperse Blue 79Environmental Science & Technology, 1995
- Fate of azo dyes in sludgesWater Research, 1994