Journal ArticleDOI
The Role of Metal Ion Dopants in Quantum-Sized TiO2: Correlation between Photoreactivity and Charge Carrier Recombination Dynamics
TLDR
In this article, the presence of metal ion dopants in the TiO_2 crystalline matrix significantly influences photoreactivity, charge carrier recombination rates, and interfacial electron-transfer rates.Abstract:
A systematic study of metal ion doping in quantum (Q)-sized (2-4 nm) TiO_2 colloids is performed by measuring their photoreactivities and the transient charge carrier recombination dynamics. The presence of metal ion dopants in the TiO_2 crystalline matrix significantly influences photoreactivity, charge carrier recombination rates, and interfacial electron-transfer rates. The photoreactivities of 21 metal ion-doped colloids are quantified in terms of both the conduction band electron reduction of an electron acceptor (CCl_4 dechlorination) and the valence band hole oxidation of an electron donor (CHCl_3 degradation). Doping with Fe^(3+), Mo^(5+), Ru^(3+), Os^(3+), Re^(5+), V^(4+), and Rh^(3+) at 0.1-0.5 at.% significantly increases the photoreactivity for both oxidation and reduction while Co^(3+) and Al^(3+) doping decreases the photoreactivity. The transient absorption signals upon laser flash photolysis (λ_(ex) = 355 nm) at λ = 600 nm are extended up to 50 ms for Fe^(3+)-, V^(4+)-, Mo^(5+)-, and Ru^(3+)-doped TiO_2 while the undoped Q-sized TiO_2 shows a complete "blue electron" signal decay within 200 μs. Co^(3+)- and Al^(3+)-doped TiO_2 are characterized by rapid signal decays with a complete loss of absorption signals within 5 μs. The quantum yields obtained during CW photolyses are quantitatively correlated with the measured transient absorption signals of the charge carriers. Photoreactivities
are shown to increase with the relative concentration of trapped charge carriers. The photoreactivity of doped TiO_2 appears to be a complex function of the dopant concentration, the energy level of dopants within the TiO_2 lattice, their d electronic configuration, the distribution of dopants, the electron donor concentration, and the light intensity.read more
Citations
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Journal ArticleDOI
Synthesis, characterization and photocatalyticactivity of ZnFe2O4/TiO2 nanocomposite
TL;DR: In this article, a new nanocomposite material ZnFe2O4/TiO2 was developed by a colloid chemistry method and characterized through X-ray diffraction and transmission electron microscopy.
Journal ArticleDOI
Comparative study of the photocatalytic performance of boron–iron Co-doped and boron-doped TiO2 nanoparticles
TL;DR: In this article, a series of nanosized boron-doped anatase TiO2 represented as Bx,Fey-TiO2 (x = 0, 0.5, 1, 3, 5 in wt%) were synthesized by a modified sol-gel method and characterized by various spectroscopic and analytical techniques.
Journal ArticleDOI
Visible-light responsive dye-modified TiO2 photocatalyst
TL;DR: In this article, a series of dye-modified TiO 2 photocatalysts were synthesized using dye Chrysoidine G (CG), tolylene-2,4-diisocyanate (TDI), as starting materials.
Journal ArticleDOI
Suppression of photocatalytic efficiency in highly N-doped anatase films
TL;DR: In this paper, the role of N in epitaxial films of anatase was reported, where the films were artificially grown with a two-step temperature-tuned epitaxy which utilized the high-temperature cubic phase of the substrates.
Journal ArticleDOI
First-principles calculation of nitrogen-tungsten codoping effects on the band structure of anatase-titania
Run Long,Niall J. English +1 more
TL;DR: The electronic properties and photocatalytic activity of nitrogen (N) and tungsten (W)-doped anatase are calculated using density functional theory in this paper, showing that N 2p states above the top of the valence band are responsible for experimentally observed redshifts in the optical absorption edge.
References
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Book
Inorganic Chemistry: Principles of Structure and Reactivity
TL;DR: In this article, inorganic chemistry principles of structure and reactivity are presented. But, they do not cover how to use these principles in the design of products, and they are not available in any type of product.
Book
Transition Metal Oxides: An Introduction to Their Electronic Structure and Properties
TL;DR: In this article, the authors present a chemical aspects structural principles of electronic classification and models of electronic structure: ionic models cluster models band theory intermediate models, point-defects and semiconduction, electronic carrier properties.
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