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
Tailored synthesis of anatase–brookite heterojunction photocatalysts for degradation of cylindrospermopsin under UV–Vis light
Said M. El-Sheikh,Tamer M. Khedr,Geshan Zhang,Vasileia Vogiazi,Adel A. Ismail,Kevin E. O'Shea,Dionysios D. Dionysiou +6 more
TL;DR: Anatase-brookite heterojunction TiO2 (ABH) photocatalysts were tailored by introducing different glycine concentrations through hydrothermal treatment at 200°C for 20h.
Journal ArticleDOI
Photocatalytic performance of Cu-doped TiO 2 nanofibers treated by the hydrothermal synthesis and air-thermal treatment
TL;DR: In this article, a series of transition metal-doped TiO2 (metal/TiO2) is prepared by combining the hydrothermal synthesis and air-thermal treatment without any reduction process.
Journal ArticleDOI
Recent Overview of Solar Photocatalysis and Solar Photo-Fenton Processes for Wastewater Treatment
A. G. Gutierrez-Mata,S. Velazquez-Martínez,Alberto Álvarez-Gallegos,Mehdi Ahmadi,José Alfredo Hernández-Pérez,Farshid Ghanbari,S. Silva-Martínez +6 more
TL;DR: In this paper, the degradation and mineralization of organics like catalyst preparation, type and load of catalyst, catalyst phase, pH, applied potential, and type of organic pollutant are addressed.
Journal ArticleDOI
Designing Optimal Metal-Doped Photocatalysts: Correlation between Photocatalytic Activity, Doping Ratio, and Particle Size
TL;DR: In this article, a theoretical model that describes the correlation between photocatalytic activity, doping ratio, and particle size is developed, and a collection of optimal doping data for different particle sizes of doped titanium dioxide and zinc oxide was used.
Journal ArticleDOI
Preparation of anatase TiO2/Ti nanotube-like electrodes and their high photoelectrocatalytic activity for the degradation of PCP in aqueous solution
Shaogui Yang,Ya-zi Liu,Cheng Sun +2 more
TL;DR: In this article, a new type of photoelectrode, a TiO2 nanotube electrode, was successfully prepared by a sol-gel method and then by treatment to form the tubular structure in NaOH aqueous solution.
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.
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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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