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
Understanding the high photocatalytic activity of (B, Ag)-codoped TiO2 under solar-light irradiation with XPS, solid-state NMR, and DFT calculations.
Ningdong Feng,Qiang Wang,Anmin Zheng,Zhengfeng Zhang,Jie Fan,Shang-Bin Liu,Jean-Paul Amoureux,Feng Deng +7 more
TL;DR: It was found that the [B(int.)-O-Ag] units could trap the photo induced electron to form a unique intermediate structure in the (B, Ag)-codoped TiO(2) during the irradiation, which is responsible for the photoinduced shifts of the B 1s and Ag 3d peaks observed in the in situ XPS spectra.
Journal ArticleDOI
Electronic properties of N- and C-doped TiO2
TL;DR: In this article, first-principles density-functional calculations for the electronic properties of nitrogen(N)-doped as well as carbon(C)doped titanium dioxide (TiO2) were presented.
Journal ArticleDOI
Virus inactivation by silver doped titanium dioxide nanoparticles for drinking water treatment.
TL;DR: The increased production of hydroxyl free radicals was found to be responsible for the enhanced viral inactivation of Bacteriophage MS2 in aqueous media.
Journal ArticleDOI
Enhancement of the photocatalytic activity of TiO2 through spatial structuring and particle size control: from subnanometric to submillimetric length scale
TL;DR: This review summarizes the physical approaches towards enhancement of the photocatalytic activity of titanium dioxide by controlling this semiconductor in a certain length scale from subnanometric to submillimetric distances and provides examples in which this activity is promoted by doping, changes in the chemical composition, or by application of physical concepts and spatial structuring of the semiconductor.
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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