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
Systematic effects of S-doping on the activity of V2O5/TiO2 catalyst for low-temperature NH3-SCR
TL;DR: S-doped V2O5/TiO2 catalyst for low-temperature selective catalytic reduction (SCR) of NO with NH3 was synthesized using the sol-gel and impregnation methods with (NH4)2TiF6 as a precursor, and characterized by X-ray powder diffraction (XRD), Brunauer-Emmett-Teller surface area (BET), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), photoluminescence spectra (UV-vis
Journal ArticleDOI
The effect of lanthanide on the degradation of RB in nanocrystalline Ln/TiO2 aqueous solution
TL;DR: In this article, the role of lanthanide doping on the photocatalytic activity in the degradation of rhodamine B (RB) in aqueous solution was studied.
Journal ArticleDOI
Characterizations and photocatalytic activity comparisons of N-doped nc-TiO2 depending on synthetic conditions and structural differences of amine sources
TL;DR: In this paper, N-doped TiO2 nanoparticles were prepared by using 1° and 2° alkyl and alcohol amines through microwave and hydrothermal growth (HT) methods.
Journal ArticleDOI
Processing of iron-doped titania powders in flame aerosol reactors
TL;DR: In this paper, a flame aerosol reactor was used to synthesize Fe(III)-doped titania powders and the defect structure was explored by Raman spectroscopy, revealing an increased shift and broadening of the anatase peaks with an increasing iron dopant concentration.
Journal ArticleDOI
Band gap engineered, oxygen-rich TiO2 for visible light induced photocatalytic reduction of CO2
TL;DR: A facile and dopant-free strategy was employed to fabricate oxygen-rich TiO2 (O2-TiO2) with enhanced visible light photoactivity that exhibited high photoactivity towards CO2 reduction under visible light.
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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