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
Facet-Level Mechanistic Insights into General Homogeneous Carbon Doping for Enhanced Solar-to-Hydrogen Conversion
TL;DR: In this paper, a general homogeneous carbon doping strategy is established and then serves as the doping model for a mechanistic investigation, as encouraged by its versatility in enabling homogeneous incorporation of carbon and improving solar-to-hydrogen conversion for typical oxides including TiO 2, ZnO, and BiOCl.
Journal ArticleDOI
Transition Metal Modified TiO2-Loaded MCM-41 Catalysts for Visible- and UV-Light Driven Photodegradation of Aqueous Organic Pollutants
TL;DR: In this article, a number of transition metal (Cr, V, Fe, Cu, Mn, Co, Ni, Mo, and La) incorporated MCM41 mesoporous molecular sieves with Si/Me = 80 have been synthesized by a hydrothermal method.
Journal ArticleDOI
BiFeO3/TiO2 core-shell structured nanocomposites as visible-active photocatalysts and their optical response mechanism
TL;DR: Anatase titania-coated bismuth ferrite nanocomposites (BiFeO3/TiO2) have been fabricated via a hydrothermal approach combined with a hydrolysis precipitation processing as mentioned in this paper.
Journal ArticleDOI
Photocatalytic degradation of gaseous toluene on Fe-TiO2 under visible light irradiation: A study on the structure, activity and deactivation mechanism
TL;DR: The Fe-TiO2 photocatalysts synthesized by a sol-gel method have the mesoporous structure with a narrow pore size distribution, large pore volume and high surface area.
Journal ArticleDOI
An electrochemical strategy to incorporate nitrogen in nanostructured TiO 2 thin films: modification of bandgap and photoelectrochemical properties
TL;DR: In this article, a simple and facile electrochemical method to introduce anionic dopants into TiO2 was described, which can be used for nanostructuring and doping of growing anodic oxide.
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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