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
Photocatalytic properties of TiO2 and Fe-doped TiO2 prepared by metal organic framework-mediated synthesis
María José Valero-Romero,Jara G. Santaclara,Lide Oar-Arteta,L. van Koppen,Dmitrii Osadchii,Jorge Gascon,Jorge Gascon,Freek Kapteijn +7 more
TL;DR: In this article, the presence of highly dispersed Fe3+ ions incorporated into the TiO2 crystal lattice was confirmed, which led to a significant red shift of photoresponse towards visible light and reduced the recombination rate of electron-hole pairs at low iron content.
Journal ArticleDOI
Facile synthesis and photocatalytic properties of AgAgClTiO2/rectorite composite.
Yanqing Yang,Gaoke Zhang,Wei Xu +2 more
TL;DR: The mechanism suggested that the high photocatalytic activity is due to the charge separation and the surface plasmon resonance of metallic Ag particles in the region of visible light.
Journal ArticleDOI
Doping Behavior of Zr4+ Ions in Zr4+-Doped TiO2 Nanoparticles
TL;DR: In this paper, the phase transition temperature from anatase to rutile increases significantly after doping Zr4+ ions, due to their larger electropositivity and radius than those of TiO2.
Journal ArticleDOI
Modified titanium oxide (TiO2) nanocomposites and its array of applications: a review
S. Ghosh,Alok Prasad Das +1 more
TL;DR: A recent surge in the research activity, involving modified TiO2 nanoparticles (NP), which are considered to be more effective due to different physicochemical properties in comparison to unmodified fine particle analogs, is reported in this paper.
Journal ArticleDOI
Synthesis, Characterization, and Photocatalytic Activity of Sr2+ Doped TiO2 Nanoplates
TL;DR: In this article, Strontium doped titania (TiO2) nanoplates and titania nanoparticles were synthesized by sol−gel method and the characterization of the materials revealed the mesoporous nanoplate-like structure for Sr2+ doped TiO2.
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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