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
Selective sensing of isoprene by Ti-doped ZnO for breath diagnostics
TL;DR: An inexpensive isoprene detector has been developed that could be easily incorporated into a portable breath analyzer for non-invasive monitoring of metabolic disorders (e.g. cholesterol) and can be detected accurately down to 5 ppb with high signal-to-noise ratio.
Journal ArticleDOI
Enhanced photocatalytic water splitting activity of carbon-modified TiO2 composite materials synthesized by a green synthetic approach
Sreenivasan Koliyat Parayil,Harrison S. Kibombo,Chia-Ming Wu,Rui Peng,Jonas Baltrusaitis,Ranjit T. Koodali +5 more
TL;DR: A green and facile approach for the preparation of carbon modified (C-modified) TiO2 composite materials by hydrothermal synthesis followed by pyrolytic treatment was reported in this article.
Journal ArticleDOI
Characterization, adsorption and photocatalytic activity of vanadium-doped TiO2 and sulfated TiO2 (rutile) catalysts: Degradation of methylene blue dye
TL;DR: In this paper, the degradation of methylene blue (MB) dye was tested for the effectiveness of the samples by means of X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and particle size analyzer.
Book ChapterDOI
Semiconductor Photocatalysis for Water Purification
TL;DR: In this paper, the application of various nanomaterials (such as metal nanoparticles, metal oxides, carbon compounds, zeolite, filtration membranes, etc.) in the field of wastewater treatment by photocatalysis is discussed.
Journal ArticleDOI
Enhanced photoinduced super-hydrophilicity of the sol–gel-derived TiO2 thin films by Fe-doping
TL;DR: In this paper, Fe-doped TiO2 nanometer thin films were prepared on soda-lime glass pre-coated with a SiO2 layer by a dip-coating method from a precursor solution containing ferric nitrate followed by calcination at 500°C for 2.h.
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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