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
Structural color via layer-by-layer deposition: layered nanoparticle arrays with near-UV and visible reflectivity bands
TL;DR: In this paper, a nature-inspired 1D photonic crystal structure that has simultaneous narrow stop bands in the NUV and visible wavelength range was developed, resulting in a NUV reflector with tunable structural color in the visible region of the spectrum.
Journal ArticleDOI
Photodegradation of rhodamine B under visible light by bimetal codoped TiO2 nanocrystals.
TL;DR: The results showed that Fe(0.1%)/Co (0.4%) codoped TiO(2) had the highest photoactivity among all as-prepared samples under visible light, though less absorbency ofvisible light, indicating that the photoactivity not only benefits from absorbency but also relates to the cooperative effect of the two dopants.
Journal ArticleDOI
Enhanced photocatalytic degradation of humic acids using Al and Fe co-doped TiO2 nanotubes under UV/ozonation for drinking water purification.
TL;DR: O3/UV/TiO2 was used to effectively decompose humic acids (HAs) in drinking water and, in a neutral solution, SO4(2-) slightly promoted HAs removal, but HCO3(-) was found to significantly inhibit the catalyst activity, whereas Cl(-) had negligible effect on photocatalytic ability.
Journal ArticleDOI
Non-thermal plasma-induced photocatalytic degradation of 4-chlorophenol in water
TL;DR: Pulsed high-voltage discharge process with TiO(2) had a promoted effect for the degradation of these pollutants under a broad range of liquid conductivity, and enhanced the yields of chemically active species, which were available for highly efficient removal and mineralization of organic pollutants.
Journal ArticleDOI
Evaluation of Diffusibility of Adsorbed Propionaldehyde on Titanium Dioxide-Loaded Adsorbent Photocatalyst Films from Its Photodecomposition Rate
TL;DR: In this article, the degradation of gaseous propionaldehyde over TiO2-loaded adsorbent films was investigated after adsorption equilibrium was obtained using silica, alumina, activated carbon, and severa...
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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