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
Application of iron-based materials in heterogeneous advanced oxidation processes for wastewater treatment: A review
TL;DR: In this paper, the possible applications of different iron-based materials (e.g., zero-valent iron, iron (hydr)oxides, and iron composite materials) in AOPs and their activation and catalytic mechanisms are introduced.
Journal ArticleDOI
Preparation and characterization of N–S-codoped TiO2 photocatalyst and its photocatalytic activity
Fengyu Wei,Liangsuo Ni,Peng Cui +2 more
TL;DR: The photocatalytic tests indicated that NSTO exhibited a high activity for decompositions of methyl orange both under UV-light and vis-light irradiation comparing to S-doped TiO(2) (STO) and undoped Ti O(2), which can be related to the results of the synergetic effects of strong absorption in the UV-vis region, red shift in adsorption edge, oxygen vacancies and the enhancement of surface acidity induced by N
Journal ArticleDOI
Copper and Nitrogen co-doped TiO2 photocatalyst with enhanced optical absorption and catalytic activity
Richa Jaiswal,J. Bharambe,Nainesh Patel,Nainesh Patel,Alpa Dashora,D.C. Kothari,Antonio Miotello +6 more
TL;DR: In this article, a (Cu, N)-codoped TiO 2 photocatalyst is synthesized by sol-gel method to obtain enhanced optical absorption in the visible region, which is attributed to the formation of isolated intermediate band (IB) occurring due to the strong hybridization between Cu 3d and N 2p orbitals.
Journal ArticleDOI
Photodegradation of benzoic acid over metal-doped TiO2
TL;DR: A modified sol−gel method was employed to synthesize metal-doped TiO2 with varied dopant concentrations using titanium butoxide and metal nitrate hydrate as the precursors and hydrothermal posttreatment as discussed by the authors.
Journal ArticleDOI
Two-dimensional germanium monochalcogenides for photocatalytic water splitting with high carrier mobility
TL;DR: In this paper, an efficient photocatalytic photocatalyst for water splitting was proposed by using deformation potential theory, where the authors observed that GeS exhibits an indirect band gap of 229 eV while GeSe reveals a direct band gap with 159 eV by HSE hybrid functional.
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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