Journal ArticleDOI
Photocatalytic degradation of 4-nitrophenol in aqueous TiO2 suspensions: Theoretical prediction of the intermediates
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TLDR
In this paper, the effects of the catalyst loading, the initial concentration of 4-nitrophenol, H2O2 and the added Cu2+ ions on the degradation rate have been examined.Abstract:
The kinetics of the photocatalytic degradation of 4-nitrophenol (4-NP) in the presence of TiO2 has been investigated experimentally and theoretically. The effects of the catalyst loading, the initial concentration of 4-NP, H2O2 and the added Cu2+ ions on the degradation rate have been examined. A pseudo-first order kinetic model has been used to describe the results. A linear dependence of the rate constant upon the reciprocal of the initial 4-NP concentration has been obtained. The addition of H2O2 increases the reaction rate while Cu2+ ions has a detrimental effect. With the intention of predicting the primary intermediates, geometry optimizations of the reactants, the products and the transition state complexes have been performed with the semi-empirical PM3 method. The molecular orbital calculations have been carried out by an SCF method using RHF or UHF formalisms. Based on the results of the quantum mechanical calculations, the rate constants of the two possible reaction paths have been calculated by means of the transition state theory, and 1,2-dihydroxy-4-nitro-cyclohexadienyl radical which then forms 4-nitrocatechol has been determined as the most probable primary intermediate by the application of three different theoretical shortcut methods.read more
Citations
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Photoinduced reactivity of titanium dioxide
TL;DR: In this paper, photo-induced superhydrophilicity was used on the surface of a wide-band gap semiconductor like titanium dioxide (TiO 2 ) for photocatalytic activity towards environmentally hazardous compounds.
Journal ArticleDOI
A surface science perspective on TiO2 photocatalysis
TL;DR: The field of surface science provides a unique approach to understand bulk, surface and interfacial phenomena occurring during TiO2 photocatalysis as mentioned in this paper, including photon absorption, charge transport and trapping, electron transfer dynamics, adsorbed state, mechanisms, poisons and promoters, and phase and form.
Journal ArticleDOI
Size dependency of nanocrystalline TiO2 on its optical property and photocatalytic reactivity exemplified by 2-chlorophenol
TL;DR: In this article, the electro-optical and photocatalytic properties of the synthesized TiO2 nanoparticles were studied along with several commercially available ultra-fine TiO 2 particles (e.g., 3.8-5.7nm).
Journal ArticleDOI
Performance of nano-Co3O4/peroxymonosulfate system: Kinetics and mechanism study using Acid Orange 7 as a model compound
TL;DR: Nano-Co 3 O 4 /PMS was used to activate peroxymonosulfate (PMS) and degrade a model compound Acid Orange 7 (AO7).
Journal ArticleDOI
Photocatalytic degradation of various dyes by combustion synthesized nano anatase TiO2
TL;DR: In this paper, the 8-10 nm pure anatase phase titania with $156 m^2/g$ BET surface area was prepared by solution combustion method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Xray photoelectron spectroscopy (XPS), and BET surface areas.
References
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Book
AB INITIO Molecular Orbital Theory
TL;DR: In this paper, the use of theoretical models as an alternative to experiment in making accurate predictions of chemical phenomena is discussed, and the formulation of theoretical molecular orbital models starting from quantum mechanics is discussed.
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An overview of semiconductor photocatalysis
Andrew Mills,Stephen Le Hunte +1 more
TL;DR: An overview of the field of semiconductor photocatalysis can be found in this paper, where a brief examination of its roots, achievements and possible future is presented, and the semiconductor titanium dioxide (TiO 2 ) features predominantly in past and present work.
Journal ArticleDOI
MOPAC: A semiempirical molecular orbital program
TL;DR: This work focuses on the calculations of vibrational spectra, thermodynamic quantities, isotopic substitution effects, and force constants in a fully integrated program for the study of chemical reactions involving molecules, ions, and linear polymers using MOPAC.
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Photocatalyzed destruction of water contaminants
TL;DR: Heterogeneous photocatalysis is a process in which the illumination of an oxide semiconductor, usually the anatase form of titanium dioxide, produces photoexcited electrons (e{sup {minus}}) and holes (h{sup +}). These can migrate to the oxide surface and participate in halfcell reactions that are part of a closed, catalytic cycle as mentioned in this paper.
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Photodegradation kinetics of 4-nitrophenol in TiO2 suspension
Dingwang Chen,Ajay K. Ray +1 more
TL;DR: In this paper, a two-phase swirl-flow monolithic type reactor was designed to study the kinetics of heterogeneous photocatalytic processes on semiconductor catalysts, and the photomineralization of 4-nitrophenol (4-NP) sensitized by Degussa P25 TiO2 in aqueous solution has been investigated as a function of the following different experimental parameters: initial concentration of pollutant (CS0), light intensity (Ia), partial pressure of oxygen (pO2), catalyst concentration, pH, chloride ion and temperature