Computational investigation of the adsorption and photocleavage of chlorobenzene on anatase TiO2 surfaces

Wahab, Hilal S.; Bredow, Thomas; Aliwi, S.M.

doi:10.1016/j.chemphys.2008.07.017

Cited by 21 publications

(14 citation statements)

References 71 publications

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“…[28,30] The bonding of the CB molecule to the TiO 2 (100) surface has been inferred from a study of substrate-cluster optimization starting from a perpendicular initial orientation. [19] The attachment develops through the interactions of chlorine atoms to unsaturated surface titanium, in accordance with experimental observations on the catalytic degradation of trichlorophenol. [31] The substrate is positioned perpendicularly to the lattice surface and is adsorbed with a release of a rather small energy of 121 kJ mol À1 (Table 1) …”

Section: Adsorption Of Chlorobenzenesupporting

confidence: 54%

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Comparative Study of the Adsorption of Aromatic Pollutants onto TiO2 (100) Surface via Molecular Simulation

Wahab¹,

Koutselos²

2011

Aust. J. Chem.

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The adsorption mode of benzoic acid onto the anatase TiO 2 (100) surface has been studied through the semi-empirical selfconsistent field molecular orbital method MSINDO and is compared with previously determined modes of four aromatic compounds: chlorobenzene, aniline, p-chlorophenol and nitrobenzene. The simulation results reveal that aniline and p-chlorophenol molecules are adsorbed with their aromatic ring positioned parallel to the surface although they are linked to a surface lattice titanium atom via the amino nitrogen and phenolic oxygen respectively. In contrast, chlorobenzene, nitrobenzene and benzoic acid are found in perpendicular configurations and they are attached to the surface via the chlorine and oxygen atoms of the NO 2 and COOH groups respectively. The calculated substrate-surface interaction energy is influenced by the degree of basicity of the lone pair of the donating atoms, the number of linkages between the substrate and the surface and, further, the hydrogen bonding between the acidic hydrogen and lattice oxygen atom. The computed vibrational density of states for these adsorbed organic pollutants is in reasonably good agreement with available experimental data and previous theoretical results.

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Section: Adsorption Of Chlorobenzenesupporting

confidence: 54%

“…Here, we study the adsorption configuration obtained for benzoic acid (BZA) onto the TiO 2 (100) surface through a computational method. The results are compared with previous work on chlorobenzene (CB), [19] aniline (AN), [20] p-chlorophenol (p-CP) [21] and nitrobenzene (NB). [22] Computational Approach…”

Section: Introductionmentioning

confidence: 94%

Comparative Study of the Adsorption of Aromatic Pollutants onto TiO2 (100) Surface via Molecular Simulation

Wahab¹,

Koutselos²

2011

Aust. J. Chem.

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“…Robbins and this author [929] showed that partial oxidation of propylene and isobutene on R TiO 2 (110) required trace amounts of water on the surface in order for molecular oxygen to activate these molecules. Similarly, Wahab et al [1335] proposed that water assisted O 2 in ring-opening reactions during the photooxidation of chlorobenzene on the A TiO 2 (001), TiO 2 (100) and TiO 2 (010) surfaces. As discussed in Section 5.2.1, several scanning probe studies on the R TiO 2 (110) surface have shown that water assists in moving protons and oxygen atoms along and across bridging oxygen rows, and aides in activating O 2 on the surface [526,795,797,806,807].…”

Section: Promotermentioning

confidence: 96%

A surface science perspective on TiO2 photocatalysis

Henderson

2011

Surface Science Reports

1,832

1,623

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a b s t r a c tThe field of surface science provides a unique approach to understanding bulk, surface and interfacial phenomena occurring during TiO 2 photocatalysis. This review highlights, from a surface science perspective, recent literature that provides molecular-level insights into photon-initiated events occurring at TiO 2 surfaces. Seven key scientific issues are identified in the organization of this review. These are: (1) photon absorption, (2) charge transport and trapping, (3) electron transfer dynamics, (4) the adsorbed state, (5) mechanisms, (6) poisons and promoters, and (7) phase and form. This review ends with a brief examination of several chemical processes (such as water splitting) in which TiO 2 photocatalysis has made significant contributions in the literature.

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“…However, recent electrochemical studies suggested that the aromatic rings cannot be efficiently cleaved by the ∙OH radicals in the absence of O 2 [7], indicating the ∙OH radicals are not a good active species for the cleavage of aryl rings. Other reports [54,55,56,57,58,59] also argued that the reaction of the O 2 -derived species, such as superoxide or singlet oxygen, with aromatics is the main pathway in photocatalytic ring-opening step. It is also considered that both the ∙OH radicals and O 2 are both important in the aromatic ring cleavage, i.e.…”

Section: Photocatalytic Cleavage Of Aryl-ring On Tio2 Surfacementioning

confidence: 99%

Unraveling the Photocatalytic Mechanisms on TiO2 Surfaces Using the Oxygen-18 Isotopic Label Technique

Pang

Chen

et al. 2014

Molecules

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During the last several decades TiO2 photocatalytic oxidation using the molecular oxygen in air has emerged as a promising method for the degradation of recalcitrant organic pollutants and selective transformations of valuable organic chemicals. Despite extensive studies, the mechanisms of these photocatalytic reactions are still poorly understood due to their complexity. In this review, we will highlight how the oxygen-18 isotope labeling technique can be a powerful tool to elucidate complicated photocatalytic mechanisms taking place on the TiO2 surface. To this end, the application of the oxygen-18 isotopic-labeling method to three representative photocatalytic reactions is discussed: (1) the photocatalytic hydroxylation of aromatics; (2) oxidative cleavage of aryl rings on the TiO2 surface; and (3) photocatalytic decarboxylation of saturated carboxylic acids. The results show that the oxygen atoms of molecular oxygen can incorporate into the corresponding products in aqueous solution in all three of these reactions, but the detailed incorporation pathways are completely different in each case. For the hydroxylation process, the O atom in O2 is shown to be incorporated through activation of O2 by conduction band electrons. In the cleavage of aryl rings, O atoms are inserted into the aryl ring through the site-dependent coordination of reactants on the TiO2 surface. A new pathway for the decarboxylation of saturated carboxylic acids with pyruvic acid as an intermediate is identified, and the O2 is incorporated into the products through the further oxidation of pyruvic acid by active species from the activation of O2 by conduction band electrons.

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Computational investigation of the adsorption and photocleavage of chlorobenzene on anatase TiO2 surfaces

Cited by 21 publications

References 71 publications

Comparative Study of the Adsorption of Aromatic Pollutants onto TiO2 (100) Surface via Molecular Simulation

Comparative Study of the Adsorption of Aromatic Pollutants onto TiO2 (100) Surface via Molecular Simulation

A surface science perspective on TiO2 photocatalysis

Unraveling the Photocatalytic Mechanisms on TiO2 Surfaces Using the Oxygen-18 Isotopic Label Technique

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