Visible light degradation of Orange II using xCuyOz/TiO2 heterojunctions

Helaïli, N.; Bessekhouad, Y.; Bouguelia, A.; Trari, M.

doi:10.1016/j.jhazmat.2009.02.066

Cited by 73 publications

(44 citation statements)

References 37 publications

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“…For example, Helaili et al prepared Cu2O/TiO2, Cu/Cu2O/TiO2 and Cu/Cu2O/CuO/TiO2 heterojunctions using chemical methods, and examined their potential application as photocatalysts for oxidative reactions (Orange II as a model dye pollutant) under visible light irradiation [106]. The obtained results …”

Section: Mixed Copper Species Deposited On Titania Surfacementioning

confidence: 99%

“…Frequently, during preparation of copper-modified TiO 2 , a mixture of copper species is obtained [58,59] [106]. The obtained results suggested the following rules, which could govern the electrons transfer mechanism: (a) metallic Cu improved the photocatalytic activity of single semiconductor by the formation of apparent Ohmic junction enhancing the charges transfer kinetics; (b) electromotive forces developed from semiconductor/semiconductor heterojunction suppressed the effect of metallic Cu due to the formation of an apparent Schottky type junction; (c) diffusion potential developed from multiple steps electrons transfer had more impact for improving the efficiency than that developed from one step transition; and (d) heterojunction cascade obtained from monobloc of photosensitizers was more efficient than that obtained from direct mixture of the semiconductors [106].…”

Section: Mixed Copper Species Deposited On Titania Surfacementioning

confidence: 99%

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On the Origin of Enhanced Photocatalytic Activity of Copper-Modified Titania in the Oxidative Reaction Systems

2017

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Modification of titania with copper is a promising way to enhance the photocatalytic performance of TiO 2 . The enhancement means the significant retardation of charge carriers' recombination ratio and the introduction of visible light activity. This review focuses on two main ways of performance enhancement by copper species-i.e., originated from plasmonic properties of zero-valent copper (plasmonic photocatalysis) and heterojunctions between semiconductors (titania and copper oxides). The photocatalytic performance of copper-modified titania is discussed for oxidative reaction systems due to their importance for prospective applications in environmental purification. The review consists of the correlation between copper species and corresponding variants of photocatalytic mechanisms including novel systems of cascade heterojunctions. The problem of stability of copper species on titania, and the methods of its improvement are also discussed as important factors for future applications. As a new trend in the preparation of copper-modified titania photocatalyst, the role of particle morphology (faceted particles, core-shell structures) is also described. Finally, in the conclusion section, perspectives, challenges and recommendations for future research on copper-modified titania are formulated.

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Section: Mixed Copper Species Deposited On Titania Surfacementioning

confidence: 99%

Section: Mixed Copper Species Deposited On Titania Surfacementioning

confidence: 99%

On the Origin of Enhanced Photocatalytic Activity of Copper-Modified Titania in the Oxidative Reaction Systems

2017

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“…Many efforts have been focused on heterosystems which could not only extend the spectral response of wide band gap semiconductors (SCs) toward lower energies but also inhibit the charge recombination and in this way increase the photocatalytic performance [10]. TiO 2 can mediate the electron transfer and plays a crucial role when the potential of its conduction band (CB) is less cathodic than that of the photosensitizer [11].…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic degradation of orange II on the novel hetero-system WS2/TiO2 under UV light

Bassaid

Bellal

Trari

2015

Reac Kinet Mech Cat

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The photodegradation of orange II (OII) is successfully achieved on the new hetero-system WS 2 /TiO 2 under UV illumination. The nano sized bi-functional catalyst is prepared by sol gel and calcined at *450°C. The X-ray diffraction shows noticeably broad peaks and TiO 2 is therefore less crystallized with the anatase phase. The sensitizer WS 2 presents a direct optical transition at 1.72 eV. The Mott-Schottky plot (C -2 -V) is characteristic of n type conduction from which a flat band potential of 0.17 V SCE and a donor density of 5.30 9 10 17 cm -3 are determined. An energy band diagram is established, predicting an electron transfer from WS 2 to TiO 2 ; the injection process is confirmed by the photocurrent measurements at different concentrations. Upon increasing the mass of WS 2 , the activity increases and the best performance occurs on 30 % WS 2 /TiO 2 . A conversion of 98 % is reported in aerated solution for OII concentration of 10 ppm in less than 90 min. The oxidation follows a first order kinetic with a rate constant of 4.8 9 10 -2 min -1 .

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“…Cu 2 O/TiO 2 p-n junction has already exhibited enhanced performance as catalysts [11][12][13][14]. The Cu 2 O with absorption in visible light spectrum, associated with the favorable band energy alignment with TiO 2 , leads to an efficient pathway for charge transfer.…”

Section: Introductionmentioning

confidence: 99%