Enhanced photocatalytic activity in composites of TiO2 nanotubes and CdS nanoparticles

Kim, Jin Chul; Choi, Jungkweon; Lee, Yong-Bok; Hong, Jung Hoon; Lee, Jong In; Jin, Can; Lee, Wan In; Hur, Nam Hwi

doi:10.1039/b612572g

Cited by 159 publications

(54 citation statements)

References 20 publications

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“…At shorter wavelength values (< 300 nm), the activity of the TiO 2 nanotubes increases and the sensitization of the CdS for TiO 2 weakens, finally causing the close absorption of both of them. [44,45] As can be seen from curve c, the band gap absorption edge of TiO 2 NT/CdS/ZnO NR is the same as that of TiO 2 NT/CdS, corresponding to an E g value of 2.32 eV, and ZnO is transparent to visible light. The final photocatalyst has a strong and wide absorption in the range from 200 to 535 nm in the UV/Vis region.…”

Section: Characterization Of the Photocatalystmentioning

confidence: 85%

CdS‐Encapsulated TiO₂ Nanotube Arrays Lidded with ZnO Nanorod Layers and Their Photoelectrocatalytic Applications

et al. 2010

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A novel TiO(2) nanotube array/CdS nanoparticle/ZnO nanorod (TiO(2) NT/CdS/ZnO NR) photocatalyst was constructed which exhibited a wide-absorption (200-535 nm) response in the UV/Vis region and was applied for the photoelectrocatalytic (PEC) degradation of dye wastewater. This was achieved by chemically assembling CdS into the TiO(2) NTs and then constructing a ZnO NR layer on the TiO(2) NT/CdS surface. Scanning electron microscopy (SEM) results showed that a new structure had been obtained. The TiO(2) NTs looked like many "empty bottles" and the ZnO NR layer served as a big lid. Meanwhile the CdS NPs were encapsulated between them with good protection. After being sensitized by the CdS NPs, the absorption-band edge of the obtained photocatalyst was obviously red-shifted to the visible region, and the band gap was reduced from its original 3.20 eV to 2.32 eV. Photoelectric-property tests indicated that the TiO(2) NT/CdS/ZnO NR material maintained a very high PEC activity in both the ultraviolet (UV) and the visible region. The maximum photoelectric conversion efficiencies of TiO(2) NT/CdS/ZnO NR were 31.8 and 5.98% under UV light (365 nm) and visible light (420-800 nm), respectively. In the PEC oxidation, TiO(2) NT/CdS/ZnO NR exhibited a higher removal ability for methyl orange (MO) and a high stability. The kinetic constants were 1.77×10(-4) s(-1) under UV light, which was almost 5.9 and 2.6 times of those on pure TiO(2) NTs and TiO(2) NT/ZnO NR, and 2.5×10(-4) s(-1) under visible light, 2.4 times those on TiO(2) NT/CdS.

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Section: Characterization Of the Photocatalystmentioning

confidence: 85%

CdS‐Encapsulated TiO₂ Nanotube Arrays Lidded with ZnO Nanorod Layers and Their Photoelectrocatalytic Applications

et al. 2010

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“…After the photodeposition of platinum on the surface of such a composite it exhibits higher activity in the release of hydrogen from solutions of sodium sulfite during the action of visible light than bulk crystalline CdS. The heterostructures of CdS nanoparticles with TiO 2 nanotubes, produced by ion exchange with subsequent sulfidization by thiourea at 70-80°C, are active photocatalysts of the release of hydrogen from aqueous solutions of Na 2 S/Na 2 SO 3 during the action of light with wavelength l > 420 nm [56][57][58].…”

Section: Photocatalytic Systems Based On Semiconductor Heterostructuresmentioning

confidence: 99%

Semiconductor photocatalytic systems for the production of hydrogen by the action of visible light

et al. 2009

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Data on investigations of recent years on the creation of semiconductor photocatalytic systems for the production of hydrogen from water and aqueous solutions of electron-donating substrates are reviewed. Physicochemical approaches to extending the range of spectral sensitivity of the semiconductors (the use of sensitizers, semiconducting heterostructures, doping with metals and metalloids) are examined. Possible ways of improving the photocatalytic systems for the production of hydrogen with metal-sulfide and other types of semiconductors are analyzed. A general description of the advances and planned developments in the creation of photocatalytic converters of solar energy is given.

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“…However, titania nanotubes have the intrinsic drawbacks of poor visiblelight absorption (wide band gap semiconductor which can only absorb UV light with the wavelength below 390 nm) and fast charge carrier recombination (photo-generated electrons and holes) which hinder its practical application [5]. Many strategies have recently been devoted to modify titania nanotubes by dye sensitization, doping with ions, coating their surface with noble metal nanoparticles or narrow band-gap semiconductor quantum dots and coupling with low band gap semiconductors like PbS, CdTe, CdSe, ZnFe 2 O 4 , Cu 2 O, CdS; which may overcome the above defects and improve the catalytic efficiency [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Among the low band gap semiconductors, cadmium sulfide (CdS) has attracted much attention; it can be excited by visible light to produce electrons and holes due to the narrow band gap of 2.4 eV [22,23].…”

Section: Introductionmentioning

confidence: 99%

The effect of number of SILAR cycles on morphological, optical and photo catalytic properties of cadmium sulfide–titania films

Momeni

Mozafari

2016

J Mater Sci: Mater Electron

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In this paper, cadmium sulfide-titania nanocomposites were successfully synthesized by electrochemical anodizing and successive ionic layer adsorption and reaction (SILAR) methods. Cadmium sulfide was successfully deposited on titania nanotubes with tunable loading amounts by controlling deposition cycles of SILAR. The morphology, crystal structure, elemental composition and light absorption capability of samples were characterized by FE-SEM, XRD, EDX and UV-Vis methods. Titania nanotubes with 90-220 nm in diameter and 15-30 nm in wall thickness were prepared by one-step anodizing method and then cadmium sulfide deposited onto titania to form cadmium sulfide-titania heterostructure. Characterization of the cadmium sulfide-titania sample indicated that the number of SILAR cycles significantly influenced the morphology and photo catalytic activity of fabricated films. Rh B and MO were adopted as the model dyes and the photo catalytic tests were carried out in detail. Results showed that the photo catalytic activity of cadmium sulfide-titania samples is higher than that with bare titania sample. The incorporation of cadmium sulfide on titania improves the photo catalytic activity due to the synergetic effect. The photo catalytic activity increase with the proper increase of cadmium sulfide amount; however, the activity decreases when the amount of cadmium sulfide is further increased which may result in the formation of the compact films on the surface and a decrease in surface area of samples.Cadmium sulfide-titania sample prepared by SILAR deposition with 5 cycles gives the highest degrading rate, which can be attributed to appropriate cadmium sulfide content. Cadmium sulfide-titania is easy to be recycled and has good stability for repeated use. A mechanism is also studied and an electron transfer route is provided and accounts for the enhanced photo catalytic activity. With the improved visible light degradation performance, cadmium sulfide-titania samples would be expected to be used in water purification.

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Enhanced photocatalytic activity in composites of TiO2 nanotubes and CdS nanoparticles

Cited by 159 publications

References 20 publications

CdS‐Encapsulated TiO₂ Nanotube Arrays Lidded with ZnO Nanorod Layers and Their Photoelectrocatalytic Applications

CdS‐Encapsulated TiO₂ Nanotube Arrays Lidded with ZnO Nanorod Layers and Their Photoelectrocatalytic Applications

Semiconductor photocatalytic systems for the production of hydrogen by the action of visible light

The effect of number of SILAR cycles on morphological, optical and photo catalytic properties of cadmium sulfide–titania films

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Enhanced photocatalytic activity in composites of TiO2 nanotubes and CdS nanoparticles

Cited by 159 publications

References 20 publications

CdS‐Encapsulated TiO2 Nanotube Arrays Lidded with ZnO Nanorod Layers and Their Photoelectrocatalytic Applications

CdS‐Encapsulated TiO2 Nanotube Arrays Lidded with ZnO Nanorod Layers and Their Photoelectrocatalytic Applications

Semiconductor photocatalytic systems for the production of hydrogen by the action of visible light

The effect of number of SILAR cycles on morphological, optical and photo catalytic properties of cadmium sulfide–titania films

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CdS‐Encapsulated TiO₂ Nanotube Arrays Lidded with ZnO Nanorod Layers and Their Photoelectrocatalytic Applications

CdS‐Encapsulated TiO₂ Nanotube Arrays Lidded with ZnO Nanorod Layers and Their Photoelectrocatalytic Applications