Core–shelled Zn/ZnO microspheres synthesised by ultrasonic irradiation for photocatalytic applications

Ma, Qing-Lan; Xiong, Rui; Zhai, Bao-gai; Huang, Yuan Ming

doi:10.1049/mnl.2013.0394

Cited by 19 publications

(5 citation statements)

References 26 publications

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“…For both semiconductor materials, the valence band is composed of O 2− (2p orbital), which is of anionic character, that induces interactions and oxidation composition with the vat dyes (alkali metal salts) [ 187 – 190 ]. However, this anionic character gains rapid recombination and holes during the oxidation process and in turn diminishes the efficiency of the photocatalytic reaction [ 191 , 192 ]. From this viewpoint, efforts have been allocated to extend the adsorption of TiO 2 and ZnO to deal with the photosensitization by vat dye molecules.…”

Section: Photocatalytic Decolorization Of Synthetic Dyesmentioning

confidence: 99%

Recent Advances in Heterogeneous Photocatalytic Decolorization of Synthetic Dyes

Julkapli

Bagheri

Hamid

2014

The Scientific World Journal

280

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During the process and operation of the dyes, the wastes produced were commonly found to contain organic and inorganic impurities leading to risks in the ecosystem and biodiversity with the resultant impact on the environment. Improper effluent disposal in aqueous ecosystems leads to reduction of sunlight penetration which in turn diminishes photosynthetic activity, resulting in acute toxic effects on the aquatic flora/fauna and dissolved oxygen concentration. Recently, photodegradation of various synthetic dyes has been studied in terms of their absorbance and the reduction of oxygen content by changes in the concentration of the dye. The advantages that make photocatalytic techniques superior to traditional methods are the ability to remove contaminates in the range of ppb, no generation of polycyclic compounds, higher speed, and lower cost. Semiconductor metal oxides, typically TiO2, ZnO, SnO, NiO, Cu2O, Fe3O4, and also CdS have been utilized as photocatalyst for their nontoxic nature, high photosensitivity, wide band gap and high stability. Various process parameters like photocatalyst dose, pH and initial dye concentrations have been varied and highlighted. Research focused on surface modification of semiconductors and mixed oxide semiconductors by doping them with noble metals (Pt, Pd, Au, and Ag) and organic matter (C, N, Cl, and F) showed enhanced dye degradation compared to corresponding native semiconductors. This paper reviews recent advances in heterogeneous photocatalytic decolorization for the removal of synthetic dyes from water and wastewater. Thus, the main core highlighted in this paper is the critical selection of semiconductors for photocatalysis based on the chemical, physical, and selective nature of the poisoning dyes.

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Section: Photocatalytic Decolorization Of Synthetic Dyesmentioning

confidence: 99%

Recent Advances in Heterogeneous Photocatalytic Decolorization of Synthetic Dyes

Julkapli

Bagheri

Hamid

2014

The Scientific World Journal

280

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“…[43,44,54,56] Among these factors, the surface area of a photocatalyst is one of the key factors to influence its photocatalytic activity. BET theory aims to explain the physical adsorption of gas molecules on a solid surface and serves as basis for an important analysis technique to measure the specific area of materials.…”

Section: Resultsmentioning

confidence: 99%

“…In the present work, the concentration of methyl orange solution was about 56 mM (i.e., 18.3 mg/L). Detailed descriptions on the geometry of the photocatalytic reactor were available elsewhere [43,44]. After having been loaded with ZnWO 4 nanoplates (400 mg), the solution of methyl orange was magnetically stirred in the dark for 30 min to ensure the establishment of an adsorption–desorption equilibrium.…”

Section: Materials and Characterizationsmentioning

confidence: 99%

Eu2+ and Eu3+ Doubly Doped ZnWO4 Nanoplates with Superior Photocatalytic Performance for Dye Degradation

Huang

Yang

et al. 2018

Nanomaterials

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Eu2+ and Eu3+ doubly doped ZnWO4 nanoplates with highly exposed {100} facets were synthesized via a facile hydrothermal route in the presence of surfactant cetyltrimethyl ammonium bromide. These ZnWO4 nanoplates were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectrometry, diffuse UV-vis reflectance spectroscopy, photoluminescence spectrophotometry, and photoluminescence lifetime spectroscopy to determine their morphological, structural, chemical, and optical characteristics. It is found that Eu-doped ZnWO4 nanoplates exhibit superior photo-oxidative capability to completely mineralize the methyl orange into CO2 and H2O, whereas undoped ZnWO4 nanoparticles can only cleave the organic molecules into fragments. The superior photocatalytic performance of Eu-doped ZnWO4 nanoplates can be attributed to the cooperative effects of crystal facet engineering and defect engineering. This is a valuable report on crystal facet engineering in combination with defect engineering for the development of highly efficient photocatalysts.

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“…It is obvious that each PL spectrum in Figure 3 consists of an ultraviolet PL band with its peak at about 378 nm and a green PL band with its peak at about 540 nm. The ultraviolet PL band is generally attributed to the band-edge recombination of excitons whereas the green PL band is produced by defects in ZnO [15][16][17][22][23][24][25]. Therefore, the higher fraction of the green PL intensity in the PL spectrum suggests the presence of higher defect density in ZnO nanorods.…”

Section: Resultsmentioning

confidence: 99%

Improving the Efficiency of Dye-Sensitized Solar Cells by Growing Longer ZnO Nanorods on TiO₂ Photoanodes

Zhai¹,

Yang²,

Huang³

2017

Journal of Nanomaterials

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By increasing the temperature of hydrothermal reactions from 70 to 100 ∘ C, vertically aligned ZnO nanorods were grown on the TiO 2 thin film in the photoanode of dye-sensitized solar cells (DSSCs) as the blocking layer to reduce the electron back recombinations at the TiO 2 /electrolyte interfaces. The length effects of ZnO nanorods on the photovoltaic performances of TiO 2 based DSSCs were investigated by means of scanning electron microscope, X-ray diffractometer, photoluminescence spectrophotometer, and the photocurrent-voltage measurement. Under the illumination of 100 mW/cm 2 , the power conversion efficiency of DSSC with ZnO nanorods decorated TiO 2 thin film as its photoanode can be increased nearly fourfold from 0.27% to 1.30% as the length of ZnO nanorods increases from 300 to 1600 nm. The enhanced efficiency of DSSC with ZnO nanorods decorated TiO 2 thin film as the photoanode can be attributed to the larger surface area and the lower defect density in longer ZnO nanorods, which are in favor of more dye adsorption and more efficient transport in the photoanode.

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Core–shelled Zn/ZnO microspheres synthesised by ultrasonic irradiation for photocatalytic applications

Cited by 19 publications

References 26 publications

Recent Advances in Heterogeneous Photocatalytic Decolorization of Synthetic Dyes

Recent Advances in Heterogeneous Photocatalytic Decolorization of Synthetic Dyes

Eu2+ and Eu3+ Doubly Doped ZnWO4 Nanoplates with Superior Photocatalytic Performance for Dye Degradation

Improving the Efficiency of Dye-Sensitized Solar Cells by Growing Longer ZnO Nanorods on TiO₂ Photoanodes

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Core–shelled Zn/ZnO microspheres synthesised by ultrasonic irradiation for photocatalytic applications

Cited by 19 publications

References 26 publications

Recent Advances in Heterogeneous Photocatalytic Decolorization of Synthetic Dyes

Recent Advances in Heterogeneous Photocatalytic Decolorization of Synthetic Dyes

Eu2+ and Eu3+ Doubly Doped ZnWO4 Nanoplates with Superior Photocatalytic Performance for Dye Degradation

Improving the Efficiency of Dye-Sensitized Solar Cells by Growing Longer ZnO Nanorods on TiO2 Photoanodes

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Improving the Efficiency of Dye-Sensitized Solar Cells by Growing Longer ZnO Nanorods on TiO₂ Photoanodes