ZnO for application in photocatalysis: From thin films to nanostructures

Mauro, Alessandro Di; Fragalà, Maria Elena; Privitera, V.; Impellizzeri, G.

doi:10.1016/j.mssp.2017.03.029

Cited by 268 publications

(112 citation statements)

References 41 publications

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“…Among the various semiconductors used for the photocatalytic applications, recently, cerium oxide (CeO 2 , commonly called ceria), a largely used catalyst in many thermo-catalytic reactions [17,18], was examined as an alternative to the most used metal oxide photocatalysts (such as TiO 2 and ZnO [19][20][21][22]). The most attractive properties of CeO 2 are: the lower band-gap (around 2.7-2.8 eV) compared to TiO 2 and ZnO, making the material sensitive to visible light; the presence of empty 4f energy levels that facilitate the electron transfers; the high stability in the reaction medium; the high oxygen mobility related to the reversible Ce 4+ /Ce 3+ transformation, and the ability to form nonstoichiometric oxygen-deficient CeO 2-x oxide [23].…”

Section: Introductionmentioning

confidence: 99%

CeO2 for Water Remediation: Comparison of Various Advanced Oxidation Processes

et al. 2020

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Three different Advanced Oxidation Processes (AOPs) have been investigated for the degradation of the imidacloprid pesticide in water: photocatalysis, Fenton and photo-Fenton reactions. For these tests, we have compared the performance of two types of CeO2, employed as a non-conventional photocatalyst/Fenton-like material. The first one has been prepared by chemical precipitation with KOH, while the second one has been obtained by exposing the as-synthetized CeO2 to solar irradiation in H2 stream. This latter treatment led to obtain a more defective CeO2 (coded as “grey CeO2”) with the formation of Ce3+ sites on the surface of CeO2, as determined by Raman and X-ray Photoelectron Spectroscopy (XPS) characterizations. This peculiar feature has been demonstrated as beneficial for the solar photo–Fenton reaction, with the best performance exhibited by the grey CeO2. On the contrary, the bare CeO2 showed a photocatalytic activity higher with respect to the grey CeO2, due to the higher exposed surface area and the lower band-gap. The easy synthetic procedures of CeO2 reported here, allows to tune and modify the physico-chemical properties of CeO2, allowing a choice of different CeO2 samples on the basis of the specific AOPs for water remediation. Furthermore, neither of the samples have shown any critical toxicity.

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Section: Introductionmentioning

confidence: 99%

CeO2 for Water Remediation: Comparison of Various Advanced Oxidation Processes

et al. 2020

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“…Zhu et al [14] prepared this material by mechanical ball milling method, using zinc oxide (ZnO) and calcium hydroxide Ca(OH) 2 in an aqueous medium. TiO 2 and ZnO have proven their efficiency for photocatalytic degradation of pollutants because of the faster electron transfer to molecular oxygen [15]. However, metal oxide nanoparticle like calcium zincate (CaZnO 2 ), zinc oxide (ZnO), and composites of zinc oxide were also found to degrade dyes as an effective and alternative photocatalyst to TiO 2 , such as Coralene Dark Red 2B, Acid Orange 7, and Coraline Red F3BS, respectively [10].…”

Section: Introductionmentioning

confidence: 99%

Ca-hydroxyzincate: Synthesis and Enhanced Photocatalytic Activity for the Degradation of Methylene Blue Under UV-Light Irradiation

et al. 2019

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This paper involves the investigation of the calcined Ca-hydroxyzincate dehydrate (CHZ) as solid base catalysts for photocatalytic degradation of methylene blue. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG-DTA), and UV-Vis spectroscopy were carried out to characterize and evaluate the as-prepared samples. The calcined catalysts performances were promising compared to non-calcined material. All the photocatalysts prepared under different processing temperatures (200, 400 and 600 °C) displayed 100% methylene blue degradation compared to the non-calcined sample with 100% dye removal.

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“…Favorable position of the bands energy of ZnO with respect to TiO 2 expects a more efficient photocatalytic performance [4,5]. The 3.37 eV of its optical bandgap at room temperature, the 60 eV of exciton energy [6], added to the fact that it is a GRAS (Generally Recognized as Safe) material and present a large variety of morphologies allows ZnO to be considered a promising candidate for photocatalytic water purification [7][8][9][10]. 1D structures [11][12][13][14] presents a charge transport property different from those of spheroidal nanoparticles, modifying positively its surface-to-volume ratio and electrochemical double layer, resulting in an enhancement of the photocatalytic efficiency [15].…”

Section: Introductionmentioning

confidence: 99%

ZnO (Ag-N) Nanorods Films Optimized for Photocatalytic Water Purification

et al. 2019

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ZnO nanorods (NRs) films, nitrogen-doped (ZnO:N), and ZnO doped with nitrogen and decorated with silver nanostructures (ZnO:N-Ag) NRs films were vertically supported on undoped and N doped ZnO seed layers by a wet chemical method. The obtained films were characterized structurally by X-ray diffraction. Morphological and elemental analysis was performed by scanning electron microscopy, including an energy dispersive X-ray spectroscopy facility and their optical properties by Ultraviolet-Visible Spectroscopy. Analysis performed in the NRs films showed that the nitrogen content in the seed layer strongly affected their structure and morphology. The mean diameter of ZnO NRs ranged from 70 to 190 nm. As the nitrogen content in the seed layer increased, the mean diameter of ZnO:N NRs increased from 132 to 250 nm and the diameter dispersion decreased. This diameter increase occurs simultaneously with the incorporation of nitrogen into the ZnO crystal lattice and the increase in the volume of the unit cell, calculated using the X-ray diffraction patterns and confirmed by a slight shift in the XRD angle. The diffractograms indicated that the NRs have a hexagonal wurtzite structure, with preferential growth direction along the c axis. The SEM images confirmed the presence of metallic silver in the form of nanoparticles dispersed on the NRs films. Finally, the degradation of methyl orange (MO) in an aqueous solution was studied by UV-vis irradiation of NRs films contained in the bulk of aqueous MO solutions. We found a significant enhancement of the photocatalytic degradation efficiency, with ZnO:N-Ag NRs film being more efficient than ZnO:N NRs film, and the latter better than the ZnO NRs film.

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ZnO for application in photocatalysis: From thin films to nanostructures

Cited by 268 publications

References 41 publications

CeO2 for Water Remediation: Comparison of Various Advanced Oxidation Processes

CeO2 for Water Remediation: Comparison of Various Advanced Oxidation Processes

Ca-hydroxyzincate: Synthesis and Enhanced Photocatalytic Activity for the Degradation of Methylene Blue Under UV-Light Irradiation

ZnO (Ag-N) Nanorods Films Optimized for Photocatalytic Water Purification

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