UV and visible-light driven photocatalytic removal of caffeine using ZnO modified with different noble metals (Pt, Ag and Au)

Vaiano, Vincenzo; Jaramillo-Páez, C.; Matarangolo, Mariantonietta; Navı́o, J.A.; Hidalgo, M.C.

doi:10.1016/j.materresbull.2018.12.034

Cited by 84 publications

(34 citation statements)

References 70 publications

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“…ZnO is also an abundant, environmentally friendly material, and it is easy and inexpensive to grow in nanostructures [3,4]. Under UV light irradiation, organic pollutants in waste water streams can be decontaminated in the presence of ZnO nanostructures, where the photogenerated electrons and holes travel to the catalyst surface and produce highly oxidizing species such as hydroxyl radicals and super oxide ions responsible for degradation reactions [5]. Despite their remarkable photocatalytic activity, ZnO nanostructures suffer from the rapid recombination of photogenerated electron-hole pairs and low utilization of the solar spectrum due to their limited spectral response to visible light [5].…”

Section: Introductionmentioning

confidence: 99%

“…Under UV light irradiation, organic pollutants in waste water streams can be decontaminated in the presence of ZnO nanostructures, where the photogenerated electrons and holes travel to the catalyst surface and produce highly oxidizing species such as hydroxyl radicals and super oxide ions responsible for degradation reactions [5]. Despite their remarkable photocatalytic activity, ZnO nanostructures suffer from the rapid recombination of photogenerated electron-hole pairs and low utilization of the solar spectrum due to their limited spectral response to visible light [5]. Since the UV region covers a small fraction (4%~5%) of the solar spectrum, photocatalysts with better optical absorption in the visible spectrum (~43% of solar spectrum) lead to the increased utilization of solar energy.…”

Section: Introductionmentioning

confidence: 99%

“…Tremendous efforts have been made to boost the optical response of ZnO in the visible region, including metal doping (e.g., Ag, Au, Cu) [2,5], non-metal doping (e.g., N, C, S) [2,6], and coupling with narrow-bandgap semiconductors [7]. The latter two approaches to hybrid photocatalytic materials are especially promising because ZnO-metal or ZnO-semiconductor heterojunctions suppress carrier recombination by separating electrons and holes at the interface, and enhance the optical absorption by effectively narrowing down the bandgap [7].…”

Section: Introductionmentioning

confidence: 99%

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Si Nanocrystals/ZnO Nanowires Hybrid Structures as Immobilized Photocatalysts for Photodegradation

et al. 2020

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Numerous semiconductor-based hybrid nanostructures have been studied for improved photodegradation performance resulting from their broadband optical response and enhanced charge separation/transport characteristics. However, these hybrid structures often involve elements that are rare or toxic. Here, we present the synthesis and material characterization of hybrid nanostructures consisting of zinc oxide (ZnO) nanowires (NWs) and silicon nanocrystals (Si-NCs), both abundant and environmentally benign, and evaluate them for photodegradation performance under various illumination conditions. When incorporating Si-NCs into the vertically-aligned ZnO NWs immobilized on substrates, the resulting photocatalysts exhibited a narrowed band gap, i.e., more responsive to visible light, and enhanced charge separation at the interface, i.e., more reactive species produced for degradation. Consequently, the hybrid Si-NCs/ZnO-NWs displayed a superior photodegradability for methylene blue under UV and white light in comparison to the pristine ZnO NWs. Based on the optical measurements, we hypothesize the band structures of Si-NCs/ZnO-NWs and the potential mechanism for the improved photodegradability.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Si Nanocrystals/ZnO Nanowires Hybrid Structures as Immobilized Photocatalysts for Photodegradation

et al. 2020

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“…Electron and hole pairs produced during photon absorption will be rapidly recombined due to the direct band-gap energy, while wide band-gap energy allows ZnO to absorb only UV light that is about 5% of solar energy. To improve the photocatalytic activity of ZnO, metal oxides [20,21] and noble metals such as Ag [22][23][24], Au [24,25], and Pt [24,26], were incorporated to reduce the recombination rate and collect photogenerated carriers. Besides, an ITO layer was also used as a photogenerated electron collecting layer [27].…”

Section: Introductionmentioning

confidence: 99%

Fabrication and characteristics of Zn_1–xSn_xO nanorod/ITO composite photocatalytic films

Dung

Tran

Duc

et al. 2020

Mater. Res. Express

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Zn 1−x Sn x O NRs/ITO composite photocatalytic films were fabricated by the hydrothermal method. A concentration of Sn dopant in Zn 1−x Sn x O nanorods (NRs) was varied from 0% to 7%. The structural and surface morphology characteristics of Zn 1−x Sn x O NRs/ITO composite photocatalytic films were investigated by X-Ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. In addition, photocatalytic properties of synthesized materials were evaluated by degradation rates of Rhodamine-B aqueous solutions under UV light irradiation. The SEM results indicated that, with an increasing concentration of Sn dopant in Zn 1−x Sn x O NRs/ITO, the effective surface areas were declined by an exponential decay function and the reduction was negligible as the Sn doping concentration was higher than 3%. With the similarity in effective surface area, the contribution of Sn in the enhancement of the photocatalytic activity of Zn 0.93 Sn 0.07 O NRs/ITO is clearly observed with 41% improvement in comparison to ZnO NRs/ITO.

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“…As observed in Table 1, the most commonly used photocatalyst in this field is TiO 2 . However, in addition to TiO 2 , several semiconductors, such as ZnO [20] and LaFeO 3 [21] have been proposed in the literature, whose performances seem to be competitive compared to those of TiO 2. Among these photocatalysts, it is well known that ZnO is an environment-friendly semiconductor with a bandgap of 3.37 eV.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Removal of Methyl Orange Azo Dye with Simultaneous Hydrogen Production Using Ru-modified ZnO Photocatalyst

Vaiano

Iervolino

2019

Catalysts

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The aim of this work is to demonstrate the effectiveness of the photocatalytic process in the Methyl Orange azo dye degradation and simultaneous H2 production by using ZnO doped with ruthenium. Ru-modified ZnO photocatalysts were prepared by precipitation method and were characterized by different techniques (XRF, Raman, XRD, N2 adsorption at −196 °C, and UV–vis DRS). The experiments were carried out in a pyrex cylindrical reactor equipped with a nitrogen distributor device and irradiated by four UV lamps with the main wavelength emission at 365 nm. Different Ru amounts (from 0.10 to 0.50 mol%) were tested in order to establish the optimal amount of the metal to be used for the ZnO doping. The photocatalytic activity was evaluated both in terms of Methyl Orange removal and hydrogen production. The experimental results showed that the best activity, both in terms of H2 production and Methyl Orange degradation, was obtained with the Ru-modified ZnO photocatalyst at 0.25 mol% Ru loading. In particular, after four hours of UV irradiation time, the discoloration and mineralization degree were equal to 83% and 78%, with a simultaneous hydrogen production of 1216 µmol L−1. This result demonstrates the ability of the photocatalytic process to valorize a dye present in wastewater, managing to obtain a hydrogen production comparable with the data present in the literature today in the presence of other sacrificial substances.

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UV and visible-light driven photocatalytic removal of caffeine using ZnO modified with different noble metals (Pt, Ag and Au)

Cited by 84 publications

References 70 publications

Si Nanocrystals/ZnO Nanowires Hybrid Structures as Immobilized Photocatalysts for Photodegradation

Si Nanocrystals/ZnO Nanowires Hybrid Structures as Immobilized Photocatalysts for Photodegradation

Fabrication and characteristics of Zn_1–xSn_xO nanorod/ITO composite photocatalytic films

Photocatalytic Removal of Methyl Orange Azo Dye with Simultaneous Hydrogen Production Using Ru-modified ZnO Photocatalyst

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UV and visible-light driven photocatalytic removal of caffeine using ZnO modified with different noble metals (Pt, Ag and Au)

Cited by 84 publications

References 70 publications

Si Nanocrystals/ZnO Nanowires Hybrid Structures as Immobilized Photocatalysts for Photodegradation

Si Nanocrystals/ZnO Nanowires Hybrid Structures as Immobilized Photocatalysts for Photodegradation

Fabrication and characteristics of Zn1–xSnxO nanorod/ITO composite photocatalytic films

Photocatalytic Removal of Methyl Orange Azo Dye with Simultaneous Hydrogen Production Using Ru-modified ZnO Photocatalyst

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Product

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Fabrication and characteristics of Zn_1–xSn_xO nanorod/ITO composite photocatalytic films