Special Issue "Application of Nanomaterials in Photocatalysis"

A special issue of Nanomaterials (ISSN 2079-4991). This special issue belongs to the section "Energy and Catalysis".

Deadline for manuscript submissions: closed (30 June 2021).

Special Issue Editor

Dr. Moisés Canle
E-Mail Website
Guest Editor
Universidade da Coruña, A Coruna, Spain
Interests: Advanced oxidation processes, catalysis, photochemistry, photoreactivity. reduction/abatement of persistent organic pollutants, photofunctionalization of surfaces, free radicals and oxidative stress, reaction mechanisms
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Photocatalysis applications are of utmost relevance in a plethora of active fields nowadays, such as pollution abatement, water splitting, artificial photosynthesis or even others that we do not foresee today but will be a reality tomorrow. A lot of effort is being invested into the synthesis and fabrication of stable and recyclable nanomaterials for many different applications. Some of these can be enhanced by making use of the special properties of nanosized materials, and tuning them.

This Special Issue intends to compile a self-contained set of papers related to potential applications of nanomaterials in different fields that can give a realistic picture of current state-of-the-art research in this cutting-edge field, showing the wide spectrum of topics that will benefit from research and developments in the area. These may be mini-reviews, research papers, or short communications describing new breakthroughs.

All researchers in the field are cordially encouraged to submit their manuscripts for consideration for publication in this Special Issue.

Dr. Moisés Canle
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Nanomaterials is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • nanomaterials
  • photocatalysis
  • pollution abatement
  • water splitting
  • artificial photosynthesis

Published Papers (8 papers)

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Article
Photodeposition of Silver on Zinc/Calcium Ferrite Nanoparticles: A Contribution to Efficient Effluent Remediation and Catalyst Reutilization
Nanomaterials 2021, 11(4), 831; https://doi.org/10.3390/nano11040831 - 24 Mar 2021
Viewed by 534
Abstract
The efficient photodegradation of textile dyes is still a challenge, especially considering resistant azo dyes. In this work, zinc/calcium mixed ferrite nanoparticles prepared by the sol–gel method were coupled with silver by a photodeposition method to enhance the photocatalytic potency. The obtained zinc/calcium [...] Read more.
The efficient photodegradation of textile dyes is still a challenge, especially considering resistant azo dyes. In this work, zinc/calcium mixed ferrite nanoparticles prepared by the sol–gel method were coupled with silver by a photodeposition method to enhance the photocatalytic potency. The obtained zinc/calcium ferrites are mainly cubic-shaped nanoparticles sized 15 ± 2 nm determined from TEM and XRD and an optical bandgap of 1.6 eV. Magnetic measurements indicate a superparamagnetic behavior with saturation magnetizations of 44.22 emu/g and 27.97 emu/g, respectively, for Zn/Ca ferrite and Zn/Ca ferrite with photodeposited silver. The zinc/calcium ferrite nanoparticles with photodeposited silver showed efficient photodegradation of the textile azo dyes C.I. Reactive Blue 250 and C.I. Reactive Yellow 145. Subsequent cycles of the use of the photocatalyst indicate the possibility of magnetic recovery and reutilization without a significant loss of efficiency. Full article
(This article belongs to the Special Issue Application of Nanomaterials in Photocatalysis)
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Article
Suitability of Different Titanium Dioxide Nanotube Morphologies for Photocatalytic Water Treatment
Nanomaterials 2021, 11(3), 708; https://doi.org/10.3390/nano11030708 - 11 Mar 2021
Cited by 5 | Viewed by 886
Abstract
Photocatalysis has long been touted as one of the most promising technologies for environmental remediation. The ability of photocatalysts to degrade a host of different pollutants, especially recalcitrant molecules, is certainly appealing. Titanium dioxide (TiO2) has been used extensively for this [...] Read more.
Photocatalysis has long been touted as one of the most promising technologies for environmental remediation. The ability of photocatalysts to degrade a host of different pollutants, especially recalcitrant molecules, is certainly appealing. Titanium dioxide (TiO2) has been used extensively for this purpose. Anodic oxidation allows for the synthesis of a highly ordered nanotubular structure with a high degree of tunability. In this study, a series of TiO2 arrays were synthesised using different electrolytes and different potentials. Mixed anatase-rutile photocatalysts with excellent wettability were achieved with all the experimental iterations. Under UVA light, all the materials showed significant photoactivity towards different organic pollutants. The nanotubes synthesised in the ethylene glycol-based electrolyte exhibited the best performance, with near complete degradation of all the pollutants. The antibacterial activity of this same material was similarly high, with extremely low bacterial survival rates. Increasing the voltage resulted in wider and longer nanotubes, characteristics which increase the level of photocatalytic activity. The ease of synthesis coupled with the excellent activity makes this a viable material that can be used in flat-plate reactors and that is suitable for photocatalytic water treatment. Full article
(This article belongs to the Special Issue Application of Nanomaterials in Photocatalysis)
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Article
TiO2 Nanowires with Doped g-C3N4 Nanoparticles for Enhanced H2 Production and Photodegradation of Pollutants
Nanomaterials 2021, 11(1), 254; https://doi.org/10.3390/nano11010254 - 19 Jan 2021
Cited by 1 | Viewed by 1370
Abstract
With the rapid consumption of fossil fuels, along with the ever-increasing environmental pollution, it is becoming a top priority to explore efficient photocatalysts for the production of renewable hydrogen and degradation of pollutants. Here, we fabricated a composite of g-C3N4 [...] Read more.
With the rapid consumption of fossil fuels, along with the ever-increasing environmental pollution, it is becoming a top priority to explore efficient photocatalysts for the production of renewable hydrogen and degradation of pollutants. Here, we fabricated a composite of g-C3N4/TiO2 via an in situ growth method under the conditions of high-temperature calcination. In this method, TiO2 nanowires with a large specific surface area could provide enough space for loading more g-C3N4 nanoparticles to obtain C3N4/TiO2 composites. Of note, the g-C3N4/TiO2 composite could effectively photocatalyze both the degradation of several pollutants and production of hydrogen, both of which are essential for environmental governance. Combining multiple characterizations and experiments, we found that the heterojunction constructed by the TiO2 and g-C3N4 could increase the photocatalytic ability of materials by prompting the separation of photogenerated carriers. Furthermore, the photocatalytic mechanism of the g-C3N4/TiO2 composite was also clarified in detail. Full article
(This article belongs to the Special Issue Application of Nanomaterials in Photocatalysis)
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Article
Microwave-Assisted Synthesis of Chalcopyrite/Silver Phosphate Composites with Enhanced Degradation of Rhodamine B under Photo-Fenton Process
Nanomaterials 2020, 10(11), 2300; https://doi.org/10.3390/nano10112300 - 20 Nov 2020
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Abstract
A new composite by coupling chalcopyrite (CuFeS2) with silver phosphate (Ag3PO4) (CuFeS2/Ag3PO4) was proposed by using a cyclic microwave heating method. The prepared composites were characterized by scanning and transmission electron [...] Read more.
A new composite by coupling chalcopyrite (CuFeS2) with silver phosphate (Ag3PO4) (CuFeS2/Ag3PO4) was proposed by using a cyclic microwave heating method. The prepared composites were characterized by scanning and transmission electron microscopy and X-ray diffraction, Fourier-transform infrared, UV–Vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. Under optimum conditions and 2.5 W irradiation (wavelength length > 420 nm, power density = 0.38 Wcm−2), 96% of rhodamine B (RhB) was degraded by CuFeS2/Ag3PO4 within a 1 min photo-Fenton reaction, better than the performance of Ag3PO4 (25% degradation within 10 min), CuFeS2 (87.7% degradation within 1 min), and mechanically mixed CuFeS2/Ag3PO4 catalyst. RhB degradation mainly depended on the amount of hydroxyl radicals generated from the Fenton reaction. The degradation mechanism of CuFeS2/Ag3PO4 from the photo-Fenton reaction was deduced using a free radical trapping experiment, the chemical reaction of coumarin, and photocurrent and luminescence response. The incorporation of CuFeS2 in Ag3PO4 enhanced the charge separation of Ag3PO4 and reduced Ag3PO4 photocorrosion as the photogenerated electrons on Ag3PO4 were transferred to regenerate Cu2+/Fe3+ ions produced from the Fenton reaction to Cu+/Fe2+ ions, thus simultaneously maintaining the CuFeS2 intact. This demonstrates the synergistic effect on material stability. However, hydroxyl radicals were produced by both the photogenerated holes of Ag3PO4 and the Fenton reaction of CuFeS2 as another synergistic effect in catalysis. Notably, the degradation performance and the reusability of CuFeS2/Ag3PO4 were promoted. The practical applications of this new material were demonstrated from the effective performance of CuFeS2/Ag3PO4 composites in degrading various dyestuffs (90–98.9% degradation within 10 min) and dyes in environmental water samples (tap water, river water, pond water, seawater, treated wastewater) through enhanced the Fenton reaction under sunlight irradiation. Full article
(This article belongs to the Special Issue Application of Nanomaterials in Photocatalysis)
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Article
Study of the Photothermal Catalytic Mechanism of CO2 Reduction to CH4 by Ruthenium Nanoparticles Supported on Titanate Nanotubes
Nanomaterials 2020, 10(11), 2212; https://doi.org/10.3390/nano10112212 - 06 Nov 2020
Cited by 3 | Viewed by 778
Abstract
The Sabatier reaction could be a key tool for the future of the renewable energy field due to the potential of this reaction to produce either fuels or to stabilize H2 in the form of stable chemicals. For this purpose, a new [...] Read more.
The Sabatier reaction could be a key tool for the future of the renewable energy field due to the potential of this reaction to produce either fuels or to stabilize H2 in the form of stable chemicals. For this purpose, a new composite made of ruthenium oxide nanoparticles (NPs) deposited on titanate nanotubes (TiNTs) was tested. Titanate nanotubes are a robust semiconductor with a one-dimensional (1D) morphology that results in a high contact area making this material suitable for photocatalysis. Small ruthenium nanoparticles (1.5 nm) were deposited on TiNTs at different ratios by Na+-to-Ru3+ ion exchanges followed by calcination. These samples were tested varying light power and temperature conditions to study the reaction mechanism during catalysis. Methanation of CO2 catalyzed by Ru/TiNT composite exhibit photonic and thermic contributions, and their ratios vary with temperature and light intensity. The synthesized composite achieved a production rate of 12.4 mmol CH4·gcat−1·h−1 equivalent to 110.7 mmol of CH4·gRu−1·h−1 under 150 mW/cm2 simulated sunlight irradiation at 210 °C. It was found that photo-response derives either from Ru nanoparticle excitation in the visible (VIS) and near-infrared (NIR) region (photothermal and plasmon excitation mechanism) or from TiNT excitation in the ultraviolet (UV) region leading to electron–hole separation and photoinduced electron transfer. Full article
(This article belongs to the Special Issue Application of Nanomaterials in Photocatalysis)
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Article
Improved Photocatalyzed Degradation of Phenol, as a Model Pollutant, over Metal-Impregnated Nanosized TiO2
Nanomaterials 2020, 10(5), 996; https://doi.org/10.3390/nano10050996 - 22 May 2020
Cited by 7 | Viewed by 1339
Abstract
Photocatalyzed degradation of phenol in aqueous solution over surface impregnated TiO2 (M = Cu, Cr, V) under UV-Vis (366 nm) and UV (254 nm) irradiation is described. Nanosized photocatalyts were prepared from TiO2-P25 by wet impregnation, and characterized by X-ray [...] Read more.
Photocatalyzed degradation of phenol in aqueous solution over surface impregnated TiO2 (M = Cu, Cr, V) under UV-Vis (366 nm) and UV (254 nm) irradiation is described. Nanosized photocatalyts were prepared from TiO2-P25 by wet impregnation, and characterized by X-ray diffraction, X-ray fluorescence, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy, Raman spectroscopy, and adsorption studies. No oxide phases of the metal dopants were found, although their presence in the TiO2-P25 lattice induces tensile strain in Cu-impregnated TiO2-P25, whereas compressive strain in Cr- and V-impregnated TiO2-P25. Experimental evidences support chemical and mechanical stability of the photocatalysts. Type IV N2 adsorption–desorption isotherms, with a small H3 loop near the maximum relative pressure were observed. Metal surface impregnated photocatalysts are mesoporous with a similar surface roughness, and a narrow pore distribution around ca. 25 Å. They were chemically stable, showing no metal lixiviation. Their photocatalytic activity was followed by UV-Vis spectroscopy and HPLC–UV. A first order kinetic model appropriately fitted the experimental data. The fastest phenol degradation was obtained with M (0.1%)/TiO2-P25, the reactivity order being Cu > V >> Cr > TiO2-P25 under 366 nm irradiation, while TiO2-P25 > Cu > V > Cr, when using 254 nm radiation. TOC removal under 366 nm irradiation for 300 min showed almost quantitative mineralization for all tested materials, while 254 nm irradiation for 60 min led to maximal TOC removal (ca. 30%). Photoproducts and intermediate photoproducts were identified by HPLC–MS, and appropriate reaction pathways are proposed. The energy efficiency of the process was analysed, showing UV lamps are superior to UVA lamps, and that the efficiency of the surface impregnated catalyst varies in the order Cu > V > Cr. Full article
(This article belongs to the Special Issue Application of Nanomaterials in Photocatalysis)
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Article
Enhanced Photocatalytic Degradation of the Imidazolinone Herbicide Imazapyr upon UV/Vis Irradiation in the Presence of CaxMnOy-TiO2 Hetero-Nanostructures: Degradation Pathways and Reaction Intermediates
Nanomaterials 2020, 10(5), 896; https://doi.org/10.3390/nano10050896 - 08 May 2020
Cited by 2 | Viewed by 1196
Abstract
The determination of reaction pathways and identification of products of pollutants degradation is central to photocatalytic environmental remediation. This work focuses on the photocatalytic degradation of the herbicide Imazapyr (2-(4-methyl-5-oxo-4-propan-2-yl-1H-imidazol-2-yl) pyridine-3-carboxylic acid) under UV-Vis and visible-only irradiation of aqueous suspensions of Cax [...] Read more.
The determination of reaction pathways and identification of products of pollutants degradation is central to photocatalytic environmental remediation. This work focuses on the photocatalytic degradation of the herbicide Imazapyr (2-(4-methyl-5-oxo-4-propan-2-yl-1H-imidazol-2-yl) pyridine-3-carboxylic acid) under UV-Vis and visible-only irradiation of aqueous suspensions of CaxMnOy-TiO2, and on the identification of the corresponding degradation pathways and reaction intermediates. CaxMnOy-TiO2 was formed by mixing CaxMnOy and TiO2 by mechanical grinding followed by annealing at 500 °C. A complete structural characterization of CaxMnOy-TiO2 was carried out. The photocatalytic activity of the hetero-nanostructures was determined using phenol and Imazapyr herbicide as model pollutants in a stirred tank reactor under UV-Vis and visible-only irradiation. Using equivalent loadings, CaxMnOy-TiO2 showed a higher rate (10.6 μM·h−1) as compared to unmodified TiO2 (7.4 μM·h−1) for Imazapyr degradation under UV-Vis irradiation. The mineralization rate was 4.07 µM·h−1 for CaxMnOy-TiO2 and 1.21 μM·h−1 for TiO2. In the CaxMnOy-TiO2 system, the concentration of intermediate products reached a maximum at 180 min of irradiation that then decreased to a half in 120 min. For unmodified TiO2, the intermediates continuously increased with irradiation time with no decrease observed in their concentration. The enhanced efficiency of the CaxMnOy-TiO2 for the complete degradation of the Imazapyr and intermediates is attributed to an increased adsorption of polar species on the surface of CaxMnOy. Based on LC-MS, photocatalytic degradation pathways for Imazapyr under UV-Vis irradiation have been proposed. Some photocatalytic degradation was obtained under visible-only irradiation for CaxMnOy-TiO2. Hydroxyl radicals were found to be main reactive oxygen species responsible for the photocatalytic degradation through radical scavenger investigations. Full article
(This article belongs to the Special Issue Application of Nanomaterials in Photocatalysis)
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Erratum
Erratum: Canle, M., et al. Improved Photocatalyzed Degradation of Phenol, as a Model Pollutant, over Metal-Impregnated Nanosized TiO2. Nanomaterials 2020, 10, 996
Nanomaterials 2020, 10(6), 1109; https://doi.org/10.3390/nano10061109 - 03 Jun 2020
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Abstract
The authors wish to make the following corrections to this paper: [...] Full article
(This article belongs to the Special Issue Application of Nanomaterials in Photocatalysis)
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