Hydroxyl radical and free and shallowly trapped electron generation and electron/hole recombination rates in TiO2 photocatalysis using different combinations of anatase and rutile

Jiménez-Relinque, Eva; Castellote, Marta

doi:10.1016/j.apcata.2018.07.045

Cited by 43 publications

(21 citation statements)

References 34 publications

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“…To determine photocatalytic efficiency, the evaluation of dye degradation was only performed under UV light because the dyes are inappropriate for evaluating the photocatalytic activity. Operations under visible light are severely limited by a variety of factors, most of which are related to the presence of a second mechanism, sensitization (Wu et al, 1998 ; Rochkind et al, 2015 ; Jimenez-Relinque and Castellote, 2018 ).…”

Section: Methodsmentioning

confidence: 99%

Photocatalytic Activity of ZnxMn3−xO4 Oxides and ZnO Prepared From Spent Alkaline Batteries

et al. 2020

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Oxides with Zn x Mn 3−x O 4 stoichiometries and ZnO were synthesized from the “black mass” material recovered from spent alkaline batteries. The oxides were characterized by XRF, XRD with Rietveld refinement, SEM, and TEM methods. Optical characterization included diffuse reflectance (DRS) and photoluminescence (PL) measurements. ZnO presented a clear band edge in the UV region, and PL signals were detected. The Zn/Mn oxides showed strong absorption in the UV region and a continuous absorption band in the Vis-IR regions. There is a non-detected PL signal due to excited charges being trapped on sub-band energy states and/or transfer by non-radiative paths. Photocatalytic activity under both irradiation conditions was evaluated using the resazurin dye test, terephthalic acid fluorescence probe method, and NO x air purification evaluation. In the three photoactivity tests, ZnO performed well under both UV and Vis irradiation, whereas no evidence of any appreciable photocatalytic activity was observed for the Zn/Mn oxides. The results are discussed in terms of the findings of previously reported optical measurements.

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Section: Methodsmentioning

confidence: 99%

Photocatalytic Activity of ZnxMn3−xO4 Oxides and ZnO Prepared From Spent Alkaline Batteries

et al. 2020

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“…Under the influence of UV radiation, ZnO NPs generate reactive oxygen species such as ● OH or H 2 O 2 , causing GSH depletion [ 33 , 90 ]. The rate of ● OH generation and the total photocatalytic activity depends on the physical properties of the nanomaterial used, e.g., TiO 2 NPs [ 34 ]. Cu NPs play an important role as a cofactor in a number of enzymes such as cytochrome c oxidase [ 91 ].…”

Section: Reactive Oxygen Speciesmentioning

confidence: 99%

Detection of Oxidative Stress Induced by Nanomaterials in Cells—The Roles of Reactive Oxygen Species and Glutathione

Čapek

Roušar

2021

Molecules

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The potential of nanomaterials use is huge, especially in fields such as medicine or industry. Due to widespread use of nanomaterials, their cytotoxicity and involvement in cellular pathways ought to be evaluated in detail. Nanomaterials can induce the production of a number of substances in cells, including reactive oxygen species (ROS), participating in physiological and pathological cellular processes. These highly reactive substances include: superoxide, singlet oxygen, hydroxyl radical, and hydrogen peroxide. For overall assessment, there are a number of fluorescent probes in particular that are very specific and selective for given ROS. In addition, due to the involvement of ROS in a number of cellular signaling pathways, understanding the principle of ROS production induced by nanomaterials is very important. For defense, the cells have a number of reparative and especially antioxidant mechanisms. One of the most potent antioxidants is a tripeptide glutathione. Thus, the glutathione depletion can be a characteristic manifestation of harmful effects caused by the prooxidative-acting of nanomaterials in cells. For these reasons, here we would like to provide a review on the current knowledge of ROS-mediated cellular nanotoxicity manifesting as glutathione depletion, including an overview of approaches for the detection of ROS levels in cells.

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“…Several semiconductors (TiO 2 , SnO 2 , ZrO 2 , Fe 2 O 3 , ZnO, ZnS, CdS) nanoparticles have been studied as photocatalysts [15,16] and, among them, TiO 2 and ZnO nanomaterials have been the most investigated due to their good photocatalytic performances [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic activity of silica and silica-silver nanocolloids based on photo-induced formation of reactive oxygen species

Romolini

Gambucci

Ricciarelli

et al. 2021

Photochem Photobiol Sci

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Semiconductor nanomaterials are often proposed as photocatalysts for wastewater treatment; silica nanomaterials are still largely unexploited because their photocatalytic performances need improvements, especially under visible light. The present study is a proof-of-concept that amorphous silica colloids once submitted to the proper surface modifications change into an efficient photocatalyst even under low-energy illumination source. For this reason, silica-based colloidal nanomaterials, such as bare (SiO2 NPs), aminated (NH2-SiO2 NPs), and Ag NPs-decorated (Ag-SiO2 NPs) silica, are tested as photocatalysts for the degradation of 9-anthracenecarboxylic acid (9ACA), taken as a model aromatic compound. Interestingly, upon irradiation at 313 nm, NH2-SiO2 NPs induce 9ACA degradation, and the effect is even improved when Ag-SiO2 NPs are used. On the other hand, irradiation at 405 nm activates the plasmon of Ag-SiO2 NPs photocatalyst, providing a faster and more efficient photodegradation. The photodegradation experiments are also performed under white light illumination, employing a low-intensity fluorescent lamp, confirming satisfying efficiencies. The catalytic effect of SiO2-based nanoparticles is thought to originate from photo-excitable surface defects and Ag NP plasmons since the catalytic degradation takes place only when the 9ACA is adsorbed on the surface. In addition, the involvement of reactive oxygen species was demonstrated through a scavenger use, obtaining a yield of 17%. In conclusion, this work shows the applicability of silica-based nanoparticles as photocatalysts through the involvement of silica surface defects, confirming that the silica colloids can act as photocatalysts under irradiation with monochromatic and white light. Graphic abstract Silica and Ag-decorated silica colloids photosensitize the formation of Reactive Oxygen Species with 17% efficiencies. ROS are able to oxidase aromatic pollutants chemi-adsorbed on the surface of the colloids. Silica-silver nanocomposites present a photocatalytic activity useful to degrade aromatic compounds.

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Hydroxyl radical and free and shallowly trapped electron generation and electron/hole recombination rates in TiO2 photocatalysis using different combinations of anatase and rutile

Cited by 43 publications

References 34 publications

Photocatalytic Activity of ZnxMn3−xO4 Oxides and ZnO Prepared From Spent Alkaline Batteries

Photocatalytic Activity of ZnxMn3−xO4 Oxides and ZnO Prepared From Spent Alkaline Batteries

Detection of Oxidative Stress Induced by Nanomaterials in Cells—The Roles of Reactive Oxygen Species and Glutathione

Photocatalytic activity of silica and silica-silver nanocolloids based on photo-induced formation of reactive oxygen species

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