Facet-dependent generation of superoxide radical anions by ZnO nanomaterials under simulated solar light

2018 ◽  
Vol 5 (12) ◽  
pp. 2864-2875 ◽  
Author(s):  
Qianwu Wang ◽  
Huaxi Zhou ◽  
Xinlei Liu ◽  
Tong Li ◽  
Chuanjia Jiang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Superoxide Radical ◽  
Solar Light ◽  
Radical Anions ◽  
Oxygen Species ◽  
Environmental Implications ◽  
Simulated Solar Light ◽  
Zno Nanomaterials ◽  
Photocatalytic Applications ◽  
Exposed Facets

The capability of ZnO nanomaterials to generate reactive oxygen species under solar light, which is critical for their photocatalytic applications and may affect their environmental implications, can be substantially influenced by exposed facets.

scholarly journals Generation of reactive oxygen species by promoting the Cu(II)/Cu(I) redox cycle with reducing agents in aerobic aqueous solution

2018 ◽  
Vol 78 (6) ◽  
pp. 1390-1399 ◽  
Author(s):  
Wenshu Li ◽  
Peng Zhou ◽  
Jing Zhang ◽  
Yongli Zhang ◽  
Gucheng Zhang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Aqueous Solution ◽  
Superoxide Radical ◽  
Reactive Oxygen ◽  
Reducing Agents ◽  
Oxygen Species ◽  
Redox Cycle ◽  
Copper Species ◽  
Chain Reactions ◽  
H2o2 Generation

Abstract This study investigated the generation of reactive oxygen species (ROS) (O2−•, H2O2, and HO•) by promoting the Cu(II)/Cu(I) redox cycle with certain reducing agents (RAs) in aerobic aqueous solution, and benzoic acid (BA) was employed as indicator for the hydroxyl radical (HO•). Hydroxylamine (HA) can reduce Cu(II) to Cu(I) to induce chain reactions of copper species resulting in the generation of the superoxide radical (O2−•) and hydrogen peroxide (H2O2), and the intermediate Cu(I) can further activate H2O2 via a Fenton-like reaction to produce HO•, creating the remarkable BA degradation. O2 is indispensable, and unprotonated HA is the motive power in the O2/Cu/HA system. Moreover, pH is a crucial factor of the O2/Cu/HA system due to the protonated HA not being able to reduce Cu(II) into Cu(I). The oxidation of HA can be effectively induced by trace amounts of Cu(II), and both a higher HA dosage and a higher Cu(II) dosage can enhance H2O2 generation and BA degradation. In addition, some other RAs that can reduce Cu(II) into Cu(I) could replace HA in the O2/Cu/HA system to induce the generation of these ROS in aerobic aqueous solution.

scholarly journals Rapid evaluation of oxygen vacancies-enhanced photogeneration of the superoxide radical in nano-TiO2 suspensions

RSC Advances ◽  
2020 ◽  
Vol 10 (49) ◽  
pp. 29082-29089
Author(s):  
Wanchao Yu ◽  
Fengjie Chen ◽  
Yarui Wang ◽  
Lixia Zhao
Keyword(s):  
Reactive Oxygen Species ◽  
Photocatalytic Degradation ◽  
Oxygen Vacancies ◽  
Superoxide Radical ◽  
Surface Defects ◽  
Reactive Oxygen ◽  
Rapid Evaluation ◽  
Oxygen Species ◽  
Nano Tio2 ◽  
Degradation Of Pollutants

Reactive oxygen species (ROS) play an important role in the photocatalytic degradation of pollutants and are closely related to the surface defects of a semiconductor.

scholarly journals The enzyme-like catalytic activity of cerium oxide nanoparticles and its dependency on Ce3+ surface area concentration

Nanoscale ◽  
2018 ◽  
Vol 10 (15) ◽  
pp. 6971-6980 ◽  
Author(s):  
V. Baldim ◽  
F. Bedioui ◽  
N. Mignet ◽  
I. Margaill ◽  
J.-F. Berret
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Surface Area ◽  
Cerium Oxide ◽  
Superoxide Radical ◽  
Cerium Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Oxygen Species ◽  
Surface Area Concentration

Cerium oxide nanoparticles are known to catalyze the decomposition of reactive oxygen species such as the superoxide radical and hydrogen peroxide.

Emerging investigator series: could the superoxide radical be implemented in decontamination processes?

2021 ◽  
Author(s):  
Junye Ma ◽  
Zongsu Wei ◽  
Richard Spinney ◽  
Dionysios D. Dionysiou ◽  
Ruiyang Xiao
Keyword(s):  
Reactive Oxygen Species ◽  
Water Treatment ◽  
Superoxide Radical ◽  
Reactive Oxygen ◽  
Aquatic Systems ◽  
Oxygen Species ◽  
Treatment Processes

The superoxide radical (O2˙−) is an important reactive oxygen species (ROS) in diverse natural aquatic systems and engineered water treatment processes.

Ophiostoma mitovirus 3a, ascorbic acid, glutathione, and photoperiod affect the development of stromata and apothecia by Sclerotinia homoeocarpa

2011 ◽  
Vol 57 (5) ◽  
pp. 398-407 ◽  
Author(s):  
A.M. Orshinsky ◽  
G.J. Boland
Keyword(s):  
Reactive Oxygen Species ◽  
Ascorbic Acid ◽  
Alternative Oxidase ◽  
Superoxide Radical ◽  
Reactive Oxygen ◽  
Potato Dextrose Agar ◽  
Oxygen Species ◽  
Sclerotinia Homoeocarpa ◽  
Starting Point ◽  
Increased Activity

Hypovirulence in Sclerotinia homoeocarpa is associated with infection by Ophiostoma mitovirus 3a (OMV3a). OMV3a is also present in asymptomatic isolates, with growth and virulence comparable to that of virus-free isolates. Hypovirulent isolates have impaired mitochondrial function resulting in increased activity of the alternative oxidase pathway, which is implicated in the reduction of reactive oxygen species in other fungi. In this study, hypovirulent, asymptomatic, and virus-free isolates were grown on potato dextrose agar amended with ascorbic acid or glutathione and were incubated under various photoperiods to determine the importance of reactive oxygen species, light, and OMV3a infection for differentiation of stromata and apothecia by S. homoeocarpa. Hypovirulent isolates did not form stromata or apothecia. Glutathione and darkness reduced stromata size and apothecia production by virulent and asymptomatic isolates. Apothecia formed under several different photoperiods, and ascorbic acid increased apothecia production. Ascospores were not detected in these apothecia. The results suggest that hypovirulence, light, and the superoxide radical are important factors in the formation of stromata and apothecia by S. homoeocarpa isolates. This is the first report of sterile apothecia production by North American isolates of S. homoeocarpa and provides a starting point for attempts to produce fertile apothecia.

scholarly journals Action of chondroitin sulfate on the level of cytokines and reactive oxygen species in blood serum upon carrageenan-induced inflammation

2017 ◽  
Vol 22 (1) ◽  
pp. 9-11
Author(s):  
K. Dvorshchenko ◽  
M. Ashpin ◽  
O. Korotkyi ◽  
Ye. Torgalo ◽  
T. Falalyeyeva
Keyword(s):  
Reactive Oxygen Species ◽  
Blood Serum ◽  
Chondroitin Sulfate ◽  
Inflammatory Cytokines ◽  
Superoxide Radical ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Tnf Α ◽  
Rat Paw ◽  
Pro Inflammatory Cytokines

Increase of concentration of pro-inflammatory cytokines (IL-1β, TNF-α) is fixed in blood serum at carrageenan-induced rat paw inflammation, as well as increase of the content of reactive oxygen species (superoxide radical, hydrogen peroxide). At introduction of the preparation on the basis of chondroitin sulfate the level of pro-inflammatory cytokines and reactive oxygen species in blood serum decreases, while the concentration of IL10 increases in 1,7 times concerning the group of animals with сarrageenan-induced inflammation.

scholarly journals Enhanced Sulfamerazine Removal via Adsorption–Photocatalysis Using Bi2O3–TiO2/PAC Ternary Nanoparticles

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2273
Author(s):  
Xiaoxuan Zhuang ◽  
Xing Li ◽  
Yanling Yang ◽  
Nan Wang ◽  
Yi Shang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Mass Transfer ◽  
Active Sites ◽  
Photocatalytic Performance ◽  
Superoxide Radical ◽  
Oxygen Species ◽  
Ring Fracture ◽  
Mass Transfer Mechanism ◽  
Alkaline Conditions ◽  
Better Than

The presence of sulfonamides (SAs) in water has received increasing attention due to the risk to ecosystems. The adsorption and photocatalysis performance for sulfamerazine (SMZ) of Bi2O3–TiO2 supported on powdered activated carbon (Bi2O3–TiO2/PAC) nanoparticles was evaluated. The amount of doped Bi2O3 not only influenced the photocatalytic performance but also impacted the adsorption capacity. The adsorption mass transfer mechanism of Bi2O3–TiO2/PAC was elucidated and is further discussed in combination with the photocatalytic mechanism. It was indicated that Bi2O3–TiO2/PAC(10%–700 °C) performed best, and the SMZ removal by the adsorption–photocatalysis of Bi2O3–TiO2/PAC(10%–700 °C) reached 95.5%. Adsorption onto active sites was a major adsorption step, and external diffusion was assisted. Superoxide radical (●O2−) and hole (h+) were identified as the major reactive oxygen species (ROS) for SMZ removal. Benzene ring fracture, SO2 extrusion and nitrogenated SMZ were proposed as the main pathways for photocatalysis. Meanwhile, alkaline conditions enhanced photocatalytic performance, while contrary effects were observed for adsorption. The adsorption–photocatalysis removal performance for SMZ in lake water was better than that for river water. It can be generalized for the potential application of photocatalysis coupling with adsorption to remove refractory antibiotics in water.

scholarly journals Photogeneration of reactive oxygen species over ultrafine TiO2 particles functionalized with rutin–ligand induced sensitization and crystallization effects

2019 ◽  
Vol 45 (12) ◽  
pp. 5781-5800 ◽  
Author(s):  
Przemysław Łabuz ◽  
Joanna Gryboś ◽  
Piotr Pietrzyk ◽  
Kamila Sobańska ◽  
Wojciech Macyk ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Charge Transfer ◽  
Visible Light ◽  
Colloidal Stability ◽  
Reactive Oxygen ◽  
Hydroxyl Groups ◽  
Oxygen Species ◽  
Environmental Implications ◽  
Transfer Processes

Abstract Interaction of amorphous and crystalline TiO2 ultrafine particles (2–6 nm) with rutin results in the formation of colored nanomaterials of an excellent dispersity and enhanced colloidal stability in aqueous media. The FTIR and Raman spectra confirmed attachment of the rutin ligand via vicinal hydroxyl groups in a catechol-like fashion. The binding of rutin to amorphous TiO2 gives rise to spontaneous crystallization of the parent nanoparticles into hydrogen titanates (H2Ti3O7 and H2Ti12O25). Such structural transformations result in photosensitization toward visible light with enhanced efficiency of the charge separation and interfacial charge transfer processes, confirmed by detailed photoelectrochemical studies of the examined nanomaterials. The effectiveness of the photocatalytic ROS generation reactions was also strongly influenced by hydrogen peroxide, which plays a double role of a reactant prone to reduction and generation of hydroxyl radicals or a redox agent destroying the intra-band gap electronic states, suppressing thereby charge recombination. The photoinduced charge transfer processes lead to generation of various reactive oxygen species, which were detected by EPR using DMPO spin trap (HOO· detection) and in the reaction with terephthalic acid acting as a chemical scavenger (HO· detection). Complexation of TiO2 particles with rutin shifts the photogeneration of hydroperoxyl (HOO·) and hydroxyl (HO·) radicals toward visible light (λ > 400 nm). A triple effect of rutin attachment to titania was established. It consists in pronounced photosensitization, promotion of crystallization and enhancement of the colloidal stability of ultrafine titania particles. Environmental implications of these assets on the photoinduced redox reactions with hydrogen peroxide in aqueous solutions upon UV or visible light irradiation were also discussed.

scholarly journals ZnO nanoparticles sensitized by CuInZn x S2+ x quantum dots as highly efficient solar light driven photocatalysts

2017 ◽  
Vol 8 ◽  
pp. 1080-1093 ◽  
Author(s):  
Florian Donat ◽  
Serge Corbel ◽  
Halima Alem ◽  
Steve Pontvianne ◽  
Lavinia Balan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Zno Nanoparticles ◽  
Average Diameter ◽  
High Photocatalytic Activity ◽  
Solar Light ◽  
Zno Nanoparticle ◽  
Electron Hole ◽  
Simulated Solar Light ◽  
Photodegradation Mechanism ◽  
Photocatalytic Applications

Alloyed CuInZn x S2+ x (ZCIS) quantum dots (QDs) were successfully associated to ZnO nanoparticles by a thermal treatment at 400 °C for 15 min. The ZnO/ZCIS composite was characterized by TEM, SEM, XRD, XPS and UV–vis absorption spectroscopy. ZCIS QDs, with an average diameter of ≈4.5 nm, were found to be homogeneously distributed at the surface of ZnO nanoparticles. ZCIS-sensitized ZnO nanoparticles exhibit a high photocatalytic activity under simulated solar light irradiation for the degradation of Orange II dye (>95% degradation after 180 min of irradiation at an intensity of 5 mW/cm2). The heterojunction built between the ZnO nanoparticle and ZCIS QDs not only extends the light adsorption range by the photocatalyst but also acts to decrease electron/hole recombination. Interestingly, the ZnO/ZCIS composite was found to produce increased amounts of H2O2 and singlet oxygen 1O2 compared to ZnO, suggesting that these reactive oxygen species play a key role in the photodegradation mechanism. The activity of the ZnO/ZCIS composite is retained at over 90% of its original value after ten successive photocatalytic runs, indicating its high stability and its potential for practical photocatalytic applications.

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