Plasma generation in liquid as a new efficient synthesis approach of titania–zinc ferrite nano(photo)catalyst

Ignat, Maria; Samoilă, Petrişor; Coromelci, Cristina; Săcărescu, Liviu; Asaftei, Iuliean Vasile; Harabagiu, Valeria; Miron, Camelia

doi:10.1016/j.crci.2017.05.006

Cited by 4 publications

(3 citation statements)

References 30 publications

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“…Corona-like discharges that are generated directly in water are currently utilized for the development of a number of applications, e.g. the synthesis of nanoparticles [1], degradation of chemical compounds in water [2], and the extraction of heatsensitive compounds from algae [3]. These technologies benefit from specific properties of discharges in liquids and most of them increase their efficiency by applying high-voltage pulses of a few microseconds or even subnanosecond duration.…”

Section: Introductionmentioning

confidence: 99%

Reillumination of submicrosecond pulsed corona-like discharges in water

Rataj

Hoeft

Kolb

2019

Plasma Sources Sci. Technol.

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Pronounced reilluminations can be observed for discharges that are generated in water by submicrosecond high-voltage pulses. This phenomenon can appear during the decrease of the applied voltage, depending on the pulse characteristics, especially fall times. The respective processes are expected to be crucial for optical investigations of discharge characteristics and also for applications. Accordingly, the development of individual corona-like discharges in water was investigated in a needle-to-plate geometry for their ignition by single rectangular highvoltage pulses with a duration of 100 ns. The pulse amplitudes of about 50 kV and adjusted pulse fall times of 20, 26, and 43 ns were used. Voltages, currents and light emissions were synchronized with subsequent images of individual discharge events. Two distinct stages, a propagation phase and a reillumination phase, were identified. The individual discharges expanded for all investigated fall times with the same velocity of (29 ± 2) km s −1 . No significant differences of streamer morphologies and electrical characteristics were observed for the propagation phase. As the voltage began to decrease, light emissions first went through a minimum before increasing again. The following maxima were strongly dependent on fall times. Corresponding images showed that discharge channels were reilluminated within 6 ns. However, not all of the previously observed filaments reignited at once for longer fall times and instead single channels reilluminated subsequently. The development of reillumination can be explained from the external electric field in the electrode gap during the streamer propagation, which determines the head charge distributions at the discharge channel ends. This space charges generate an internal electrical field in the filaments resulting in the reillumination during the falling edge of the applied high-voltage pulse.

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Section: Introductionmentioning

confidence: 99%

Reillumination of submicrosecond pulsed corona-like discharges in water

Rataj

Hoeft

Kolb

2019

Plasma Sources Sci. Technol.

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“…Thus, extensive research has been conducted on many nanostructured metaloxide semiconductors such as TiO 2 , ZnO, and WO 3 [3]. Despite being one of the most commonly employed photocatalytic materials [4], TiO 2 has a relatively wide band gap ranging from 3.0 to 3.3 eV [5,6]. As a result, bare TiO 2 exhibits photoactivity only under UV excitation, making it disadvantaged from this point of view.…”

Section: Introductionmentioning

confidence: 99%

Conjugated Polymer Modifying TiO2 Performance for Visible-Light Photodegradation of Organics

Coromelci

Turcu²,

Doroftei³

et al. 2023

Polymers

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Up to now, the use of TiO2 has been considered a promising advanced technology for organic pollutants removal from air or water, since it has high biological and chemical stability, high photoactivity, low toxicity, and low-cost production. However, there are issues to be addressed in enhancing TiO2 performance, and one of the current key issues is redesigning UV-active photocatalysts and making them active in the visible region of the electromagnetic spectrum. This way, solar light absorption will be insured, and thus, a more efficient photocatalyst could be obtained. For this reason, conjugated polymers and their derivatives are considered to act as photosensitizers, being able to shift the TiO2 activity from the UV to the visible region. Therefore, this study focuses on the synthesis of TiO2/conjugated polymer systems, which was accomplished by the deposition of poly-3,4-ethylene-dioxy-thiophene (PEDOT [-C6H4O2S-]n), a low-band semiconductor with an excellent stability due to its extending π-conjugated electron system, on titania nanoarchitecture. First of all, a TiO2 nanoarchitecture was synthesized by an ultrasound-assisted sol–gel method. Then, TiO2/PEDOT systems were obtained and characterized by using different techniques such as X-ray diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, UV–Vis diffuse reflectance, and N2 sorption measurements. The synthesized composites confirmed their mesoporosity and lower band gap values compared to bare titania, which clearly shows the ability to work as photocatalysts under visible-light activity. Further, we demonstrated that an organic pollutant, Congo Red dye, used as a model molecule could be photodegraded with the synthesized TiO2/PEDOT systems, with efficiencies of up to 95% in the case of TconvPEDOT under UV light and up to 99% for TconvPEDOT under visible-light irradiation, accomplishing in this way a successful synthesis of visible-light-activated titania photocatalyst.

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“…According to the AOPs mechanism, the toxic pollutants are transformed into less hazardous compounds with a diminished impact on the environment. In this context, many researchers have focused their efforts on improving several aspects of the photocatalytic processes [11]. For instance, the coupling of the photocatalytic and adsorption process can ameliorate water reclamation and reduce the operational costs [12].…”

Section: Introductionmentioning

confidence: 99%

Development of Porous Titania Structure with Improved Photocatalytic Activity: Response Surface Modeling and Multi-Objective Optimization

et al. 2020

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Porous titania was successfully synthesized by an ultrasound-assisted sol-gel route. The synthesis process was empirically modeled and optimized using the response surface methodology (RSM). Input variables adopted for optimization dealt with the weight ratio of precursors (r) and the sonication time (t), representing the used factors in the synthesis procedure. With regard to application, the synthesized TiO2 samples were tested for the photodegradation of two water-soluble organic pollutants under UV–Vis irradiation. Optimal conditions for the efficient pollutants’ photodegradation were found to involve a precursors ratio of 3 and a sonication time of 60 min. Thus, the M5 sample prepared under the founded optimal conditions yielded the maximal removal efficiencies of 98.4% and 46.3% for the photodegradation of CR dye and 2,4-D herbicide, respectively. In addition, the photodegradation kinetics revealed the pseudo first-order rate constants, showing the photodegradation of CR (k1 = 8.86 × 10−2 min−1) by M5 sample is about 1.3-fold faster than the photodegradation of 2,4-D pesticide (k2 = 6.84 × 10−2 min−1).

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Plasma generation in liquid as a new efficient synthesis approach of titania–zinc ferrite nano(photo)catalyst

Cited by 4 publications

References 30 publications

Reillumination of submicrosecond pulsed corona-like discharges in water

Reillumination of submicrosecond pulsed corona-like discharges in water

Conjugated Polymer Modifying TiO2 Performance for Visible-Light Photodegradation of Organics

Development of Porous Titania Structure with Improved Photocatalytic Activity: Response Surface Modeling and Multi-Objective Optimization

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