Emission of the third continuum of argon excited by a pulsed volume discharge

Lissovski, A.; Treshchalov, Alexey

doi:10.1063/1.3259356

Cited by 8 publications

(5 citation statements)

References 36 publications

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“…The continuum has been assigned to the emission of double charge molecular ions + Ar 2 2 and has a maximum in the UV region of 190 nm [29]. In the RF discharge, the electron's energy is about 1 eV, and the generation of a substantial amount of + Ar 2 2 is very unlikely [30]. Correspondingly, the contribution of the third continuum bands of Ar in the observed discharge radiation has been considered negligible in our experimental conditions.…”

Section: Third Continuum Appearing In Ar Discharges In Thementioning

confidence: 85%

Characterization of a planar 8 mm atmospheric pressure wide radiofrequency plasma source by spectroscopy techniques

Nikiforov

Ionita

Dinescu

et al. 2015

Plasma Phys. Control. Fusion

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Classification numbers: PACS: 52.70.Kz, 52.80.TnAtmospheric pressure planar RF 13.56 MHz discharge in Ar gas generated in long gap is investigated. The discharge operation with and without dielectric barrier on the electrodes is studied as a function of the applied power and gas flow. The source afterglow is characterized and analyzed for possible large scale biomedical applications where low gas temperature is required. The discharge is studied by relative and absolute emission spectroscopy. The gas temperature as low as 330±50 K is determined from rotationalvibrational band of OH emission. The absolute value of the discharge continuum irradiation is used to determine the electron density and the electron temperature. The electron-atom and electron-ion contributions to the Bremsstrahlung radiation are calculated and compared with measured spectra. The electron density of 1.91×10 20 m -3 and electron temperature of 1.750.25 eV are measured in the discharge without dielectric barrier. It is found that presence of the dielectric has negligible effect on electron temperature whereas electron number density is almost 6 times lower in the discharge with dielectric barrier.

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Section: Third Continuum Appearing In Ar Discharges In Thementioning

confidence: 85%

Characterization of a planar 8 mm atmospheric pressure wide radiofrequency plasma source by spectroscopy techniques

Nikiforov

Ionita

Dinescu

et al. 2015

Plasma Phys. Control. Fusion

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“…Continuum emission was observed in the entire experimental range of 300 to 850 nm as shown by the dashed line in Figure 9. The continuum is assumed to originate from e-Ar + 2 recombination and the emission is proportional to electron density squared [31,33]. In experiments measuring the spectral line intensity, the continuum signal was first determined and subtracted.…”

Section: Microwave Circuit Analysismentioning

confidence: 99%

Instability control in microwave-frequency microplasma

Miura

Hopwood

2012

Eur. Phys. J. D

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Abstract. Atmospheric argon microplasmas driven by 1.0 GHz power were studied by microwave circuit analyses and spatially-resolved optical diagnostics. These studies illuminate the mechanisms responsible for microplasma stability. A split-ring resonator (SRR) microplasma source is demonstrated to reflect excess microwave power, preventing the ionization overheating instability while limiting electron density to approximately 1 × 10 14 cm −3 and OH rotational temperature to 760 K at 0.76 W. Providing the SRR microplasma with an electrical path to ground, however, allows the microplasma to transition from the SRR mode to the so-called transmission line mode (T-line). This transition is due to matching of the microplasma and transmission line impedances. The higher power T-line mode supports a more intense microplasma with electron density of 1 × 10 15 cm −3 and OH rotational temperature of 1480 K with 15 W absorbed power. While the SRR mode is optimized for ignition and sustaining a stable nonequilibrium plasma, and T-line mode is better suited for driving a hot, high density microplasma. The estimated microwave discharge voltages were 15 V and 35 V in SRR mode and T-line mode, respectively, and the voltages are rather independent of input power. Microplasma stability is due to a combination of impedance mismatching and direct control of power, both inherent to microwave circuitry.

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“…This voltage generated an electric field between the two plate electrodes, with 2.67 kV/cm field strength and the field direction towards the Pt electrode. Such a field is below the breakdown voltage limit for Ar and falls in the Townsend discharge regime for Ar + generation . An immediate activity recovery of the deactivated Pt was observed, evidenced by instant increases in the H 2 and CO 2 gas products (Figure b).…”

Section: Figurementioning

confidence: 95%

“…Such a field is below the breakdown voltage limit for Ar and falls in the Townsend discharge regime for Ar + generation. [14] An immediate activity recovery of the deactivated Pt was observed, evidenced by instant increases in the H 2 and CO 2 gas products ( Figure 2b). Interestingly, a low content of CO was also detected, which would result from desorption of this poisoning species from the deactivated Pt surface.…”

mentioning

confidence: 93%

Competitive Transient Electrostatic Adsorption for In Situ Regeneration of Poisoned Catalyst

et al. 2019

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Catalyst deactivation by poisoning species is one important concern in catalysis processes and causes significant catalyst material and operation costs due to process shutdown and catalyst replacement. We report one new in situ catalyst regeneration method, which utilizes competitive electrostatic adsorption of charged ions which are generated with moderate DC voltage supply following the Townsend discharge mechanism to desorb poisoning species and the transient characteristic of electrostatically adsorbed ions to recover the active sites for catalysis. We demonstrate effectiveness of this new concept using HCOOH decomposition on Pt catalyst as model reaction and find the deactivated Pt regains the activity in presence of Ar+ generation. DFT simulations and classical electrical discharge calculations show Ar+ ions have significantly higher electrostatic adsorption energy than desorption energy of CO poisoning species that helps to desorb CO from Pt and generate more available active sites. This new in situ catalyst regeneration method, with convenient, noninvasive and low operation cost features, provides a promising strategy to overcome the challenges associated with current technologies that handle catalyst deactivation.

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Emission of the third continuum of argon excited by a pulsed volume discharge

Cited by 8 publications

References 36 publications

Characterization of a planar 8 mm atmospheric pressure wide radiofrequency plasma source by spectroscopy techniques

Characterization of a planar 8 mm atmospheric pressure wide radiofrequency plasma source by spectroscopy techniques

Instability control in microwave-frequency microplasma

Competitive Transient Electrostatic Adsorption for In Situ Regeneration of Poisoned Catalyst

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