Papers by Keyword: Arc Discharge

Abstract: This study presents results of an arc discharge synthesis of nanomaterials containing graphene and nanoparticles of SiC ceramic. It has been established that the usage of the silicon-carbon composition of the sputtered electrode in the arc discharge synthesis allows to synthesize graphene structures with silicon carbide nanoparticles with the average size of about 6.2 nm. On the other hand, the usage of the graphite-silica composite electrode also leads to the formation of graphene structures, but at the same time the resulting nanoparticles of silicon carbide have the larger average size of about 9.5 nm. This paper presents the results of the structure analyses of the synthesized materials and offers the explanation for effects of the silicon oxide usage on the increasing in the average size of synthesized SiC nanoparticles.

Abstract: This study describes the structural modifications of char electrodes and the resulting carbon nanoparticles using method of arc discharge in liquid method, an approach which is simpler and less expensive than other techniques such as CVD and laser vaporization. The nanoparticles are obtained from powder floating on the water surface during arc discharge between two electrodes submerged in water. X-ray diffraction analysis (XRD) profiles show peak formation at 24-26^o 2Ѳ, associated with hexagonal graphite structure.Transmission electron microscopy (TEM) confirmed the presence of graphitic-structured nanoparticles after arc discharge; these nanoparticles have diameters ranging from 20 to 100 nm. In contrast, nanoparticles produced using graphite electrodes with current source variations show more complicated and varied stuctures, for example, structures such as nanoonions, graphene, and amorphous nanoparticles.

Abstract: The various carbon nanostructures e.g. single-walled carbon nanotubes (SWCNTs) web, graphene nanosheets and metal nanoparticle decorated graphene sheets have been synthesized in large quantity by electrical arc discharge method under an argon atmosphere. The as-synthesized nanostructures were characterized by different characterization techniques such as XRD, SEM, TEM, Energy dispersive X-ray spectroscopy, Raman and FTIR spectroscopy. The SWCNT webs of length ~6 cm abundantly containing aligned SWCNTs have diameter of about 1.8 nm and form buckybook like structure. Few layer graphene (FLG) sheets were prepared by electric arc discharge of high purity graphite electrodes in a varying argon gas atmosphere (250-500T). The largest areal extent of graphene (with lowest number of layer i.e. four) has been found at 350T argon pressure. A one step method is also reported for the decoration of these graphene nanosheets with iron and nickel nanoparticles through arc discharge method.

Abstract: Magnetic cobalt nanostructured was synthesized by a two-stage method. First, a solution of cobalt precursor droplets was prepared by an ultrasonic nebulizer. Second, the arc discharge method between two electrodes in an inert gas at atmospheric pressure is used to obtain the nanostructured cobalt powder. The sample obtained was characterized by X-ray diffraction (XRD). Scanning electron microscope (SEM), High Resolution Transmission Electron Microscope (HR-TEM), UV-Vis Spectrophotometry, zeta potential (ZP) and vibrating sample magnetometer (VSM). The dielectric constant, and AC conductivity of the prepared sample was determined in the frequency range of 4 Hz to 8 MHz. The investigations showed that the Co nanoparticles prepared in this way have smaller and homogeneous nanoparticles with spherical shape morphology with good stability and unique magnetic properties as compared with the bulky one. The dielectric properties analysis shows an enhancement in the dielectric constant and the AC conductivity of the Co nanoparticles.

Abstract: In this paper the synthesis method for nano- and micro- powders in arc discharge in the liquid phase is considered. The proposed method allows to synthesize nano- and microparticles of different chemical compositions. The synthesis mechanism and the scheme of combination of chemical compositions of electrodes and the liquid medium are described.

Abstract: Pt-C material was synthesized by arc-discharge method for application in creation of a gas diffusion electrode for an Al-air battery. The material was burned and mixed with graphite powder to replacement poor conductive carbon matrix, which closes Pt nanoparticles. Gas-diffusion electrodes produced by usage such materials have work characteristics of industrial level. Improving of work characteristic of gas diffusion electrodes is associated with increasing of electrical conductivity of carbon matrix which closes Pt nanoparticles. The arc discharge parameter dependence of structural and conductive properties of pure carbon material was studied, and it’s determined that the main parameter is buffer gas pressure. The carbon materials synthesized at pressure lower than 12 Torr have several times larger conductivity due to disappearance of the amorphous carbon layers and decreasing of contact resistance.

Abstract: This Composite Fe-C anode sputtering in a low-pressure arc discharge has been used to produce Fe-containing nanoparticles on a carbon matrix. Magnetic susceptibility as a function of background pressure has been measured. The data obtained showed the complex, no-monotonous dependency. The material synthesized at optimal pressure (maximal value of magnetic susceptibility) was investigated by means of transmission electron microscopy, X-ray diffraction and magnetometry. Size distribution function of iron containing nanoparticles has been measured. Chemical composition includes iron, iron carbide and carbon soot. Saturation magnetization have been measured and it was shown that the synthesized material is superparamagnetic. The physical processes resulting in the complex behavior of magnetic susceptibility are discussed.

Abstract: Herein we modified TiO₂ anatase with carbon material using an electrical arc discharge technique in liquid medium to produce a nanoparticle of TiO₂/Carbon photocatalyst. The electrical arc discharge was performed using two graphite electrodes submerged in TiO₂ suspended in ethanol by passing electrical 20-40 V (10-50 A). X-ray Diffraction (XRD) peak profile analysis shows the successful modification confirmed from the presenting peaks which represent to crystalline TiO₂ and carbon element. The fabrication was then followed by the assessment of photocatalytic activity of fabricated nanoparticles in methylebe blue degradation under mercury lamp irradiation. After 60 minutes irradiation, the photocatalytic activity of TiO₂/Carbon increased more than three times higher compared to the photocatalytic activity of pristine TiO₂.

Abstract: Endohedral metallofullerenes were prepared by DC arc discharge method with yttrium oxide and yttrium-nickel alloy as metal source, respectively. Mass spectroscopy and high-performance liquid chromatography analyses evidence that yttrium-nickel alloy has advantages over yttrium oxide in higher yield of soot, more species and higher yield of soluble metallofullerenes.

Abstract: Contact net of motor vehicle in coal mine tunnel is a powerful industrial disturbance source, pulse interference generated by contact net is some pulse group with random, repetitive amplitude and duration. When the train is in the rated working current situation, the pantograph and overhead line is in the process of separation to contact, the motor vehicle running speed is lower, the discharge current is larger, the more arc radiation interference.