Polishable composite electrode based upon graphite powder modified with an electrochemically deposited catalyst

1994 ◽  
Vol 6 (11-12) ◽  
pp. 976-981 ◽  
Author(s):  
James A Cox ◽  
Krzysztof Lewinski
2018 ◽  
Author(s):  
Umesh S. Devarushi ◽  
Nagaraj P. Shetti ◽  
Shikandar D. Bukkitgar ◽  
Suresh M. Tuwar

2014 ◽  
Vol 39 (2) ◽  
pp. 183-190
Author(s):  
M Emran Quayum ◽  
Bablu Biswas ◽  
Md Khairul Hassan Bhuiyan

In the present study Cu nanoparticles (NPs), ZnO nanorods have been deposited on indium tin oxide (ITO) electrode and thereby Cu-NPs /ZnO / ITO composite film electrode has been prepared. The prepared nanostructures have been characterized by using scanning electron microscope (SEM). The shape of the electrochemically deposited ZnO follow rod like structure on ITO electrode, Cu–NPs follow irregular spherical shape when electrodeposited on ITO electrode. Oxidation of ascorbic acid on bare ITO electrode is favorable than that of ZnO modified ITO electrode but Cu-NPs/ ZnO composite electrode had high sensitivity and stability and showed higher catalytic current for glucose oxidation. DOI: http://dx.doi.org/10.3329/jasbs.v39i2.17855 J. Asiat. Soc. Bangladesh, Sci. 39(2): 183-190, December 2013


2019 ◽  
Author(s):  
Moritz Wolf ◽  
Nico Fischer ◽  
Michael Claeys

<p>The inert nature of graphitic samples allows for characterisation of rather isolated supported nanoparticles in model catalysts, as long as sufficiently large inter-particle distances are obtained. However, the low surface area of graphite and the little interaction with nanoparticles result in a challenging application of conventional preparation routes in practice. In the present study, a set of graphitic carbon materials was characterised in order to identify potential support materials for the preparation of model catalyst systems. Various sizes of well-defined Co<sub>3</sub>O<sub>4</sub> nanoparticles were synthesised separately and supported onto exfoliated graphite powder, that is graphite after solvent-assisted exfoliation <i>via</i> ultrasonication resulting in thinner flakes with increased specific surface area. The developed model catalysts are ideally suited for sintering studies of isolated nano-sized cobaltous particles as the graphitic support material does not provide distinct metal-support interaction. Furthermore, the differently sized cobaltous particles in the various model systems render possible studies on structural dependencies of activity, selectivity, and deactivation in cobalt oxide or cobalt catalysed reactions.</p>


2018 ◽  
Vol 84 (11) ◽  
pp. 9-14
Author(s):  
E. S. Koshel ◽  
V. B. Baranovskaya ◽  
M. S. Doronina

The analytical capabilities of arc atomic emission determination of As, Bi, Sb, Cu, Te in rare earth metals (REM) and their oxides after preparatory group concentration using S,N-containing heterochain polymer sorbent are studied on a high-resolution spectrometer “Grand- Extra” (“WMC-Optoelectron-ics” company, Russia). Sorption kinetics and dependence of the degree of the impurity extraction on the solution acidity are analyzed to specify conditions of sorption concentration. To optimize the procedure of arc atomic emission determination of As, Bi, Sb, Cu, and Te various schemes of their sorption preconcentration and subsequent processing of the resulted concentrate with the addition of a collector at different stages of the sorption process have been considered. Graphite powder is used as a collector in analysis of rare earth oxides due to universality and relative simplicity of the emission spectrum. Conditions of analysis and parameters of the spectrometer that affect the analytical signal (mass and composition of the sample, shape and size of the electrodes, current intensity and generator operation mode, interelectrode spacing, wavelengths of the analytical lines) are chosen. The evaporation curves of the determinable impurities were studied and the exposure time of As, Bi, Sb, Cu, and Te in the resulted sorption concentrate was determined. Correctness of the obtained results was evaluated using standard samples of the composition and in comparisons between methods. The results of the study are used to develop a method of arc chemical-atomic emission analysis of yttrium, gadolinium, neodymium, europium, scandium and their oxides in a concentration range of n x (10-2 - 10-5) wt.%.


2020 ◽  
Vol 38 (9A) ◽  
pp. 1352-1358
Author(s):  
Saad K. Shather ◽  
Abbas A. Ibrahim ◽  
Zainab H. Mohsein ◽  
Omar H. Hassoon

Discharge Machining is a non-traditional machining technique and usually applied for hard metals and complex shapes that difficult to machining in the traditional cutting process. This process depends on different parameters that can affect the material removal rate and surface roughness. The electrode material is one of the important parameters in Electro –Discharge Machining (EDM). In this paper, the experimental work carried out by using a composite material electrode and the workpiece material from a high-speed steel plate. The cutting conditions: current (10 Amps, 12 Amps, 14 Amps), pulse on time (100 µs, 150 µs, 200 µs), pulse off time 25 µs, casting technique has been carried out to prepare the composite electrodes copper-sliver. The experimental results showed that Copper-Sliver (weight ratio70:30) gives better results than commonly electrode copper, Material Removal Rate (MRR) Copper-Sliver composite electrode reach to 0.225 gm/min higher than the pure Copper electrode. The lower value of the tool wear rate achieved with the composite electrode is 0.0001 gm/min. The surface roughness of the workpiece improved with a composite electrode compared with the pure electrode.


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