Water in Sugar Electrolytes and Application to Electrodeposition of Superconducting Rhenium

A systematic electrochemical study is carried out on electrolytes with superhigh concentrations of fructose. The effect of fructose concentration on the viscosity and conductivity of electrolyte are determined and analyzed using Walden rule and the theory of rate process. The diffusion rates of proton and cupric cation are calculated from the peak current in cyclic voltammogram on stationary electrode and the limiting current on rotating electrodes. Raman spectroscopy is used to characterize the hydrogen bond network in water and the effect of fructose concentration on such network. Rhenium deposition with different fructose concentrations is studied on rotating disc electrodes. X-ray fluorescence, X-ray diffraction, and four point probe measurements at cryogenic temperature are used to study the deposition rate, crystallographic structure, and superconductivity of film, respectively.

13 Electrochemistry in Laboratory Flow Systems

Organic electrosynthesis in flow reactors is an area of increasing interest, with efficient mass transport and high electrode area to reactor volume present in many flow electrolysis cell designs facilitating higher rates of production with high selectivity. The controlled reaction environment available in flow cells also offers opportunities to develop new electrochemical processes. In this chapter, various types of electrochemical flow cells are reviewed in the context of laboratory synthesis, paying particular attention to how the different reactor environments impact upon the electrochemical processes, and the factors responsible for good cell performance. Coverage includes well-established plane-parallel-plate designs, reactors with small interelectrode gaps, extended-channel electrolysis cells, and highly sophisticated designs with rapidly rotating electrodes to enhance mass transport. In each case, illustrative electrosyntheses are presented.

Plasma-catalytic NOx production in a three-level coupled rotating electrodes air plasma combined with nano-sized TiO2

A novel three-level coupled rotating electrodes air plasma with nano-sized TiO2 photocatalysts is developed for plasma-catalytic NOx production. The effects of plasma catalysis on NOx production with different air flow rates, different N2 fractions and different humidity levels are evaluated. Final results show that the exceptionally synergistic effect between TiO2 and three-level coupled rotating electrodes air plasma significantly increases the NOx concentration by 68.32% (from 4952 to 8335 ppm) and reduces the energy cost by 40.55% (from 2.91 to 1.73 MJ mol-1) at an air flow rate of 12 l min-1 and relative humidity level of 12%, which beats the ideal thermodynamic energy limit ~2.5MJ/mol for the thermal gas-phase process. A possible mechanism for enhanced NOx production with TiO2 is discussed: Highly energetic electrons in plasma contribute to the formations of the electron–hole pairs and oxygen vacancy (Vo) on the TiO2 catalyst surface, it may facilitate the dissociative adsorption of O2 molecules to form superoxide radical groups (like O2.-), and H2O molecules to form surface hydroxyl groups (like OH.), and thus, improving energy efficiency.

Measurement of Dielectric Liquid Electrification in the Shuttle System with Two Parallel Electrodes

In this paper, a device with swinging plate electrodes has been proposed to measure contact electrification of a liquid sample. The proposed structure is composed of two parallel metallic plates immersed in a dielectric liquid. One of the plates is swinging with a constant frequency in a range from 0.4 to 4 Hz. The paper investigates the dependence in time and frequency of electrode velocity and streaming electrification. The measured current occurs for a very low intermittent velocity of less than 10 mm/s. In this range, the electrification current is around 50 pA. For higher velocities of up to 150 mm/s, the current is at the level of 1200 pA. The time–frequency characteristic using short-time Fourier transform shows no temporal changes in the frequency spectrum. The dependence of electrification on shuttle speed was calculated and it can be approximated with a second order polynomial model with the determination coefficient higher than 0.9. The advantage of the sensor is the ability to measure electrification phenomena without the necessity of having rotating electrodes or having a large volume of flowing liquids.

Review on Plasma Atomizer Technology for Metal Powder

The application of plasma process is growing field covering a wide range of activities, from welding technology, coating technology, deposition technology, manufacturing technology of metal powder, and other important engineering technology. The manufacture of metal powders can be generated from the process of gas atomization, water atomization, plasma atomization, and plasma rotating electrodes process atomization. In the process of plasma atomization provides advantages in addition to producing round powder, it is also very potential for efficient processing and recycling of used and alloy materials, thus saving fuel and essential materials. These operations will have a continuing impact on our industrial society as a whole. The industry of future metal powder manufacturers that utilize plasma atomization technology is an investment strategy that has a great opportunity to grow rapidly. A variety of plasma processes for the manufacture of metal powders will be reviewed in this paper, among others, are plasma atomization and plasma rotating electrodes process atomization. They are all potentially able to control and to produce of metal powders of spherical particles, making it very profitable on powder technology applications. The purpose of this review is to summarize and provide future research for activities in the field of metal powders by plasma atomization processes. The emphasis on plasma engineering technology future research in powder making available for exploration and research needs to be met so that these future research can be realized. Finally, the future challenges of automation from the use of plasma atomization technology for additives manufacturing, powder welding and medical manufacturing.