Journal of Metastable and Nanocrystalline Materials Vol. 33

Abstract: Activated carbon powder is a popular material used as an electrode material for large scale applications, especially supercapacitors because of its excellent physical and electrochemical properties. Self-adhesive carbon powder based on coconut coir was prepared via single-step pyrolysis and chemical activation with NaOH solution. A single-step pyrolysis was performed, including carbonization and physical activation in the N₂/CO₂ atmosphere. The physical temperature of 750 °C, 800 °C, 850 °C and 900 °C is the major focus to evaluate the behavior of self-adhesive activated carbon. The density and the microcrystalline characteristics of the electrodes are influenced by the physical activation temperature. The density feature was evaluated based on the approach of self-adhesive carbon reduction dimensions such as mass, diameter, and thickness. Microcrystalline behavior was performed by using X-ray diffraction method, and it has shown the good amorphous properties of the activated carbon. The self-adhesive activated carbon electrodes were characterized and evaluated in symmetrical supercapacitor cells. The electrochemical characterization of the carbon electrodes using cyclic voltammetry method found that the high specific capacitance of 96 F.g^-1 in 1 M H₂SO₄ electrolyte at a low scan rate of 1 mV.s^-1 with energy specific and power specific of 13.33 Wh.kg^-1 and 48.03 W.kg^-1, respectively.

Abstract: The functional magnetite nanoparticles are one of the most important functional materials for nucleic acid separation. Cell lysis and magnetic separation are two essential steps involve in optimizing nucleic acid extraction using the magnetic beads method. Many coating materials, coupling agents, chemical cell lysis, and several methods have been proposed to produce the specific desired properties for nucleic acid extraction. The important properties, such as biocompatibility, stability, linking ability, hydrophobicity, and biodegradable, were considered. The appropriate coating material of magnetite core and coupling agent are necessary to give biomolecules a possibility to link with each other through chemical conjugation. In this review, progress in functional magnetite nanoparticles to optimize the high binding performance in nucleic acid extraction is discussed.

Abstract: The result of burning hydrogen which is environmentally friendly makes hydrogen as a very attractive fuel. Hydrogen storage is interesting research material. One alternative to hydrogen storage is a metal-hydride as NaBH₄. In this paper, the catalyst for hydrogen production from storage, namely The result of burning hydrogen, which is environmentally friendly, makes hydrogen a desirable fuel. Hydrogen storage is exciting research material. One alternative to hydrogen storage is a metal-hydride as NaBH₄. In this paper, the catalyst for hydrogen production from storage, namely NaBH₄, was synthesized by electrochemical. Ni-B catalyst with hydroxyapatite as catalyst support was prepared by electrochemical. Ni-B/HA catalyst was synthesized at various current densities (namely 67, 133, and 200 mA/cm²) and various electrolysis times (namely 30, 60, and 90 minutes). The resulting catalysts were analyzed by XRD and used as the catalyst for hydrogen production from the hydrolysis reaction of NaBH₄. The fastest hydrogen production was obtained using a catalyst generated at 133 mA/cm² and an electrolysis time of 60 minutes. The reaction rate equation for the hydrolysis of NaBH₄ has a first-order reaction to the concentration of NaBH₄. The resulting reaction rate constant ranged from 233.33 mL/g/min to 861.11 mL/g/min. The relationship between reaction temperature and reaction rate constant can be expressed by the equation k = 2.2x10⁶exp (5534/T).

Abstract: Simple and low environmental impact methods for producing chemically-stable nanoparticles of metallic zinc (Zn) are asked to be developed, because metallic Zn nanoparticles are easily oxidized in air, and organic solvents, which can be used for the fabrication of metallic Zn particles, give a great environmental impact. The present work focuses on the chemical reaction in protonic solvents containing aqueous solvents, of which the use will give a smaller environmental load, and proposes a method for producing metallic Zn nanoparticles by reduction of Zn ions in the protonic solvent. Two kinds of hydrophilic solvents were examined: water and ethylene glycol (EG). The use of water and EG as the solvents produced Zn oxide. Though the addition of aluminum salt to EG also produced Zn oxide, the crystallinity of Zn oxide was lower than that for with no addition of aluminum salt. In the case of the aluminum salt addition, nanoparticles with a size of 27. 5±13.3 nm were fabricated, and not only bonds of Zn-O-Zn and Zn-OH but also a bond of Zn-Zn were confirmed to be formed, which indicated the production of low crystallinity metallic Zn nanoparticles.