Sou Hosokai

Synthesis of copper/copper oxide nanoparticles by solution plasma

This paper describes the synthesis of copper/copper oxide nanoparticles via a solution plasma, in which the effect of the electrolyte and electrolysis time on the morphology of the products was mainly examined. In the experiments, a copper wire as a cathode was immersed in an electrolysis solution of a K2CO3 with the concentration from 0.001 to 0.50 M or a citrate buffer (pH = 4.8), and was melted by the local-concentration of current. The results demonstrated that by using the K2CO3 solution, we obtained CuO nanoflowers with many sharp nanorods, the size of which decreased with decreasing the concentration of the solution. Spherical particles of copper with/without pores formed when the citrate buffer was used. The pores in the copper nanoparticles appeared when the applied voltage changed from 105 V to 130 V, due to the dissolution of Cu2O.

Size-Controlled Ni Nanoparticles Formation by Solution Glow Discharge

We report the size control of Ni nanoparticles generated via solution glow discharge and focus on the effect of electrolyte concentration on Ni nanoparticles. In our experiments, voltage was applied to generate a plasma in NaOH electrolytes with concentrations ranging from 1.0 to 0.001 kmol m -3 . The applied voltage strongly depended on the electrolyte concentration, and interestingly, product size decreased with electrolyte concentration; for example, (mean diameter, applied voltage, electrolyte concentration) = (148 nm, 90 V, 0.5 kmol m -3 ), and (70 nm, 590 V, 0.001 kmol m -3 ). These results suggested the possibility of using plasma electrolysis for synthesizing size-controlled nanoparticles by changing only electrolyte concentration.

Surface morphology of a glow discharge electrode in a solution

This paper describes the surface morphology of a glow discharge electrode in a solution. In the experiments detailed in the paper, the effects of electrolysis time, solution temperature, voltage, electrolyte concentration, and surface area on the size of nanoparticles formed and their amount of nanoparticles produced were examined to study the surface morphologies of the electrodes. The results demonstrated that the amount of nanoparticles produced increased proportionally with the electrolysis time and current. When the voltages were below 140 V, surfaces with nanoparticles attached, called “Particles” type surfaces, were formed on the electrode. These surfaces changed and displayed ripples, turning into “Ripple” type surfaces, and the nanoparticle sizes increased with an increase in the amount of nanoparticles produced. In contrast, at voltages over 160 V, the surfaces of the electrodes were either “Random” or “Hole” type and the particle sizes were constant at different amount of nanoparticles produced.

Ripple formation on a nickel electrode during a glow discharge in a solution

We investigated ripple formation on a nickel electrode during a glow discharge in a solution. A nickel wire was partially melted to produce nanoparticles during glow discharge electrolysis. When the electrolysis time was over 30 min, a ripple pattern was formed on the electrode surface, and particle size increased. In this study, we investigated the relationship between the ripple formation and crystal orientation of the electrode. As a result, the ripple patterns were formed on all planes, except (111)- and (100)-oriented planes; their direction was [001].

Ironmaking with Ammonia at Low Temperature

This paper describes the reduction of hematite with ammonia for ironmaking, in which the effect of temperature on the products was examined. The results showed that the reduction process began at 430 °C during heating, and with an increase in temperature, the reduction mechanism changed apparently from a direct reduction of ammonia (Fe(2)O(3) + 2NH(3) → 2Fe + N(2) + 3H(2)O) to an indirect reduction via the thermal decomposition of ammonia (2NH(3) → N(2) + 3H(2), Fe(2)O(3) + 3H(2) → 2Fe + 3H(2)O) at temperatures over 530 °C. The final product obtained at 600 and 700 °C was pure metallic iron, in contrast with that formed at 450 °C, that is, a mixture of metallic iron and iron nitride. The results suggest the possibility of using ammonia as a reducing agent for carbonless ironmaking, which is operated at a much lower temperature than 900 °C in conventional coal-based ironmaking.

Estimation of thermodynamic properties of liquid fuel from biomass pyrolysis

Estimation method for thermodynamic properties of organics in liquid fuel are proposed in this work. Especially this method can be applied to bio-oil produced from biomass pyrolysis. Thermodynamic properties of more than 600 compounds, which can be obtained in NIST chemistry webbook, were investigated for the estimation of thermodynamic properties. Simple estimation methods for the heat capacity and heating value are successfully provided with only the elemental composition of unknown compounds.