Hiroya Yamashita

Application of the solid polymer electrolyte (SPE) method to organic electrochemistry—III. Kolbe type reactions on Pt-SPE

Abstract The feasibility of a solid polymer electrolyte (SPE) method for Kolbe type reactions was investigated by using Pt-SPE composed with Nafion 415 and platinum. The Kolbe reaction of acetic acid proceeded effectively on one side and both sides Pt-SPE composites. The lower current efficiency was observed on the latter than on the former. Neat acetic acid could also be electrolysed on both sides SPE though the cell voltage was fairly high. A methanolic solution of monomethyl adipate was electrolysed to give dimethyl sebacate on both sides Pt-SPE according to the Brown-Walker reaction. The current efficiency and the terminal voltage increased with the concentration of monomethyl adipate. Pt-SPE behaved as an active electrode of a high roughness factor, eg about 6, for the Kolbe reaction of acetate.

The Relation Between Catalytic Ability for Hydrogen Evolution Reaction and Characteristics of Nickel‐Tin Alloys

The relation between catalytic ability for hydrogen evolution reaction and characteristics of nickel-tin alloys prepared by electroplating was investigated. The catalytic ability was found to strongly depend on preparation conditions. Hydrogen overvoltage was drastically decreased with an increase of the width at half height of x-ray diffraction peaks which was related to the tin content. The nickel-arsenide-type structure and the initial high catalytic ability remained unchanged after an 800 day durability test, suggesting that the addition of the specific amount of tin, which itself had high overvoltage, enhanced the catalytic ability of nickel

Application of a membrane-electrode composite assembly to the cathodic reaction in brine electrolysis

Abstract A membrane-electrode composite assembly (MECA) was applied to the cathodic reaction in brine electrolysis. The cell voltage stably exhibited a value of 2.93V, which is lower by 0.07V than that obtained with the zero gap system with an activated cathode. Neither reduction of the caustic current efficiency nor increase in the sodium chloride content of caustic soda was observed, suggesting that the MECA should be applied to the cathodic reaction rather than to the anodic reaction in brine electrolysis.

Preparation of Li2B4O7 thin films by sol-gel method and their characterization

The sol-gel method using lithium and boron-n-tributoxide as starting materials has been applied to prepare Li2B4O7 coating films on silica glass, silicon and sapphire single crystal substrates. The effects of the amounts of water and acid added to coating solutions, and the kinds of substrate on the crystallization of Li2B4O7 coating films were fully investigated. It was found that a sufficient amount of water is required for obtaining well-crystallized Li2B4O7 films of single phase, the addition of acids such as hydrochloric and acetic acids to the coating solution suppresses crystallization up to 600°C and gives highly oriented Li2B4O7 single phase films on further heating at 800°C.