Hydrothermal synthesis of one-dimensional yttrium hydroxide particles by a two-step alkali-addition method

Abstract

One-dimensional yttrium hydroxide particles of hexagonal crystal structure were selectively synthesized through a hydrothermal reaction of yttrium chloride solution that was alkalized by two-step addition of sodium hydroxide solution. Keeping the YCl₃ solution at pH ∼ 6.8 for a few minutes before raising the pH to the sufficient level (pH ∼ 13) was concluded to be the practical requirement for the one-dimensional Y(OH)₃ particle formation. This requirement was successfully achieved by the two-step addition procedure that was applicable to adjust the pH values independently. The size distribution of one-dimensional particles was changed depending on the interval time between alkali-additions and on the pH of the hydrothermal reaction. The formation mechanism of the one-dimensional particles was also discussed.