The Role of Cation Concentration on Particle Formation Mechanism during Hydrothermal Synthesis of Nanosized Tin Oxide (SnO2)

Abstract

Preparation of SnO2 particles via hydrothermal synthesis was investigated as a function of cation concentration and treatment time to develop a fundamental understanding on determination of effective formation and growth mechanisms. SnO2 particles were synthesized at pH 9.0 and 200 degrees C from hydrous tin oxide gel. When the initial cation concentration increases from 0.025 to 1.0 M, mechanism of particle formation shifts from Ostwald ripening to classical nucleation theory at critical cation concentration. Accordingly, particle size increases from 2.80 to 3.50 nm. However, particle size decreases from 3.50 to 2.93 nm with further increasing of cation concentration from 0.10 to 1.00 M. It was observed that particle growth mechanism is not a function of cation concentration and it is diffusion controlled. Particle size of the synthesized SnO2 increases from 2.51 to 2.93 nm as the hydrothermal synthesis time increases from 1 to 24 hours for 1.0 M cation containing system.