Synthesis of silica particles through conventional sol-gel and sonochemistry methods and the effect of catalyst, water concentration and sample environment to the particle size

Abstract

Various methods have been carried out in an effort to obtain SiO2 (Silica) particles with relatively the same grain size distribution and a uniform shape. This fine Silica particle size will be useful in the formation of SiC in the next stage. In this works, Silica particles has been synthesized through two different methods: conventional sol-gel and sonochemistry (using ultrasonic probe). Silica was synthesized by mixing TEOS, ethanol, ammonia, and D.I water with the molar ratio of 1 : 75.9 : x : y respectively. In sol-gel method, x was varied with 2.85, 5.7, and 8.54 M while y was fixed at 61.6 M. In sonochemistry method, y was varied with 6.69, 12.3, and 75.9M while x was fixed at 2.85 M Additional variation of sample environment including with and without ice has also been done in sonochemistry method. Amorphous phase was found in all samples from the XRD profiles. FT-IR results showed that the IR spectral peaks of all samples match the FT-IR spectrum of SiO2 with symmetric and asymmetric stretching mode of Si-O functional groups at 802 – 810 cm−1 and 1093 – 1103 cm−1 wavenumber. SEM images indicated that the average of SiO2 particle size tends to increase with the higher amount of ammonia concentration used and lesser concentration of water used results in smaller particle size. The influence of sample environment in sonochemistry method showed an interesting phenomenon where a lot of small particles sticked with bigger particles.