수소 확산화염에서 화염온도가 TiO2 나노입자의 합성에 미치는 영향

Abstract

In this work, TiO2 nanoparticles were synthesized using a N2-diluted hydrogen coflow diffusion flame. The effects of flame temperature on the crystalline structure and the size of formed nanoparticles were investigated. The maximum centerline temperature of the flame ranged from 1,920K for H2-only flame to 863K for 81% N2-diluted flame. The morphology and the crystal structure of TiO2 nanoparticles were analyzed by a TEM and a XRD, respectively. The particle size distribution was also measured by using a scanning mobility particle sizer (SMPS). The mean particle diameter was calculated from the TEM images depended on the flame temperature, having minimum at about 1,200K. Based on the SMPS measurements, the mean particle diameter of TiO2 nanoparticles at flame temperatures > 1,300K was smaller than that at flame temperatures < 1,300K. From the XRD analysis, it was evident that the anatase fraction increased with decreasing the flame temperature. The portion of anatase phase in TiO2 nanoparticles might be greater than 80% when the flame temperature was lower than 1,000K.