Sol-gel preparation and spectroscopic study of the pyrophanite MnTiO3 nanoparticles

摘要

The nanosized xerogel of titanium dioxide (TiO2) and manganese oxides (MnO2, Mn2O3, Mn3O4) was prepared by the sol-gel method using manganese chloride (MnCl2·4H2O) and titanium isopropoxide (Ti(O-iPr)4) as precursors in cetyltrimethylammonium bromide (CTAB)/ ethanol/H2O/HCl micelle solutions, following the calcinations of the produced powders at difference temperatures. The nanostructure and phase composition of these nanoparticles were characterized with X-ray powder diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The spectroscopic characterizations of these nanoparticles were also done with UV-Vis spectroscopy and laser Raman spectroscopy (LRS). XRD patterns show that the pyrophanite MnTiO3 phase was formed at the calcinations temperature of 900℃. The TEM images show that the nanoparticles are almost spherical or slight ellipose and the sizes are 50 nm on average. The UV-Vis spectra show that the nanosized MnTiO3 have significant absorption bands in the visible region. There are new absorption peaks of MnTiO3 nanoparticles in LRS compared with the pure TiO2 powder.