Crystal phase control and photocatalytic activity of nanosized TiO2 colloidal particles prepared from low temperature hydrolysis of tianyl organic compounds (TOCs)

摘要

The paper reported the method for controlling crystal phases of nanosized TiO2 colloidal particles prepared from low temperature hydrolysis of tianyl organic compounds (TOCs), and the influences of the synthetic conditions on photocatalytic activity. The asprepared samples have been characterized by X-ray diffractometer (XRD), laser scattering analysis (LS), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The results indicated that when the concentration ratio of nitric acid (concentrated) to TOCs was less than 0.75, the nanosized anatase TiO2 were synthesized, which resembled rice-grain or quasi-sphere with size about 5-7 nm, and 0.352 nm lattice space agreed with {101} face of anatase phase. The increase of concentration ratio enhanced the formation of rutile phase, which were strip-shaped and grew up along with {001} orientation. The photo-degradation experiments of rhodamine B revealed that hydrolytic conditions influenced the photo-catalytic activity. The photo-degradation rates of rhodamine B were enhanced by the increases of reaction temperature and reaction time, as well as the proper concentration ratio of nitric acid to TOCs (less than 2).