Effect Of Temaplate Of Microstructure Of La-Doped Mesoporous Nano-TiO₂

Lanthanum-doped mesoporous nanometer TiO2 were prepared by sol-gel method with three different template(PEG, CTAB, ODA) respectively . It chose a good template, used orthogonal design method to optimize experimental condition to prepare a better La-doped mesoporous nanometer TiO2 . Finally, it has studied the influence for the composite template agent to the structure and photoelectric property of La-doped mesoporous nanocrystalline TiO2 .We detected crystal structure and grain size of the sample with X-ray diffraction (XRD), analyzed lattice vibration mode of the sample tested by laser Raman spectroscopy (Laser Raman), used differential thermal-gravimetric analysis (DSC-TG) to study precursors changes in the heat treatment process, used specific surface area (BET) method to test ratio surface and void distribution of sample, used transmission electron microscopy (TEM) to characterize the sample's microstructure and appearance, and studied photo-induced surface charge transfer transition properties according to photo-acoustic spectroscopy (PAS), surface photo-voltage spectroscopy (SPS) and electric field induced surface photo-voltage spectroscopy (EFISPS).It concluded that the La-doped can effectively suppress the growth of anatase Grain, improved the surface photovoltaic effect strength of titanium dioxide during controlling phase transition from anatase to rutile. Taking 3.0g PEG as a template agent, with calcinations temperature to 500℃, it got the sample as worm-like mesoporous structure. Compared to other template agents, it got large specific surface are and strong surface photo-voltage. With the electric field induced surface photo-voltage spectroscopy detected, the surface photovoltaic response peak induced by La-doped mesoporous nano-TiO2 sample during the wavelength of 375 and 400 nano, which is corresponding to two totally different nature of the surface state and charge transfer transitions between the energy band respectiv ely; It existed energy complementary relationship between the photo-acoustic and surface photovoltaic effect; It proved that composite template has significantly effected the sample surface on photovoltaic properties; when the molar ratio reach to 1:1 of the poly - ethylene glycol and acetyl trim-ethyl ammonium bromide or octadecylamine, the sample surface photovoltaic response to be strong.