Synthesis Of Niobium-oxide Nano-materials And Investigation Of Their Properties

As a valuable oxide material, niobium oxide (Nb2O5) possess promising applications in electron industry, ceramcis materials, photocatalytic, optical glasse, aviation industry and so on. In recent years, with the rapid development of the new materials and nanotechnology, it is found that the related materials based nano niobium oxide (Nb2O5) has been widely applied in the areas of functional ceramcis. So the research of synthesize, property and application of oxide nano-materials is an interesting subject.In this paper, we developed a novel simple method to prepare Nb2O5:Tb3+ microstructure and BaNbO3 nanocrystal using the composite–hydroxide–mediated (CHM) method, which is a new strategy that provides a one–step, convenient, low–cost, nontoxic and the method was suitable for large–scale preparation. As a new kind of crystal materials, the nestlike microsphere Nb2O5:Tb3+ was synthesized by doping niobium oxide (Nb2O5) with some terbium (Tb) element using composite–hydroxide–mediated (CHM) method. The obtained sample exhibits a unique geometrical shape, and they were characterized by X–ray diffraction (XRD) and field emission scanning electron microscopy (FE–SEM). XRD and SEM show that the Nb2O5:Tb3+ particles is single–phase with the monoclinic structure, average crystal size around 1μm. The research of the luminescence of the Tb3+ ions in the Nb2O5 lattice indicates that the terbium (Tb) element we doped make the luminescence of the niobium oxide (Nb2O5) crystal more salience, and there is a strong emission peak at 613 nm when we use wavelengh of 535 nm to excitated, which indicates that the Nb2O5:Tb3+ microstructure can be used as a promising phosphor for red luminescent display systems and lighting devices.At the same time, we study the best technics conditions of the BaNbO3 nanocrysstal powder using composite–hydroxide–mediated (CHM) method, and we study the effect of the reaction time to grain size of BaNbO3 nanocrysstal, the humidity sensitivity based on BaNbO3 nanocrysstal. The products were characterized by X–ray diffraction (XRD), field emission scanning electron microscopy (FE–SEM), transmission electron microscopy (TEM) and UV–Vis analysis, the results indicates that the morphology of sample was regulation and homogeneous, the average size of the nanopaticles is found to be very small, about 50–200nm, and as the reaction time was prolong the grain size diminution. Humidity sensors based on BaNbO3 nanocubes were fabricated. The responsiveness to humidity for static and dynamic testing proved the ultrasensitive properties of the sensors. The resistance changed from 932.4 M? to 2.2 M? as the relative humidity (RH) increases from 10% to 80%. The response–time and recovery–time of the resistance is 12s and 32s versus the changes of relative humidity from 20% to 60%. These results indicate promising applications of BaNbO3 nanocubes in a highly sensitive environmental monitoring and humidity controlled electronic device. At last, we discuss the sensing principles of the humidity sensor by ionic conduction model.