Hydrothermal Synthesis Of Vanadium Dioxide Nanostructure And Their Morphologies Control

VO2is a typical of thermochromic materials, because of its special kind, VO2has great application potentials in a lot of fields. Since it was found that VO2, and VO2thin film have been widely studied. VO2power is becoming investigative hot point in people in recent years. The power not only can inhibit the switch directly, but also can further make the films, can also pass the organism lies the quality adjusts the syrup, then make films, although primitive, very practical, will extend the VO2application doubtless.The VO2products were fabricated via hydrothermal synthesis by reduction of V2O5with oxalic acid (H2C2O4·2H2O) as a reducing agent. The samples were prepared by varying the system temperature, the reaction time and the filling ratio for VO2polymorphs. The microstructures of samples were characterized using X-ray diffraction (XRD), scanning and transmission electron microscopy, respectively. Especially for VO2(A) has carried on the comprehensive analysis, the optical properties of VO2powder has been preliminary research, the doping of VO2phase change be analyzed.Our experiment shows that the structure and morphology can be controlled in this system by varying temperatures and hydrothermal reaction periods of time and filling ration. Experiments revealed the VO2(B) phase were firstly formed and then it transformed into VO2(A) phase as increasing hydrothermal process temperature or extending reaction space of time. A assembling and following structural adjustment model was proposed for explanation the formation mechanism of VO2(A) from VO2(B). For pure VO2(A) samples, the phase transition temperature for VO2(A) raised about7℃might be ascribed to the lower crystallinity or nonstoichiometry in VO2(A) nanorads. Our results indicated that the desired morphs and basic properties in VO2can be precisely controlled via a facile hydrothermal process. The experimental samples were processed for annealing and the temperature have a certain influence on the VO2(M/R) particle size. On the basis of above experiment, VO2(M/R) phase transition temperature was reduced from67℃to42℃by doping tungsten, which provide reference for the application of VO2.