Abstract:M-phase vanadium dioxide(VO2(M)) is a kind of intelligent heat-insulating window material with special phase change characteristics at around 68℃.However, the phase change stability of VO2(M) is still poor and its ability to modulate sunlight it is not high enough, which severely limits its industrial application in smart thermal insulation windows.This article mainly uses vanadium pentoxide as the vanadium source,oxalic acid as the reducing agent,urea as the precipitant,titanium sulfate as the dopant, and the hydrothermal reduction method to prepare powder M-phase titanium(Ti) doped VO2,referred to as Ti-VO2(M) powder.Through X-ray diffractometer(XRD),field emission scanning electron microscope(SEM),ultraviolet-visible-near infrared spectrophotometer(UV-Vis-NIR),differential scanning calorimeter(DSC) and X-ray energy spectrometer(EDS) analyze the element/phase composition and structure,crystal form,sunlight reflectance/transmittance and phase transition temperature of the synthesized powder,and optimize the Ti4+ doping amount.The study found that when the Ti4+ doping amount is controlled at 3%,the overall performance of the prepared Ti-VO2(M) powder is the best,which provides important data and technical support for the further application of intelligent thermal insulation plexiglass.