Preparation And Characterizations Of Ti-O Compounds And Their Composite Functional Materials

Well-crystallized Ti-O compound nanobelts such as sodium titanate, hydrogen titanatic acid, and titanium dioxide have been prepared by the alkaline hydrothermal method. The corresponding samples were examined by XRD, SEM, TEM, TG-DSC, IR, and UV-Vis techniques. Reaction conditions containing the starting materials, reaction temperature and reaction time were investigated and optimized to explore their effects on morphology of the product. In addition, Ti-O/polyaniline (Ti-O/PANI) composite nanowires have been synthesized via in-situ polymerization method. Reaction conditions concerning uniform core-shell structure of the composite nanowires have been explored, and characterizations of the resulting product have been performed. It shows that:(1) The widths of the Ti-O compound nanobelts prepared by the solvothermal method are 40-200 nm, and their length are in the range from several tens to one hundred-extra um.(2) Single crystallized Ti-O compound nanobelts with high yield were obtained in our experiments.(3) A 'dissolution-crystallization' mechanism is proposed for the formation of Ti-O compound nanobelts, comprising the formation of precursors originating from the dissolution of TiO₂ in aqueous NaOH solution and oriented growth of the precursors, resulting in the formation of sodium titanate nanobelts.(4) Ion exchange between Na⁺ and H⁺ occurs in acid solution, resulting in the formation of hydrogen titanic acid nanobelts. TiO₂ nanobelts are obtained by annealing of the hydrogen titanic acid nanobelts at 500℃for 1 h.(5) PANI are strongly contacted with the Ti-O compound nanobelts to form a compact shell. The width of the PANI shell is depended on the weight ratio of aniline/titanic oxide.(6) Absorbance peaks of the Ti-O/PANI composite wires related to the PANI blue-shift, while peaks stemming from the titanic oxide red-shift.(7) Blue band related to the PANI blue shifts and red band splits up into several peaks in the acid-doped composite wires. Furthermore, a green band is newly formed due to the strong interaction between PANI and titanic oxide in the hybrid system.