Direct Synthesis of Nanowires with Anatase and TiO₂-B Structures at near Ambient Conditions

Abstract

In this study, we present a new approach toward titanium oxide nanowires. In this approach, the growth formation of the wires sets in at a temperature as low as 40 degrees C under ambient pressure. Moreover, we provide evidence that nanowires with distinctive TiO2-anatase and TiO2-B structures can be directly produced without further thermal treatment using controlled reaction conditions.

Preparation of fine, uniform nitrogen- and sulfur-modified TiO2nanoparticles from titania nanotubes

“…High-resolution TEM of individual nanocrystals revealed well-resolved crystalline planes with a spacing of 0.34 nm, which is similar to that of the (101) planes in anatase [17]. The particle size distribution was rather homogeneous with an average diameter of 10 nm (inset, figure 1(c)).…”

Thermal Stability of (KxNayH1–x–y)2Ti6O13 Nanofibers

“…[4,7,21] Some authors prefer to designate the product as being of somewhat variable stoichiometry, e.g. Na x TiO 2+δ , [20] or H 2 Ti x O 2x+1 ·nH 2 O, [19] whereas others find that the product resulting from the NaOH process is all or partially TiO 2 in the anatase, rutile, brookite or TiO 2 -B forms, [2,15,17] i.e. not a titanate at all.…”

“…The segments were not hollow ( Figure 3, a and b) and a characteristic layered structure was clearly visible (Figure 3, c). [17] This is unlike the case for the fibers produced using NaOH, which are often (but not invariably) reported as hollow. [4,7,20,23] The interlayer spacing observed in the TEM images was approximately 0.75 Ϯ 0.03 nm.…”

“…We suggest that the protracted washing and sonication in water may have resulted in the extraction of K + from K 2 Ti 6 O 13 and its conversion to short pieces of pseudomorphous layered TiO 2 -B, a process already known to occur in other types of titanate fibers. [2,17,32] The fit of the putative K 2 Ti 6 O 13 structure to the X-ray diffraction pattern of the K-rich material was explored further by simulating the patterns with a degree of disorder ( Figure 3, d). A pattern calculated from a CIF file for K 2 Ti 6 O 13 , but with all peaks broadened by imposing a Gaussian shape with a width of 1.5°, is shown as ii.…”

“…[15,16] However the formation, structure, morphology, and properties of these and other fibrous titanates are not yet completely understood. [1,[17][18][19] Most investigations have been conducted on fibers grown in NaOH solution [2][3][4]7,8,16,[19][20][21][22][23] but even in this relatively well-studied system there is still disagreement about the composition and structure of the fibers, and the mechanisms of their formation and/or destruction. Here, however, we report an investigation on the nanofibers produced by hydrothermal digestion of TiO 2 in concentrated KOH solution.…”