Tubular Nanostructures of Cr₂Te₄O₁₁and Mn₂TeO₆through Room-Temperature Chemical Transformations of Tellurium Nanowires

Abstract

Tubular ternary nanostructures of tellurium were made through chemical transformations of tellurium nanowires (Te NWs). These transformations occur through reactions with CrO3 and KMnO4, two of the strongest oxidizing agents. In the case of CrO3, the 1D structure of the NWs remained intact and the morphology changed to hollow wires of Cr2Te4O11, but reaction with KMnO4 resulted in the loss of 1D structure, forming a carbon onion-like object composed of Mn2TeO6. As the reaction proceeded, the crystallinity of the NWs decreased, and the final products were amorphous. The reaction products were characterized using different spectroscopic and microscopic techniques. Time-dependent transmission electron microscopic (TEM) analysis of both of the reaction products showed that first a shell is formed around the NWs. Further reaction results in the formation of hollow structures. During the reaction with CrO3, TEM in the intermediate stages showed that the periphery of the material was amorphous, whereas the inside, where unreacted parts of Te NWs remained, was crystalline with a clear lattice structure. X-ray photoelectron spectroscopy (XPS) as well as Raman spectroscopy showed a redox reaction in both cases. Studies suggest that both redox reactions and nanoscale Kirkendall effect might be involved in the formation mechanism.

Curving of tellurium nanowires with gold in the presence of bovine serum albumin

“…Te NWs are semiconducting, known to show luminescence depending upon the aspect ratio of the NWs [24]. The as grown Te NWs show an emission maxima at 394 nm when excited at 352 nm.…”

“…The reactivity of tellurium nanowires (Te NWs) with thiol-containing molecules has also been studied [23] and it was reported that there was a redox reaction between TeO 2 , present on the NW surface, and thiols added into the solution that resulted in the reduction of TeO 2 to Te (0) with simultaneous oxidation of thiols to disulfides. These studies and studies such as the formation mechanism of Tubular Nanostructures of Cr 2 Te 4 O 11 and Mn 2 TeO 6 through room temperature chemical transformations of Te NWs indicated the combined effect of both redox reactions and nanoscale Kirkendall effect (NKE) in its formation [24]. As An example for the biocompatibility of NWs, Tellurium Platinate Nanowires has recently been used for Photothermal therapy of Cancer cells [25].…”

“…Development of shape controlled nanowires is crucial for nanoelectronics. While these studies deal with inorganic and other toxic non-biological chemicals [23,24] it is very much necessary to explore use of biological materials that are environmentally friendly to create nanowires of desires shapes. Also the study of reactivity of Te NWs with metals in the presence of biological molecules will be very useful in nanomedicine.…”