Tellurium nanowire-induced room temperature conversion of graphite oxide to leaf-like graphenic structures

Abstract

A simple nanomaterial-based reduction strategy that can form leaf-like graphenic structures from graphite oxide (GO) at room temperature is described. Mixing of Te nanowires (Te NWs) with GO at room temperature was found to reduce GO while Te NWs are oxidized to TeO₃^2-. The reaction was followed time-dependently with use of UV/vis spectroscopy, fluorescence spectroscopy, and transmission electron microscopy (TEM). Raman spectroscopy was used to characterize the graphenic material. The G band, which was blue-shifted (with respect to graphite) in the case of GO, came back to the original position confirming the reduction. From IR spectroscopy, it was confirmed that the carboxylic acid groups in the GO are not getting reduced and the product gets stabilized electrostatically because of the repulsion between the negatively charged carboxylic acid groups. Reduction was confirmed by X-ray photoelectron spectroscopy (XPS) also. The reaction showed strong pH dependence and was found to be happening only in basic pH. In acidic medium, GO aggregates, making reduction difficult, while at higher temperature, the reaction was faster and at lower temperature it was retarded considerably.