Study on the interfacial structures of Tin oxide/multiwalled carbon nanotube heterojunctions

Abstract

Tin oxide/multiwalled carbon nanotube (SnO₂/MWCNT) heterojunctions were synthesized using the SnCl₂ solution method. The interfacial structures, especially the interactions between the SnO₂ and MWCNTs, were investigated by field emission scanning electron microscopy, transmission electron microscopy, ultrasonic destruction experiments, Raman spectroscopy, and thermal analysis. At the initial reaction stage, chemical bonds were the predominant interactions between the MWCNTs and SnO₂. Physical interactions, including Coulomb interactions and van der Waals forces, play key roles under an increasing reaction time. Raman spectroscopy and thermal analysis proved to be two valid methods for the characterization of the interactions between SnO₂ and MWCNTs. The strong interactions result in a low G/D strength ratio, as well as a low thermal stability of the MWCNTs in the SnO₂/MWCNT heterojunctions. The binding energy of the MWCNTs and SnO₂ was calculated based on differential thermal analysis and Hess's law and the results agreed with the interfacial morphological characteristics. This work presents a facile and low-cost approach to study the interfacial structures of carbon-based nanomaterials and opens a new possibility for investigating structural property relationships.