Fabrication of Few Layer Graphene/ZrO2 composite powders

Abstract

Graphene, a monolayer form of carbon with two dimensional honeycomb lattices (sp2 hybridization) has shown excellent mechanical, electrical, thermal and optical properties. It is a promising component for many applications in the fields of electronics, composites, sensors as well as energy storage and conversion. As a derivative of graphene, graphene oxide has also become an attractive material and been investigated widely in many areas since the ease of synthesizing graphene oxide and its solution processability. Among many other factors, pH of the medium, size of the graphene oxide sheets, etc. are some of the important parameters which makes the graphene dispersible in the medium, detailed study of which is absent in literature. The present work focuses on studying the effect of the pH on the stabilization and dispersability of GO in a polar solvent i.e. water. In this paper, we prepared graphene oxide by the modified Hummers method. The hydrophilicity of graphene oxide with different pH values was characterized with adsorbance in UV-Visible range. Chemically converted graphene was prepared by partial reduction of GO. Few Layer Graphene/zirconia nanocomposites were fabricated by wet chemical method. Such a composite is desired where a percolating network of graphene in the ZrO2 matrix can increase the electrical conductivity of the composite, while retaining the functional property of the ceramic phase (ZrO2 in this case). An interesting result was observed. The crystallization of zirconia was delayed, to about 900 oC, which is 200-300 oC higher than the same prepared from comparable chemical methods in absence of graphene or graphene oxide. Various characterization techniques including SEM, FTIR-spectroscopy, XRD, UV-Vis spectroscopy were used to study the quality of graphene oxide, CCG and FLG – zirconia composites.