Microwave synthesis and characterisation of tin dioxide (SnO2) coated multi-walled carbon nanotubes

Abstract

Metal nanoparticles coated onto carbon nanotubes (CNTs) provide a way to obtain novel materials with useful properties for gas sensing and catalyst application. Metal oxides are well-known materials suitable for detecting a wide spectrum of gases with enough sensitivity. Among the materials functionalised by CNTs, intensive attention is on Tin Dioxide (SnO2) because of its unique properties such as high optical transparency, electrical conductivity and chemical sensitivity, which made it become an attractive material for application in solar cells, field effect transistors, catalysis and gas-sensing1-3. Nanostructured composite materials of carbon nanotubes and metal oxides promise superior performance over conventional approaches due to the ability to direct the selective uptake of gaseous species based on their controlled pore size and chemical properties, increased adsorptive capacity due to their increased surface area, and the effectiveness of carbon nanotubes as matrix materials for gas and vapour detection. In addition, CNTs can be functionalised, doped with catalysts and mixed with polymers accordingly to achieve the selectivity. In this research, microwave irradiation was used in the fabrication of nanocomposites as a novel technique to disperse SnO2 nanoparticles uniformly on multi-walled carbon nanotubes (MWCNTs) surface to composite properties. The advantage of using microwave irradiation is the rapid volumetric heating, higher reaction rate, reducing reaction time, uniform surface decoration and smaller particle size. This method of preparation was compared with the conventional technique ‘wet impregnation’. Characterisation of the composites was done using techniques such Raman, transmission electron microscopy (TEM) and scanning electron microscopy (SEM).