Fabrication of Gold Nanoparticles on Multiwalled Carbon Nanotubes Nanohybrids

A nanostructured hybrid consisting of a high-density and uniform assembly of gold nanoparticles (AuNPs) on multiwalled carbon nanotubes (MWCNTs) is always desired and demanded in various applications. However, a simple, cost effective and highly efficiency method is required in the fabrication of MWCNTs-AuNPs nanohybrids. This study introduces a method where MWCNTs were functionalizing with nitric acid (HNO3) and sulphuric acid (H2SO4) in ratio of 1:3 v/v by using ultrasonication. These functionalized MWCNTs served as substrates for gold nanoparticle deposition. Later, it was pre-mixed with tri-sodium citrate (Na3C6H5O7.2H2O), next it was reacted with nobel metal (AuNPs) via the addition of chloroauric acid (HAuCl4) at various pH. When HAuCl4 was added to the reaction system, Au3+ was directly reduced at the surface of the MWCNTs and gold nanoparticles were assembled along the MWCNTs. Fourier Transform Infrared (FTIR), Thermogravimetric Analysis (TGA), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray (EDX) analysis and dispersion test were used to characterize the MWCNTs/AuNPs nanocomposites. The fully functionalized MWCNTs using acid oxidation at 4 hour using ultrasonication were used in synthesis of nanohybrids, and the optimum gold yield on MWCNTs obtained at pH 4. Compared to other methods, these procedures require low temperature without involving the need of any catalyst or surfactant which results in a simple and efficient method for fabrication of gold nanoparticles on carbon nanotubes.