Self-Assembly of Gold Nanoparticles and Multiwalled Carbon Nanotubes on Graphene Oxide Nanosheets for Electrochemical Sensing Applications

In this work, graphene oxide (GO) nanosheets were decorated with gold nanoparticles (AuNPs) and multiwalled carbon nanotubes (MWCNTs) with cetyltrimethyl ammonium bromide (CTAB) as the molecular linker. The anchoring of AuNPs and MWCNTs on GO occurred simultaneously with the formation of the membrane of CTAB/GO complex on glassy carbon electrode (GCE). The obtained binder-free electrode was denoted as AuNP/MWCNT/CTAB/GO/GCE. CTAB played a crucial role in the construction of the modified electrode. First, the film formed by CTAB and GO was highly stable in aqueous solution and adhesive to the GCE surface. Second, CTAB acted as the molecular linker to immobilize AuNPs and MWCNTs on the graphene nanosheets. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) and amperometry were used to investigate the electrochemical behaviors of AuNP/MWCNT/CTAB/GO/GCE. It was found out that the modified electrode presented excellent catalytic capabilities towards the oxidation of hydrazine and the reduction of H2O2. The oxidation current of hydrazine and the reduction current of H2O2 are linear with their concentrations in the range of 1.0-1000 mu M and 10-5000 mu M, respectively. The detection limits for hydrazine and H2O2 are 0.38 mu M and 1.78 mu M, respectively.