Amperometric hydrazine sensor based on the use of Pt-Pd nanoparticles placed on reduced graphene oxide nanosheets

An amperometric method for hydrazine detection is described that is based on the use of electrochemically reduced graphene oxide (ERGO) that was modified with Pt-Pd nanoparticles. A glassy carbon electrode (GCE) was first modified with GO nanosheets and then electrochemically reduced, by applying a negative potential of −1.1 V, to form a film of ERGO. The ERGO-modified GCE was further modified by immersing it into a solution containing Pt(II) and Pd(II) ions solution and reduction via cyclic voltammetry to form the respective nanoparticles. The morphology and structure of the nanohybrid were characterized using field emission scanning electron microscopy (FESEM), atomic force microscopy and X-ray energy dispersive spectroscopy. FESEM images revealed the Pt-Pd nanoparticles on ERGO to have dimensions of <100 nm. Cyclic voltammetry of this GCE showed the oxidation current for hydrazine in 0.1 M NaOH solution to be higher than that for a Pt-Pd/GCE or an ERGO/GCE. In parallel, the overpotential for hydrazine oxidation is reduced. The amperometric nanosensor, best operated at a working potential of −0.71 V (vs. Ag|AgCl|KCl), has a linear response in the 0.007–5.5 mM hydrazine concentration range and a 1.7 μM detection limit. It has good selectivity over other species.