Pd Nanoparticles on Functionalized Graphene for Excellent Detection of Nitro aromatic Compounds

An efficient sensing platform based on functionalized reduced graphene oxide (rGO) for the detection of nitro aromatic compounds was developed in this work. Firstly, rGO was functionalized with 1,3,6,8-pyrene tetra sulfonic acid sodium salt (PyTS) through π–π interaction among molecules, which could not only improve the solubility and dispersibility of the rGO in aqueous solution but also provide more binding sites for nanoparticles. Secondly, palladium nanoparticles (Pd NPs) were uniformly decorated on the functionalized rGO nanosheets with the help of sulfonic acid group. The obtained nanocomposite (marked as Pd NPs-PyTS/rGO) was then characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-Ray Diffraction (XRD) and Electrochemical Impedance Spectroscopy (EIS). Finally, the electrochemical sensor was built up by casting Pd NPs-PyTS/rGO on the surface of glassy carbon electrode (GCE) and electrochemical properties of the nitro aromatic compounds have been studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The results showed that Pd NPs-PyTS/rGO modified electrode possessed higher electrocatalytic activity and sensitivity for nitrobenzene (NB). The detection limit was as low as 0.62 ppb. This may be attributed to the combination of the large surface area of rGO and effective electrocatalytic property of Pd NPs. Experimental results showed that Pd NPs-PyTS/rGO modified the electrode was a fast, simple and controllable method for electrochemical sensor.