Hierarchical polystyrene@reduced graphene oxide–Pt core–shell microspheres for non-enzymatic detection of hydrogen peroxide

Abstract

A non-enzymatic electrochemical sensor based on polystyrene@reduced graphene oxide (RGO)–Pt core–shell microspheres was developed for sensitive detection of hydrogen peroxide (H₂O₂). The polystyrene@RGO–Pt microspheres were prepared by microwave-assisted reduction of graphene oxide (GO) and a Pt precursor (H₂PtCl₆) that were adsorbed on polystyrene microspheres. No surfactants or polyelectrolytes were used as stabilizing agents for the preparation of the nanocomposite. Alternatively, polystyrene microspheres served as the core for supporting RGO nanosheets and Pt nanoparticles, which prevented the aggregation of the electrode material and resulted in the high electrochemically active surface area. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), Ultraviolet-vis absorption spectroscopy (UV), and Brunauer–Emmett–Teller (BET) measurements characterized the nanostructure of the polystyrene@RGO–Pt microspheres. Cyclic voltammetry revealed the enhanced electrocatalytic activity of these core–shell microspheres. Such a non-enzymatic electrochemical sensor is capable of detecting H₂O₂ with a wide linear range (0.5 μM–8000 μM), high sensitivity (38.57 μA mM⁻¹ cm⁻²), low detection limit (0.1 μM, S/N = 3), long-term stability, and good selectivity. Furthermore, this sensor was found to be suitable for the determination of H₂O₂ in human serum samples. Considering their simple synthetic procedure and high catalytic activity, the polystyrene@RGO–Pt microspheres hold great promise in the development of high performance electrochemical sensors.