An Electrochemical Sensor for Dopamine Detection Based on Ternary Pd-Au-P Composites Supported on PDDA/RGO

A gas-liquid interface approach was developed for the synthesis of ternary Pd-Au-P composites, which were supported on poly(diallyldimethylammonium chloride)-functionalized reduced graphene oxide (PDDA/RGO). The as-synthesized composites were characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Pd-Au-P-PDDA/RGO composites as an electrochemical dopamine (DA) sensor showed superior electrocatalytic activity and stability toward DA oxidation as compared with Pd- Au-PDDA/RGO and Pd-Au-P/RGO. The enhanced electrochemical performance could be attributed to the effect of electronic structure and long-range disorder and short-range structure due to the doping of P element. By studying the kinetics of DA oxidation, electrochemical DA oxidation was proven to be irreversible and follow Laviron Equation. Using differential pulse voltammetry (DPV), the Pd-Au- P/PDDA/RGO sensor had low detection limit of 0.7 ^M, wide linear range of 3.5-125 ^M and relatively high sensitivity (0.2858 μA/μM), which was suitable for the detection of biological and environmental samples.