Fine-tuning of Pd–CeO2/rGO nanocomposite: A facile synergetic strategy for effective electrochemical detection of dopamine in pharmaceutical and biological samples

Abstract

A facile, sensitive, and rapid electrochemical sensor based on reduced graphene oxide (rGO) supported palladium–cerium oxide nanocomposite on the surface of a glassy carbon electrode (Pd–CeO2/rGO/GCE) was prepared by a two-step process. The Pd–CeO2/rGO nanocomposite was synthesized by the polyol method, and the as-synthesized nanocomposite was then drop-cast onto the surface of the electrode; Pd–CeO2/rGO/GCE. The microstructural and morphological properties of the as-prepared electrocatalysts were investigated using powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), and electron microscopy techniques. These results show that rGO sheets are embellished with a face-centred cubic phase of Pd and a cubic fluorite structure of CeO2, resulting in an electrode material with a well-connected conducting network. The synergy of Pd–CeO2 composite with the support of rGO results in a significant increase in the electrocatalytic activity and active surface area of the electrode, which enables the excellent detection of dopamine (DA) with remaining paracetamol (PC), and tyrosine (TY). The optimized electrode demonstrated a good linear range of 5–240 µM, a low limit of detection (LOD) of 0.69 µM, and a sensitivity of 0.894 µM−1 cm−2. Additionally, the selectivity of the sensor was also successfully accomplished in the presence of several interfering substances. Some inherent properties of the produced sensor, such as reproducibility and stability, were also investigated. The developed sensor was also effectively used for DA sensing in human serum samples and pharmaceutical drug injection samples with satisfactory recoveries.