An in-situ synthesis of novel Au@NG-PPy nanocomposite for enhanced electrocatalytic activity toward selective and sensitive sensing of catechol in natural samples

Abstract

This paper describes a highly sensitive and selective electrochemical sensing of catechol (CC) using gold nanoparticles decorated nitrogen doped graphene covalently grafted polypyrrole (Au@NG-PPy) nanocomposite modified electrode. The Au@NG-PPy nanocomposite was synthesized by in-situ oxidative polymerization method and characterized by various techniques such as FT-IR, XRD, Raman, SEM, HR-TEM, EDX and mapping analysis. Under the optimized condition, the Au@NG-PPy nanocomposite modified electrode shows a higher electrocatalytic activity towards oxidation of catechol compared to NG and NG-PPy. The enhanced electrochemical activity of the catalyst is owing to better electron transfer efficiency, good conductivity and high surface area of the nanocomposite. A very good selectivity is able to be achieved by as-synthesized Au@NG-PPy toward the determination of 0.1μM CC in the presence of 100-fold higher concentrations of common interferents including hydroquinone. The catechol sensor exhibits a wide sensing linear range from 0.1–0.9μM and the detection limit is found to be 0.0016μM (S/N=3). The proposed method has been successfully applied for the selective determination of CC in various real samples such as apple juice, green tea and tap water with good recoveries.