Controlled synthesis of Au@Pd core-shell nanocomposites and their application for electrochemical sensing of hydroquinone.

In this study, a facile and effective method for the synthesis of Au@Pd nanocomposites via a chemical reduction method was proposed. Moreover, a novel electrochemical sensor based on the Au@Pd core-shell nanocomposites were constructed and used for detection of hydroquinone (HQ). The morphologies and structures of Au nanorods (NRs) and Au@Pd nanomaterials were characterized by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and electrochemical methods. By tuning the amount of Pd precursor, different Au@Pd core-shell nanocomposites were gained. It could be clearly shown that the Au3@Pd6 (nAu:nPd = 3:6) modified the glassy carbon electrode (Au3@Pd6/GCE) possessed a sensitive electrochemical response toward HQ and the oxidation peak appeared at nearly 0 V at the potential window range of -0.3 to 0.3 V. Meanwhile, the experimental results found a broad concentration range of 4-5000 µM, a low detection limit of 0.63 µM and desirable sensitivity of 1.127 mA mM-1 cm-2. The mentioned sensor was successfully applied for HQ determination in the lake water and tap water samples. It is expected that the proposed method can be used for the synthesis of other metal nanostructures with distinguished electrocatalytic abilities and used for environmental monitoring of hydroquinone.