A sensitive and selective amperometric hydrazine sensor based on mesoporous Au/ZnO nanocomposites

Abstract

Herein, a facile synthesis of mesoporous Au/ZnO nanocomposite using photochemical reduction approach is demonstrated. The findings indicated that Au nanoparticles with size ranging from 4 to 10nm were homogenously distributed on the surface of mesoporous ZnO. The synthesized mesoporous Au/ZnO nanocomposite as efficient electrochemical sensor towards hydrazine detection was assessed using different electrochemical techniques including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and amperometric i-t response. The results showed that the mesoporous Au/ZnO modified GCE (glassy carbon electrode) yields an enhanced hydrazine oxidation peak at a relatively lower potential of ~0.45V vs. Ag/AgCl (Ipa=2.6μA, 150% higher than pure mesoporous ZnO). The amperometric detection of hydrazine at the mesoporous Au/ZnO sensor exhibits a rapid increase in the oxidation current upon the successive additions of hydrazine. The relation between the current vs. hydrazine concentration is linear (R2=0.9973) over the concentration range of 0.2–14.2μM, with a diffusion-controlled kinetic process. The sensitivity and limit of detection (LOD) of the sensor was estimated to be 0.873μAμM−1cm−2 and 0.242μM, respectively. The key result in our synthesized mesoporous Au/ZnO nanocomposite showed significant selectivity for hydrazine detection in the presence of different interferences. Moreover, the mesoporous Au/ZnO sensor demonstrated long-term stability that exhibited high selectivity, sensitivity, repeatability, reproducibility, and fast kinetic detection within 10s.