Zinc oxide/graphene nanocomposites as novel electrode for electrochemical sensor

Abstract

Zinc Oxide (ZnO) nanorods were prepared using zinc acetate as a precursor via modified thermal pyrolysis method and used to synthesize ZnO/graphene (ZnO/G) nanocomposites. The as prepared nanocomposites were successfully synthesized by a facile room-temperature approach using the colloidal coagulation effect. Afterwards, ZnO/G nanocomposites were used for electrode surface modification in an electrochemical sensor for the simultaneous determination of cadmium (Cd2+) and lead (Pb2+). The results obtained from transmission electron microscopy and scanning electron microscopy showed that ZnO nanarods with an average diameter of 93 ± 21 nm were uniformly dispersed on G nanosheets. Moreover, the factors affecting the electrochemical sensitivity of this system for the simultaneous determination of Cd2+ and Pb2+ were optimized using square-wave anodic stripping voltammetry. Under the optimized conditions, this system provided the detection limits (S/N=3) of 0.6 and 0.8 µg·L-1 for Cd2+ and Pb2+, respectively and a linear range was found to be 10-200 µg·L-1. Furthermore, this system provided the satisfied results for determination of Cd2+ and Pb2+ in wastewater samples compared with a standard inductively coupled plasma-optical emission spectroscopy.