GCE Modified by Graphene-doped ZnO/PVA Nanocomposites for Highly Sensitive Pb Detection

Abstract Heavy metals, including lead (Pb), have contaminated a number of rivers that provide drinking water to the residents of West Java. Even at low amounts, lead is a dangerous heavy metal. It is crucial to detect Pb in liquid samples for this reason. Using three electrodes—the Working Electrode (WE), the Counter Electrode (CE), and the Reference Electrode (RE)—an electrochemical approach was used to detect the presence of Pb. A modification was performed to the WE in order to improve the sensitivity, selectivity, and response time of the Pb detection. This work modified WE using ZnO/PVA nanocomposites doped with graphene. ZnO is a frequently used nanomaterial that has been shown to improve heavy metal detection sensitivity. ZnO has a band-gap energy of 3.37 eV and a high electron mobility of about 3 cm 2 /V.s. ZnO also has high surface area, which makes it possible for positively charged heavy metal ions to attach to active sites. ZnO nanoparticles are treated with PVA to create nanocomposites with flexible surfaces. To increase electrical conductivity in ZnO/PVA nanocomposites, graphene can be used as a doping agent. In this work, a thin film of graphene was synthesized from 0.1 grams of ZnO, 1.5 grams of PVA, and 0.324 grams of graphene. The surface and contents of the thin film are then examined using an Scanning Electron Microscope (SEM) and a Energy Dispersive Spectrophotometer (EDS), respectively. The thin film’s electrochemical characteristics were then investigated through the application of Cyclic Voltammetry (CV) and Square Wave Voltammetry (SWV). The CV and SWV technique results clearly indicate that ZnO/PVA doped graphene will be involved in the redox reaction with Pb via 0.1 M NaOH. The peak anodic current at CV and oxidation peak at SWV increases with the concentration of Pb, according to the results of two methods for detecting Pb at concentrations of 0, 0.5, 2, 3, 4, and 5 ppm. These results showed that thin film modified with ZnO/PVA nanocomposites doped with graphene have better Pb detection sensitivity capabilities than those without.