Dopamine detection using leaf-shaped ZnO synthesized from zinc shells of recycled batteries

Abstract

This study presents a cost-effective and sustainable method for synthesizing ZnO from electronic waste (e-waste) for the electrochemical detection of dopamine (DA) using a single metal oxide. The purity and various properties of the ZnO were confirmed using advanced techniques. The growth of ZnO clusters along the [0001] direction results in the formation of leaf-shaped ZnO with a direct band gap of 3.27 eV. Cyclic voltammetry, differential pulse voltammetry, and amperometric studies demonstrated successful DA detection at the ZnO-glassy carbon electrode in aqueous media, with an equal number of electron and proton pathways for DA oxidation. The sensor exhibited a linear response over a wide concentration range (0.01 to 100 μM), with a low limit of detection of 0.47 nM and a high sensitivity of 0.0389 A M−1. Additionally, the sensor showed high selectivity, repeatability and reproducibility with relative standard deviation of 4.80% in DA detection and proved effective in real sample analysis. These results suggest that the developed sensor holds great potential as a sensitive, practical, and cost-efficient tool for DA monitoring. Furthermore, the approach contributes to sustainable management of zinc-carbon battery waste by producing valuable ZnO.