Polymer-coated Cd-doped ZnO nanostructures for dual sensing of volatile organic compounds and battery vapours

Abstract

Cost-effective sensor fabrication methods are characterized by their simplicity, requiring minimal processing steps to produce nanomaterial-based devices capable of detecting volatile organic compounds (VOCs) and battery-emitted vapours for various applications in environmental and healthcare fields. In this work, we present a sensor based on Cd-doped zinc oxide (ZnO:Cd) nanocolumns synthesized via a solution chemical synthesis (SCS) method and coated with a poly ethylene glycol dimethacrylate (PEGDMA) layer. The resulting composite device exhibits a novel dual-temperature functionality, enabling the detection of 2-propanol (response up to ~58%) at higher operating temperatures (350 °C), while nearly doubling the selectivity over n-butanol compared to the uncoated sensor. It also detects the critical battery vapour 1,3-dioxolane (C3H6O2, response up to ~18%) at lower temperatures (150 °C). Crucially, the PEGDMA coating dramatically improved sensor kinetics, reducing the recovery time for 2-propanol at 250 °C from over 42 s to approximately 8 s. The presence of Zn, O and Cd atoms was confirmed through energy-dispersive X-ray spectroscopy (EDX), while the conformal polymer coverage was verified via morphological characterization in scanning electron microscope (SEM). The obtained experimental results are important for EV industrial, biomedical and space nanosatellites applications, demonstrating a clear pathway for developing versatile, multi-purpose sensors with tailored operational modes.