Microrecycled zinc oxide nanoparticles (ZnO NP) recovered from spent Zn-C batteries for VOC detection using ZnO sensor.

Non-intrusive techniques for diagnosis and biomonitoring - for example, breath testing to detect biomarkers - have the potential to support the advancement of versatile and remote point-of-care (PoC) diagnostics. This paper investigates tuning the sensitivity and selectivity performance of chemo-resistive sensors to detect volatile organic compound (VOC) biomarkers using a hybridized material of pristine graphene (pG) and zinc oxide nanoparticles (ZnO NP) recovered from spent Zn-C batteries. This hybridized graphene nanocomposite material of ZnO nanoparticles showed enhanced sensing performance because of high conductive property of graphene along with the synergetic interplay between graphene composite materials and ZnO NPs. The elevated surface area as well as adsorption capability of ZnO NPs provided improved sensitivity and selectivity for particular VOCs. It was proposed that this hybridized material could be used to fabricate chemo-resistive sensors with sensing performances tailored for VOC biomarker detection. To test this hypothesis, the ability of graphene hybrid nanocomposites with ZnO NPs to improve the sensing characteristics and efficiency of distinguishing diverse VOC biomarkers such as ethanol, acetone, methanol, chloroform, acetonitrile and terahydrofuran (THF) was investigated. Results demonstrated that the microrecycled ZnO based hybrid sensor has good selectivity along with the sensitivity towards ethanol and chloroform VOCs at room temperature (20 °C).