The research proposal aims to study the graphene acid (GA) effect on hollow cerium dioxide (CeO2) and Pd-CeO2 yolk-shell structures for volatile organic compounds (VOCs) detection under wet atmosphere. Hollow GA/CeO2 and GA/Pd-CeO2 yolk-shell will be obtained by a template-free microwave-assisted hydrothermal method (MAH). Both heterostructures will be evaluated for detecting different VOCs (e.g. benzene, xylene, toluene, acetone, diethylamine aniline) by conductometric measurement in high relative humidity environments (e.g. 60 to 98%), similar to environmental conditions and exhaled breath. It is expected that the prepared materials show improvements on parameters such as sensitivity, selectivity, limit of detection and response time, by the combination of different effects: (i) enhancement of diffusion and surface area by using hollow CeO2 structures, (ii) VOCs activation by the catalytic effect promoted by Pd particles, (iii) minimizing the undesirable effect of humidity by the interaction between GA and water molecules. In addition, a research challenge is the X-ray absorption spectroscopy (XAS) application in similar conditions of the sensor operation to characterize in situ the reactions on the materials' surface, correlating the electronic structure and properties. Thus, the studied materials may have the potential to developing new sensors for non-invasive diseases diagnosis and environmental monitoring.
News published in Agência FAPESP Newsletter about the scholarship: