Volatile organic compounds sensors based on hollow CoO, Co3O4, VO2, V2O5 and their composites with graphene acid

Abstract

The advance of sensor gas for volatile organic compounds (VOCs) is important for sustainable development of materials science. This project refers to the evaluation of composite based on graphene acid (GA) with oxide metallic (OM) type-n (ex: VO2 and V2O5) and type-p (ex: CoO and Co3O4) and their isolated itself to enhance sensibility and selectivity of gas sensors. The GA (new derivate from graphene) will be synthetized by re-oxidation of graphene oxide. The hollow OMs nano or micro-structured will be prepared from its precursors and modellers like SiO2, oxygen bubbles, surfactants (ex: sodium dodecyl sulfate), zeolite (ZIF-67) and without any agent just in a solvothermal synthesis assisted by microwave. Lastly, the GA-OM junction will be prepared by an ultrasonic spray. We expect that GA tends to collaborate with increasing the surface composite area and selective sorption of gases due to its high surface area and carboxylic groups. In another hand, the main benefits of OM hollow structures are high gas diffusivity in their internal and external layers and increase numbers of porous. The quantity of active sites by sorption of oxygen and gas molecules also tends to be enhanced by hollow structures. The responses of VOCs (ex: acetaldehyde, ethanol, methanol, benzene, xylene, toluene) will be evaluated in different gas concentrations (ppm and ppb) and high relative moisture (ex: 98%). In this way, intends to study new graphene derivate in a composite with OM hollow structures few explored in literature wishing gas sensors more selective, sensitive and faster. This proposal will be supported by FAPESP grant (17 / 01267-1).