New Nanomaterials for the Development of High-performance Chemical Sensors for Environmental Applications

The PhD project focused on the development of chemical sensors with particular attention to conductometric gas sensors and then with electrochemical sensors. The design of a chemical sensor follows several phases, the first of which focuses on the study of the analyte or gas that is intended to be detected and the most suitable sensitive material to be used. The second phase concerns the synthesis of the sensitive material, we try to synthesize nanomaterials using simple methods. Once the nanomaterial has been synthesized, in the next phase it is characterized with appropriate analytical techniques to verify its morphology and chemical physical properties. Subsequently, methods of deposition of the nanomaterial on the sensor platform for fabricating the sensor devices are developed and finally sensing tests are carried out to validate their performances in the laboratory and in field. In this project, sensitive nanomaterials were synthesized and deposited on suitable platforms. Sol-gel, spray-pyrolysis, Atomic Layer Deposition (ALD) and co-precipitation have been adopted to design new sensitive nanomaterials to be deposited on resistive platforms for the development of conductometric gas sensors and on screen-printed carbon electrode (SPCE) platform for fabricating electrochemical sensors. Semiconductor metal oxides such as zinc oxide (ZnO), cobalt oxide/iron oxide heterojunctions (Co3O4/Fe2O3), cobalt oxide/ copper oxide (Co3O4 / CuO), carbon dots from biomass, films with specific thicknesses (WS2 and NiO), nickel ferrite spinels (NiFe2O4) and metal-organic compounds (MOFs) have been developed for the design of chemical sensors discussed in this thesis. The developed conductometric sensors allow the detection of gases such as formaldehyde, NO, NO2, NH3, ethanol, acetone. The electrochemical sensor was designed for the monitoring of glucose.