GS3.1 - Materials Architectures for Chemoresistive Gas-Sensing by Cross-Talk with Heterogeneous Catalysis. Principles, Synthesis and Applications

17th International Meeting on Chemical Sensors - IMCS 2018
2018-07-15 - 2018-07-19
Vienna, Austria
Gas Sensors 3
M. Epifani - Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi, Lecce (Italy)
126 - 127


A relationship may be established between chemoresistive gas sensors and heterogeneous catalysis. In catalysis, the focus is on the desired chemical transformations of a known gas-phase. In gassensors, the gas-phase is expected to be of unknown composition and in very low concentrations (ppm or even ppb). It is necessary to amplify and translate into a readable signal the outcome of the chemical reactions at the sensor-gas interface. For this reason the focus is on the electrical behavior of the oxide sensing layer. It is then not surprising that the same concepts of catalysis can be useful in gas-sensors, provided the considered materials have semiconducting properties. For instance, an oxide nanocrystal surface-covered with a layer of another oxide, an architecture which is the nanosized counterpart of bulk catalytic systems, may provide enhanced gas response if the surface oxide has enhanced reaction with the gaseous analyte and may efficiently transport the generated charges. In this work, the synthesis of the related architectures suggested by the heterogeneous catalysis field will be reviewed, comprising TiO2-V2O5, TiO2-WO3 and TiO2-MoO3 systems. The complex characterization work necessary for unravel their complex composition and structure will be summarized. Finally, examples of gas-sensing properties will be shown, aimed to demonstrate that the starting principle was actually implemented, and that the results pave the way for the design and application of a whole class of materials architectures.