Tailoring the Structural and Microstructural Properties of Nanosized Tantalum Oxide for High Temperature Electrochemical Gas Sensors

摘要

Ta_2O_5 nanopowders to be used as sensing electrodes in high temperature electrochemical gas sensors for hydrocarbons detection were synthesized using a sol-gel method and their structural and microstructural properties were investigated. The as-synthesized powders were heated at different temperatures in the range 250-1000℃ and characterized by TG-DTA, XRD, SEM, TEM and FT-IR. This investigation allowed to identify the correct thermal treatments to achieve the microstructural, textural and functional stability of materials working at high temperature, preserving their nano-metric grain size. Planar sensors fabricated by using Ta_2O_5 powders treated at 750℃ showed promising results for the selective detection of propylene at high temperature (700℃). The good stability of the sensing response after gas exposure at high temperature was correlated to the stable microstructure the electrodes. Thus, Ta_2O_5 powders seems good candidate as sensing electrode for sensors for automotive exhausts monitoring.