Microstructural study of nanocrystalline pure and doped tin dioxide to be used for resistive gas sensors

M.F. BIANCHETTI, N.E. WALSÖE DE RECA; C. ARRIETA

Buenos Aires

Congreso; 15th International Meeting on Chemical Sensors; 2014

Asociación Argentina de Cristalografía

Nanocrystalline pure and doped SnO2 has been intensively studied for a long time to build resistive gas sensors being, however, still useful to synthesize the nanopowders to build them with the smallest crystallite size to increase the sensitivity and to decrease the operation temperature. A modified gel-combustion method and a novel reactive oxidation process are proposed for nanopowders synthesis and results are compared. Materials are characterized by XRD, Scherrer equation to evaluate the crystallite size, BET absorption to determine specific area and HRTEM to observe the crystallites (evaluating their mean size and distribution), defects and effect of calcination treatments. The authors ́ previous studies showed that if nano-SnO2 replaced the conventional microcrystalline-SnO2 to build resistive gas sensors, sensitivity increased (>30%) and the operation temperature considerably decreased. A heating and measuring system was designed and fabricated for sensors to save energy to reach the operation temperature and simultaneously to measure the sensor surface resistivity variation