Nanocrystalline Tin Oxide to be Applied in a Gas Sensor

The aim of this paper was to describe the methods of nanocrystalline SnO^sub 2^ preparation and to show the improvement of the behaviour of a hydrogen sensor built with the grown SnO^sub 2^ nanoparticles since particular properties of the nanomaterial are related to the sensor response. Nanocrystalline SnO^sub 2^ was synthesized by gel-combustion and by reactive oxidation methods. Characterization was performed by X-Ray Diffraction (XRD), Brunauer-Emmer-Teller isotherms (BET) absorption and by High Resolution Transmission Electron Microscopy (HRTEM). A careful characterization enabled to control the crystallites size and properties to improve the behaviour of a hydrogen sensor. It was proved that if nanocrystalline SnO^sub 2^ was used to build the resistive sensor, replacing the conventional microcrystalline SnO^sub 2^, the sensor sensitivity increased between 30 and 35 % (according to the grown crystallites size of nanocrystalline SnO^sub 2^) and the working temperature (T^sub w^) decreased from 350-450 °C to 180-220 °C. The T^sub w^ decrease obliged to improve the heating and measuring system of sensor which is also described. [PUBLICATION ABSTRACT]