Relationships between sensitivity, catalytic activity, and surface areas of SnO gas sensors

SnO2 having different surface areas were synthesized using a surfactant-tem plating synthetic method. The effects of surface areas of the obtained SnO2 on their gas sensing and catalytic properties were investigated. interesti ngly, a linear relationship was found between the surface areas of SnO2 and their gas sensitivities to H-2 and CO. Furthermore, a linear relationship was observed between the surface areas and the catalytic activities of SnO2 in the oxidation of H-2 and CO. Based on the fact that the mechanisms for catalytic reactions and gas-sensing processes both involve surface adsorpti on and reaction between surface-adsorbed oxygen species and surrounding gas es (H-2 or CO), the relationship between these two mechanisms occurring on SnO2 surfaces is discussed. (C) 1999 Elsevier Science S.A. All rights reser ved.