Synthesis of SnO2 < Pt > films for room-temperature CO detection

An optimized spray pyrolysis technique was used to prepare thin SnO2 films doped with ultrafine Pt particles for room-temperature CO detection via res istance measurements. This method makes it possible to achieve uniform disp ersion of the Pt particles, catalyzing CO oxidation. The effects of deposit ion temperature (400-560 degrees C) and Pt content (0.1-5 at. %) on the sen sitivity of the films were examined. Dynamic and quasisteady-state electric al measurements were made in air containing 3 x 10(-2)% CO. SnO2 films dope d with 2 at. % Pt exhibited a sharp peak of sensitivity at temperatures bet ween 25 and 100 degrees C. Selectivity of the films was studied by comparin g responses to water vapor, 8 x 10(-3)% ethanol, and 0.1% methane.