SNO2 BI2O3 - A SUITABLE SYSTEM FOR SELECTIVE CARBON-MONOXIDE DETECTION/

An SnO2 based gas sensor composition with Bi2O3 and Sb2O3 is shown to respond selectively to CO gas even in the presence of other gases. X-r ay diffraction and laser-Raman studies of the compound confirm the for mation of bismuth stannate (Bi2Sn2O7) above 800 degrees C, which seems to act as a molecular sieve. The operating temperature for maximum se nsitivity is around 200 degrees C. Temperature programmed desorption s tudies were conducted to determine the nature of oxygen species adsorb ed on the semiconductor surface responsible for the gas sensing.