Gas-sensing properties of SnO2-TiO2-based sensor for volatile organic compound gas and its sensing mechanism

We report the microstructure and gas-sensing properties of the SnO2-TiO2 composite oxide dope with Ag ion prepared by the sol-gel method. Of all various volatile organic compounds (VOCs) such as ethanol, methanol, acetone and formaldehyde were examined, the sensor exhibits remarkable selectivity to each VOCs at different operating temperature. Further investigations based on quantum chemistry calculation show that difference orbital energy of VOCs molecule may be a qualitative factor to affect the selectivity of the sensor.