Highly Sensitive and Selective PbTiO3 Gas Sensors with Negligible Humidity Interference in Ambient Atmosphere.

Three PbTiO3 nanostructures were synthesized using a one-step hydrothermal reaction with different TiO2 powders as Ti sources, and their gas-sensing properties were investigated. The sensor comprising PbTiO3 nanoplates (NPs) exhibited a high response (resistance ratio = 80.4) to 5 ppm ethanol at 300 °C and could detect trace concentrations of ethanol down to 100 ppb. Moreover, the sensor showed high ethanol selectivity and nearly the same sensing characteristics despite the wide range of humidity variation from 20 to 80% RH. The mechanism for humidity-independent gas sensing was elucidated using diffuse reflectance infrared Fourier transform spectra. PbTiO3 NPs are new and promising sensing materials that can be used for detecting ethanol in a highly sensitive and selective manner with negligible interference from ambient humidity.