Synthesis of TiO2-Nb2O5 and TiO2-CuO Nano Co-Oxides and Their Application as Solid State Humidity Sensors

ABSTRACT The present paper reports the synthesis and characterizations of TiO2-Nb2O5 and TiO2-CuO systems and their applications as humidity sensors. The co-powders were prepared by sol-gel method and were characterized by XRD and SEM. The pellets of powders were made by applying uniaxial pressure of 500 MPa and annealed in an electric furnace at 100, 200, 300, and 400°C for 3 h each. After each step of annealing, each of these pellets was exposed to humidity in a specially designed humidity chamber. It was observed that as relative humidity (%RH) increased, the resistance decreased for the entire range of humidity, that is, from 10% to 95%. The %RH has been measured using standard hygrometer; variations in the resistance have been recorded using multimeter.