The fabrication and gas-sensing characteristics of the formaldehyde gas sensors with high sensitivity

Gas-sensing characteristics of CdO-mixed In2O3 to formaldehyde were investigated. Gas sensors of indirect heating type were fabricated by the sensitive materials. The phases in the resulting materials and the morphologies of the sensing layers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively, before and after calcination. The effects of operating temperature on the sensor response and the response versus gas concentration properties of the CdO–In2O3 sensors were investigated. It was shown that the sensors exhibited good response properties to formaldehyde gas at low operating temperature, making them to be promising candidates for practical detectors to formaldehyde gas.