Effects of calcining temperature on the phase structure and the formaldehyde gas sensing properties of CdO-mixed In2O3

The CdO-mixed In2O3 materials with a molar ratio of 1:1 calcined at different temperatures were prepared using the solid-state synthesis technologies. The effect of the different calcining temperatures on the phase structures of CdO-mixed In2O3 was investigated by powder X-ray diffraction. Indirect-heating sensors using CdO-mixed In2O3 calcined at different temperatures as sensitive materials were fabricated on an alumina tube with Au electrodes and Platinum wires. Gas-sensing characteristics of CdO-mixed In2O3 to formaldehyde were investigated. It is found that CdIn2O4 came into be formed from CdO-mixed In2O3 more than 700 degrees C. The results show that the phase structure, the electronic and the gas sensing properties to formaldehyde were changed with the different calcining temperatures. The CdO-mixed In2O3 based gas sensors exhibit highest response to formaldehyde after calcining at 650 degrees C, making them to be promising candidates for practical detectors for formaldehyde. (c) 2008 Elsevier B.V. All rights reserved.