High sensitivity chlorine gas sensors using CdIn2O4 thick film prepared by co-precipitation method

Gas-sensing properties to dilute Cl₂ have been investigated for CdIn₂O₄ thick film sensors prepared by co-precipitation method. Cadmium nitrate and indium nitrate were mixed in de-ionized water. The 0.1 M NaOH was added to the mixed solution. The co-precipitate obtained was washed, filtered, dried, and calcined at 600-900 °C for 4 h. The CdIn₂O₄ sensor prepared using the powder calcined at 600 °C showed high sensitivity (S=R_g/R_a) to dilute Cl₂ at 250 °C. In particular, the CdIn₂O₄ sensor showed the sensitivity as high as 1200 even to 0.2 ppm Cl₂. The crystal structure and surface morphology were examined by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively.