Carbon dioxide sensing properties of bismuth cobaltite

Bismuth cobaltite with sillenite-type structure was prepared from Co(OH)2 and Bi(NO3)3·6H2O through solid state reaction at 600 °C. Neutron powder diffraction (NPD) data and X-ray absorption spectroscopy revealed the existence of mixed oxidation states for cobalt in this compound, the chemical formula being Bi12(Bi0.55Co0.45)O19.6. The gas sensing properties of Bi12(Bi0.55Co0.45)O19.6 were characterized by alternating current, at 200, 300 and 400 °C. The optimal response was observed at 400 °C, using a frequency of 100 kHz.