Gas sensing characteristics of BaTiO3-based ceramics

The gas sensing characteristics of porous BaTiO3-based ceramics, fabricated by adding graphite powders, were studied. All the sintered ceramics showed a tetragonal structure, irrespective of the added graphite content. The porosity of the BaTiO3-based ceramics increased with increasing graphite contents. It was found that the discrepancy in the resistivities measured at high temperatures (≳200 °C) in air and CO atmospheres became remarkable with temperatures. The sensitivity of CO gas was increased with porosity since the reactions between CO gas and O− and between CO gas and O are active at high porosity. The porous BaTiO3-based ceramics could be promising as a sensing material for CO gas sensor.