Co3O4-based isobutane sensor operating at low temperatures

Co3O4 ceramic was utilized to fabricate a low temperature-operating butane gas sensor because the oxide strongly catalyzes the oxidation reaction of methane that is chemically the most stable hydrocarbon. The Co3O4 sensor has shown high sensitivity to isobutane even at 250°C. However, the sensor was very unstable on consecutive measurements. It might be due to the presence of oxides in several valence states. As a stabilizer, 10–50 wt.% NiO powders were added to the Co3O4 ceramic because NiO is only oxide form in NiO system. The Co3O4–NiO sensor exhibits excellent repeatability on consecutive measurements as well as long-term stability.