Enhancement of SO2 Gas Sensing Performance of Co3O4 Spinel by Cu Substitution

Single-phase spinel cobalt oxide (Co 3 O 4 ) and copper-substituted cobalt oxide (Co 2.8 Cu 0.2 O 4 ) nanomaterials were synthesized via a co-precipitation route. To explore the potential applicability of the Co 3 O 4 and Co 2.8 Cu 0.2 O 4 materials for gas sensor fabrication, their SO 2 gas sensing characteristics were studied at three different temperatures using the gas concentration of 3 ppm. Unsubstituted Co 3 O 4 sample exhibits poor response towards SO 2 gas whereas the Cu-substituted sample showed superior gas sensing characteristics such as gas response, response time and recovery time at all three temperatures. Among the three studied temperatures, the maximum gas response of 7.5% was found at 200 °C with recovery and response times of 26 sec, indicating an optimal temperature. Our results demonstrate that the nanostructured Co 2.8 Cu 0.2 O 4 material could be a potential candidate to design SO 2 gas sensor for detection of low concentration gas.