Co3O4/In2O3 p-n heterostructures based gas sensor for efficient structure-driven trimethylamine detection

In this paper, sensors based on a new Co3O4/In2O3 flower-like p-n heterostructure is designed by one step hydrothermal method and used to improve the trimethylamine (TMA) gas sensitivity. A variety of means were used to test the structure, constituent elements and their valence of Co3O4/In2O3. Compared with former works, the sensor which is made of 5% Co3O4/In2O3 provides the following improvements: quicker cyclic response time to 10 ppm TMA, lower operating temperature (50 °C lower than pure In2O3), outstanding selectivity, excellent sensitivity (detection limit to 1 ppm), ultrahigh repeatability and long-term stability to TMA. The construction of p-n heterostructure can effectively improve the gas-sensitive response. The catalytic action of Co3O4 can reduce the activation energy of the reaction. This study perfected the mechanism of heterojunction promotes gas-sensing performance and provided a novel strategy for the design of gas-sensitive materials.