Ultrasensitive xylene gas sensor based on flower-like SnO 2 /Co 3 O 4 nanorods composites prepared by facile two-step synthesis method

Xylene is a volatile organic compound which is harmful to the human health and requires precise detection. The detection of xylene by an oxide semiconductor gas sensor is an important research direction. In this work, Co 3 O 4 decorated flower-like SnO 2 nanorods (SnO 2 /Co 3 O 4 NRs) were synthesized by a simple and effective two-step method. The SnO 2 /Co 3 O 4 NRs show high xylene response ( R g / R a = 47.8 for 100 ppm) and selectivity at the operating temperature of 280 °C, and exhibit high stability in continuous testing. The resulting SnO 2 /Co 3 O 4 NRs nanocomposites show superior sensing performance towards xylene in comparison with pure SnO 2 nanorods. The remarkable enhancement in the gas-sensing properties of SnO 2 /Co 3 O 4 NRs are attributed to larger specific surface area and the formation of p–n heterojunction between Co 3 O 4 and SnO 2 . These results demonstrate that particular nanostructures and synergistic effect of SnO 2 and Co 3 O 4 enable gas sensors to selectively detect xylene.