Fast-response MEMS xylene gas sensor based on CuO/WO hierarchical structure.

CuO/WO hierarchical hollow microspheres, assembled from irregular two dimensional (2D) nanosheets, were prepared by ultrasonic-wet chemical etching and pyrolysis in this study. The sensing performance of Micro-Electro-Mechanical System (MEMS) xylene gas sensor based on CuO/WO hierarchical structure were evaluated. It was found that the CuO/WO MEMS sensors showed an enhanced gas sensing performance compared with pristine WO sensor. The CuO/WO-3 (the mass ratio of CuO to WO is 3%) sensor exhibited faster response-recover speed and the highest response value to xylene. Moreover, the CuO/WO-3 sensor possessed higher selectivity and long-term stability. The good sensing properties can be attributed to the unique three dimensional (3D) hierarchical structure and p-n heterojunction of CuO-WO. Considering the above advantages, the CuO/WO-3 sensor has a great potential for the rapid detection and monitoring of xylene.