SnO2/ZnSnO3 double-shelled hollow microspheres based high-performance acetone gas sensor

In this study, the preparation process and the sensing performance toward acetone of SnO2/ZnSnO3 composite microspheres with the double-shelled hollow structure were reported. It was synthesized by one-step chemical vapor deposition (CVD) method using sucrose as solid precursor pyrolysis carbon template. In addition, the internal structure of the composite microspheres can be effectively controlled by changing the sucrose concentration. The perfect double-shelled hollow structure (average diameter of about 500 nm) of the prepared sensitive materials was observed through SEM and TEM. It is noteworthy that the double-shelled hollow structure had a large specific surface area (188.60 m2/g), which can both increase the internal and external reactive sites of the sensitive material effectively. Compared with other obtained composite microspheres, the SnO2/ZnSnO3 sample with double-shelled hollow structure presented the best sensing performance, and the response to 100 ppm acetone reached 30 at 290 °C. Furthermore, it also presented excellent selectivity and long-term stability to acetone. The excellent performance was attributed to the synergistic effect of the double-shelled hollow structure with large specific surface area and the n-n heterojunction at the interface of the SnO2/ZnSnO3 composite. The sensing mechanisms of the double-shelled hollow SnO2/ZnSnO3 composite material were discussed in detail.