SnO/SnO2 heterojunction: an alternative candidate for sensing NO2 with fast response at room temperature

The SnO2-based family is a traditional but important gas-sensitive material. However, the requirement for high working temperature limits its practical application. Much work has been done to explore ways to improve its gas-sensing performance at room temperature (RT). For this report, SnO2, SnO, and SnO/SnO2 heterojunction was successfully synthesized by a facile hydrothermal combined with subsequent calcination. Pure SnO2 requires a high operating temperature (145 degrees C), while SnO/SnO2 heterojunction exhibits an excellent performance for sensing NO2 at RT. Moreover, SnO/SnO2 exhibits a fast response, of 32 s, to 50 ppm NO2 at RT (27 degrees C), which is much faster than that of SnO (139 s). The superior sensing properties of SnO/SnO2 heterojunction are attributed to the unique hierarchical structures, large number of adsorption sites, and enhanced electron transport. Our results show that SnO/SnO2 heterojunction can be used as a promising high-performance NO2 sensitive material at RT.

Automated summary

The SnO2-based family is an important gas-sensitive material, but its practical application is limited by the high working temperature. SnO/SnO2 heterojunction shows excellent performance for sensing NO2 at room temperature, with a faster response compared to SnO.