Two-dimensional net-like SnO2/ZnO heteronanostructures for high-performance H2S gas sensor

Abstract

H₂S gas in the environment, even at a concentration as low as 20 ppb, is very harmful to the health of human beings. Therefore, the design and fabrication of sensors for detecting trace H₂S gas in the environment are highly desirable. However, it remains a challenge to develop gas sensors that can detect H₂S at ppb concentration levels and at a relatively low temperature. Herein we developed a facile method to fabricate porous two-dimensional net-like SnO₂/ZnO heteronanostructures. Both the SnO₂ and ZnO nanoparticles were significantly smaller in the net-like heteronanostructures than in net-like SnO₂ and ZnO homonanostructures. Heterojunctions formed at the interfaces between SnO₂ and ZnO—and, as a result, the net-like SnO₂/ZnO heteronanostructures—exhibited better H₂S-sensing properties, including higher sensor response, better selectivity and long-term stability, than did the net-like SnO₂ and ZnO homonanostructures, and other types of metal oxide-based nanocomposites. Importantly, the SnO₂/ZnO heteronanostructures could detect 10 ppb H₂S even at a working temperature of 100 °C. Therefore, the net-like SnO₂/ZnO heteronanostructures have very promising applications in high-performance H₂S sensors. In addition, the fabrication method presented here is facile, repeatable and operable, and may thus be extended to synthesize other types of metal oxide-based heteronanostructures for applications in various fields.