New strategy towards assemble hierarchical heterostructure of SnO2/ZnO for NO2 detection in ppb-level
Metal oxide hierarchical heterostructures (HHSs) gas sensors with controllable and novel nanostructures have attracted tremendous attention due to its multi-junctions, multi-phases, interfacial and synergic effects. Based on the various metal oxide materials, multifarious hierarchical nanostructures and heterostructures can be constructed to enhance sensor performance of the primary structure. Herein, the SnO2/ZnO HHSs are successfully prepared via the fast, simple, and low-cost microwave-assistant hydrothermal (MWAH) approach. Epitaxial growth of SnO2 nanorods (NRs) on the ZnO nanoflowers (NFs) formed the hierarchical structures are conducive to promoting the sensor performance. The detection limit is 2 ppb for NO2 based on the SnO2/ZnO HHSs. The sensor response toward 10 ppm NO2 is 52.3, which is 5- and 10-times higher than SnO2 and ZnO. The response and recovery time of SnO2/ZnO HHSs is 16 and 10 s, respectively. We believe that the strategy of synthesizing metal oxide with hierarchical heterostructures based on the MWAH method provides a novel insight for the next generation of gas sensors.