Novel ginkgo-like core-shell WO3 for enhanced ppb-level NO2 sensing at room temperature

As one of the typical sensing materials, metal oxide semiconductors (MOSs) have important application in the detection of toxic and hazardous gas. Yet so far, detecting ppb-level nitrogen dioxide (NO2) at room temperature is challenging. Herein, novel ginkgo-like hollow and core-shell tungsten trioxide (WO3) nanostructures with different exposed surfaces have been synthesized. For the synthesized ginkgo-like core-shell WO3, the inner core and outer shell are both assembled by a large number of nanosheets. Compared with the hollow WO3, the core-shell WO3 exhibits enhanced NO2 sensing performance. Specifically, it possesses good selectivity, long-term stability and anti-humidity at room temperature. The enhanced sensing properties can be attributed to the formation of (020) exposed surface and unique core-shell structure.