UV assisted ppb-level acetone detection based on hollow ZnO/MoS2 nanosheets core/shell heterostructures at low temperature

It is challenging for current metal oxides based acetone sensors to realize excellent ppb-level acetone sensing properties at low working temperature. Herein, the hollow ZnO/MoS2 nanosheets (HZnO/MoS2) core/shell heterogeneous structures are originally produced. Fast gas transport channels and n-p heterojunctions are produced by the decoration of MoS2 nanosheets on HZnO surface, resulting in high acetone response and fast response/recovery speed. Ultraviolet (UV) light is introduced to further improve acetone response and drastically reduce working temperature. The light diffraction and reflection caused by the decoration of hierarchical MoS2 nanosheets could significantly enhance light harvesting. Hence, the excellent acetone sensing properties are obtained by the synergistic effect of UV light and HZnO/MoS2 core/shell heterogeneous structures. Exactly, at 100 degrees C, the HZnO/MoS2 possesses a stable response (1.52) to 100 ppb acetone with UV irradiation while it exhibits no response to 100 ppb acetone without UV. Even at room temperature (30 degrees C), UV activated HZnO/MoS2 still exhibits a stable response (similar to 1.33) and fast recovery/recovery time (19 s/97 s) to 50 ppm acetone. Furthermore, the DFT calculations are performed to demonstrate the underlying acetone sensing mechanism. The results demonstrate that UV activated HZnO/MoS2 heterostructure could achieve trace-acetone detection at low temperature.