Hollow Cu2O nanospheres loaded with MoS2/reduced graphene oxide nanosheets for ppb-level NO2 detection at room temperature

Low energy consumption, high sensing response and high selectivity are the important indexes of metal oxide semiconductor (MOS) gas sensors applied in many application fields. However, the high working temperature and poor selectivity of MOS sensors severely restrict their scope of application in the Internet of Things (IoT). Herein, ternary MoS2-rGO-Cu2O (MG-Cu) composites with boosting ppb-level NO2 sensing characteristics are synthesized by combining hydrothermal method and soft-template method. The optimal proportion of MoS2, rGO and Cu2O is systematically explored. The SEM and TEM analyses confirm the hollow Cu2O is anchored on the surface of MG. The gas sensing tests illustrate that optimum composite sensor exhibits highest response to 500 ppb NO2 at room temperature, which is 11 and 5 times higher compared to pure MoS2 and binary MG15, respectively. Besides, it displays excellent selectivity and superior stability. The synergy of shell-structure with abundant mesoporous, heterojunction construction and enhanced conductivity lead to the enhanced sensing performance of ternary sensor.