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

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.