Controllable synthesis of intercalated γ-Bi2MoO6/graphene nanosheet composites for high performance NO2 gas sensor at room temperature

Intercalated γ-Bi2MoO6/graphene nanosheet composites (BMO/GNCs) were prepared by vacuum-assistant and solvothermal technique. In BMO/GNCs, BMO nanoparticles (NPs) were uniformly distributed on the surface and interlayer of graphene nanosheets (GNs), simultaneously along with a large number of defects and interface on GNs and BMO NPs. As synthesized with solvothermal temperature at 160 °C and graphite content of 80 mg, BMO/GNCs-8-160 sample exhibits the remarkable gas sensitivity, reversibility and selectivity to NO2 at room temperature (RT, 22 °C). The relative response rate of the sensor toward 100 ppm NO2 is 96.73, which is about 6.41 times of pure BMO NPs. Furthermore, the response time and recovery time is merely 2.5 and 34.1 s, respectively. The detection limit can reach 10 ppb with response value of 1.51. The improved NO2 sensing performance is attributed to the effective electron transfer between BMO NPs and GNs and typical structure characteristics of BMO/GNCs, which is rarely reported in the room temperature type of Bi2MoO6 sensor. [Display omitted] •Intercalated BMO/GNCs formed p-p heterojunction and provide extensive active sites.•The multilayer GNs (from EG) enhances the conductivity of the BMO/GNCs sensor.•The response of the BMO/GNCs-8-160 sensor to 100 ppm NO2 at RT is as high as 96.73•The sensor kept a good long-term stability in the whole 35 days.