Nanosheets-assembled hollowed-out hierarchical Co3O4 microrods for fast response/recovery gas sensor

Hollowed-out hierarchical Co3O4 microrods has been synthesized via the interfacial-reaction of CoC2O4·2H2O with NaOH. Field emission scanning electron microscopic and transmission electron microscopic results revealed that the Co3O4 samples were hollowed-out hierarchical microrod-like structure assembled by interlaced thin nanosheets (with thickness of around 7 nm). The gas sensing properties of the porous microrods Co3O4 were evaluated. The response/recovery time of the gas sensor to 100 ppm methanol and ethanol are 0.8/7.2 s and 0.8/10.8 s, respectively. Gas sensing measurement revealed that the hollowed-out hierarchical Co3O4 microrods exhibit high performance, especially fast response/recovery characteristics to methanol and ethanol. The enhancement of gas sensing properties is attributed to the thin thickness of nanosheets, large specific surface area, loose interior and through-pore structure. The good sensing performance suggests this hollowed-out hierarchical Co3O4 microrods could be a promising candidate as a sensing material for real-time monitoring gas sensor.