Polyvinylpyrrolidone-mediated Co3O4 microspheres assembled in size-tunable submicron spheres with porous core-shell structure for high-performance gases sensing

Metal-organic frameworks (MOFs) derived cobalt oxide (Co3O4) microspheres assembled in size-tunable submicron spheres with porous core-shell structure are regulated by adjusting the amount in different weight of polyvinylpyrrolidone (PVP) and successfully fabricated via a combined hydrothermal and calcination method. Gas sensing mechanism toward ethanol and acetone with 0.10 of PVP, indicates that the sensor based on complex hierarchical structure can display long-term durability and outstanding responsiveness at operating temperatures of 180 and 200 °C. The formation of the special structure labeled as C/Co-P(0.10) − 350 and the ultra-high sensing capability are attributed to the presence of surface-adsorbed oxygen molecules with chemical activity induced by the hierarchical configuration. Herein, the strategy whereby the surface-adsorbed oxygen molecules contribute toward enhancing the gas sensing performance, is a novel route for the development of high-performance sensing materials.