Construction of porous LaFeO3 microspheres decorated with NiO nanosheets for high response ethanol gas sensors

Designing novel structural constructions and adopting appropriate catalyst materials are the key to overcoming inherent limitations of metal oxide gas sensors. In this paper, porous LaFeO3 microspheres decorated with NiO nanosheets were prepared by simple hydrothermal method, and the p-p heterojunction was successfully constructed. Characterization results showed that the NiO nanosheets were uniformly grown on the surface of the porous LaFeO3 microspheres and the size of nanosheets was very uniform. This kind of morphology effectively improves the contact area between metal oxides and the target gases. Gas-sensing tests revealed that the combination of porous LaFeO3 microspheres and NiO nanosheets endows superior ethanol sensing performance with high response, good selectivity and rapid responding and recovering speed. The well-defined NiO@LaFeO3 nanocomposites offered unique hierarchical structure and p-p junctions at the heterointerfaces, which could induce the large hole depletion regions and hence benefited for oxygen adsorption and gas-sensing reactions at the interfaces. This work not only demonstrates the NiO@LaFeO3 nanocomposite is a promising material for fabricating ethanol sensors but also provides a useful guidance for design well-defined core@shell p-p hetero-jucntions in gas-sensing applications.