NiO functionalized Co3O4 hetero-nanocomposites with a novel apple-like architecture for CO gas sensing applications

Abstract An innovative NiO functionalized Co3O4 hetero-nanocomposite exhibiting an unusual apple-like architecture has been successfully fabricated via a facile two-step chemical route for CO gas sensing applications. The unique mimetic morphology constructed by spike-like NiO nanobundles with sharp tips planted on the surface of the preformed extremely porous Co3O4 nanospheres not only creates specific structural advantages but, more importantly, induces chemical activation required for gas sensing. Higher sensitivity and lower operating temperature are thus obtained for the present NiO-Co3O4 hetero-nanocomposite in comparison with those for the bare Co3O4 nanospheres and also for most reported intrinsic or heterogeneous Co3O4 nano-oxides.