Controlled synthesis and gas sensing properties of porous Fe2O3/NiO hierarchical nanostructures

Porous Fe2O3/NiO hierarchical nanostructures with cuboid-like and flower-like architectures are prepared by directly annealing the coordination polymer (CP) precursor Fe(3-Clpy)(2)[Ni(CN)(4)]. Both of the hierarchical architectures are constructed by porous sheet-like building blocks, which are further composed of nanocrystals with a size smaller than 6 nm. Fe2O3 and NiO components display highly uniform distribution in the composites. An interesting monocrystal-like electron diffraction pattern is demonstrated in the cuboidlike Fe2O3/NiO composite. It is revealed that the crystal structure of the CP precursor can exert an obvious effect on the morphology and microstructure of the calcined products. The potential application of the Fe2O3/NiO composites in gas sensors is investigated towards various organic vapors. It is found that the cuboid-like Fe2O3/NiO shows a much higher gas sensing performance than the flower-like counterpart, demonstrating that the different architectures of hierarchical nanostructures have an important influence on the gas sensing performance. The facile and effective CP precursor approach presented here can be extended to synthesize a wide range of metal oxide composites with unique architectures, highly tailored compositions and improved functions.