Facile post-synthesis and gas sensing properties of highly porous NiO microspheres

In this report, the porous NiO microspheres were fabricated by a post-simple route using alpha-Ni(OH)(2) microflowers as precursor that were synthesized by a hydrothermal method without using surfactants. The three-dimensional (3D) NiO microspheres ranging from 2 to 10 mu m in diameters composes of connected NiO nanoparticles, results in the sintering and phase transformation from primary alpha-Ni(OH)(2) nanosheets to NiO nanoparticles during thermal procedures. The porous NiO microspheres-based sensor was tested with some toxic and flammable gases including H2S, NH3, H-2, and CO. The hierarchical porous sensors exhibit high selectivity and sensitivity toward H2S in comparison with other interfering gases. The results may be related to some factors such as the catalytic effect of NiO on the oxidation of hydrosulfide, a moderately chemical affinity between Ni and S, and well-aligned porous architectures. The results exhibit the potential of hierarchical porous NiO microspheres as a gas-sensing material for excellent H2S detection. (C) 2019 Elsevier B.V. All rights reserved.