Synthesize Of ZnO?CuO Porous Nanomaterials And Their Gas-sensing Applications

The main research content of this paper is to use ZnO and CuO as research objects,and modify them by adjusting the morphology and composition.Self-assembled CuO hollow microspheres from nanorods,hollow ZnO nanospheres independently assembled from ultra-thin nanosheets,and ZnO nanosheets(CdS NP/ZnO PNs)modified by CdS nanoparticles were prepared by hydrothermal and solvothermal methods.The samples were characterized by morphology and gas sensitivity.The main research contents are as follows:(1)The hierarchical CuO hollow microspheres were synthesized through a facile hydrothermal method.The as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).The results show that the hierarchical CuO hollow microspheres with a uniform size of 3?m are self-assembled by hundreds of primary nanorods with diameters of about 20 nm.The wall thickness of the hollow microspheres is about 200nm.The hierarchical CuO hollow microspheres exhibit good sensing performance in H₂S detection.The optimal operating temperature is 180?.And,in a large range,the hierarchical CuO hollow microspheres display excellent linear sensing performance in ethanol detection.The detecting limit is lower to 1 ppm.Furthermore,the hierarchical CuO hollow microspheres demonstrate excellent selectivity in H₂S detection.The sensing mechanism also has been discussed.It can be expected that the novel morphology of the hierarchical CuO hollow microspheres may bring amazing development for H₂S detection.(2)By the simple solvothermal method,ZnO nanosheets and hollow ZnO nanospheres were synthesized.The prepared samples were characterized by XRD,SEM,TEM,and other means.The results verify the porosity and single-crystal structure of ZnO nanosheets and hollow ZnO nanospheres.Hollow ZnO nanospheres are approximately 4?m in diameter.And the nanospheres are self-assembled by porous single crystal ZnO nanosheets.Hollow ZnO nanospheres exhibit excellent sensing activity and selectivity for ethanol.The hollow ZnO nanosphere sample had a linear response range of 1 ppm-150 ppm and a detection limit of 5 ppm at an optimal operating temperature of 330°C.The response to isopropanol decreased by less than5%within 30 days.ZnO nanospheres have high selectivity for ethanol,and the sensing performance of ethanol is significantly higher than that of other VOC gases.Therefore,hollow ZnO nanospheres have great application potential in ethanol detection.(3)The CdS nanoparticle decorated ZnO porous nanosheets(CdS NP/ZnO PNs)were successfully synthesized through a facile wet-chemistry method.The as-prepared samples were characterized by XRD,SEM,TEM,and energy dispersive spectrum(EDS).The results proved the porous and monocrystalline structures of the ZnO nanosheets.A huge number of tiny CdS nanoparticles evenly cover the surface of the ZnO porous nanosheets,and the average size of the CdS nanoparticles is about 5nm.The CdS NP/ZnO PNs exhibit excellent sensing activity and selectivity towards isopropanol.The linear response range is 1 ppm-100 ppm under the optimized operation temperature of 320?,and the detection limit is 1 ppm.The sensing performance of the CdS NP/ZnO PNs towards isopropanol is dramatically higher than that of other VOC gases,indicating the high selectivity to isopropanol.The CdS NP/ZnO PNs based sensor even can distinguish isopropanol from the complex mixed gases.Besides,the responses of the as-prepared sample to isopropanol seldom changed within 15 days.It is believed that the CdS NP/ZnO PNs have great application potential in isopropanol detection.Figure[44]table[5]reference[149]...