Construction Of Cobalt-based Nanocomposites And Their Gas-sensing Properties

With the development of industry,the heavy combustion of industrial fuel and the emission of vehicle exhaust make air pollution more serious.In order to detect the air quality,gas sensors have attracted wide attention.Semiconductor metal oxide sensors as potential sensor materials due to their high sensitivity,fast response.Co₃O₄ has been widely used as gas sensing material to detec toxic and harmful gases.In this paper,Co₃O₄ nanomaterials were prepared by different methods.The effects of morphology and structure of the materials are studied.The paper doses the following three aspects:(1)Co₃O₄/PEI-GO composites were prepared by hydrothermal method at 190?C.The XRD and FT-IR showed that the composites had been successfully synthesized.Co₃O₄ was showed 1D acicular structure by TEM and the Co₃O₄ are dispersed on the surface of GO with modified PEI.The gas sensing properties of the composites was studied at room temperature.The results of gas sensing test showed that Co₃O₄/PEI-GO composite have good NOx gas performance.Corresponding gas sensing mechanism model,the mechanism of gas sensing is discussed.(2)A series of Co₃O₄/Al OOH composites were successfully synthesized by two-step method(hydrothermal method and subsequent calcination method).The XRD characterization showed that the material has high purity.TEM characterization shows that the Co₃O₄ nanoparticles are highly dispersed on the surface of the Al OOH substrate.Co₃O₄/Al OOH composite shows good NOx gas performance at room temperature.The outstanding NOx gas sensing performance may attribute to the structure of the Co₃O₄/Al OOH composite materials and the formation of the p-n junctions in materials.(3)Co₃O₄ single crystal nanoparticles were synthesized by one step of thermal treatment.The chain structure Co₃O₄ nanomaterials composed of single crystal nanoparticles.The chain structure Co₃O₄ shows better electron transportation than Co₃O₄ nanoparticals by the EIS detect.The chain structure Co₃O₄ nanomaterials show good NOx performance at room temperature.The gas sensing mechanism model was established,which used to analyze the gas response mechanism.