Synthesis Of ZnSe Nanoframes And PbSe/ZnSe Hetero-Nanobelts And Their Sensing Properties

The concept of colorimetric sensing and photoelectrochemical sensing has attracted extensive attention since it was proposed.In recent years,through the advanced nanotechnology,interfacial assembly method and the combination of various reaction,colorimetric sensors and photoelectric analytical method to improve the sensitivity and selectivity of great,application scope also expanded into detection of biological recognition,heavy metals and pesticide molecular,etc.With the development of colorimetric sensors and photoelectrochemical sensors,the exploration and modification of photosensitive materials as well as the miniaturization and convenience of sensors have become the challenges of sensor development.In this paper,a novel vision colorimetric sensor based on cation exchange strategy is proposed.Based on the idea of cation exchange,a partial cation exchange method was proposed to modify Zn Se nanomaterials,and L-B self-assembly technology and in-situ calcination method were applied in the sensor construction process,which improved the poor stability and repeatability in the sensor construction process.The main research work is as follows:1.Construction of a visual colorimetric sensor for the detection of heavy metal ions based on cation exchange strategy:A novel band-like Zn Se nanoframe was successfully synthesized by hydrothermal method using Zn Se·0.5N₂H₄nanobelts as precursors.The growth mechanism was found to be Ostwald ripening process.The band-like Zn Se nanoframes were used as the colorimetric reagent and transferred to the circular filter paper by drip coating method to build the colorimetric paper sensor,which realized the visual detection of Cu²⁺,Ag⁺and Hg²⁺at room temperature.Studies have shown that the change of composition caused by cation exchange reaction leads to the change of color.According to the color change and intensity of the colorimetric sensor after adding Cu²⁺,Ag⁺and Hg²⁺,not only can distinguish the heavy metal cations Cu²⁺,Ag⁺and Hg²⁺,but also can determine their concentrations.In particular,the concentration of Cu²⁺can be reduced to 1 ppm by visual measurement.In addition,the sensor has good anti-interference performance of various typical cations and anions.2.Based on partial cation exchange strategy,Pb Se/Zn Se II-type hetero-nanobelts with improved photoelectric properties were synthesized:Using Zn Se·0.5N₂H₄nanobelts as precursors,combined with cation exchange strategy and in situ calcination method,the sensors with Pb Se/Zn Se hetero-nanobelts modified was successfully prepared.In the process of synthesis of Pb Se/Zn Se hetero-nanobelts,the temperature and time of partial cation exchange reaction were optimized to control the size of Pb Se nanoparticles,in order to obtain better photoelectric properties of hetero-nanobelts.Compared with Zn Se nanobelts,the formation of Pb Se/Zn Se II-type hetero-nanobelts broadens the light absorption range from the ultraviolet region to the near-infrared region,and the composition ratio of Pb Se to Zn Se in hetero-nanobelts will affect the photoelectric sensing performance of the hetero-nanobelts.By adjusting the different Pb/Zn ratios,it is concluded that Pb Se/Zn Se（Pb/Zn=0.35）has the best photoelectric sensing performance.In addition,the Pb Se/Zn Se/ITO sensor achieves low detection limit（0.038μm）and high sensitivity for the detection of dopamine in a wide linear range from 0.1μm to 1.2 m M.More importantly,the prepared sensor also shows good anti-interference performance.