Preparation And Photocatalytic Performance Of Lead Selenide Nanomaterials

With the rapid development of industries all over the world,a large amount of organic dyes are discharged into water to pollute the water environment.Due to the good stability and the high harm to animals and plants of organic dyes,solving the problem of organic dyes on water pollution has attracted worldwide attention and research.As a photocatalyst,semiconducting nanomaterials can effectively solve the problem of water pollution brought by organic dyes,and have been extensively studied and reported.Compared with semiconductor photocatalysts of wideband gaps such as Zn O and TiO₂,many semiconductor materials with narrow bandgap have larger light absorption range and strong adsorption of organic dyes,which have attracted wide attention in the field of photocatalysis.Among them,PbSe nanotubes as a typical IV-VI narrow bandgap semiconductor material have potential applications in the field of photocatalysis.In this paper,PbSe nanotubes were prepared by sacrificial template method with the assist of ascorbic acid.PbSe/TiO₂ nanotubes were synthesized by hydrothermal method using the prepared PbSe nanotubes as templates.In addition,the prepared PbSe nanotubes were decorateded by Ag.Their photocatalytic properties for different organic dye molecules were studied.The specific research content is as follows:Firstly,Se nanowires were synthesized in aqueous solution at room temperature,and then PbSe nanotubes were prepared with Se nanowires as template and Se ion source assisted by ascorbic acid.The morphology and crystal structure of the samples were analyzed by SEM,TEM and XRD.Experimental results show that the amount of ascorbic acid and Pb2+ concentration play important roles in the formation of PbSe NTs,and the possible growth mechanism of PbSe NTs has been also presented.The photocatalytic activity of the PbSe NTs was investigated and the results establish that PbSe NTs in the presence H2O2 showed a high photodegradation efficiency of methylene blue?MB?.Secondly,PbSe/TiO₂ composite nanotubes were prepared by the water bath reaction using the prepared PbSe nanotubes as template.Through SEM and TEM characterization,the average diameter and length of the composite nanotubes were 292 nm and 1.5³.7 ?m,respectively.Experimental results of photocatalytic performance show that PbSe/TiO₂ composite nanotubes have better photocatalytic activity for methyl orange than pure TiO₂ nanotubes.The study of the catalytic mechanism found that the higher photocatalytic efficiency of the PbSe/TiO₂ composite nanotube structure is attributed to the fact that the heterojunction structure can effectively promote the separation efficiency of the carrier.Finally,Ag-decorated PbSe nanotubes were synthesized successfully by a simple and low-cost method ultraviolet?365 nm?light induced reduction method.The prepared Ag-decorated PbSe nanotubes were characterized by SEM.The results show that the metallic silver nanoparticles with diameter of 20⁶0 nm are uniformly dispersed on the surface of PbSe nanotubes.Photocatalytic experiments show that Ag-modified PbSe nanotubes have excellent photocatalytic activity for malachite green in the presence of H2O2.The cyclic experimental study found that Ag-modified PbSe nanotubes have good cycle stability.In addition,the photocatalytic mechanism of Ag-modified PbSe nanotubes was systematically analyzed.