Study Of Photoelectric And Photocatalytic Properties Of Sn(O,S)-based Semiconductor Materials

Since the Industrial Revolution,the world has been in a stage of vigorous development,and people’s demand for energy has grown exponentially.However,global energy reserves are limited,and fossil energy cannot be regenerated in a short time,which cannot meet the long-term demand for energy from the rapid development of human society.In the process of the rapid development of society and the massive use of fossil energy,the corresponding environmental problems,such as greenhouse effect and water pollution,are inevitably produced.Photocatalytic degradation is an effective way to degrade substances.It can not only degrade carbon dioxide into reusable energy and reduce the greenhouse effect,but also solve the problem of water pollution by photocatalytic degradation of pollutants in water.In the process of photocatalysis,how to improve the photoelectric conversion efficiency,light absorption capacity,effective charge separation and transfer efficiency,as well as the reuse of catalysts is a hot topic at present.Tin is a kind of metal material with large reserves,low cost and non-toxic,which can be easily synthesized into tin oxides and tin sulfides.Sn(O,S)-based semiconductor materials have also become a hot research material in semiconductor industry in recent years because of their special conduction band valence position and excellent photoelectric properties.In this paper,stannous tetroxide(Sn3O4)with different morphologies were prepared by hydrothermal method,and the morphologies were changed by substrate growth method to improve the light absorption performance.A palm-shaped SnS2 with multilayer structure was synthesized by anion exchange method using vertically aligned Sn3O4 nanosheet arrays as precursors.The photoelectric and photocatalytic properties of Sn(O,S)-based semiconductor materials have been studied and characterized accordingly.The details are as follows:(1)Preparation and photocatalytic properties of Sn3O4:Sn3O4 nanospheres were successfully synthesized by hydrothermal method.Scanning electron microscopy(SEM)and high resolution transmission electron microscopy(HRTEM)showed that Sn3O4 nanospheres consisted of overlapping nanosheets tens of nanometers thick and hundreds of nanometers in size.X-ray diffraction(XRD)and Raman spectroscopy results show that the synthesized sample is Sn3O4,rather than the mixture of tin oxide and tin dioxide.Furthermore,X-ray photoelectron spectroscopy(XPS)test proves that Sn3O4 has Sn2+ and Sn4+ mixed valence states.Under visible light irradiation,Rhodamine B(RhB)has a good photocatalytic degradation rate.By photocatalytic degradation of carbon dioxide experiment,for the first time proved Sn3O4 gas carbon dioxide can be degraded to have carbon monoxide and 100%selectivity and yield of carbon monoxide was 1.01 μmol/g/h.(2)Self-assembly of Sn3O4 on FTO and carbon fiber paper substrates and its photocatalytic properties:The vertical array of Sn3O4 nanosheets on the FTO/carbon paper substrate was prepared by hydrothermal method,and the successful loading of Sn3O4 on the surface of FTO/carbon paper was verified by SEM,HRTEM,XRD and Raman tests.The vertical array of Sn3O4 nanosheets prepared on FTO/carbon paper substrate was tested by UV-VIS diffuse reflection absorption spectroscopy(UV).The light absorption capacity of Sn3O4 nanospheres was stronger than that of Sn3O4 nanospheres.And in carbon dioxide photocatalytic degradation experiments prove that the FTO vertically Sn3O4 nanometer chips array substrate preparation is higher than red Sn3O4 nanometer photocatalytic degradation ability of carbon dioxide,carbon monoxide production rate of 4.78 μmol/g/h is red Sn3O4 nanometer catalytic rate 4.72 times.(3)Preparation and photocatalytic properties of multilayer palm fibrous SnS2:By SEM,HRTEM,XRD,Raman,XPS and Elemental Mapping tests,Sn3O4 was fully converted to SnS2.The results of UV and Thermal Image tests show that SnS2 with multi-layer structure has stronger visible and near infrared light absorption capacity and photothermal performance than SnS2 with single structure.The photocatalytic degradation of Rhodamine B by SnS2 and the photocatalytic degradation of carbon dioxide by SnS2 proved that SnS2 with multilayer structure had better catalytic performance and cycle stability than SnS2 with monolayer structure.