Synthesis And Catalytic Properties Of Tungsten Semiconductor Nanomaterials

Environmental pollution and energy shortages have been a serious threat to human’s subsistence development. In a variety of environmental pollution, chemical pollution has attracted more and more attention. It is important to solve the problem that prevention chemical contamination of water resources. The key to protect environment is to develop a practical technology, which can decompose chemical contaminants harmlessly. As a progressive environmental technologies photocatalytic technology is gradually developing under this background. The electrons and holes excited by visible light react with organic contaminants, what’s more semiconductor material itself is non-toxic, no corrosive. Organic contaminants can also be completely decomposed into H2O and CO2, which is harmless to the environment and human beings, there is no secondary pollution.Due to SrTiO3 has a large number of photocatalytic sites, which can improve the photocatalytic activity. Based on the above-described problems, synthesize the heteroj unction photocatalysts by a two-step hydrothermal method. The heteroj unction structure, morphology, formation of the catalytic activity are analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), EDX-mapping, X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectroscopy (UV-vis DSC). Synthesis of different mass fractions of SrTiO3/Bi2WO6 heteroj unction photocatalyst and SrTiO3/Bi2MoO6 heteroj unction photocatalyst. Assessing the efficency of the photocatalytic activity of different composite amounts of heteroj unction photocatalyst by means of the degradation of Rhodamine B under visible light.The results showed:The surface of Bi2WO6 catalyst complex three-dimensional shape of SrTiO3 in lamellar. The reaction rate constant of bare Bi2WO>6 catalyst is 0.0245 min-1; when 8 wt% SrTiO3 compound at Bi2WO6, the highest degradationrate constant of Rhodamine B is 0.0463 min-1. Heteroj unction photocatalyst separated photo-generated electrons and holes effectively, so that suppressing the recombination of electron-hole pairs, improving the photocatalytic activities. What’s more, after compositing SrTiO3, there is no atomic metastasis, the morphology, size and crystalline phases of SrTiO3/Bi2WO6 heterojunction catalyst are not changed.In addition, the crystal structure of Bi2MoO6 is similar to Bi2WO6, but Bi2MoO6 has a smaller band gap, it can optimize the photocatalytic activity with SrTiO3. SrTiO3/Bi2MoO6 has been successfully prepared in the same method. The effect of compositing SrTiO3 and the photocatalytic mechanism have been investigated by degradation of Rhodamine B dyes under visible-light irradiation. The results show that the effect of balanced copositing SrTiO3 can efficiently suppress recombination of electron-hole pairs, leading to high photocatalytic degradation activity. Rhodamine B dyes with concentration of 30 mg/L can be 58.0% in 90 min under visible light with bare Bi2MoO6 photocatalyst. While Rhodamine B dyes with concentration of 30 mg/L can be completely degraded in 80 min under visible light with 8 wt% SrTiO3/Bi2MoO6 photocatalyst. Because of SrTiO3 match the energy band gap effectively, inhibiting the of compound photo-generated electrons and holes, hydroxyl radical, at the same time, (·OH) having a strong oxidizing, which may decompose the organic dye.