激光熔融法制备缺陷型金属氧化物及其性能研究

发布时间：2018-04-20 19:13

  本文选题：激光熔融法 + 金属氧化物　； 参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：金属氧化物具有较为广泛的应用,如光催化、生物医药和太阳能电池等领域。文献中,传统的改性方法有元素掺杂、形貌调控等。但元素掺杂会在材料中引入杂质,而自掺杂的方法可以有效解决该问题。本论文采用缺陷自掺杂的方法对材料进行改性。本论文采用激光熔融法,制备得到了缺陷型TiO_2、Fe_3O_4和SrTiO_3,并对其进行系统表征。研究发现:(1)激光熔融处理后得到的TiO_2样品中出现了Ti_8O_(15)相,且其禁带宽度由3.03 eV降低到2.52 eV,表明激光熔融法成功在TiO_2中引入了氧缺陷和Ti~(3+),能增强其对可见光的吸收能力。具有缺陷的TiO_2不仅具有优异的光催化降解有机物和光催化制氢性能,还具有良好的稳定性。TiO_2激光熔融后的产氢率为8.54mmol/(h·g),约为市售TiO_2(P25)样品的8倍。(2)利用激光熔融法处理Fe_2O_3和Fe_3O_4,均最终获得了Fe_3O_4。激光熔融法使Fe_2O_3转变成Fe_3O_4,表明激光熔融法成功在Fe_3O_4中引入了缺陷。具有缺陷的Fe_3O_4是一种超顺磁性材料,其饱和磁化强度高,而矫顽力和剩磁分别是6.6Oe和0.4 emu/g(近似为零)。此外,由于磁晶各向异性对温度敏感,所以激光熔融处理后Fe_3O_4样品在低温下饱和磁化强度略有增强。(3)激光熔融处理后得到的SrTiO_3样品的相组成没有变化,但是根据其禁带宽度从3.20 eV降低到3.05 eV,表明激光熔融法成功在SrTiO_3中引入了缺陷,从而增强SrTiO_3对可见光的吸收能力。具有缺陷的SrTiO_3的光催化制氢性能有所提高,且具有良好的循环稳定性。SrTiO_3激光熔融后的产氢率为2.46μmol/(h·g),约为原始样品的3.5倍。
[Abstract]:Metal oxides have a wide range of applications, such as photocatalysis, biopharmaceutical and solar cells. In the literature, the traditional modification methods include element doping, morphology regulation and so on. However, impurity doping can be introduced into the material, and the self doping method can effectively solve the problem. The defect type TiO_2, Fe_3O_4 and SrTiO_3 were prepared and characterized by laser melting method. The study showed that: (1) the Ti_8O_ (15) phase appeared in the TiO_2 samples obtained after laser melting, and the band gap was reduced from 3.03 eV to 2.52 eV, indicating that the laser melting method successfully introduced oxygen in TiO_2. Defects and Ti~ (3+) can enhance their absorptive capacity to visible light. The defective TiO_2 not only has excellent photocatalytic degradation of organic matter and photocatalytic hydrogen production, but also has good stability after.TiO_2 laser melting, the hydrogen production rate is 8.54mmol/ (H. G), about 8 times that of commercial TiO_2 (P25) samples. (2) treatment of Fe_2O_3 by laser melting method. And Fe_3O_4, the Fe_3O_4. laser melting method finally obtained the transformation of Fe_2O_3 into Fe_3O_4, which indicates that the laser melting method successfully introduced the defect in Fe_3O_4. The defective Fe_3O_4 is a superparamagnetic material with high saturation magnetization, while the coercive force and the remanence are 6.6Oe and 0.4 emu/g (approximately zero), respectively. In addition, magnetocrystalline anisotropy The opposite sex is sensitive to temperature, so the saturation magnetization of Fe_3O_4 samples at low temperature is slightly enhanced after laser melting. (3) the phase composition of SrTiO_3 samples obtained after laser melting is not changed, but the band gap is reduced from 3.20 eV to 3.05 eV, indicating that laser melting method has successfully introduced defects in SrTiO_3 and thus enhanced S. RTiO_3 absorbs the visible light. The photocatalytic hydrogen production performance of the defective SrTiO_3 has improved, and has good cyclic stability. The hydrogen production rate after.SrTiO_3 laser melting is 2.46 mol/ (H. G), which is about 3.5 times that of the original sample.

【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ123.4
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本文编号：1779066