【作者】 张浩；

【导师】 殷立雄；

【作者基本信息】 陕西科技大学 ， 材料物理与化学， 2018， 硕士

【摘要】 随着工业的发展,大量工业有机物污染物排入水中造成水体受到严重污染,解决水体污染问题实现人与自然的和谐相处成为了科技工作者研究的热点。光催化技术是利用光激发半导体产生电子-空穴对的氧化还原能力对水中污染物进行氧化还原使得污染物转变为对水体没有污染的小分子。与传统的污水处理方式相比,光催化技术具有能耗低、二次污染小等特点。稀土元素具有特殊的能级结构,在光催化领域有着巨大的应用潜力。本论文探究了Sm（OH）₂Cl和SmOCl及其复合物的制备工艺,并研究了其光学性能、光催化性能。本论文以SmCl₃·H₂O为原料,采用溶剂热法制备出了Sm（OH）₂Cl晶体,探究了溶剂热过程中反应时间、添加剂加入量（TAA）及溶剂种类对Sm（OH）₂Cl晶体结构的影响,并对Sm（OH）₂Cl晶体的生长机制进行了探索。结果表明,由于TAA的加入使得Sm（OH）₂Cl晶体的生长方式发生变化。通过改变反应溶剂,可以获得具有不同微观结构的Sm（OH）₂Cl晶体。通过光降解罗丹明B对制备样品光催化活性进行了研究,采用异丙醇为溶剂制备的Sm（OH）₂Cl晶体对罗丹明B具有最高的降解活性。通过研究其能级结构发现该样品具有最低的导带电位,表明样品高的光催化性能可能是由于样品受光激发后光生电子具有最强的还原能力所致。通过两步法制备出了SmOCl晶体,研究了热处理温度、时间及前驱体结构对SmOCl晶体结构的影响。结果表明随着热处理温度的增加会导致（102）晶面发生偏移,同时热处理温度对制备SmOCl晶体的能级结构会产生较大影响。SmOCl晶体在生长过程中经历了晶粒析出、晶粒生长、晶粒自组装和晶体生成等四个生长阶段。采用乙醇为溶剂合成前驱体所制备样品暴露出了（110）晶面,而（110）晶面的暴露会导致样品的吸光性能发生蓝移。采用Ag负载SmOCl可以有效扩宽样品的光吸收范围改善样品的光催化性能。通过改变AgNO₃加入量研究了Ag负载量对制备样品光催化性能的影响,表明当AgNO₃加入量为15%时所制备样品对罗丹明B展示出了最好的降解活性,在光照70 min后,其对罗丹明B的降解达到了95%以上。通过选用不同晶体结构的SmOCl和Ag进行复合,表明（110）晶面的暴露不利于样品光催化性能的提升,这可能是由于（110）的暴露不利于光生载流子的迁移,导致光生电子-空穴的复合效率提高,使得电子-空穴对失去了催化活性。更多还原

【Abstract】 With the development of industry,a large amount of organic materials are discharged into the water and lead to serious pollution of the water.It is a hot research topic for scientists to solve the problem of water pollution in harmony between man and nature.Photocatalytic technology can utilize illumination induced semiconductor to produce redox ability of electron-hole pairs which can redox pollutants in water into environmentally friendly small molecules.Photocatalytic technology usually possess advantages of low energy consumption and low secondary pollution compared with the traditional sewage treatment.Rare earth elements can generally show great potential in the field of catalysis and optics due to its special band structure.It is particularly important for our country to extend the field of application of rare earth materials because of the large reserves of rare earth elements in our country.The preparation process of Sm（OH）₂Cl,SmOCl and their composites were investigated,and their optical properties and photocatalytic properties were studied in our work.Sm（OH）₂Cl crystals were synthesized by solvothermal method with SmCl₃·H₂O as raw material.The effects of reaction time,addition amount of Thioacetamide（TAA）and solvent type on the crystal structure of Sm（OH）₂Cl were studied.The growth mechanism of Sm（OH）₂Cl crystal was also explored.The results show that the growth mechanism of Sm（OH）₂Cl crystals maybe change due to the addition of TAA.Sm（OH）₂Cl crystals with different microstructures can be obtained by changing the reaction solvent.The photocatalytic activity of prepared samples was studied by degradation of Rhodamine B（Rh B）,indicating that Sm（OH）₂Cl crystals prepared with isopropanol（IPA）have the highest degradation activity on Rhodamine B.It is found that the sample has the lowest conduction band during studying its band structure,which leads to the photo-generated electrons have the stronger reducing power and results in the highest photocatalytic activity of the sample.SmOCl crystals were prepared by two-step method,and the effects of heat treatment temperature,time and precursor structure on the crystal structure of SmOCl were investigated.The results show that the（102）crystal plane can shifts with the increase of the heat treatment temperature,and the heat treatment temperature greatly affects the band structure of the SmOCl crystal.The growth mechanism of SmOCl crystal was studied during the heat treatment,and SmOCl crystal underwent four growth stages,including grain growth,grain growth,crystal self-assembly and crystal growth.The sample prepared by using ethanol as the solvent for the synthesis of the precursor can exposure of the（110）crystal plane of SmOCl,which leads to blue shift of the absorbance of the sample.Ag laden SmOCl can effectively widen the light absorption range and improve the photocatalytic performance of the sample.The photocatalytic activity of prepared samples with different addition amount of Ag was investigated.The results show that the prepared sample exhibited the best degradation activity to Rhodamine B when the addition amount of Ag was 15%,and the degradation of Rhodamine B reached more than 95%after 70 min of illumination.We investigated Ag laden SmOCl with different crystal structures and result indicates that the exposure of the（110）crystal plane is not conducive to the improvement of the photocatalytic performance of the sample.This may be due to the fact that the exposure of（110）crystal plane is adverse to the migration of photo-generated carriers,results in the increase of recombination efficiency of photo-generated electron-holes and leads to the loss of catalytic activity of electron-hole pairs.更多还原