层状化合物论文：不同温度退火下纳米片的发光和Cu_2O修饰对其催化活性的影响.docVIP

层状化合物论文：不同温度退火下H_(1.77)[Sr_(0.8)Bi_(0.21)Ta_2O_7]纳米片的发光及Cu_2O修饰对其催化活性的影响 【中文摘要】Bi2SrTa2O9 （BST）是一种传统的铁电材料,它的薄膜具有比较好的铁电性质而受到比较多的研究。BST是一类层状钙钛矿氧化物,层间距比较大,层之间的离子结合也不是很牢固,里面的离子容易移动,因此可以利用化学方式剥离。BST通过酸处理质子化生成薄层状的H1.77,它展示出一些有趣的物理性质,比如在紫外光辐照下一定的光解水能力和在305nm左右波长的光激发下的蓝光发射。但对这类材料的微结构和物理性质等的认识才刚开始,研究有待深入。本论文讨论了以下两个方面,一是退火温度对H1.77的发光影响,期望理解这类材料在不同退火温度下结构变化及其发光性质变化之间的联系;二是采用不同浓度Cu2O包裹H1.77,期望获得好的光催化活性。首先用固相烧结的方法制备BST陶瓷颗粒,然后用盐酸处理BST颗粒制备出薄层状H1.77,研究了不同脱水条件下, H1.77粉末的微结构和发光性质的变化。研究结果表明:（1）热重分析显示了温度从2000C到4000C明显脱水现象。（2）退火温度从2000C到4000C,激发峰和发光峰的位置朝长波长方向偏移,且4000C退火的样品峰值的强度最大。（3）在脱水过程中微结构即其四方结构c轴的变化趋势和激发峰位置的变化趋势相一致。论文对上述现象给与了解释。相关结果已发表在Materials Research Bulletin。另外,根据文献报道,禁带宽度2.0eV左右的p型半导体Cu2O对于提高TiO2太阳光光催化利用是个非常好的敏化剂,因为TiO2/Cu2O异质结结构一方面可以有效阻止电子空穴对的复合,另一方面可以提高对可见光的吸收范围。H1.77是一种禁带宽度比较大的n型半导体,它只有紫外光活性。本论文制备了Cu2O/ H1.77异质结构,研究了含有不同浓度的Cu2O的异质结构在可见光下降解罗丹明B光催化性质效率,发现了异质结构确实能增强H1.77的光催化活性,含有Cu2O质量分数为10%时的光催化效果是最好的。 【英文摘要】Bi2SrTa2O9 （BST） is a traditional ferroelectric material. It has attracted much attention since its excellent ferroelectric properties in the form of thin film. BST could be protonated into H1.77[Sr0.8Bi0.21Ta2O7] through an acid treatment because its layer distance is relatively large and interlayer ion is feasibly removable. Thus, it exhibited interesting properties, such as effective water splitting ability under UV light irradiation and emission of blue light under the excitation of near 305 nm. The layered perovskite microstructural and physical properties has just begun to be studied. In the thesis, we discussed two parts, one is the effect of annealing on the photoluminescence of layered perovskite H1.77[Sr0.8Bi0.21Ta2O7] powders. The other is to have a try to enhance its photocatalytic efficiencies using the combination of Cu2O.Firstly, the synthesis of BST powder was conducted by a conventional solid-state procedure. H1.77[Sr0.8Bi0.21Ta2O7] could be obtained by an HCl treatment. The microstructural and luminescent properties of H1.77[Sr0.8Bi0.21Ta2O7] powders und