含铋类普鲁士蓝化合物的热转化及其产物的应用研究

发布时间：2018-06-20 19:56

本文选题：类普鲁士蓝 + 介晶　；参考：《华东师范大学》2015年硕士论文

【摘要】：在近几年的研究中,类普鲁士蓝(PBA)这一类金属有机框架物的应用越来越受到关注。而将其作为一种前驱体通过热转化得到形貌各异,结构多样,用途广泛的各类金属氧化物也取得大量的研究成果。本工作选取一类铋系的含氧酸盐和氧化物作为目标产物,特别是多功能性的BiFeO3和Bi2O3,研究了含铋类普鲁士蓝向这类化合物的热转换过程,及目标产物的应用。具体工作主要分为以下三个方面：1.X片状类普鲁士蓝介晶向单晶多孔钙钛矿结构金属氧化物的低温热转化通过在酸性条件下,以柠檬酸三钠(Sc)和聚乙烯吡咯烷酮(PVP)作为减速剂,通过硝酸铋和铁氰化钾室温共沉淀的方法,得到X型片状结构的纯相Bi-Fe PBA介晶。通过对不同反应时段样品SEM图表明Bi-Fe PBA是由纳米级单晶快速取向聚集形成超大的介晶颗粒。将得到的Bi-Fe PBA介晶在400℃条件下煅烧2h得到纯相的钙钛矿结构BiFeO3。通过SEM结果显示煅烧后产物形貌与前驱体保持一致,并产生多孔结构。,TEM分析显示煅烧后产物为单晶。研究表明,这种介晶到单晶的转换经历了无定型的中间过程。这有效地避免了较高的能耗,相较于传统固相反应法,合成温度降低了将近400℃,这对于工业化具有潜在的商业价值。该发现提供了一种制备单晶介孔材料的新途径。以这种单晶多孔结构BiFeO3作为光催化剂对罗丹明B有机物进行降解,发现在4h内降解了97%的有机物,表现出良好的催化效率。2.单分散的掺镧Bi-Fe PBA的合成及其热转化产物Bi1-xLaxFeO3的介电响应在室温条件下,以前一体系的合成方法为基础,在硝酸铋的酸溶液中添加不同摩尔比例的硝酸镧。与铁氰化钾的酸溶液均匀混合得到掺镧的Bi-Fe PBA。通过SEM发现不同掺镧比的样品的形貌结构相同,呈棱柱状微米级颗粒。TEM可发现样品均为典型的介晶颗粒。在空气气氛中,400℃条件下煅烧前驱物得到纯相的Bi1-xLaxFeO3。通过SEM, TEM发现样品均保持与前驱物的形貌一致,同样为介晶颗粒,并存在多孔结构。这说明,利用这种单晶到单晶热转化的方法可作为一种有效的掺杂途径。BET和VSM测试显示随着掺镧比的增加,样品的比表面积和磁性有所增加,这说明通过镧的掺入对晶体结构有一定的影响,有助于BiFeO3内禀磁性的释放。作为一种典型的钙钛矿结构氧化物,BiFeO3是少数能够在室温下铁磁性和铁电性共存的多铁材料,这种多孔结构Bi1-xLaxFeO3存在一定的介电响应。3. Bi-Co PBA多晶向多孔Bi2-xCoxO3的热转化及其光催化性能研究通过按摩尔计量比称量的硝酸铋的酸溶液均匀混合到含有钴氰化钾的酸性溶液,室温条件下恒温6h得到得到纯相的Bi-Co PBA。通过SEM图像分析说明Bi-Co PBA颗粒为长方形块状,表面粗糙。在500℃,空气气氛条件下煅烧2h得到黑色的粉末。对比XRD标准卡和EDS确定产物为高比例Co掺杂的(Bi2-xCoxO3),掺杂量为x≈0.5。而这种高比例的掺杂量并未发生相分离,这在文献中少见报道。通过紫外可见光吸收光谱发现,相对于商业Bi2O3,样品Bi2-xCoxO3的吸收峰发生了红移,并且在整个可见光范围都有吸收作用。通过对比商业Bi2O3, Co3+的掺杂使得Bi2O3的具有微弱的铁磁性。在对于有机物罗丹明B的光催化效果方面,样品表现出了相对较好的降解性能。
[Abstract]:In recent years, the application of the metal like organic frame like Prussian blue (PBA) has attracted more and more attention, and a large number of research results have been obtained as a precursor of various kinds of metal oxides with different morphologies, various structures and wide uses. As the target products, especially the multi-functional BiFeO3 and Bi2O3, the thermal conversion process of bismuth Prussian blue to these compounds and the application of the target products are studied. The specific work is mainly divided into three aspects: the low temperature thermal transformation of the 1.X plate-like Prussian Lan Jiejing to the single crystal porous calcium titanium structure metal oxide. Under the acid condition, the pure phase Bi-Fe PBA mesophase of X type sheet structure was obtained by the method of co precipitation of bismuth nitrate and polyvinylpyrrolidone (PVP) as decelerator, through the co precipitation of bismuth nitrate and potassium ferricyanide at room temperature. Through the SEM diagram of the samples at different reaction periods, the Bi-Fe PBA was formed by the rapid orientation of the nanoscale single crystal to form the super large PBA. Mesocrystalline particles. The Bi-Fe PBA mesocrystalline was calcined at 400 centigrade to get the perovskite structure of the pure phase, and the perovskite structure of the pure phase was obtained by the SEM result. The results showed that the morphology of the product was consistent with the precursor and produced the porous structure. The TEM analysis showed that the calcined product was single crystal. The study showed that the transformation of this kind of mesophase to single crystal has experienced an amorphous structure. The intermediate process. This effectively avoids the high energy consumption. Compared with the traditional solid state reaction method, the synthesis temperature is reduced by nearly 400 degrees C, which has potential commercial value for industrialization. The discovery provides a new way to prepare the single crystal mesoporous materials. This single crystal porous structure BiFeO3 is used as a photocatalyst to the Luo Danming B organic matter. It was found that 97% of organic matter was degraded in 4h, showing a good catalytic efficiency of.2. monodisperse lanthanum doped Bi-Fe PBA and the dielectric response of Bi1-xLaxFeO3 in the heat conversion product at room temperature. At room temperature, the synthesis method of the previous system was based on the addition of lanthanum nitrate with different molar ratios in the acid solution of bismuth nitrate and iron cyanide. The Bi-Fe PBA. of lanthanum mixed with the acid solution of the potassium chloride is obtained by SEM. The samples with different lanthanum ratio are found to have the same morphology and structure, and the prismatic micron grade particle.TEM can find that all the samples are typical mesocrystalline particles. In the air atmosphere, the calcined precursors of the calcined precursors at 400 degrees C are obtained through SEM, and TEM is found to be preserved by TEM. This shows that the method of using this single crystal to the single crystal heat conversion can be used as an effective doping method.BET and VSM test to show that the specific surface area and magnetic properties of the sample increase with the increase of the ratio of lanthanum, which indicates that the crystal structure is doped through the addition of Lanthanum. It is helpful to the release of intrinsic magnetic properties of BiFeO3. As a typical perovskite structure oxide, BiFeO3 is a few ferromagnetic materials capable of coexisting ferromagnetism and ferroelectricity at room temperature. This porous structure Bi1-xLaxFeO3 has a certain dielectric response to the thermal transformation of.3. Bi-Co PBA polycrystalline to porous Bi2-xCoxO3 and its light acceleration. The study of chemical properties is even mixed with acid solution of bismuth nitrate, which is weighed by massage, to acid solution containing cobalt cyanide. At room temperature, the Bi-Co PBA. of pure phase is obtained at constant temperature 6h to show that Bi-Co PBA particles are rectangular block and surface is rough. At 500 degrees, the calcined 2H gets black under air atmosphere. A high proportion of Co doped (Bi2-xCoxO3) is compared to the XRD standard card and EDS, and the amount of doping is x 0.5., and the high proportion of doping does not occur. This is rarely reported in the literature. A visible light range have absorption effect. By comparing the commercial Bi2O3, Co3+ doped Bi2O3 with weak ferromagnetic. In the photocatalytic effect on organic matter of rhodamine B, the sample shows relatively good performance degradation.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ135.32

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