层状钒氧酸盐合成,表征及质子导电性质毕业论文
2022-01-09 21:19:21
论文总字数:18505字
摘 要
钒作为前过渡金属元素,其具有多种不同的价态(V3 ,V4 ,V5 ),并且其可以与氧原子形成不同的钒氧多面体。而钒氧多面体通过共边或者共角的方式可以形成钒氧簇,钒氧层等结构,其中层状钒氧酸盐具有可插层性质,受到科研工作者的广泛关注。而关于层状钒氧酸盐的质子导电性质的研究相对较少。
本文首先对层状钒氧酸盐的研究进展进行讨论,详细描述了部分已合成的钒氧酸盐的种类和结构,并讨论了质子传导的定义、意义、研究进展和研究重点。
论文的第二章描述了通过水热法合成[C6H14N2][V6O14]·H2O(1),详细说明了所合成的目标化合物的原料与试剂、所用仪器与实验过程。
论文的第三章列出了经表征所知的该目标化合物的不对成单元、钒氧阴离子层立体结构、晶胞堆积图、并详细得对晶型、点群和结构做出描述。此外,我们还测试了化合物1在有湿度和无湿度环境下的质子电导率。化合物1在无湿度环境中,电导率表现出较强的温度依赖性,当温度达到473 K时,电导率可以达到7.06×10-7 Scm-1,相比于303 K,电导率提高了三个数量级。但化合物1处于有湿度的环境中,质子导电性质相比于无湿度环境,会发生大幅度提高。化合物1在室温,相对湿度99%的条件下,离子电导率为5.01×10-4 Scm-1。相比于在303 K,在无湿度条件下,化合物1的电导率1.94×10-10 Scm-1,提高了6个数量级。说明化合物吸水可以有效增加氢键网络的密度,有效提高化合物1的质子电导率。
最后,得出关于目标化合物水热稳定性的推测性结论,并基于本论文研究内容,对未来的进一步研究进行了展望。
关键词:层状钒氧酸盐 质子导电 水热合成
Abstract
Vanadium as a pre-transition metal element has many different valence states (V3 , V4 , V5 ), and it can form different vanadium-oxygen polyhedra with oxygen atoms. Vanadium polyhedrons can form vanadium oxygen clusters, vanadium oxide layers and other structures through co-edges or co-angles. Among them, layered vanadium oxide salts have intercalable properties, and have attracted wide attention from researchers. However, there are relatively few studies on the proton conductive properties of layered vanadate.
This article first discusses the research progress of layered vanadate, describes in detail the types and structures of some of the synthesized vanadate, and discusses the definition, significance, research progress and research focus of proton conduction.
The second chapter of the thesis describes the synthesis of [C6H14N2] [V6O14] • H2O (1) by hydrothermal method, and details the raw materials and reagents of the target compounds synthesized, the instruments and experimental procedures used.
The third chapter of the thesis lists the misaligned units, the three-dimensional structure of the vanadium oxyanion layer, the unit cell stack diagram known by the characterization, and describes the crystal form, point group and structure in detail. In addition, we also tested the proton conductivity of compound 1 in the presence and absence of humidity. In the humidity-free environment, the conductivity of compound 1 shows a strong temperature dependence. When the temperature reaches 473 K, the conductivity can reach 7.06 × 10-7 Scm-1, which is three orders of magnitude higher than 303 K. However, when compound 1 is in a humid environment, the proton conductivity will be greatly improved compared to a non-humid environment. Compound 1 has an ion conductivity of 5.01 × 10-4 Scm-1 at room temperature and a relative humidity of 99%. Compared with 303 K, under no humidity conditions, the conductivity of compound 1 is 1.94 × 10-10 Scm-1, an increase of 6 orders of magnitude. It shows that the water absorption of the compound can effectively increase the density of the hydrogen bonding network and effectively improve the proton conductivity of compound 1.
Finally, we draw a speculative conclusion about the hydrothermal stability of the target compound, and based on the research content of this paper, we look forward to further research in the future.
目录
摘要 I
第一章 绪论 1
1.1层状钒氧酸盐 1
1.2 层状钒氧酸盐的种类 1
1.3质子传导机理 4
1.4质子导电材料 5
1.5 本论文选题思路 7
第二章实验部分 8
2.1 原料与试剂 8
2.2 实验仪器与方法 8
2.3 [C6H14N2][V6O14]·H2O(1)的制备 9
第三章 结构与讨论 10
3.1 化合物1晶体结构 10
3.2 粉末x射线衍射分析 12
3.3 化合物1无水质子导体 13
3.4 化合物1有湿度条件下的质子导电性 14
第四章 结论与展望 16
4.1 结论 16
4.2 展望 16
参考文献 18
致谢 21
第一章 绪论
1.1 层状钒氧酸盐
钒是一种前过渡金属元素,可以与氧原子通过共价键形成不同构型的钒氧多面体。钒氧多面体之间可以通过共边或者共顶点的方式相互连接形成不同维度的钒氧结构单元。其中钒氧阴离子层可以与不同阳离子形成不同的层状钒氧酸盐。层状钒氧酸盐不仅具有多样的结构,而且其结构具有独特的可插层性,在离子导体,电极材料,电催化等领域有着广泛的运用。而层状钒氧酸酸盐在质子导体领域还没有深入的研究。
1.2 层状钒氧酸盐的种类
由于钒氧多面体的多样性,所以钒氧阴离子层表现出结构的多样性,已知的钒氧阴离子层结构单元存在V3O7-,V3O82-,V4O102-,V4O92-等,而这些钒氧酸盐层间可以是碱金属离子(Na ,Li 等),有机胺阳离子(乙二胺阳离子,咪唑阳离子,哌嗪阳离子等),无机胺阳离子(NH4 ),所以层状钒氧酸盐化合物种类繁多,其也一直都是科研工作者研究的重点。
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