石墨烯基多酸复合材料的制备、表征及性能研究

发布时间：2018-04-16 13:11

本文选题：多金属氧酸盐 + 石墨烯　；参考：《辽宁师范大学》2015年硕士论文

【摘要】：多金属氧酸盐(简称多酸)易于在原子和分子水平上进行结构调变和修饰,因多样的几何与电子结构,具有优异的氧化还原性质和较好稳定性。同时,多酸还是一类环境友好型功能材料,在催化、医药、磁性及光学材料等领域具有广泛的应用前景。然而,多金属氧簇比表面积小、不易分离和回收困难等缺点限制了它的应用。实现多金属氧簇与其他功能材料的复合,是突破多金属氧酸盐应用瓶颈的重要途径。本工作以制备氧化石墨工艺为主体,通过原位合成法合成石墨烯基多酸(POMs/GS)复合材料。探索了反应条件对实验结果的影响,优化了各项合成工艺参数,制备出一系列石墨烯基多酸复合材料。利用红外光谱(FT-IR)、X-射线粉末衍射(XRD)、拉曼光谱(Raman)、扫描电镜(SEM)、热重(TG)等技术手段,对自制复合物的结构进行了科学表征。通过对该类复合材料进行循环伏安(CV)及氧化脱硫性能测试,深入研究并讨论了新型复合材料的电化学性能和催化氧化脱硫特性。论文主要工作和研究结果如下:1.采用原位合成法制备了石墨烯基Dawson类型磷钼酸复合物。通过大量实验研究,对各项合成条件进行探索,选择并确定了最佳工艺条件及路线。结果表明,当低温插层时间7h,中温氧化时间为40min时,得到产物中磷钼酸微粒可均匀分布在氧化石墨烯片层中,石墨烯片层结构完整,表面缺陷相对较少。2.石石墨烯基取代型磷钼酸复合材料的合成。选取石墨烯及PMo11V、PMo10V2等取代型磷钼酸为构筑基元,合成了系列取代型磷钼酸石墨烯杂化材料。对新材料进行了IR、Raman、XRD、TG等结构测试,实验结果表明,复合材料中各取代型磷钼酸的结构完整,石墨烯片层的缺陷度较少。所选工艺的氧化程度适中,石墨化效果优异。新材料的对热稳定性较比多酸原料得到了较大改善。3.石墨烯基多酸复合材料的电化学性能研究。以碳糊电极为基底,用滴涂法制得多酸石墨烯复合材料的修饰电极。循环伏安实验测试结果表明,自制复合材料的电化学性能与母体多酸相似,循环伏安曲线中显现出明显的多酸的电化学特征。这预期该类复合材料具有潜在的催化氧化活性。4.石墨烯基多酸复合材料催化氧化脱硫实验研究。以所制石墨烯基多酸催化材料为催化剂,H2O2为氧化剂,进行催化二苯并噻吩氧化脱硫实验研究。结果表明,新型催化材料对二苯并噻吩催化脱硫效果明显。由于新型催化材料难溶于反应体系中的极性有机溶剂,催化剂的分离和回收问题得到很好的解决,降低了生产成本。催化剂的重复使用研究表明,新型复合材料可循环再生利用。新催化材料具有催化活性高、选择性好且寿命较长的优异特性。
[Abstract]:Polyoxometalates (polyoxometalates) are easy to modify and modify at the atomic and molecular levels. Because of their various geometric and electronic structures, polyoxometalates have excellent redox properties and good stability.At the same time, polyacids are also a class of environment-friendly functional materials, which have a wide range of applications in catalysis, medicine, magnetic and optical materials.However, its application is limited by its small specific surface area, difficulty in separation and recovery.It is an important way to break through the bottleneck of application of polyoxometalates to realize the compounding of polyoxometalates with other functional materials.In this work, graphene polyacid POMs / GScomposites were synthesized by in-situ synthesis of graphite oxide.The influence of reaction conditions on the experimental results was explored. The synthesis parameters were optimized and a series of graphene polyacid composites were prepared.The structure of the self-made composite was characterized scientifically by means of infrared spectroscopy (FT-IR), X-ray powder diffraction (XRDX), Raman spectroscopy (Ram), scanning electron microscope (SEM), thermogravimetric (TG) and so on.The electrochemical and catalytic oxidation desulfurization properties of the composites were studied and discussed by means of cyclic voltammetry (CV) and oxidative desulfurization test.The main work and results are as follows: 1.Graphene-based Dawson-type phosphomolybdate complexes were prepared by in situ synthesis.Through a large number of experimental studies, various synthetic conditions were explored, and the optimum technological conditions and routes were selected and determined.The results show that when the intercalation time at low temperature is 7 h and the oxidation time is 40min at moderate temperature, the phosphomolybdic acid particles in the product can be uniformly distributed in the graphene oxide lamellae, the structure of the graphene layer is complete, and the surface defects are relatively few. 2.Synthesis of Shigene substituted phosphomolybdic Acid Composites.A series of substituted graphene phosphomolybdate hybrid materials were synthesized by using substituted phosphomolybdic acid, such as graphene and PMo11V, PMo10V2, as building units.The structure of the new material was tested by IR Ramanhe XRDX TG and the experimental results showed that the structure of the substituted phosphomolybdic acid in the composite was complete and the defect degree of the graphene lamellar was less.The oxidation degree of the selected process is moderate and the graphitization effect is excellent.The thermal stability of the new material is much better than that of the polyacid raw material.Study on Electrochemical Properties of Graphene Polyacid Composites.The modified carbon paste electrode was prepared by drip coating method.The results of cyclic voltammetry test show that the electrochemical properties of the composite are similar to those of the parent polyacid, and the electrochemical characteristics of polyacid are obvious in the cyclic voltammetry curve.It is expected that the composite has potential catalytic oxidation activity. 4. 4.Experimental study on Catalytic Oxidation Desulfurization of Graphene Polyacid Composites.The catalytic oxidation desulfurization of dibenzothiophene was studied using graphene polyacid as catalyst and H _ 2O _ 2 as oxidant.The results showed that the catalytic desulfurization of dibenzothiophene by the new catalytic material was obvious.The separation and recovery of the catalyst are well solved and the production cost is reduced because the new catalytic materials are insoluble in the polar organic solvents in the reaction system.The study of catalyst reuse shows that the new composite material can be recycled and reused.The new catalytic materials have the advantages of high catalytic activity, good selectivity and long life.
【学位授予单位】：辽宁师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332

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