掺氮、还原石墨烯量子点的一步温和制备及其环境催化应用研究

发布时间：2018-01-04 17:17

  本文关键词：掺氮、还原石墨烯量子点的一步温和制备及其环境催化应用研究　出处：《中国科学院大学(中国科学院过程工程研究所)》2017年硕士论文　论文类型：学位论文

  更多相关文章： 还原石墨烯量子点 掺氮 无金属芬顿 一步制备 环境催化

【摘要】：以氧化石墨烯(GO)为原料,通过一步还原制备得到掺氮、还原性的石墨烯量子点(Nitrogen-doped reduced graphene oxide quantum dots,N-rGQDs),其具有良好的荧光性能、化学稳定性及生物兼容性,目前已被广泛应用于生物成像、光催化、能量转换等领域。然而,N-rGQDs的制备通常采用较复杂、高能耗的两步法,且N-rGQDs表面结构可控性差。因此,本课题提出了一种温和、一步制备N-rGQDs的绿色制备方法,且在制备过程中同时实现尺寸、结构可控;制备得到的量子点具有良好的环境催化应用前景,本课题对其在环境催化领域的催化性能和机理进行了探讨和分析,取得了以下创新性成果:1)在常温常压下,利用无金属芬顿切割制得N-rGQDs,N-rGQDs切割制备过程进行的跟踪、分析和监控结果显示,发现氧化石墨烯量子点的氧化损伤有一定修复,其含有的C-O键和C=O键降低了 21%,并成功实现了对芳环氮(Nar)、叔胺氮[Ar-N-(CH3)2]以及氨基氮(C-NH2)三种主要含氮结构的有效控制。因N-rGQDs具有优异的催化性能,本文将其应用在了臭氧催化体系,并通过计算化学手段对催化机理进行了分析探讨,得出N-rGQDs的三种N结构中Nar为主要活性位点,Ar-N-(CH3)2为辅助活性位点,为定向调控和制备高效催化剂提供了思路。2)设计、制备并最终获得了一种光催化活性较强的多孔C3N4/N-rGQDs复合光催化剂,并考察了 N-rGQDs结构、负载量对催化性能的影响。复合光催化剂的光催化性能对照组提升1.8倍,从不同N-rGQDs结构、N-rGQDs负载量等角度探讨了催化机理,发现N-rGQDs中的Nar结构最有利于促进催化活性,通过优化条件,N-rGQDs的最佳负载量为 gN-rGQDs/g多孔C3N4=3.4× 10-5。3)选取最优结构的N-rGQDs及负载条件,制备得到N-rGQDs与不同结构C3N4复合的光催化材料,并主要从材料物理形貌特点和化学键改变情况两个角度考察不同C3N4结构对光催化性能的影响。体相C3N4/N-rGQD5、多孔C3N4/N-rGQD5以及纳米片层C3N4/N-rGQD5三种材料作为催化剂时,目标污染物的去除率依次为53.8%,98.0%和99.0%。由此可见,具有多孔和纳米片层结构的复合材料有利于促进材料的复合效率。
[Abstract]:Using graphene oxide (GOO) as raw material, nitrogen was prepared by one step reduction. Reduced graphene quantum dots Nitrogen-doped reduced graphene oxide quantum dots. N-rGQDsO, with good fluorescence properties, chemical stability and biocompatibility, has been widely used in biological imaging, photocatalysis, energy conversion and other fields. The preparation of N-rGQDs is usually by two-step method with complex and high energy consumption, and the surface structure of N-rGQDs has poor controllability. Therefore, a mild method is proposed in this paper. The green preparation method of N-rGQDs is one-step, and the size and structure of N-rGQDs are controlled simultaneously in the preparation process. The prepared QDs have a good prospect of environmental catalysis. In this paper, the catalytic performance and mechanism of QDs in the field of environmental catalysis are discussed and analyzed. At room temperature and atmospheric pressure, N-rGQDsN-rGQDs were obtained by non-metal Fenton cutting. The results showed that the process of N-rGQDsN-rGQDs was tracked, analyzed and monitored. It was found that the oxidative damage of graphene oxide QDs was repaired to some extent, and the C-O bond and Cno bond contained in the QDs were reduced by 21%, and the aryl cyclic nitrogen Naran and tertiary amine nitrogen were successfully realized. [Ar-N-(CH3)2] and amino nitrogen C-NH _ 2) were effectively controlled because N-rGQDs had excellent catalytic performance. In this paper, the catalytic mechanism of N-rGQDs was analyzed and discussed by means of computational chemistry. It was found that Nar was the main active site in the three N structures of N-rGQDs. Ar-N-(CH3)2 is the auxiliary active site, which provides the design of orientation regulation and preparation of high activity catalyst. 2). A porous C3N4 / N-rGQDs composite photocatalyst with strong photocatalytic activity was prepared and the structure of N-rGQDs was investigated. The effect of loading amount on the catalytic performance. The photocatalytic performance of the composite photocatalyst was 1.8 times higher than that of the control group. The catalytic mechanism was discussed from the different N-rGQDs structure and the loading amount of N-rGQDs. It was found that the structure of Nar in N-rGQDs was the most favorable to promote the catalytic activity by optimizing the conditions. The optimal loading amount of N-rGQDs is gN-rGQDs/g porous C3N4N 3.4 脳 10-5.3) the optimal structure N-rGQDs and loading conditions are selected. N-rGQDs and C _ 3N _ 4 with different structures were prepared. The effects of different C _ 3N _ 4 structures on photocatalytic properties were investigated from the aspects of physical morphology and chemical bond changes. The bulk C _ 3N _ 4 / N-rGQD5 was investigated. When porous C _ 3N _ 4 / N-rGQD _ 5 and nano-scale C _ 3N _ 4 / N _ r GQD _ 5 were used as catalysts, the removal efficiency of target pollutants was 53.8%. It can be seen that the composite materials with porous and nanolamellar structures can promote the composite efficiency.
【学位授予单位】：中国科学院大学(中国科学院过程工程研究所)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11;X505;O643.36
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本文编号：1379338