石墨烯与MOF复合材料的合成及性能研究

发布时间：2018-11-29 08:44

【摘要】：近年来,金属-有机骨架(MOFs)由于具有可控的纳米结构、超高的孔隙率和大的比表面积,从而成为潜在的存储气体的媒介。二维的石墨烯片上下表面有-OH、-C-O-C-官能团,边缘有.COOH官能团,因此可以利用石墨烯表面的官能团或对石墨烯的官能团进行功能化,进而实现石墨烯或功能化石墨烯与金属有机骨架的面-面组装。本论文利用功能化石墨烯与HKUST-1、氧化石墨烯及石墨烯与NENU-5、石墨烯量子点与HKUST-1形成了一系列的复合材料。由于两者的协同作用,表现出良好的C02吸脱附和HER性能。(1)将表面含有羟基和桥氧基的氧化石墨烯(GO)还原,然后将化学还原的GO进行功能化得到功能化石墨烯(BFG)。接着将BFG与合成HKUST-1的前驱物混合得到BFG/HKUST-1=1:3、1:4、1:5的复合材料。为了证明所得复合材料的孔结构,进行了77 K,1 atm条件下的N2吸附测试,结果表明该系列复合材料均属于微孔结构。在273 K,1 atm条件下测得的CO2吸附表明,当BFG/HKUST-1=1:5时,其C02吸附量为8.84 mmol/g,比HKUST-1提高31%。当BFG/HKUST-1=1:3时,其HER的起始电位最低,电流密度最大,塔菲尔斜率最小,因此可作为降低HER活化能的催化材料。(2)我们利用溶液法和研磨法合成了一系列的GO/NENU-5=4%、6%、15%复合材料。在77 K,1 atm条件下测得的N2吸附表明,GO/NENU-5=4%、6%、15%复合材料均属于微孔结构。273 K,1 arm条件下C02及CH4吸附表明,复合材料中GO的加入并不能提高C02、CH4的吸附量。当GO/NENU-5=6%时,该复合材料的起始电位最正,电流密度最大,塔菲尔斜率最小,说明该材料是—种较好的降低HER活化能的材料。另一方面,合成了一系列rGO/NENU-5=4%、6%、15%复合材料。然而,在273 K,1 arm条件下,该系列的复合材料并不能提高C02、CH4的吸附量。但是当rGO/NENU-5=15%时,该复合材料HER的性能最好。(3)我们使用了一种简单的方法合成了石墨烯量子点(GQDs)。通过将GQDs与合成HKUST-1的前驱物混合得到了一系列GQDs/HKUST-1=3:1、1:5、2：5的混合物。在77 K,1 atm条件下的N2吸附表明,该系列复合材料均属于微孔结构。然而,复合材料中GQDs的加入并不能提高复合材料的CH4 (273 K,1 atm)吸附能力。当GQDs/HKUST-1=2:5寸,其273 K,1 atm条件下的C02吸附量为9.30 mmol/g,比单纯的HKUST-1提高38%,说明该复合材料是一种极好的CO2储存媒介。
[Abstract]:In recent years, metal-organic skeleton (MOFs) has become a potential gas storage medium due to its controllable nanostructure, high porosity and large specific surface area. There are-OH,-C-O-C- functional groups on the upper and lower surfaces and. COOH functional groups on the edge of the two-dimensional graphene sheets. Therefore, the functional groups on the graphene surface or on the graphene functional groups can be used to functionalize the graphene functional groups. Then the surface-surface assembly of graphene or functionalized graphene and organometallic skeleton is realized. In this paper, a series of composite materials were formed by functionalized graphene and HKUST-1, oxide, graphene and NENU-5, graphene quantum dots and HKUST-1. Because of the synergistic effect of the two methods, the adsorbing and desorption properties of CO2 and HER are good. (1) the graphene oxide (GO) with hydroxyl and bridged groups on the surface is reduced, and then the chemically reduced GO is functionalized to obtain the functionalized graphene (BFG). Then the BFG/HKUST-1=1:3,1:4,1:5 composite was obtained by mixing BFG with the precursor of synthetic HKUST-1. In order to prove the pore structure of the composites, N _ 2 adsorption at 77K ~ (-1) atm was carried out. The results showed that the composites were all microporous. The adsorption of CO2 at 273 K ~ (-1) atm shows that the adsorption capacity of CO2 at BFG/HKUST-1=1:5 is 8.84 mmol/g, which is 31cm higher than that of HKUST-1. When BFG/HKUST-1=1:3 is used, the HER has the lowest initial potential, the highest current density and the lowest Taffel slope. Therefore, it can be used as a catalytic material to reduce the activation energy of HER. (2) A series of GO/NENU-5=4%,6%,15% composites were synthesized by solution method and grinding method. The N _ 2 adsorption at 77K ~ (-1) atm showed that the GO/NENU-5=4%,6%,15% composites were of microporous structure. The adsorption of C02 and CH4 at 273K ~ (-1) arm showed that the addition of GO in the composites could not improve C02. The adsorption capacity of CH4. When GO/NENU-5= is 6, the initial potential, current density and Taffel slope of the composite are the most positive, and the Taffer slope is the smallest, which indicates that the composite is a better material for reducing the activation energy of HER. On the other hand, a series of rGO/NENU-5=4%,6%,15% composites were synthesized. However, under the condition of 273K ~ (-1) arm, the adsorption capacity of C _ (02) H _ (4) was not increased by the composite. But when rGO/NENU-5= is 15, the composite HER has the best properties. (3) We have synthesized graphene quantum dots (GQDs).) by a simple method. A series of GQDs/HKUST-1=3:1,1:5,2:5 mixtures were obtained by mixing GQDs with the precursor of synthetic HKUST-1. The N _ 2 adsorption at 77K ~ (-1) atm shows that the composites are of microporous structure. However, the addition of GQDs in the composites can not improve the adsorption ability of CH4 (273K ~ (-1) atm). The adsorptive capacity of CO2 in GQDs/HKUST-1=2:5 inch is 9.30 mmol/g, and the adsorption capacity of CO2 is 9.30 mmol/g, which indicates that the composite is an excellent storage medium for CO2.
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332

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