Yue Man-Li, Jiang Yi-Fan, Zhang Lin, Yu Cheng-Yan, Zou Kang-Yu, Li Zuo-Xi
College of Chemistry and Material Sciences, Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), Shaanxi Key Laboratory of Physico-Inorganic Chemistry, Northwest University, Xi'an, 710069, P. R. China.
Chemistry. 2017 Nov 7;23(62):15680-15693. doi: 10.1002/chem.201702694. Epub 2017 Sep 1.
In this work, five new cadmium metal-organic frameworks (Cd-MOFs 1-5) have been synthesized from solvothermal reactions of Cd(NO ) ⋅4 H O with isophthalic acid and 1,4-bis(imidazol-1-yl)-benzene under different solvent systems of CH OH, C H OH, (CH ) CHOH, DMF, and N-methyl-2-pyrrolidone (NMP), respectively. Cd-MOF 1 shows a 3D diamondoid framework with 1D rhombic and hexagonal channels, and the porosity is 12.9 %. Cd-MOF 2 exhibits a 2D (4,4) layer with a 1D parallelogram channel and porosity of 23.6 %. Cd-MOF 3 has an 8-connected dense network with the Schäfli symbol of [4 ⋅6 ] based on the Cd cluster. Cd-MOFs 4-5 are isomorphous, and display an absolutely double-bridging 2D (4,4) layer with 1D tetragonal channels and porosities of 29.2 and 28.2 %, which are occupied by DMF and NMP molecules, respectively. Followed by the calcination-thermolysis procedure, Cd-MOFs 1-5 are employed as precursors to prepare MOF-derived porous carbon materials (labeled as PC-me, PC-eth, PC-ipr, PC-dmf and PC-nmp), which have the BET specific surface area of 23, 51, 10, 122, and 96 m g , respectively. The results demonstrate that the specific surface area of PCs is tuned by the porosity of Cd-MOFs, where the later is highly dependent on the solvent. Thereby, the specific surface area of PCs could be adjusted by the solvent used in the synthese of MOF precusors. Significantly, PCs have been further activated by KOH to obtain activated carbon materials (APCs), which possess even higher specific surface area and larger porosity. After a series of characterization and electrochemical investigations, the APC-dmf electrode exhibits the best porous properties and largest specific capacitances (153 F g at 5 mV s and 156 F g at 0.5 Ag ). Meanwhile, the APC-dmf electrode shows excellent cycling stability (ca. 84.2 % after 5000 cycles at 1 Ag ), which can be applied as a suitable electrode material for supercapacitors.
在本工作中，通过将Cd(NO₃)₂·4H₂O与间苯二甲酸和1,4 - 双(咪唑 - 1 - 基) - 苯在CH₃OH、C₂H₅OH、(CH₃)₂CHOH、DMF和N - 甲基 - 2 - 吡咯烷酮(NMP)的不同溶剂体系中分别进行溶剂热反应，合成了五种新型镉金属有机框架材料（Cd - MOFs 1 - 5）。Cd - MOF 1呈现出具有1D菱形和六边形通道的3D类金刚石框架，孔隙率为12.9%。Cd - MOF 2展现出具有1D平行四边形通道的2D(4,4)层，孔隙率为23.6%。Cd - MOF 3基于镉簇具有Schäfli符号为[4⁶]的8连接致密网络。Cd - MOFs 4 - 5是同构的，呈现出具有1D四方通道的绝对双桥连2D(4,4)层，孔隙率分别为29.2%和28.2%，分别被DMF和NMP分子占据。经过煅烧 - 热解过程后，Cd - MOFs 1 - 5被用作前驱体来制备MOF衍生的多孔碳材料（标记为PC - me、PC - eth、PC - ipr、PC - dmf和PC - nmp），其BET比表面积分别为23、51、10、122和96 m² g⁻¹。结果表明，多孔碳材料的比表面积由Cd - MOFs的孔隙率调节，而后者高度依赖于溶剂。因此，多孔碳材料的比表面积可以通过MOF前驱体合成中使用的溶剂来调节。值得注意的是，多孔碳材料已通过KOH进一步活化以获得活性炭材料（APCs），其具有更高的比表面积和更大的孔隙率。经过一系列表征和电化学研究，APC - dmf电极表现出最佳的多孔性能和最大的比电容（在5 mV s⁻¹时为153 F g⁻¹，在0.5 A g⁻¹时为156 F g⁻¹）。同时，APC - dmf电极显示出优异的循环稳定性（在1 A g⁻¹下5000次循环后约为84.2%），可作为超级电容器的合适电极材料。
