Zou Kang-Yu, Liu Yi-Chen, Jiang Yi-Fan, Yu Cheng-Yan, Yue Man-Li, Li Zuo-Xi
Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry and Material Sciences, Northwest University , Xi'an 710069, P.R. China.
Inorg Chem. 2017 Jun 5;56(11):6184-6196. doi: 10.1021/acs.inorgchem.7b00200. Epub 2017 May 19.
Herein three novel cobalt metal-organic frameworks (Co-MOFs) with similar ingredients, [Co(bib)(o-bdc)] (1), [Co(bib)(m-bdc)] (2), and {Co(bib)(p-bdc)(HO)} (3), have been synthesized from the reaction of cobalt nitrate with 1,4-bis(imidazol-1-yl)benzene (bib) and structure-related aromatic acids (1,2-benzenedicarboxylic acid = o-bdc, 1,3-benzenedicarboxylic acid = m-bdc, and 1,4-benzenedicarboxylic acid = p-bdc) by the solvothermal method. It is aimed to perform systematic research on the relationship among the conformation of benzoate acid, lattice dimension of Co-MOF, and pore diameter of MOF-derived carbon composite. Through the precursor strategy, Co-MOFs 1-3 have been utilized to synthesize porous cobalt@carbon nanotube composites (Co@CNTs). After the in situ gas-sulfurization, secondary composites CoS@CNTs were successfully obtained, which kept similar morphologies of corresponding Co@CNTs without destroying previous highly dispersed structures. Co-MOFs and two series of composites (Co@CNTs and CoS@CNTs) have been well characterized. Topology and Brunauer-Emmett-Teller analyses elucidate that the bdc ion could control the pore diameters of MOF-derived carbon composites by adjusting the lattice dimension of Co-MOFs. The systematic studies on electrochemical properties demonstrate that (p)-CoS@CNT possesses hierarchical morphology, moderate specific surface area, proper pore diameter distribution, and high graphitization, which lead to remarkable specific capacitances (839 F g at 5 mV s and 825 F g at 0.5 A g) in 2 M potassium hydroxide solution. In addition, the (p)-CoS@CNT electrode exhibits good electrochemical stability and still retains 82.9% of initial specific capacitance at the current density of 1 A g after 5000 cycles.
在此，通过硝酸钴与1,4-双（咪唑-1-基）苯（bib）以及结构相关的芳香酸（1,2-苯二甲酸 = o-bdc、1,3-苯二甲酸 = m-bdc和1,4-苯二甲酸 = p-bdc）的溶剂热反应，合成了三种成分相似的新型钴金属有机框架（Co-MOFs），即[Co(bib)(o-bdc)]（1）、[Co(bib)(m-bdc)]（2）和{Co(bib)(p-bdc)(HO)}（3）。目的是对苯甲酸盐的构象、Co-MOF的晶格尺寸以及MOF衍生碳复合材料的孔径之间的关系进行系统研究。通过前驱体策略，利用Co-MOFs 1-3合成了多孔钴@碳纳米管复合材料（Co@CNTs）。经过原位气体硫化后，成功获得了二次复合材料CoS@CNTs，其保持了相应Co@CNTs的相似形态，而没有破坏先前高度分散的结构。对Co-MOFs以及两个系列的复合材料（Co@CNTs和CoS@CNTs）进行了充分表征。拓扑结构和布鲁诺尔-埃米特-泰勒分析表明，bdc离子可通过调节Co-MOFs的晶格尺寸来控制MOF衍生碳复合材料的孔径。对电化学性能的系统研究表明，(p)-CoS@CNT具有分级形态、适中的比表面积、合适的孔径分布和高石墨化程度，这使其在2 M氢氧化钾溶液中具有显著的比电容（在5 mV s时为839 F g，在0.5 A g时为825 F g）。此外，(p)-CoS@CNT电极表现出良好的电化学稳定性，在5000次循环后，在1 A g的电流密度下仍保留初始比电容的82.9%。
