Tannic acid-mediated synthesis of dual-heteroatom-doped hollow carbon from a metal-organic framework for efficient oxygen reduction reaction
Tannic acid-mediated synthesis of dual-heteroatom-doped hollow carbon from a metal-organic framework for efficient oxygen reduction reaction
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单宁酸介导的金属有机骨架合成双杂原子掺杂空心碳用于有效的氧还原反应
DOI：
10.1039/c8dt01517a
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发表时间：
2018
影响因子：
4
通讯作者：
Liu Rui
中科院分区：
文献类型：
--
作者：
Wu Mengchen;Li Congling;Zhao Jing;Ling Yun;Liu Rui
在此，我们报道了一种新颖的策略，在单宁酸的辅助下制备N/B共掺杂的空心碳（表示为NB-HC）。受其固有多孔结构的启发，我们使用ZIF-8作为结构模板和N掺杂源。将单宁酸（TA）作为次要材料均匀涂覆在ZIF-8表面，得到ZIF-8@TA核壳复合材料。TA改性的壳介导了硼酸-多元醇键的后形成，其中1，4-苯二硼酸（BDBA）用作含硼反应物和掺杂源。碳化后，该复合材料成功地变成了中空的N/B共掺杂碳，具有936 m2 g−1的高表面积。它表现出明显的ORR反应性，起始电位为−0.12 V（vs. Ag/AgCl）沿着，具有极好的甲醇交叉耐受性和长期稳定性。第一性原理计算证明，N和B掺杂的协同效应可以产生活性位，从而降低了速率控制步骤中的自由能变化值.这阐明了碳结构和分级多孔结构中B和N的均匀协同偶联赋予所制备的NB-HC增强的ORR参数。
Herein, we report an original strategy to fabricate N/B co-doped hollow carbon (denoted as NB–HC) with the assistance of tannic acid. Inspired by its inherent porous structures, we used ZIF-8 as a structural template and a N-doping source. Tannic acid (TA) as a secondary material is uniformly coated on the surface of ZIF-8 to obtain ZIF-8@TA core–shell composites. The TA-modified shell mediates the post-formation of boron acid-polyol bond, where 1,4-benzene diboronic acid (BDBA) is used as a boron-containing reactant and doping source. After carbonization, the composite successfully turns into hollow N/B co-doped carbon with a high surface area of 936 m2 g−1. It exhibits a pronounced ORR reactivity with an onset potential of −0.12 V (vs. Ag/AgCl) along with superb methanol cross-over tolerance and long-term stability. The first-principles calculation proves that the synergistic effect arising from N and B dopants can create active sites; therefore, the value of free energy change in the rate-determining step decreases. This elucidates that the homogeneously synergistic coupling of B and N in the carbon structure and hierarchical porous structures endow the as-prepared NB–HC with enhanced ORR parameters.