Fabricating Single-Atom Catalysts from Chelating Metal in Open Frameworks
Fabricating Single-Atom Catalysts from Chelating Metal in Open Frameworks
复制标题
在开放框架中用螯合金属制造单原子催化剂
DOI：
10.1002/adma.201808193
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发表时间：
2019-05-03
影响因子：
29.4
通讯作者：
Chen, Liang
中科院分区：
文献类型：
--
作者：
Lin, Yichao;Liu, Pingying;Chen, Liang
在本研究中，报道了一种高效的策略，使用具有丰富螯合配体的开放框架平台来制造一系列稳定的金属单原子催化剂（SACS）。在这里，金属离子最初通过合成后修饰固定在活性联吡啶位点上，然后进行热解和酸浸。所得的单个金属原子均匀分布在氮掺杂碳（N-C）基质上。有趣的是，发现每个金属原子与五个氮原子配位，而之前报道的平均配位数为四个。所制备的Fe SAC/N-C催化剂表现出优异的氧还原反应（ORR）活性（半波电位为0.89 V）、出色的稳定性和良好的甲醇耐受性。密度泛函计算表明，配位吡啶可以有利地调节氧与Fe离子的相互作用强度，从而提高ORR活性。更重要的是，事实证明，只需改变金属化步骤中使用的金属前体，该策略就可以成功扩展到其他过渡金属 SAC 的制备。
In the present study, a highly efficient strategy is reported using open framework platforms with abundant chelating ligands to fabricate a series of stable metal single-atom catalysts (SACS). Here, the metal ions are initially anchored onto the active bipyridine sites through postsynthetic modification, followed by pyrolysis and acid leaching. The resulting single metal atoms are uniformly distributed on a nitrogen-doped carbon (N-C) matrix. Interestingly, each metal atom is found to be coordinated with five N atoms, in contrast to the average coordination number of four as previously reported. The as-prepared Fe SAC/N-C catalyst exhibits excellent oxygen reduction reaction (ORR) activity (with a half-wave potential of 0.89 V), outstanding stability, and good methanol tolerance. The density functional calculations reveal that the coordinated pyridine can favorably modulate the interaction strength of oxygen on the Fe ion and thus improve the ORR activity. More importantly, it is demonstrated that this strategy can be successfully extended to the preparation of other transition metal SACs, simply by altering the metal precursors used in the metalation step.