Electronic synergism of pyridinic- and graphitic-nitrogen on N-doped carbons for the oxygen reduction reaction
Electronic synergism of pyridinic- and graphitic-nitrogen on N-doped carbons for the oxygen reduction reaction
复制标题
氮掺杂碳上吡啶氮和石墨氮的电子协同作用用于氧还原反应
DOI：
10.1039/c8sc04596h
复制
发表时间：
2019-02-14
期刊：
影响因子：
8.4
通讯作者：
Yu, Hao
中科院分区：
文献类型：
--
作者：
Ning, Xiaomei;Li, Yuhang;Yu, Hao
氮掺杂的碳材料（NC）被广泛研究用于氧还原反应（ORR）。然而，在NCs上的吡啶氮（N-P）或石墨氮（N-G）的活性中心的性质仍然是有争议的。在此，我们证明了NCs在碱性介质中的ORR活性取决于N-P和N-G之间的电子协同作用，而不是任何单一类型的N。我们以7 '7' 8 '8-四氰基醌二甲烷为电子受体，通过吸收光谱法测量了纳米碳的可转移电子。NCs的可转移电子量与N-P或N-G相关，导致[N-P]：[N-G]比率作为NCs的电子转移描述符，在19个NCs中以反向火山曲线方式。还发现ORR活性对NC的[N-P]：[N-G]比的类似依赖性，证明了N-P和N-G的协同效应。这些结果为理解纳米碳的氧化还原活性本质和优化氧化还原催化剂提供了新的视角。
Nitrogen-doped carbon materials (NCs) are extensively studied for the oxygen reduction reaction (ORR). However, the nature of active sites of pyridinic nitrogen (N-P) or graphitic nitrogen (N-G) on NCs is still under debate. Herein, we demonstrated that the ORR activity of NCs in alkaline media depended on the electronic synergism between N-P and N-G, rather than any single type of N. We measured the transferable electrons of NCs by absorption spectroscopy using 7'7'8'8-tetracyanoquinodimethane as an electron acceptor. The transferable electron amount of NCs is relevant to either N-P or N-G, leading to the [N-P]:[N-G] ratio as an electron transfer descriptor of NCs in a reverse volcano curve manner across nineteen NCs. The similar dependence of ORR activity on the [N-P]:[N-G] ratio of NCs was also discovered, demonstrating the synergistic effect of N-P and N-G. These results provide a new angle to understand the nature of ORR activity of NCs and optimize the ORR catalyst.