Li Xinrui, Ye Guanying, Zhu Weiwei, Tian Min, Wang Ruiting, Liu Suqin, He Zhen
College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, P. R. China.
Hunan Provincial Key Laboratory of Chemical Power Sources, Central South University, Changsha, Hunan 410083, P. R. China.
ACS Nano. 2024 Sep 3;18(35):24505-24514. doi: 10.1021/acsnano.4c08695. Epub 2024 Aug 21.
Regulating the coordination environment of Fe-N sites is an efficient but challenging approach for promoting the intrinsic catalytic activity of single-atom Fe/N-codoped carbon (Fe-N-C) toward the oxygen reduction reaction (ORR). Herein, low-coordination Fe-N sites coupled with carbon vacancies (Fe-N/C) are directionally constructed in Fe-N-C via pyrolysis of a metal-organic framework (MOF) precursor with N-Zn-O-Fe moieties, which are delicately prefabricated by chemically anchoring Fe onto a HO-etching induced linker-missing Zn-N site in the MOF precursor. The optimized Fe-N-C with the Fe-N/C sites displays a high ORR half-wave potential of 0.92 V (vs RHE), which is attributed to the optimized electronic structure and binding strengths of the active Fe center toward the ORR intermediates stemming from the synergy of the asymmetric configuration of Fe-N as well as the adjacent carbon vacancies. This work could be enlightening for the design and construction of high-activity coupling sites in metal and nitrogen-codoped carbon catalysts.
调控铁氮位点的配位环境是提高单原子铁氮共掺杂碳（Fe-N-C）对氧还原反应（ORR）本征催化活性的一种有效但具有挑战性的方法。在此，通过对具有N-Zn-O-Fe部分的金属有机框架（MOF）前驱体进行热解，在Fe-N-C中定向构建了与碳空位耦合的低配位铁氮位点（Fe-N/C），这些部分是通过将铁化学锚定到MOF前驱体中由羟基蚀刻诱导的连接体缺失的锌氮位点上精心预制而成的。具有Fe-N/C位点的优化后的Fe-N-C表现出0.92 V（相对于可逆氢电极）的高ORR半波电位，这归因于活性铁中心对ORR中间体的电子结构和结合强度的优化，这源于Fe-N的不对称构型以及相邻碳空位的协同作用。这项工作对于金属和氮共掺杂碳催化剂中高活性耦合位点的设计和构建具有启发性。
