催化作用
化学
氧还原
氧气
氧还原反应
氧化还原
化学工程
无机化学
金属
材料科学
作者
Zhaoyang Chen,Huan Niu,Jie Ding,Hongfang Liu,Pengzuo Chen,Ying-Rui Lu,Ying-Rui Lu,Wenbin Zuo,Lei Han,Yuzheng Guo,Sung Fu Hung,Yue-Ming Zhai
标识
DOI:10.1002/ange.202110243
摘要
Heteroatom doped atomically dispersed Fe1-NC catalysts have been found to show excellent activity toward oxygen reduction reaction (ORR). However, the origin of the enhanced activity is still controversial because the structure-function relationship governing the enhancement remains elusive. Herein, sulfur(S)-doped Fe1-NC catalyst was obtained as a model, which displays a superior activity for ORR towards the traditional Fe-NC materials. 57Fe Mössbauer spectroscopy and electron paramagnetic resonance spectroscopy revealed that incorporation of S in the second coordination sphere of Fe1-NC can induce the transition of spin polarization configuration. Operando 57Fe Mössbauer spectra definitively identified the low spin single-Fe3+-atom of C-FeN4-S moiety as the active site for ORR. Moreover, DFT calculations unveiled that lower spin state of the Fe center after the S doping promotes OH* desorption process. This work elucidates the underlying mechanisms towards S doping for enhancing ORR activity, and paves a way to investigate the function of broader heteroatom doped Fe1-NC catalysts to offer a general guideline for spin-state-determined ORR.
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