Unveiling the In Situ Generation of a Monovalent Fe(I) Site in the Single-Fe-Atom Catalyst for Electrochemical CO2 Reduction
Unveiling the In Situ Generation of a Monovalent Fe(I) Site in the Single-Fe-Atom Catalyst for Electrochemical CO2 Reduction
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DOI：
10.1021/acscatal.1c01621
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发表时间：
2021-06-07
期刊：
影响因子：
12.9
通讯作者：
Liu, Bin
中科院分区：
文献类型：
--
作者：
Li, Xuning;Zeng, Yaqiong;Liu, Bin
原子分散的单原子催化剂是二氧化碳还原反应（CRR）中最具吸引力的电催化剂之一。为了阐明 CRR 中原子分散的 Fe-N-C 催化剂卓越活性的起源，我们对具有明确 N 配位环境的单 Fe 原子催化剂模型进行了操作 Fe-57 穆斯堡尔光谱研究。结合原位X射线吸收光谱，原位生成的以一价铁为特征的四个吡咯氮原子配位的低自旋Fe(I) (LS FeIN4)被确定为CO2转化为CO的反应中心。此外，密度泛函理论计算表明CO2与LS(FeN4)-N-I位点的最佳结合强度，单占据的d(z)(2)轨道之间具有强轨道相互作用。 Fe(I)位点和[COOH]片段的单占据pi*轨道，是优异CRR性能的关键因素。
Atomically dispersed single-atom catalysts are among the most attractive electrocatalysts for the CO2 reduction reaction (CRR). To elucidate the origin of the exceptional activity of atomically dispersed Fe-N-C catalyst in CRR, we have performed operando Fe-57 Mossbauer spectroscopic studies on a model single-Fe-atom catalyst with a well-defined N coordination environment. Combining with operando X-ray absorption spectroscopy, the in situ-generated four pyrrolic nitrogen atom-coordinated low-spin Fe(I) (LS FeIN4) featuring monovalent iron is identified as the reactive center for the conversion of CO2 to CO. Furthermore, density functional theory calculations reveal that the optimal binding strength of CO2 to the LS (FeN4)-N-I site, with strong orbital interactions between the singly occupied d(z)(2) orbital of the Fe(I) site and the singly occupied pi* orbital of [COOH] fragment, is the key factor for the excellent CRR performance.