香港城市大学Liu Bin团队报道了快速冷冻淬灭（RFQ）穆斯堡尔谱光谱学可视化研究CO₂电还原中单Cu原子修饰SnS₂。相关研究成果发表在2024年8月21日出版的《美国化学会杂志》。

为了获得最佳性能，催化剂的高效设计和工程在很大程度上取决于对反应条件下复杂的催化动力学的深刻理解。

该文中，研究人员展示了快速冷冻淬灭（RFQ）穆斯堡尔谱作为定量监测电化学CO₂还原反应（CO₂RR）中铜单原子修饰SnS₂（Cu₁/SnS₂）催化动力学的强大技术。利用新建立的RFQ 119Sn-Mssbauer方法，清楚地确定了CO₂RR过程中Cu₁/SnS₂向Cu₁/SnS和Cu₁/Sn的动态转变，从而在158 mA cm^-2的局部电流密度下，甲酸盐生产的法拉第效率非常高（～90.9%）。

操作拉曼光谱、操作衰减全反射表面增强红外吸收光谱（ATR-SEIRAS）、准原位电子显微镜和准原位X射线光电子能谱（XPS）测量结果表明，Cu₁/SnS₂中锚定的单个Cu原子可以在CO₂RR条件下加速SnS的还原，原位形成Cu₁/Sn，有效促进了*CO₂-/*OCHO中间体的产生。理论计算进一步支持原位形成的Cu₁/Sn作为催化CO₂RR的活性位点，这降低了CO₂活化和形成*OCHO中间体的能量势垒，从而促进了CO₂转化为甲酸盐。

研究结果深入展示了CO₂RR中Sn基催化位点的动态演化，并为设计具有优化催化性能的单原子提供了线索。研究预计RFQ-Mssbauer光谱学将成为一种先进的光谱技术，能够真正可视化各种反应系统中的催化动力学。

附：英文原文

Title: Visualizing Catalytic Dynamics of Single-Cu-Atom-Modified SnS2 in CO2 Electroreduction via Rapid Freeze-Quench Mssbauer Spectroscopy

Author: Ruru Chen, Jian Zhao, Xiong Zhang, Qiao Zhao, Yifan Li, Yi Cui, Miao Zhong, Junhu Wang, Xuning Li, Yanqiang Huang, Bin Liu

Issue&Volume: August 21, 2024

Abstract: Effective design and engineering of catalysts for an optimal performance depend extensively on a profound understanding of the intricate catalytic dynamics under reaction conditions. In this work, we showcase rapid freeze-quench (RFQ) Mssbauer spectroscopy as a powerful technique for quantitatively monitoring the catalytic dynamics of single-Cu-atom-modified SnS2 (Cu1/SnS2) in the electrochemical CO2 reduction reaction (CO2RR). Utilizing the newly established RFQ 119Sn Mssbauer methodology, we clearly identified the dynamic transformation of Cu1/SnS2 to Cu1/SnS and Cu1/Sn during the CO2RR, resulting in an outstanding Faradaic efficiency for formate production (～90.9%) with a partial current density of 158 mA cm–2. Results from operando Raman spectroscopy, operando attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), quasi in situ electron microscopy, and quasi in situ X-ray photoelectron spectroscopy (XPS) measurements indicate that the anchored single Cu atom in Cu1/SnS2 can accelerate the reduction of SnS with in situ formation of Cu1/Sn under CO2RR conditions, which effectively promote the generation of *CO2–/*OCHO intermediates. Theoretical calculations further support that in situ formed Cu1/Sn works as active sites catalyzing the CO2RR, which reduces the energy barrier for the CO2 activation and formation of the *OCHO intermediate, thereby facilitating the conversion of CO2 to formate. The results of this work provide a thorough understanding of the dynamic evolution of Sn-based catalytic sites in the CO2RR and shed light for engineering single atoms with an optimized catalytic performance. We anticipate that RFQ Mssbauer spectroscopy will emerge as an advanced spectroscopic technique for enabling a genuine visualization of catalytic dynamics across various reaction systems.

DOI: 10.1021/jacs.4c05813

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c05813