Chen Ruru, Zhao Jian, Zhang Xiong, Zhao Qiao, Li Yifan, Cui Yi, Zhong Miao, Wang Junhu, Li Xuning, Huang Yanqiang, Liu Bin
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China.
J Am Chem Soc. 2024 Sep 4;146(35):24368-24376. doi: 10.1021/jacs.4c05813. Epub 2024 Aug 21.
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) Mössbauer spectroscopy as a powerful technique for quantitatively monitoring the catalytic dynamics of single-Cu-atom-modified SnS (Cu/SnS) in the electrochemical CO reduction reaction (CORR). Utilizing the newly established RFQ Sn Mössbauer methodology, we clearly identified the dynamic transformation of Cu/SnS to Cu/SnS and Cu/Sn during the CORR, resulting in an outstanding Faradaic efficiency for formate production (∼90.9%) with a partial current density of 158 mA cm. Results from Raman spectroscopy, attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), quasi electron microscopy, and quasi X-ray photoelectron spectroscopy (XPS) measurements indicate that the anchored single Cu atom in Cu/SnS can accelerate the reduction of SnS with formation of Cu/Sn under CORR conditions, which effectively promote the generation of *CO/*OCHO intermediates. Theoretical calculations further support that formed Cu/Sn works as active sites catalyzing the CORR, which reduces the energy barrier for the CO activation and formation of the *OCHO intermediate, thereby facilitating the conversion of CO to formate. The results of this work provide a thorough understanding of the dynamic evolution of Sn-based catalytic sites in the CORR and shed light for engineering single atoms with an optimized catalytic performance. We anticipate that RFQ Mössbauer spectroscopy will emerge as an advanced spectroscopic technique for enabling a genuine visualization of catalytic dynamics across various reaction systems.
高效设计和工程化具有最佳性能的催化剂在很大程度上依赖于对反应条件下复杂催化动力学的深刻理解。在这项工作中，我们展示了快速冷冻淬灭（RFQ）穆斯堡尔光谱作为一种强大的技术，用于定量监测单铜原子修饰的SnS（Cu/SnS）在电化学CO还原反应（CORR）中的催化动力学。利用新建立的RFQ Sn穆斯堡尔方法，我们清楚地确定了在CORR过程中Cu/SnS向Cu/Sn₂S和Cu/Sn的动态转变，从而在158 mA cm⁻²的部分电流密度下实现了出色的甲酸盐生成法拉第效率（约90.9%）。拉曼光谱、衰减全反射表面增强红外吸收光谱（ATR-SEIRAS）、扫描电子显微镜和X射线光电子能谱（XPS）测量结果表明，Cu/SnS中锚定的单个Cu原子可以在CORR条件下加速SnS的还原并形成Cu/Sn，这有效地促进了*CO/OCHO中间体的生成。理论计算进一步支持，形成的Cu/Sn作为催化CORR的活性位点，降低了CO活化和OCHO中间体形成的能量屏障，从而促进了CO向甲酸盐的转化。这项工作的结果提供了对CORR中Sn基催化位点动态演变的全面理解，并为设计具有优化催化性能的单原子提供了思路。我们预计RFQ穆斯堡尔光谱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。
