研究催化剂在电化学原位条件下随电压/时间的动态演化过程对深入理解催化剂活性机理至关重要。同步辐射原位XAFS方法是研究研究工作状态下催化剂的强有力手段，但仍存在数据信噪比差、催化剂随时间演化等困难。本项目拟开展低温淬冷XAFS方法和实验平台的研究工作，一方面发展液态乙烷淬冷方法以避免Leidenfrost效应，实现在毫秒时间尺度内对工作条件下电催化剂原位化学状态捕获；另一方面搭建通用型实验平台，用于淬冷后样品在低温状态下的传输和低温XAFS实验，目标获取宽k区间X(k)震荡信号，从而对催化剂活性位点局域结构进行精确解析。作为具体应用，针对几种HER和CO2还原的单原子电催化剂体系，开展低温淬冷XAFS方法研究，捕获外加电压下活性位点的化学状态，重点研究大电流、长时间条件下的催化剂状态，揭示催化剂结构随电压/时间的演化图像，为单原子催化机理研究提供原子水平的结构模型。

The comprehensive understanding of electrocatalyst requires new insights into the catalytically-active site and activity-determining structural properties under the applied potential. Operando XAFS is a very powerful tool to study the local structure and electronic structure of the catalyst under electrochemical conditions. However, there are still difficulties, such as poor signal-to-noise ratio, catalyst evolution over time, bubbles and the radiation damage. This project intends to develop an universal low-temperature operando XAFS combined with the high-efficiency freeze-quenched method which will be suitable for electrocatalytic experiments. Liquid ethane quenching method will be developed to avoid the Leidenfrost effect, and operando chemical state of the electrocatalyst could be rapid capture under the applied potential. A universal low-temperature XAFS platform will be set up for the sample after quenching and to measure wide k range X(k) oscillation. As a specific application, several kinds of the classical single atom catalyst of HER and CO2 reduction, the low-temperature freeze-quenched XAFS method will be used to capture and investigate the chemical state of the active site under electrochemical conditions, especially with the high current and long time, revealing the evolution of the catalyst structure with voltage/time.The atomic-level structural model will be provided for the study of single atom catalyst reaction mechanism.