Xiang Weikai, Yang Nating, Li Xiaopeng, Linnemann Julia, Hagemann Ulrich, Ruediger Olaf, Heidelmann Markus, Falk Tobias, Aramini Matteo, DeBeer Serena, Muhler Martin, Tschulik Kristina, Li Tong
Institute for Materials, Ruhr-Universität Bochum, Universitätsstraße 150, 44801, Bochum, Germany.
CAS Key Laboratory of Low-Carbon Conversion Science and Engineering, Shanghai Advanced Research Institute (SARI), Chinese Academy of Sciences (CAS), 201210, Shanghai, China.
Nat Commun. 2022 Jan 10;13(1):179. doi: 10.1038/s41467-021-27788-2.
The three-dimensional (3D) distribution of individual atoms on the surface of catalyst nanoparticles plays a vital role in their activity and stability. Optimising the performance of electrocatalysts requires atomic-scale information, but it is difficult to obtain. Here, we use atom probe tomography to elucidate the 3D structure of 10 nm sized CoFeO and CoFeO nanoparticles during oxygen evolution reaction (OER). We reveal nanoscale spinodal decomposition in pristine CoFeO. The interfaces of Co-rich and Fe-rich nanodomains of CoFeO become trapping sites for hydroxyl groups, contributing to a higher OER activity compared to that of CoFeO. However, the activity of CoFeO drops considerably due to concurrent irreversible transformation towards CoO and pronounced Fe dissolution. In contrast, there is negligible elemental redistribution for CoFeO after OER, except for surface structural transformation towards (Fe, Co)O. Overall, our study provides a unique 3D compositional distribution of mixed Co-Fe spinel oxides, which gives atomic-scale insights into active sites and the deactivation of electrocatalysts during OER.
催化剂纳米颗粒表面单个原子的三维（3D）分布对其活性和稳定性起着至关重要的作用。优化电催化剂的性能需要原子尺度的信息，但难以获得。在此，我们使用原子探针断层扫描来阐明10纳米大小的CoFeO和CoFeO纳米颗粒在析氧反应（OER）过程中的三维结构。我们揭示了原始CoFeO中的纳米级旋节分解。CoFeO富钴和富铁纳米域的界面成为羟基的捕获位点，与CoFeO相比，其OER活性更高。然而，由于同时向CoO的不可逆转变和明显的铁溶解，CoFeO的活性大幅下降。相比之下，OER后CoFeO的元素再分布可忽略不计，除了向（Fe,Co）O的表面结构转变。总体而言，我们的研究提供了混合Co-Fe尖晶石氧化物独特的三维成分分布，这为OER过程中活性位点和电催化剂失活提供了原子尺度的见解。
