Qi Jing, Lin Yang-Peng, Chen Dandan, Zhou Tianhua, Zhang Wei, Cao Rui
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China.
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China.
Angew Chem Int Ed Engl. 2020 Jun 2;59(23):8917-8921. doi: 10.1002/anie.202001737. Epub 2020 Mar 27.
The correlation between metal coordination and electrocatalytic water oxidation performance is elusive in many cobalt-based materials. Herein, we designed an ideal Co phosphate-based platform to explore the effect of coordination environment on oxygen evolution reaction (OER) activity. The cobalt geometry was modulated from octahedral to tetrahedral by simple removal of water ligands in Co (PO ) ⋅8 H O. Other features except the coordination structure in the two autologous materials remain similar. The two analogues display the same OER kinetics, but the anhydrous Co (PO ) exhibits a greatly enhanced OER activity. On the basis of Raman and operando XAS results, the higher intrinsic activity of the Co tetrahedral sites is because they facilitate the formation of active high valent cobalt (hydr)oxide intermediates during OER. This work not only brings insights of OER on Co-based electrocatalysts but also provides a reference system to study the effect of metal geometry on electrocatalysis.
在许多钴基材料中，金属配位与电催化水氧化性能之间的相关性难以捉摸。在此，我们设计了一个理想的磷酸钴基平台，以探索配位环境对析氧反应（OER）活性的影响。通过简单地去除Co(PO₄)·8H₂O中的水配体，钴的几何结构从八面体调制为四面体。两种同源材料中除配位结构外的其他特征保持相似。这两种类似物表现出相同的OER动力学，但无水Co(PO₄)表现出大大增强的OER活性。基于拉曼光谱和原位X射线吸收光谱结果，Co四面体位点较高的本征活性是因为它们在OER过程中促进了活性高价钴（氢）氧化物中间体的形成。这项工作不仅为基于钴的电催化剂上的OER带来了见解，而且为研究金属几何结构对电催化的影响提供了一个参考体系。
