Abstract

The structural evolution of three electrocatalytic systems for hydrogen evolution reaction using iron, cobalt, and ruthenium(II) clathrochelate complexes as catalysts in a water electrolyzer is studied by X-ray absorption near-edge structure (XANES)/extended X-ray absorption fine structure (EXAFS) spectroscopy. The complexes are shown to display essentially different robustness under water electrolysis conditions in pilot-scale hydrogen generators. The iron and cobalt(II) clathrochelates preserve their cage, macrobicyclic structure, and the encapsulated metal(II) ion is reduced to metal(I) cation; whereas in the case of ruthenium(II) clathrochelate, the cage complex undergoes partial decomposition to form sulfur-containing products of decomposition of the encapsulating macrobicyclic hexasulfide ligand, which results in the accumulation of the ruthenium disulfide RuS₂ in used clathrochelate-containing cathode material. Taking into account our experimental data on the chemical transformation of clathrochelate electrocatalysts under the conditions of 2Н⁺/Н₂ reaction, we discuss the possibilities for boosting the efficiency of electrocatalytic systems based on this class of coordination compounds.

中文翻译：

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钌，钴和铁螯合物的结构和化学转化，用作水电解槽中氢气发生反应的电催化剂

摘要

通过X射线吸收近边缘结构（XANES）/扩展的X射线吸收精细度研究了水电解槽中使用铁，钴和钌（II）的笼形螯合物作为催化剂的三种用于氢释放反应的电催化体系的结构演变结构（EXAFS）光谱。在中试规模的氢气发生器中，该配合物在水电解条件下显示出基本不同的耐用性。铁和钴（II）的笼形螯合物保留了其笼状，大双环结构，并且封装的金属（II）离子被还原为金属（I）阳离子；而在笼形钌（II）的情况下，笼状配合物会部分分解，从而形成封装的大双环六硫化物配体分解的含硫产物，₂用过的含笼形螯合物的正极材料。考虑到上笼形螯合物电催化剂2Н的条件下，化学转化我们的实验数据⁺ /Н ₂反应，我们讨论了推动基于这一类配合物的电系统的效率的可能性。