Structural and Chemical Transformations of Ruthenium, Cobalt, and Iron Clathrochelates Used as Electrocatalysts for a Hydrogen Evolution Reaction in a Water Electrolyzer

• Published in: Nanotechnologies in Russia 2020-05, Vol.15 (3-6), p.341-349
• Main Authors: Zubavichus, Ya. V., Grigor’ev, S. A., Pushkarev, A. S., Borisov, M. M., Bugaenko, M. G., Voloshin, Ya. Z., Dedov, A. G.
• Format: Article
• Language: English
• Subjects: Chemistry and Materials Science; Devices and Products Based on Nanomaterials and Nanotechnologies; Industrial and Production Engineering; Machines; Manufacturing; Materials Science; Nanotechnology; Processes
• ISSN: 1995-0780; 1995-0799
• DOI: 10.1134/S1995078020030179

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 RuS 2 in used clathrochelate-containing cathode material. Taking into account our experimental data on the chemical transformation of clathrochelate electrocatalysts under the conditions of 2Н + /Н 2 reaction, we discuss the possibilities for boosting the efficiency of electrocatalytic systems based on this class of coordination compounds.