Systematic Influence of Electronic Modification of Ligands on the Catalytic Rate of Water Oxidation by a Single-Site Ru-Based Catalyst

Catalytic water oxidation is an important process for the development of clean energy solutions and energy storage. Despite the significant number of reports on active catalysts, systematic control of the catalytic activity remains elusive. In this study, descriptors are explored that can be correla...

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Bibliographic Details
Published in:ChemSusChem 2021-12, Vol.15 (4)
Main Authors: Patel, Jully, Bury, Gabriel, Ravari, Alireza K., Ezhov, Roman, Pushkar, Yulia
Format: Article
Language:English
Subjects:
Chemistry
homogeneous catalysis
INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Raman spectroscopy
reactive intermediates
ruthenium
Science & Technology - Other Topics
water oxidation
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Summary:Catalytic water oxidation is an important process for the development of clean energy solutions and energy storage. Despite the significant number of reports on active catalysts, systematic control of the catalytic activity remains elusive. In this study, descriptors are explored that can be correlated with catalytic activity. [Ru(tpy)(pic)2(H2O)](NO3)2 and [Ru(EtO-tpy)(pic)2(H2O)](NO3)2 (where tpy=2,2': 6',2“-terpyridine, EtO-tpy=4'-(ethoxy)-2,':6',2”-terpyridine, pic=4-picoline) are synthesized and characterized by NMR, UV/Vis, EPR, resonance Raman, and X-ray absorption spectroscopy, and electrochemical analysis. Addition of the ethoxy group increases the catalytic activity in chemically driven and photocatalytic water oxidation. Thus, the effect of the electron-donating group known for the [Ru(tpy)(bpy)(H2O)]2+ family is transferable to architectures with a tpy ligand trans to the Ru-oxo unit. Under catalytic conditions, [Ru(EtO-tpy)(pic)2(H2O)](NO3)2 displays new spectroscopic signals tentatively assigned to a peroxo intermediate. In conclusion, reaction pathways were analyzed by using DFT calculations. [Ru(EtO-tpy)(pic)2(H2O)](NO3)2 is found to be one of the most active catalysts functioning by a water nucleophilic attack mechanism.
ISSN:1864-5631
1864-564X