Rational design of the molecular Ru-based Water Oxidation Catalysts

Identifier:  TDX:3404

Handle: https://hdl.handle.net/20.500.11797/TDX3404

Authors:  Vereshchuk, Nataliia

Abstract:
Water splitting with sunlight is one of the most promising strategies to obtain renewable fuels in the short to midterm. To achieve this goal one of the crucial elements that need to be fully understood and mastered is the catalytic oxidation of water to molecular oxygen. Two main approaches have been followed so far for the development of water oxidation catalysts (WOCs): the oxide and the molecular way. The latter has generated a wealth of mechanistic information mainly based on Ru complexes and has led to catalysts with turnover frequencies two orders of magnitude higher than those of OEC (Oxygen Evolving Center) in the photosystem II of green plants and algae. In this thesis, we developed the synthetic and catalytic chemistry related to Ru complexes bonded to new members of the family of FAME (Flexible Adaptative Multidentate Equatorial) ligands. Chapters 1 and 2 were dedicated to the motivations and objectives of the current studies. In Chapters 3 and 4 we developed a new Ru-based WOC, so-called Ru(tPa) complex, where tPa is [2,2 :6 ,2 -terpyridine-6,6 -diphosphonic acid], which showed significant activity toward water oxidation as well as how second coordination sphere effects are responsible not only to generate the active catalyst but also to reduce energies of activation at the rate-determining step of the catalysis. In Chapter 5 we found out the deactivation pathway that Ru(tPa) undergoes under heavy duty catalysis and in Chapter 6 we presented how to overcome this deactivation and improve stability.