Chapter 5. Proton-Coupled Electron Transfer in Natural and Artificial Photosynthesis

Abstract

Proton coupled electron transfer (PCET) is ubiquitous in redox chemistry, including important biological functions such as respiration, photosynthesis and nitrogen fixation. Understanding the role and mechanistic aspects of PCET in such contexts is crucial for the design and development of new biomimetic systems. In the context of solar energy conversion, oxygenic photosynthesis is an extraordinary example of how PCET can be used for an efficient proton management and redox levelling, to match one electron photochemistry with the challenging multi-electron/multi-proton catalysis of water oxidation. In this chapter, we will present an overview of the working principles of Photosystem II (PSII) and review the current understanding of the role of PCET in natural photosynthesis. These principles are applied to the design of functional models of PSII for the photochemical oxidation of water. Examples of catalyst structures and performances and photoelectrochemical device architectures are also discussed in the context of artificial photosynthesis for solar fuel production.