Lesson from Biological Photosystem to Make Electrocatalysts for Solar Fuel
Ki Tae Nam, Seoul National University
High valent metal-oxo moieties have been implicated as key intermediates to proceed the various oxidation process. Critical O-O bond formation step in Kok cycle to generate molecular oxygen occurs through Mn(IV)=O species of water oxidation complex(WOC), Mn4Ca cluster in photosystem II. Here, I will talk about the spectroscopic characterization and reactivity of low-spin Mn(IV)=O intermediates, generated during water oxidation catalysis. Recently, although effect of spin-state in transition metal catalyst on catalytic reactivity has been intensely studied, there is no previous example of low spin Mn (IV) intermediate species. We demonstrate that a low-spin configuration, S=1/2, stably exists during electrochemical catalysis. Additionally, I will discuss about a new C-C bonding mechanism for CO2 reduction to make long hydrocarbon chain during electrochemical reduction. Inspired by photosystem, we demonstrated the building block based approach to make C4 product as a result of CO2 reduction.