Tanja Cuk

Charge dynamics and molecular intermediates of photo-catalytic interfaces

Initiating catalysis by photons that leads to a directed charge flow creates unstable intermediates that can be followed for their ability to break and reorganize bonds of reactant molecules.  In our group, we seek to follow the transient steps of a catalytic cycle through time-resolved spectroscopy coupled to solid-state devices that control the flow of charge to the catalyst/reactant interface.  In particular, we investigate the water oxidation reaction at the solid-liquid interface of a photo-electrochemical cell from the perspective of charges leaving the solid side of the interface and the rise and decay of intermediates bound from the liquid side of the interface. We use visible transient reflection/absorption and transient infrared attenuated total reflection to target both actors.  We rely on 3d transition metal oxides that lead to stable and efficient water oxidation.  A complimentary part of the lab investigates the photo-excited carrier dynamics of 3d transition metal oxides in solid and molecular form.  Importantly for catalysis, these experiments seek to identify whether the photo-generated carriers are localized at a transition metal site at the initial time step of the reaction.