Electrochemical proton-coupled electron transfer

Proton-coupled electron transfer (PCET) reactions play a vital role in solar energy capture. This talk will focus on theoretical studies of electrochemical PCET. The quantum mechanical effects of the active electrons and transferring proton(s), as well as the motions of the proton donor-acceptor mode and solvent, are included in a general theoretical formulation. This approach enables the calculation of heterogeneous rate constants, current densities, and kinetic isotope effects for comparison to experiment. Application of this theory to an osmium complex attached to a self-assembled monolayer on a gold electrode will be presented. The calculations provide an explanation for the experimentally observed asymmetric Tafel plot and deviation of the transfer coefficient from the standard value. Application of this theory to electron transfer coupled to proton transport along a proton relay will also be presented. The calculations provide an explanation for the experimentally observed rate constants and isotope effects for single and double proton transfer systems.