Abstract

Efficient electrochemical energy conversion is critical to facilitating clean, efficient electricity generation via fuel cells and likewise generating fuels from (photo)electrocatalysis. The essence of electrochemical energy conversion involves charge transfer excitations. Quantum mechanical simulations of electrochemistry tend to employ density functional theory (DFT), but conventional DFT fails to treat these types of excitations correctly due to exchange-correlation functional limitations. We will briefly review recent advances in embedded correlated wavefunction (ECW) theory and then devote the rest of the talk to using this theory to understand (photo)electrochemical reactions at metal surfaces. ECW theory treats charge transfer accurately by properly including exact electron exchange and correlation in a region of interest while the extended metal background is described via periodic DFT , encapsulated in a so-called embedding potential. First, we shall show that ECW theory is able to accurately describe the first step of the oxygen reduction reaction that occurs at fuel cell cathodes, while conventional DFT completely fails. Second, we shall describe how an unusual form of photoelectrocatalysis can also be captured by this theory, namely plasmon-induced hot electron dissociation of molecules on gold nanoparticles.