Cation-Dependent Nonadiabaticity in Proton-Coupled Electron Transfer at Electrified Solid-Liquid Interfaces

Here we report an observation of cation-dependent nonadiabaticity in a proton-coupled electron transfer electrode process (PCET) during hydrogen evolution at electrified interfaces of Au(111) single-crystal electrode and electrolytes by employing electrochemical kinetic isotope effect analysis at ultra-clean/well-defined systems to investigate quantum-to-classical transition (QCT) in highly accuracy.