Oxygen-Terminated Diamond Electrodes in Alkaline Media: Structure and OH Generation

The structure and energetics of two types of oxygen-terminated diamond surfaces, the keto and ether configurations, were investigated by density The structure and energetics of two types of oxygen-terminated diamond surfaces, the keto and ether configurations, were investigated by density functional theory. To explore OH generation, we studied the approach of a hydroxyl radical to these surfaces. The OH radical strongly interacted with the ether-type surface, whereas the radical was repelled in the keto configuration. The kinetics of OH generation in alkaline solutions (OH- <-> OH + e(-)) on oxygen-terminated diamond electrodes was investigated in light of the theory of catalyzed electron transfer. Our results suggested that the electron transfer occurs in the outer-sphere mode with an activation energy of 0.5 eV.