Accelerating the Alkaline Water Oxidation on Ni-Based Electrode through Adjusting the Decoupled OH–/e– Transfer during Surface Ni Reconstruction

Electrochemical oxidation deprotonation of surface species on a transition metal electrode is crucial for the oxygen evolution reaction (OER). However, the relation between the electrode surface characteristics and the OER activity are not well understood. This work presents operando Raman spectroscopy, X-ray photoelectron spectroscopy, and an electrokinetic study on three typical Ni or NiFe electrodes with adjustable OER activities. The decoupled OH–/e– transfer electrochemical oxidation of surface Ni species and its influence on the following OER on Ni and NiFeOx electrodes are revealed. The NF(R)-Fe electrode with (2.69) OH–/(2) e– transfer of electrochemical oxidation is the closest process approaching the ideal Nernstian process, which resulted in a less negatively charged OER-active surface and facilitates further OH– attachment. The NF(R)-Fe electrode with a smaller pKa value has an easier and prepositioned deprotonation process in the OER cycle, which displays the fastest kinetics and best performance for the oxygen evolution reaction.