Enhancing Oxygen Evolution Reaction with Two-Dimensional Nickel Oxide on Au (111)

The nature of the active sites of transition metal oxides during the oxygen evolution reaction (OER) has attracted much attention. Herein, we constructed well-defined nickel oxide/Au (111) model catalysts to study the relationship between the structures and their OER activity using scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), electrochemical measurements, and density functional theory (DFT) calculations. The deposited nickel oxides on Au (111) were found to exhibit a two-dimensional (2D)/three-dimensional (3D) structure by regulating the annealing temperature. Combining STM, XPS and electrochemical measurements, our results demonstrated an optimal OER reactivity could be achieved for NiOx with a 2D structure on Au and provided a morphological description of the active phase during electrocatalysis.