Paving the way to the integration of smart nanostructures: Part II: Nanostructured microdispersed hydrated metal oxides for electrochemical energy conversion and storage applications

Abstract

The use of hydrogen gas produced by the electrolysis of water is the basis of a long term energy conversion and storage option that has been and still continues to be the subject of considerable research. Alkaline water electrolysis, using electricity generated by renewable sources has been proposed as an environmentally inoffensive route to the production of the large volumes of hydrogen gas required by a possible hydrogen economy. The electrochemistry of oxygen has proved to be of perennial interest both from a fundamental and an applied perspective, especially in the important areas of energy conversion and storage. Despite the recent renewal in interest in the oxygen evolution reaction (OER) at transition metal oxide based electrodes in alkaline solution, the details of the mechanism remain controversial. In the present extended essay, the redox, charge storage and electrocatalytic behavior with respect to the OER of oxidized Ni, Fe and Co oxides in alkaline solution is discussed, the acid/base properties of the oxide is emphasized, and a plausible general reaction pathway involving the rate determining formation of a superoxy (-OOH) intermediate is proposed.