Oxygen evolution electrocatalysts with carbon coated cobalt (ii, iii) oxide layers

Abstract

Oxygen evolution reaction (OER) catalysts and uses thereof are described. An OER catalyst can include a carbon support, a discontinuous catalytic cobalt (II,III) oxide (Co3O4) nanolayer in direct contact with the carbon support, and an amorphous continuous carbon layer. The Co3O4 nanolayer is positioned between the carbon support and an amorphous continuous carbon layer.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of priority of U.S. Provisional Patent Application No. 62 / 324,093 filed Apr. 18, 2016, which is hereby incorporated by reference in its entirety.BACKGROUND OF THE INVENTIONA. Field of the Invention[0002]The invention generally concerns oxygen evolution reaction (OER) electrocatalysts that includes a discontinuous catalytic Co3O4 nanolayer in direct contact with a carbon support and an amorphous continuous carbon layer. The discontinuous Co3O4 catalytic nanolayer is between the carbon support and the amorphous continuous carbon layer.B. Description of Related Art[0003]Use of hydrogen as an energy source has increased with the needed minimize CO2 emission from fossil fuels. One source of hydrogen can be from the splitting of water into hydrogen and oxygen. Water splitting can be achieved on a large scale using an electrochemical apparatus (e.g., electrolyzer). In an electrolyzer, water is split into hydro...

AI Technical Summary

Benefits of technology

The patent text describes a new solution for using cobalt in electrodes for oxygen reduction reactions (OER), which is a problem that can occur in such reactions. The solution involves using a layer of discontinuous catalytic cobalt oxide (Co3O4) between a carbon support and an amorphous carbon layer. This structure allows for efficient charge transfer between the cobalt and the carbon support, while preventing the catalyst from exfoliating from the surface. This solution does not require the use of expensive precious metals and is stable in both acid and alkaline solutions. The technical effect of this discovery is an improved OER electrocatalyst that overcomes the problems associated with cobalt usage in such reactions.

Problems solved by technology

However, their scarce nature and associated high-cost considerably limit large-scale implementation of industrial devices.

Furthermore, these catalysts can be unstable in corrosive acids.

However, the development of alkaline water electrolysis has been restricted by several issues including low current density and cross-diffusion of the produced gases.

However, anodes made with these metals also suffered from corrosion during use.

Co3O4 has shown catalytic properties and chemical stability in alkaline solutions, however, the application of Co3O4 for OER in acidic medium has not been successful as the Co3O4 suffers from corrosion at potentials higher than 1.47 V (vs.

Furthermore, the cobalt OER electrodes suffer from poor adhesion of the Co3O4 to the electrode substrate (e.g., titanium foil substrates).

These electrodes suffer in that the charge flow to and from the cobalt core is inefficient due to the cobalt being isolated from the solution by two layers of carbon.

As discussed above, many of the OER catalysts currently available suffer from anodic corrosion in acidic environments, leaching of catalytic material from the support material, and / or manufacture of the OER catalyst is not cost effective.

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