Catalysts Having Mixed Metal Oxides

Abstract

Disclosed are methods for generating oxygen via an electrolysis reaction. One places an anode and a cathode in aqueous solution, and uses an external source of electricity to drive the electrolysis reaction from the anode and cathode. The anode has at least three metal oxides, preferably with nickel oxide or cobalt oxide as at least one of the oxides. Also disclosed are electrodes designed for catalyzing oxygen consumption or formation reactions, where the electrodes have a mix of such three metal oxides.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority based on U.S. provisional No. 61 / 598,377, which was filed Feb. 14, 2012.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH / DEVELOPMENT[0002]This invention was made with government support under 0802907 awarded by the National Science Foundation. The government has certain rights in the invention.BACKGROUND OF THE INVENTION[0003]The present invention relates to electrocatalysts. More particularly it relates to electrodes comprising a mix of at least three metal oxides, and their use for catalyzing oxygen gas related reactions (especially their use as anodes in water electrolysis to generate oxygen or their use as cathodes to facilitate consuming oxygen in a fuel cell).[0004]Developing effective catalysts is important in rendering the storage of renewable energy practical. If (for example) solar or wind generated energy can be efficiently stored as hydrogen gas generated by water oxidation, this has the potent...

AI Technical Summary

Benefits of technology

This patent describes a way to prepare mixed-metal catalysts by using low-cost metal salt precursors in water solutions containing glycerol. The solutions are then combined with nitrate salts, except for certain additional additives which can be added in a different way. This method allows for the creation of cost-effective fuel generation systems that can be commercially viable.

Problems solved by technology

However, it has proved challenging to develop such catalysts which are not susceptible to oxidative or hydrolytic degradation, don't require expensive precious metals, and also don't require high overpotentials.

However, these mixed metal oxide catalysts, when applied to oxygen formation or consumption reactions, suffered from one or more deficiencies.

The search for further improved mixed metal oxide anodes for oxygen formation or consumption reactions was made difficult by the fact that the number of possible combinations of cations in more complex oxide mixtures far exceeds the number that are practical to sequentially individually synthesize and test.

Adding further complexity is the fact that performance may vary over various pH conditions of interest.

So far, few high performing anodic catalysts have been identified with this method.

It therefore suffered because it did not investigate catalysis independent of light harvesting.

However, this required expensive oxygen-selective microelectrodes that were slowly scanned across the anode surface, and also suffered from inaccuracies.

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