Storing solar energy for the periods of time when the sun isn’t shining is key to improving solar technology. The energy produced can be stored in batteries or used to produce fuel that can act as storage. Solar fuel processes are generally modeled on photosynthesis, the natural process whereby plants convert sunlight into chemical energy in the form of biomass and release oxygen into the atmosphere. Current options are expensive, but a group or researchers from the University of Wisconsin-Madison claim they have found a faster, cheaper method to find electrocatalysts that improve the water oxidation process in the search for solar energy storage.

The idea is to produce solar fuels that can store the electricity for longer periods and which can be accessed at all times. The two main tools employed by the Wisconsin-Madison researchers are ultraviolet light and fluorescent paint. During the electrolysis process, potential catalysts are photographed while the paint reacts to the oxygen being formed.

What makes this method a cheaper and less laborious solution to current approaches, where the number of catalysts is higher that the number that can be tested, is that it quickly sorts through several compounds in the search for promising materials. In general other methods use solar-powered electrolysis reactions to convert water, carbon dioxide, or other widely available raw materials into chemicals that can be stored for later use. However, using the sun to split water into oxygen and hydrogen is inefficient, the researchers say, and point to water oxidation as a better alternative that yields electrons and protons needed for hydrogen production. Less energy is lost, they claim.

So far the Wisconsin-Madison researchers have found a range of new metal-oxide catalysts made of cheaper materials such as iron, nickel and aluminum with a potential to store solar energy. "If we do this well enough, we can keep the party going all night long,” researcher James Gerken said, highlighting the need for efficient, common electrocatalysts to promote the oxidation of water necessary to produce solar fuels.

The research has been described in detail in the journal Angewandte Chemie.

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