University of Calgary

New, inexpensive, efficient catalysts offer viable way to store and reuse renewable energy

UToday HomeApril 1, 2013

The discovery by two University of Calgary researchers provides a cheap, efficient way for homeowners and energy companies to store and reuse intermittently generated electricity such as solar and wind power. Photo by Riley BrandtThe discovery by two University of Calgary researchers provides a cheap, efficient way for homeowners and energy companies to store and reuse intermittently generated electricity such as solar and wind power. Photo by Riley BrandtWhat have the two University of Calgary researchers discovered?

Curtis Berlinguette and Simon Trudel, both assistant professors in the chemistry department in the Faculty of Science at the University of Calgary, have discovered a ground-breaking way to make new affordable and highly efficient catalysts (called electrocatalysts) for converting electricity into chemical energy. A catalyst is a substance that increases the rate of a chemical reaction.

Read the UToday story about the discovery.

Why are electrocatalysts useful?

Electrocatalysts are used in electrolyzers, devices that split water into hydrogen and oxygen through a chemical reaction driven by electricity. The hydrogen can then be stored and re-converted to electricity for use whenever wanted.

Scientists have been working for several decades on the problem of trying to make efficient and inexpensive electrocatalysts.

Today’s commercial electrocatalysts are typically made of crystalline metal oxides (any chemical compound that has a metal) using rare, expensive and/or toxic metals (e.g. ruthenium, iridium). Such catalysts work well but their prohibitive cost makes them impractical for widespread use, such as in homes and by businesses.

What makes the electrocatalysts created by the University of Calgary researchers different than conventionally made, commercial catalytic materials?

Chemists have traditionally been attracted to creating catalysts out of ‘pure’ crystalline-structured materials. They’ve tended to ignore unstructured material as the “crud at the bottom of the flask.”

“There really have been few significant advances in catalyst design over the last three decades,” Berlinguette says.

He and Trudel developed a novel process that uses cheap, abundant and non-toxic metals (e.g. iron, cobalt, nickel) combined in a highly disordered, or amorphous, structure.

Think of crystalline structures as being like tiles laid in an ordered pattern on a floor, while amorphous structures are like tiles thrown on a floor. Such an amorphous material has no symmetry and is full of ‘defects.’

These ‘defects’ in amorphous mixed metal oxide materials actually make them more chemically reactive – and therefore more efficient catalysts – than crystalline materials.

Laboratory tests by the University of Calgary researchers show their catalysts perform as well as or better than catalysts now on the market – but theirs are 1,000 times cheaper.

“We’re essentially showing, even with our ‘first generation’ of catalysts, that we’re equal to or better than anything that’s sold commercially right now after 30 years of development,” Trudel says.

The researchers say they can utilize any metal in the periodic table and are able to combine as many metals as they want into their catalysts.

“Our fabrication method provides access to an entirely new domain of catalytic materials,” Berlinguette says.

What is the significance of this discovery?

The University of Calgary researchers are the first group in the world to utilize their scalable photochemical process to make heterogeneous mix-metal amorphous electrocatalysts for clean hydrogen production.

“As far as we know, there is no other method to easily make amorphous materials where we can combine the metals in any ratio we desire. Now the ‘fun’ is trying to hit the composition that produces the best catalysts,” Trudel says.

What application does their discovery have in the ‘real’ world?

Having cheap and efficient electrocatalysts would enable homeowners and energy companies to store and reuse, whenever needed, intermittently generated electricity such as solar and wind power.

There is currently no inexpensive way of storing such renewable energy. So electricity generated by the sun or the wind is available only when the sun is shining or the wind is blowing.

Electrocatalysts are used in devices called electrolyzers, which convert electricity into chemical energy by splitting water into hydrogen and oxygen fuels. These fuels can then be stored and reconverted to electricity for use whenever wanted. The only byproduct of such a ‘green’ energy system is water, which can be recycled through the system.

“This is a completely repeatable and carbon-neutral cycle . . . it’s not using carbon at all,” Trudel says.

Batteries can also be used to store electricity generated by wind and solar power. However, current battery technology is very inefficient compared with hydrogen, which can store much more energy than batteries.

“The principal role of hydrogen in the energy economy is the storage of solar and wind energy,” Berlinguette says.

Cheap and efficient catalysts would provide homeowners and businesses with affordable electrolyzers.

“People could actually start storing renewable energy when it’s available and keep that in their house all day and take advantage of it at night,” Trudel says.

For example, all of Alberta’s wind power farms are located in the southern region of the province where wind conditions are optimum. But when the wind blows, they all produce electricity at the same time.

That drives down the price at which wind farm operators can sell their power to the provincial electrical grid.

What if operators had an affordable way to store that wind-generated electricity, using an electrolyzer?

They could then store their wind power as hydrogen, and reconvert to electricity when there’s greater demand and they can get a higher price for their clean power.

Electrolyzers with cheap, efficient catalysts could be sized to a homeowner’s furnace room, or scaled up to a tractor trailer-sized unit that would store renewable power as hydrogen for reuse by a community, in a ‘green’ district energy system.

“Electrolyzers effectively enable you to purchase electricity at a discounted rate when there is no demand, and sell back to the grid at peak times,” Berlinguette says.

What are the next steps for the University of Calgary researchers?

The researchers are testing various formulations of their amorphous mixed metal oxide catalysts, to better understand the materials and design the optimal catalysts. This includes using proven nanotechnology methods to increase the amount of hydrogen produced.

They also are working toward making a “photo-electrocatalyst,” which uses sunlight to increase the hydrogen produced by the electrolyzer.

They have patented both their process for creating their electrocatalysts as well as the new catalysts they’ve created, and they’ve established a spin-off company, FireWater Fuel Corp., to commercialize their technology.

The company expects to have a commercial product in the current large-scale electrolyzer market in 2014, and a prototype electrolyzer – using their new catalysts – ready by 2015 for testing in a home.

 

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