Nav: Home

Simple equation directs creation of clean-energy catalysts

May 14, 2018

New guidelines laid down by Nebraska and Chinese researchers could steer the design of less costly, more efficient catalysts geared toward revving up the production of hydrogen as a renewable fuel.

Nebraska's Xiao Cheng Zeng and colleagues have identified several overlooked factors critical to the performance of single-atom catalysts: individual atoms, usually metallic and anchored by surrounding molecular frameworks, that kick-start and accelerate chemical reactions.

The team folded those variables into a simple equation requiring what Zeng described as "back-of-the-envelope calculations." That equation should allow researchers to easily predict how the choice of atom and its surrounding material will affect catalytic performance. To date, researchers have often relied on time-consuming trial and error to find promising single-atom catalysts.

"All this (relevant) information can be easily gathered from a textbook," said Zeng, Chancellor's University Professor of chemistry. "Even before an experiment, you can quickly see whether it's a good way to make the catalyst. We're simplifying the process."

Using its equation, the team discovered several atom-framework combinations that approximate the performance of precious-metal catalysts - platinum, gold, iridium - at mere thousandths of the cost. One swapped out a platinum atom for manganese; another replaced iridium with cobalt.

"There are two (primary) ways to reduce the price of these catalysts," Zeng said. "One is to use as little of the metals as possible - so single-atom catalysts are the cheapest. The other direction is finding alternative metals like iron or aluminum or zinc that are very cheap."

Two of the team's atom-framework combinations can split water into its constituent parts: an oxygen atom and two hydrogen atoms, the latter of which can serve as a green fuel for vehicles and other applications. Two other catalyst candidates help oxygen atoms take on more electrons, priming them to bond with positively charged hydrogen atoms and form water - the desired byproduct of hydrogen fuel cells.

"Right now, this is not the prevailing way to produce hydrogen," Zeng said. "The industry still uses fossil fuels to produce hydrogen. It's just cheaper. So that's our motivation: lower the cost so that all these cleaner, fuel-producing reactions become (viable)."

SCOUTING REPORT

The researchers found that the number and nature of atoms directly bonded to a single-atom catalyst can profoundly affect how it catalyzes chemical reactions. In some instances, the catalyzing atom might be attached to either three or four other atoms, each of which is itself part of a five- or six-atom ring. Every atom in that immediate network also has a known attraction to electrons, with the strength of that attraction further influencing catalytic performance.

The arrangement and qualities of those neighboring atoms matter, Zeng said, in the same way that an offensive line matters to a stationary, pocket-passing quarterback. And the team's new equation could act as a scouting report for researchers looking to amplify the strengths or cover the weaknesses of their personnel, he said.

For Zeng and his colleagues, that personnel consisted of more than 20 so-called transition metals that are generally worse than precious metals at catalyzing reactions. But the team showed that surrounding a cobalt, iron or other second-string atom with the right environment - sometimes a honeycomb of carbon atoms known as graphene, sometimes a network of nitrogen atoms - can elevate its performance.

"Every offensive line is different," Zeng said. "How do you make the quarterback function the best in that pocket? How do you find the best quarterback within different pockets?

"If you have a two-star quarterback, you need a better offensive line. But even a backup quarterback can perform well with the right line."

Zeng authored the study with colleagues from Beijing University of Chemical Technology. The study appeared in the journal Nature Catalysis and was highlighted in Chemical and Engineering News, a magazine published by the American Chemical Society.
-end-


University of Nebraska-Lincoln

Related Hydrogen Articles:

Paving the way for hydrogen fuel cells
The hype around hydrogen fuel cells has died down, but scientists have continued to pursue new technologies that could enable such devices to gain a firmer foothold.
Keeping the hydrogen coming
A coating of molybdenum improves the efficiency of catalysts for producing hydrogen.
Hydrogen bonds directly detected for the first time
For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope.
Argon is not the 'dope' for metallic hydrogen
Hydrogen is both the simplest and the most-abundant element in the universe, so studying it can teach scientists about the essence of matter.
Metallic hydrogen, once theory, becomes reality
Nearly a century after it was theorized, Harvard scientists have succeeded in creating metallic hydrogen.
From theory to reality: The creation of metallic hydrogen
For more than 80 years, it has been predicted that hydrogen will adopt metallic properties under certain conditions, and now researchers have successfully demonstrated this phenomenon.
Artificial leaf goes more efficient for hydrogen generation
A new study, affiliated with Ulsan National Institute of Science and Technology has introduced a new artificial leaf that generates hydrogen, using the power of the Sun to mimic underwater photosynthesis.
Hydrogen from sunlight -- but as a dark reaction
The storage of photogenerated electric energy and its release on demand are still among the main obstacles in artificial photosynthesis.
New process produces hydrogen at much lower temperature
Waseda University researchers have developed a new method for producing hydrogen, which is fast, irreversible, and takes place at much lower temperature using less energy.
Hydrogen in your pocket? New plastic for carrying and storing hydrogen
A Waseda University research group has developed a polymer which can store hydrogen in a light, compact and flexible sheet, and is safe to touch even when filled with hydrogen gas.

Related Hydrogen Reading:

The One-Minute Cure: The Secret to Healing Virtually All Diseases
by Madison Cavanaugh (Author)

Hydrogen: The Essential Element
by John S. Rigden (Author)

Hydrogen Fuel: Production, Transport, and Storage
by Ram B. Gupta (Editor)

The Hydrogen Sonata (Culture)
by Iain M. Banks (Author)

The Magic of Hydrogen Peroxide
by Emily Thacker (Author)

2014 True Power of Hydrogen Peroxide, Miracle Path To Wellness - Mary Wright, goes beyond One Minute Cure
by Mary Wright (Author)

Hydrogen (Chemistry of Everyday Elements)
by Kathryn Hulick (Author)

Hydrogen (Exploring the Elements)
by Clara Maccarald (Author)

Hydrogen Peroxide and Aloe Vera - A Home Remedies Handbook
by Conrad LeBeau (Author), Conrad LeBeau (Editor), Conrad LeBeau (Editor)

Hydrogen Peroxide Cure: Learn the Extraordinary Cures, Benefits, and Healing Properties this Magical Elixir has to Offer Using Hydrogen Peroxide to ... and Health Benefits of Hydrogen Peroxide)
by Juliette McKnight (Author)

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

The Story Behind The Numbers
Is life today better than ever before? Does the data bear that out? This hour, TED speakers explore the stories we tell with numbers — and whether those stories portray the full picture. Guests include psychologist Steven Pinker, economists Tyler Cowen and Michael Green, journalist Hanna Rosin, and environmental activist Paul Gilding.
Now Playing: Science for the People

#487 Knitting in PEARL
This week we're discussing math and things made from yarn. We welcome mathematician Daina Taimina to the show to discuss her book "Crocheting Adventures with Hyperbolic Planes: Tactile Mathematics, Art and Craft for all to Explore", and how making geometric models that people can play with helps teach math. And we speak with research scientist Janelle Shane about her hobby of training neural networks to do things like name colours, come up with Halloween costume ideas, and generate knitting patterns: often with hilarious results. Related links: Crocheting the Hyperbolic Plane by Daina Taimina and David Henderson Daina's Hyperbolic Crochet blog...