Researchers report new, more efficient catalyst for water splitting

May 15, 2017
water
Credit: George Hodan/public domain

University of Houston physicists have discovered a catalyst that can split water into hydrogen and oxygen, composed of easily available, low-cost materials and operating far more efficiently than previous catalysts.

That would solve one of the primary hurdles remaining in using water to produce hydrogen, one of the most promising sources of .

"Hydrogen is the cleanest primary energy source we have on earth," said Paul C. W. Chu, TLL Temple Chair of Science and founding director and chief scientist of the Texas Center for Superconductivity at UH. "Water could be the most abundant source of hydrogen if one could separate the hydrogen from its strong bond with in the water by using a ."

Chu and colleagues including physicists Zhifeng Ren and Shuo Chen, both of whom also are principal investigators with the Texas Center for Superconductivity at UH, report their discovery - an efficient catalyst produced without the expensive precious metals most commonly used—this week in the Proceedings of the Natural Academy of Sciences.

Other researchers involved in the project include postdoctoral researchers Haiqing Zhou and Fang Yu, and graduate students Jingying Sun and Ran He.

The catalyst, composed of ferrous metaphosphate grown on a conductive nickel foam platform, is far more efficient than previous catalysts, as well as less expensive to produce.

"Cost-wise, it is much lower and performance-wise, much better," said Zhifeng Ren, M.D. Anderson professor of physics and lead author on the paper. The catalyst also is durable, operating more than 20 hours and 10,000 cycles in testing.

"Some catalysts are outstanding but are only stable for one or two hours," Ren said. "That's no use."

Although it is simple in theory, splitting water into hydrogen and oxygen is a complex process, requiring two separate reactions - a hydrogen evolution reaction and an oxygen evolution reaction, each requiring a separate electrode. While hydrogen is the more valuable component, it can't be produced without also producing oxygen. And while efficient hydrogen catalysts are available, Ren said the lack of an inexpensive and efficient oxygen catalyst has created a bottleneck in the field.

Hydrogen has a number of advantages. "Hydrogen (H2) produced from by an electrochemical process, called water electrolysis, has been considered to be a clean and sustainable energy resource to replace fossil fuels and meet the rising global energy demand, since water is both the sole starting material and byproduct when clean energy is produced by converting H2 back to water," the researchers wrote.

And unlike solar power, wind power and other "clean" , hydrogen can be easily stored.

Currently, most hydrogen is produced through steam methane reforming and coal gasification; those methods raise the fuel's carbon footprint despite the fact that it burns cleanly.

Chen said oxygen evolution reactions often depend upon an electrocatalyst using a "noble metal" - iridium, platinum or ruthenium. But those are expensive and not readily available.

"In this work, we discovered a highly active and stable electrocatalyst based on earth-abundant elements, which even outperforms the noble metal based ones," she said. "Our discovery may lead to a more economic approach for production from water electrolysis."

Water splitting can be triggered either through electric current or through photocatalysis, using the power of the sun. Direct solar-powered water splitting is too inefficient, as water can absorb just a small portion of the light spectrum. Ideally, Ren said, solar power would be used to generate the electric power used to split .

Explore further: New approach to water splitting could improve hydrogen production

More information: Haiqing Zhou el al., "Highly active catalyst derived from a 3D foam of Fe(PO3)2/Ni2P for extremely efficient water oxidation," PNAS (2017). www.pnas.org/cgi/doi/10.1073/pnas.1701562114

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14 comments

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holoman
not rated yet May 15, 2017
Can they produce more than 450 liters in 1 hour using 130 watts ?

http://www.fundac...=visitor
ForFreeMinds
not rated yet May 15, 2017
Can they produce more than 450 liters in 1 hour using 130 watts ?

http://www.fundac...=visitor


Good question - no numbers are provided. Still, improvements may lead to further improvements yielding a new efficient source of energy.
MR166
5 / 5 (2) May 15, 2017
" hydrogen can be easily stored."

Not really, it will not liquefy unless cooled to 33K and high pressure storage tanks are very expensive. Turning it into methanol makes more sense.
betterexists
1 / 5 (2) May 15, 2017
Oceans occupy larger part of the Globe; So, Federal Govts. should step in, meet and start using it and all profits coming out of it should be devoted to bettering the Catalysts Even More...Further & Further. Awful lot of Oxygen, Dwindling Amounts of Co2 in the Air is the need of the hour! It says The Component Materials of the Catalyst are ABUNDANT and also Easily Available! So, What is Stopping it? More Worried about Abortions, Embryonic Stem Cells, Statues, BUT NOT WARS...that too with Missiles containing Nukes?
Shootist
5 / 5 (1) May 15, 2017
" hydrogen can be easily stored."

Not really, it will not liquefy unless cooled to 33K and high pressure storage tanks are very expensive. Turning it into methanol makes more sense.


Alcohol is a silly fuel at 1/2 the btu per pound of gasoline. But the H2 will do well as methane to add as feed stock for LNG.
EmceeSquared
5 / 5 (3) May 15, 2017
What kind of lame reporter writes a story about the more efficient catalyst without mentioning its efficiency, the primary fact in the story?

Also, 'unlike solar power, wind power and other "clean" energy, hydrogen can be easily stored' is a pretty stupid statement when efficiently cracking water is precisely the way to store those clean energy sources. While cracking hydrogen isn't an energy source, it is only storage.

This isn't science writing, it's science fan fiction, sciencey porn. The real thing is much better.
Lex Talonis
1 / 5 (3) May 16, 2017
Hydrogen can be safely stored in nuclear warheads.

We need more nuclear warheads.

Global nuclear annihilation, through atomic fires and terror, is just the beginning of Christ's reign on earth.
antialias_physorg
5 / 5 (2) May 16, 2017
What kind of lame reporter writes a story about the more efficient catalyst without mentioning its efficiency

The linked abstract gives an efficiency increase factor of 49 over IrO2 catalysts at 300mV.
manfredparticleboard
5 / 5 (2) May 16, 2017
Hydrogen can be safely stored in nuclear warheads.

We need more nuclear warheads.

Global nuclear annihilation, through atomic fires and terror, is just the beginning of Christ's reign on earth.

Oh wow! Just ...wow! Do people actually think like this? Is there really just creepy clown music with distorted speed effects playing constantly in some peoples' minds? Do they have abbatoir scenes on constant loop, overlaid with hymns and scenes from Mel Gibson's Passion of the Christ randomly interspersed running thorugh their head? Have Trolls suddenly become more creatively articulate?

It's a new insight to a madness that remains nameless and terrifyingly hidden. Is this person otherwise functional and it's only the occasional stare and expressionless withdrawal into a private reverie that hints at the sort of person who could bludgeon someone to death with a donkey femur and then eat their lunch from a little plastic container their mom packs for them
daily.
antialias_physorg
not rated yet May 16, 2017
Have Trolls suddenly become more creatively articulate?

We're at the point where stuff like the postmodernism essay generator makes more sense than most trolls.
http://www.elsewh...al/pomo/

Forget 'better at chess' or 'better at Go'. Computers are a lot better than these people at being coherent in general.

It's a new insight to a madness that remains nameless and terrifyingly hidden.

And able to vote. That's the scary part.
EmceeSquared
5 / 5 (2) May 16, 2017
I read that comment as satirical, indicated by "terror just the beginning of Christ's reign". But there's Poe's law:
https://en.wikipe...%27s_law

There are indeed many apocalyptic Christians among the USA's theocratic Dominionists who do believe just what that post declared. Many believe all Jews must be moved to Israel (or exterminated) so that nuclear apocalypse starting there can be the Armageddon they believe is prophecied in their bible. Islamic State's theocracy is a mirror of that, the visiting team, why they've fought so hard to control the Syrian town of Megido.

Steve Bannon and other Trump cronies from the billionaire Mercers are evidently among these theocratic lunatics.

Yes, we are that close to disgusting doomsday satire being official US policy. Backed by a crooked, but large, voting minority.

manfredparticleboard:
Oh wow!
EmceeSquared
5 / 5 (2) May 16, 2017
Thanks for doing the anonymous PhysOrg "journalist's" job for them.

The figure in the abstract is "activity enhancement by a factor of 49 in boosting water oxidation at 300 mV relative to the state-of-the-art IrO2 catalyst." I don't think "activity enhancement" is simply "energy efficiency". And so I can't find the base "activity" figure for the best IrO2 catalysts. The closest I came in a brief search for just the energy efficiency was this 6/2016 paper which hides it in the paid paper:
http://pubs.acs.o....6b01888

antialias_physorg:
The linked abstract

betterexists
not rated yet May 16, 2017
Where is The Need to store H2 ? Keep Filling with Water as it is about to run out!
EmceeSquared
5 / 5 (1) May 16, 2017
The need to store H2 is the obvious practical necessity: once you make it from water, you have to do something with it, or the process was nothing but a waste.

Are you joking?

betterexists:
Where is The Need to store H2 ? Keep Filling with Water as it is about to run out!

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