Skip to comments.Team develops new water splitting technique that could produce hydrogen fuel
Posted on 08/02/2013 2:42:18 AM PDT by LibWhacker
A University of Colorado Boulder team has developed a radically new technique that uses the power of sunlight to efficiently split water into its components of hydrogen and oxygen, paving the way for the broad use of hydrogen as a clean, green fuel.
The CU-Boulder team has devised a solar-thermal system in which sunlight could be concentrated by a vast array of mirrors onto a single point atop a central tower up to several hundred feet tall. The tower would gather heat generated by the mirror system to roughly 2,500 degrees Fahrenheit (1,350 Celsius), then deliver it into a reactor containing chemical compounds known as metal oxides, said CU-Boulder Professor Alan Weimer, research group leader.
As a metal oxide compound heats up, it releases oxygen atoms, changing its material composition and causing the newly formed compound to seek out new oxygen atoms, said Weimer. The team showed that the addition of steam to the systemwhich could be produced by boiling water in the reactor with the concentrated sunlight beamed to the towerwould cause oxygen from the water molecules to adhere to the surface of the metal oxide, freeing up hydrogen molecules for collection as hydrogen gas.
"We have designed something here that is very different from other methods and frankly something that nobody thought was possible before," said Weimer of the chemical and biological engineering department. "Splitting water with sunlight is the Holy Grail of a sustainable hydrogen economy."
A paper on the subject was published in the Aug. 2 issue of Science. The team included co-lead authors Weimer and Associate Professor Charles Musgrave, first author and doctoral student Christopher Muhich, postdoctoral researcher Janna Martinek, undergraduate Kayla Weston, former CU graduate student Paul Lichty, former CU postdoctoral researcher Xinhua Liang and former CU researcher Brian Evanko.
One of the key differences between the CU method and other methods developed to split water is the ability to conduct two chemical reactions at the same temperature, said Musgrave, also of the chemical and biological engineering department. While there are no working models, conventional theory holds that producing hydrogen through the metal oxide process requires heating the reactor to a high temperature to remove oxygen, then cooling it to a low temperature before injecting steam to re-oxidize the compound in order to release hydrogen gas for collection.
"The more conventional approaches require the control of both the switching of the temperature in the reactor from a hot to a cool state and the introduction of steam into the system," said Musgrave. "One of the big innovations in our system is that there is no swing in the temperature. The whole process is driven by either turning a steam valve on or off."
"Just like you would use a magnifying glass to start a fire, we can concentrate sunlight until it is really hot and use it to drive these chemical reactions," said Muhich. "While we can easily heat it up to more than 1,350 degrees Celsius, we want to heat it to the lowest temperature possible for these chemical reactions to still occur. Hotter temperatures can cause rapid thermal expansion and contraction, potentially causing damage to both the chemical materials and to the reactors themselves."
In addition, the two-step conventional idea for water splitting also wastes both time and heat, said Weimer, also a faculty member at CU-Boulder's BioFrontiers Institute. "There are only so many hours of sunlight in a day," he said.
The research was supported by the National Science Foundation and by the U.S. Department of Energy.
With the new CU-Boulder method, the amount of hydrogen produced for fuel cells or for storage is entirely dependent on the amount of metal oxidewhich is made up of a combination of iron, cobalt, aluminum and oxygenand how much steam is introduced into the system. One of the designs proposed by the team is to build reactor tubes roughly a foot in diameter and several feet long, fill them with the metal oxide material and stack them on top of each other. A working system to produce a significant amount of hydrogen gas would require a number of the tall towers to gather concentrated sunlight from several acres of mirrors surrounding each tower.
Weimer said the new design began percolating within the team about two years ago. "When we saw that we could use this simpler, more effective method, it required a change in our thinking," said Weimer. "We had to develop a theory to explain it and make it believable and understandable to other scientists and engineers."
Despite the discovery, the commercialization of such a solar-thermal reactor is likely years away. "With the price of natural gas so low, there is no incentive to burn clean energy," said Weimer, also the executive director of the Colorado Center for Biorefining and Biofuels, or C2B2. "There would have to be a substantial monetary penalty for putting carbon into the atmosphere, or the price of fossil fuels would have to go way up."
That line alone keeps this out of News/Activism. Worth filing away in the old memory banks, however.
I’m pretty confident that unicorn poops skittles
The Unicorn poops Skittles, not M&Ms. Although I don't possess the documentation, photos or video to back this up, it's a known fact and a 2008 campaign promise made to those who have a strong desire for Skittles. Case in point - What was Travon Martin carrying the night he was casing the wrong neighborhood?
Hydrogen one explosive element that only needs a dull glow to ignite!
Oxygen one of 3 elements required for fire.
Put em together and they are required to sustain life, and put out fires. Yep it's a created universe!
From a purely technical standpoint, I remember the late Paul Harvey talk about this on one of his radio spots. And didn’t some guy in Florida come up with a way of breaking down water into its base elements for welding? I think he even came before congress and the military was interested.
In other words, is this really a new discovery?
Might be useful in sunny, remote locations to have local energy generation. If the cost of fuel has to go “way up”, it is not a large scale solution.
I don’t see it being a large scale solution at all. Even at 100% efficiency you’re still limited by the amount of sunlight you can capture.
It’s probably not new, as in never been done. However, what makes it possibly interesting is that it can be done at such a relatively cheap price, compared to earlier methods.
I see. So the next question is... can be done cheaply enough where one could do it on a small level for home domestic use?
... or would the home production of hydrogen gas constitute a homeland security threat?
I can see now: “...We have to regulate water to make sure it doesn’t get into the hands of terrorists - especially domestic ones...”
There’s a fella (passed on now) who discovered a way to separate hydrogen molecules from salt water utilizing high frequency radio waves.
The guy was a former radio station owner that was attempting to discover a way to target cancer cells without killing healthy cells.
Take a look. It is amazing and repeatable by several lab tests at various universities.
Any process used to split water into O2 and hydrogen requires input of energy. The energy will be more than can be recovered by recombining O2 and hydrogen. Hydrogen is an energy storage medium, not an energy source.
This should be good for getting multi-billions of dollars from the gov’t.
The problem I see with liquid hydrogen is not in producing it, but in holding onto it. If you remember the Shuttle, you would note that they had to continue filling the liquid hydrogen tanks until minutes before the launch. this was because even in the heavily insulated external tank, the hydrogen was constantly boiling off.
H2 will also leak, even through steel.
“Hydrogen is much too volatile for vehicular use.”
Nonsense. You are probably thinking “Hindenburg”. You would be wrong. Suggest you read up on it.
Regarding the picture. How do they get the sun to shine on all 360 degrees?
Oh, another, more serious thought.
To create that kind of solar heat consistently enough to make it worthwhile, I would suspect you would have to built these things in the desert. You know, the places where water is scarce. So, seems like you’d have to have a massive pipeline built or expensive deep wells. This would require a huge infrastructure any way you look at it.
They’ve already built a solar mirror system to run boilers and it’s a boondoggle. They had glowing reports on it on one of those engineering shows. I did more research on it and they hardly ever run it because it’s too expensive to maintain.
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