June 26, 2003
Low Cost Biomass Hydrogen Catalyst Discovered

Researchers at the University of Wisconsin in Madison have discovered a much lower cost catalyst for producing hydrogen from organic matter.

MADISON It is thousands of times less expensive than platinum and works nearly as well.

Writing this week in the journal Science (June 27) University of Wisconsin-Madison chemical and biological engineers report the discovery of a nickel-tin catalyst that can replace the precious metal platinum in a new, environmentally sustainable, greenhouse-gas-neutral, low-temperature process for making hydrogen fuel from plants.

The new catalyst, together with a second innovation that purifies hydrogen for use in hydrogen fuel cells, offers new opportunities toward the transition of a world economy based on fossil fuels to one based on hydrogen produced from renewable resources.

James Dumesic, a professor of chemical and biological engineering, and graduate students George Huber and John Shabaker describe testing more than 300 materials to find a nickel-tin-aluminum combination that reacts with biomass-derived oxygenated hydrocarbons to produce hydrogen and carbon dioxide without producing large amounts of unwanted methane.

"Platinum is very effective but it's also very expensive," says Dumesic. "It's also problematic for large-scale power production because platinum is already in demand for use as anode and cathode materials in hydrogen fuel cells. We knew nickel was very active, but it allowed reaction to continue beyond hydrogen producing methane. We found that adding tin to what's known as a Raney-Nickel catalyst decreased the rate of methane formation without compromising the rate of hydrogen production."

Dumesic, research scientist Randy Cortright (now at Virent Energy Systems) and graduate student Rupali Davda first reported the catalytic reforming process for hydrogen production in the Aug. 29, 2002 issue of the journal Nature.

The simple, single-step process employs temperature, pressure and a catalyst to convert hydrocarbons such as glucose, the same energy source used by most plants and animals, into hydrogen, carbon dioxide, and gaseous alkanes with hydrogen constituting 50 percent of the products. More refined molecules such as ethylene glycol and methanol are almost completely converted to hydrogen and carbon dioxide. Because plants grown as fuel crops absorb the carbon dioxide released by the system, the process is greenhouse-gas neutral.

Platinum is too expensive.

The precious metal platinum (Pt) is well known to be an excellent catalyst in a number of chemical reactions. It is one component in a car's catalytic converter, for example, that helps remove toxins from automobile exhaust. Yet, platinum is rare and very expensive, costing more than $17 per gram (about $8,000 per pound).

Catalytic platinum (Pt) and nickel (Ni) stand out from other metals (such as copper or iron) because they process reaction molecules much faster. But pure nickel, unlike platinum, recombines the hydrogen product with carbon atoms to make methane, a common greenhouse gas. Dumesic and his colleagues tested over 300 catalysts to find one that could compete with platinum and perform in the APR process. Using a specially designed reactor that can test 48 samples at one time, the team finally found a match in a modified version of what researchers call a Raneynickel catalyst, named after Murray Raney, who first patented the alloy in 1927.

Raney-nickel is a porous catalyst made of about 90 percent nickel (Ni) and 10 percent aluminum (Al). While Raney-nickel proved somewhat effective at separating hydrogen from biomass-derived molecules, the researchers improved the material's effectiveness by adding more tin (Sn), which stops the production of methane and instead generates more hydrogen. Relative to other catalysts, the Raney-NiSn can perform for long time periods (at least 48 hours) and at lower temperatures (roughly 225 degrees Celsius).

According to Dumesic, a substitute for platinum catalysts is essential for the success of hydrogen technology. "We had to find a substitute for platinum in our APR process for production of hydrogen, since platinum is rare and also employed in the anode and cathode materials of hydrogen fuel cells to be used in products such as cars or portable computers," he said.

While this is an important advance by itself it does not make biomass a viable major energy source. The problem with growing crops for biomass is that it takes energy to make and transport the fertilizer, run tractors, run irrigation equipment, harvest, transport, and so on. It remains to be seen whether there is a crop that will yield enough biomass energy to make it worthwhile.

This catalyst may be useful on smaller scales in places where there is already a great amount of biomass waste being produced. For instance, the processing of existing crops produces biomass waste. Equipment to convert that biomass waste into useful hydrogen energy could be installed next to agricultural product processing facilities if this new catalyst turns out to work well in industrial use. Still, all the existing biomass waste is not sufficient as an energy source to replace much of the currently consumed fossil fuels.

Other enabling technologies such as fuel cells need to mature ot make hydrogen a more useful energy source once it has been produced. Those advances will come with time. What strikes me as less certain is whether biomass will ever become a major energy source for producing hydrogen. Plants have to be planted, tended, harvested, and processed. They are vulnerable to insects and droughts. They do not convert most of the light that hits them into stored chemical energy.

There are competing approaches that may be cheaper in the longer run. Advances in nanotechnology will eventually yield photovoltaic materials that will be cheap to produce. Then the electricity from the photovoltaics will could be used to run hydrolysis reactions to produce hydrogen from water. Also, some materials may be found that can absorb light to drive a direct catalysis reaction to produce hydrogen from water without first producing electricity. Such materials would probably be more efficient than plants at converting sunlight to energy and would even be able to do so all year around (albeit at lower rates during the shorter days of the year).

Update: Some Tufts researchers have also recently discovered a way to reduce the amount of precious metals used as catalysts to make hydrogen.

"A lot of people have spent a lot of time studying the properties of gold and platinum nanoparticles that are used to catalyze the reaction of carbon monoxide with water to make hydrogen and carbon dioxide," said Maria Flytzani-Stephanopoulos, professor of chemical and biological engineering at Tufts and the lead researcher of the project. "We find that for this reaction over a cerium oxide catalyst carrying the gold or platinum, metal nanoparticles are not important. Only a tiny amount of the precious metal in non metallic form is needed to create the active catalyst. Our finding will help researchers find a cost-effective way to produce clean energy from fuel cells in the near future"

She and her two colleagues, doctoral student Qi Fu and research professor Howard Saltsburg, were funded by a $300,000 three-year grant from the National Science Foundation, and have filed a provisional patent for their research. Their cutting-edge work in catalytic fuel processing to generate hydrogen for fuel cell applications is one of the major undertakings at Tufts' Science and Technology Center at the University's Medford campus.

The Tufts researchers' article is based on the "water-gas shift" reaction they use to make hydrogen from water and carbon monoxide over cerium oxide loaded with gold or platinum. Typically, a loading of 1-10 weight percent of gold or other precious metals is used to make an effective catalyst. But the Tufts team discovered that, after stripping the gold with a cyanide solution, the catalyst was just as active with a slight amount of the gold remaining one-tenth the normal amount used.

According to Flytzani-Stephanopoulos, "This finding is significant because it shows that metallic nanoparticles are mere 'spectator species' for some reactions, such as the water-gas shift. The phenomenon may be more general, since we show that it also holds for platinum and may also hold true for other metals and metal oxide supports, such as titanium and iron oxide."

She adds, "It opens the way for new catalyst designs so more hydrogen can be produced with less precious metal. This can pave the way for cost-effective clean energy production from fuel cells in the near future."

Share |      Randall Parker, 2003 June 26 05:52 PM  Energy Biomass


Comments
Sam said at August 2, 2003 3:56 AM:

Instead of inhibiting methane formation, why not encourage it? Methane is a heck of a lot easier to store, transport, and burn in portable devices (read automobile engines) than hydrogen, and since the carbon came from the atmosphere it is neutral with respect to atmospheric CO2.

Ira E. Smiley said at October 15, 2003 9:53 AM:

It seems that taxpayers are being taken for a ride; i.e., funding a research(?) program to the tune of $300K and letting someone else file a patent on any discoveries made with their money. Also, as mentioned in the Madison publication, why use resources to work out uneconomical methods of getting hydrogen from expensive biomass?

CK said at April 28, 2004 6:35 PM:

Why use the energy from an improved solar cell...

"There are competing approaches that may be cheaper in the longer run. Advances in nanotechnology will eventually yield photovoltaic materials that will be cheap to produce. Then the electricity from the photovoltaics will could be used to run hydrolysis reactions to produce hydrogen from water."

to produce hydrogen, when the second law of thermodynamics argues that you lose energy in the process? Why not just use the electricity from the cell directly?

Randall Parker said at April 28, 2004 6:59 PM:

CK, Actually both hydrogen and electricity are difficult to store. We do not have good batteries. We also do not have good ways to store hydrogen.

One alternative I've repeatedly argued for is to develop better ways to use electricity to fix hydrogen to carbon. Basically, use electricity to create hydrocarbons. Liquid hydrocarbons are really easy to store and transport.

Also, MIT professor Donald Sadoway argues that lithium polymer batteries can be made practical and that such batteries would make pure electric cars feasible.

Tom Dale said at September 2, 2005 9:25 PM:

Is there any similar work regarding improved catalysts for use in direct electrolysis of water, avoiding all the CO2 and methane issues?

Edward said at September 28, 2005 6:48 AM:

How would they be able to produce this on a large scale (such as for fuel-cell
hydrogen in the near future) without compromising the process and the amout of carbon dioxide to be absorbed.
Will this work for large scale?!

Ron said at October 8, 2005 4:51 PM:

I have a whole yard, garden, and horse stable full of "biomass". Can you make this work on a small scale? If everyone had a bin in their back yard, you could collect the product and refine it if needed.

Even if it produced a mixture of hydrogen, methane and a variety of small organic molecules, you could still burn it in an internal combustion, or turbine type engine, or you could burn it directly for heat. Not everything has to be turned to electricity.

Will Car catalytic converters work? What if you went to the junk yard and ground up a bunch of catalytic converters?

Marko said at December 8, 2005 12:20 PM:

Hydrogen Still
Will someone figure a way to create a storable ongoing supply of hydrogen fuel from chemical/biologic reaction using a sealed container similar to a still, that can be built and used by the everday person.
Modified algae can produce hydrogen.

K. Narayana Rao said at October 30, 2006 6:15 AM:

What is the need to produce Hydrogen?
Just go with (Bio-mass) means direct methanol fuel cells like that
i know what is the problem with BMFC
but we can cross it? then only we can use the vehicles which are going now
Other it makes much more garbage.

CHUCK STONE said at May 12, 2008 3:13 AM:

New ideas need time to develop and dedicated inventors to develop them. Do not let the nay sayers deter you. Keep trying and you may be the one person who finds the answers needed. The problem is more about politics and human greed than technology. Be like the Wright brothers and go down in history as the person who expanded the envelope beyond that defined by the universities and documented in the text books. There is no text book that shows you how to build any new idea that has never been built.

At 72 years old I have seen many new ideas developed by advocates, and read lots of history about the great works of Tesla, Edison, Ford, etc. I invite you to checkout my website at "www.waterfueledsystems.net" just for fun. That site shows water based fuels that work well and includes the Advanced Lunar Power System we developed for NASA to run on the Moon using water for the fuel and oxidizer. My final invention is a water fueled engine that uses waste heat to crack tap water into hydrogen and oxygen "on-demand" without electrolysis. Two engines are in test now and a third one is being prepared for testing.

We operate on our own funds and are having lots of fun. We sell nothing today but we expect to produce fleet vehicles for sale in 2010. Our only problems will be the politics of "BIG OIL" and dumb governments. The site has a little history of the 10 year experiment we did for the State of California (1980-1989)for the water based fuel known as Methanol. We built the first 500 vehicles and sold them and that was the start of today's 85/15 Flexfuel vehicles. Ours were high compression (12 to 1), but the "BIG THREE" automakers only built poor performance low compression vehicles and the dumb government of California let them do it.

Have fun while working on your ideas and remember - life is short so make the best out of it. Never mind the "NAY SAYERS" who never produce any solutions for anything.

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