View Full Version : Palladium: The Ultimate Hydrogen Membrane

16th April 2010, 01:33 PM
(Interesting bits bolded)

http://www.physorg.com/news94209650.html"]Removing (http://"[url) a hydrogen fuel-cell roadblock[/URL]
March 27th, 2007 in Physics / Materials

Researchers at the U.S. Department of Energy’s Ames Laboratory are employing some modern day alchemy in an effort to find a material with properties of rare and high-priced palladium. If they’re successful, it could remove a major roadblock from the path of hydrogen fuel-cell powered vehicles.

Hydrogen fuel-cell technology sounds almost too good to be true. You combine cheap and plentiful hydrogen and oxygen gas, the fuel cell generates electricity and the by-product is simply water. But it’s a little more involved.

The key is a proton exchange membrane, or PEM, containing platinum. The platinum acts as a catalyst that separates electrons from the hydrogen gas atoms. The free electrons are gathered as current and the positively charged hydrogen ions pass through the membrane where they readily combine with oxygen atoms to form water. But if the hydrogen gas contains impurities, such as water vapor or carbon monoxide, it can "gum up" the fuel cell’s separation membrane, dropping efficiency or halting the process altogether. Pure hydrogen, however, is hard to come by, and that’s where palladium enters the picture.

"Hydrogen is tough to handle because of the small size of the atoms and because it naturally wants to bond with other elements," said Ames Laboratory scientist Alan Russell, one of the investigators on the project. "Palladium acts like an atomic filter – the hydrogen atoms readily diffuse right through the metal."

In the conventional approach to purifying hydrogen, an alloy of 73 percent palladium and 27 percent silver is drawn into long thin tubes, about 3 mm in diameter and 20 feet long. Clusters of these tubes are placed inside a vacuum chamber and heated to between 400 and 500 Celsius. Impure hydrogen gas is then pumped into the small tubes, and the hydrogen readily diffuses through the palladium-silver tube walls and is captured in the outer chamber while the impurities travel out the other end of the tubes.

"Palladium is $11,000 a kilogram, and even if you didn’t choke at the price, there isn’t enough palladium in the entire world to convert the world’s automobiles to hydrogen power," Russell said. "So the trick is to find a material with the same properties as palladium that is cheaper and much more readily available."

His use of the word trick isn’t a stretch. Not only does the material have to be less expensive and readily available, it has to allow hydrogen to pass through it and be ductile enough to be drawn into long, thin tubes. It also has to resist oxidation, because oxygen and water vapor are commonly present in impure hydrogen. And finally, hydrogen has a nasty habit of making metals brittle, so the metal also has to handle repeated heating and cooling cycles, while loaded with hydrogen, without becoming brittle.
"With so many variables, we don’t really have any analytical tools that would let us mathematically predict the ideal composition," Russell said, "so we have to use a Thomas Edison approach – relying on intuition and a fair amount of luck to come up with a combination that works."

The three-year project is being spearheaded by Robert Buxbaum, president of REB Research, a Michigan firm involved in hydrogen filtration and fuel-cell technology. Buxbaum is particularly interested in a membrane reactor which combines hydrogen generation and filtration right at the fuel cell. Buxbaum obtained $2.8 million from DOE to find substitutes for platinum and palladium. Besides Russell and visiting Chinese scientist Jie Zhang, the project includes Larry Jones, director of Ames Laboratory’s Materials Preparation Center, as well as researchers at Los Alamos National Laboratory, the National Energy Technology Laboratory, and G&S Titanium, an Ohio-based materials fabrication firm.

Buxbaum proposed developing 100 different alloys, relying on the expertise of Russell and Jones in the field of metals development to pick the mixtures. "It is not by accident that I asked to work with Alan and Larry," Buxbaum said. "They are fantastically talented at what they do," adding that the program in Ames "is the best in the United States and among the best in the world."

Using X-ray diffraction technology to study the crystal microstructure of the materials, Zhang can determine whether the materials show promise in terms of ductility. This provides a shortcut of sorts so that the team doesn’t waste time on materials that are potentially brittle. A little more than a year into the project, about 60 binary alloys have been developed with additional ones in the planning stages. The results have been mixed, but Russell indicated one sample is quite promising and several others show promise.

"There have been surprises. Some alloys that you would expect to be ductile turn out to be hopelessly brittle, like glass," Russell said. "We also tried a material with 25 percent ruthenium, an element which is notorious for making alloys brittle, but that material turned out to be quite ductile." Samples produced in Ames are first cold rolled to see if they are ductile. Those showing promise are further tested and shipped to REB Research where they’re tested to determine how easily hydrogen will diffuse through the metal. Those showing promise get further testing to see if they can be formed into tubes and how they respond to heating and cooling cycles. But even those materials that are rejected as a palladium substitute, may ultimately wind up as useful for other purposes.

"I think we’ve got a good chance of finding something that works for hydrogen generation, but even if none of these alloys are good at that, the materials we’re working with will certainly have other applications." Buxbaum said. "One metal in particular is an amazing alloy – shiny, ductile, high melting, and totally resistant to aqua regia (a mixture of nitric and hydrochloric acids that dissolves gold or platinum)."

Russell added that the willingness of the DOE to fund such a program is indicative of the commitment to develop alternative energy sources.

"Research funding often depends on your ability to demonstrate specific results," he said. "It’s refreshing in a way to get to try traditional metallurgy techniques to try to solve a 21st century problem."

Source: Ames Laboratory

4th July 2010, 01:21 PM
"I think we’ve got a good chance of finding something that works for hydrogen generation, but even if none of these alloys are good at that, the materials we’re working with will certainly have other applications." Buxbaum said. "One metal in particular is an amazing alloy – shiny, ductile, high melting, and totally resistant to aqua regia (a mixture of nitric and hydrochloric acids that dissolves gold or platinum)."

what is the amazing alloy ?

or ... maybe that's the part they're keeping under wraps.

13th July 2010, 11:20 AM
Very interesting.....

Meanwhile all the hydrogen we would ever need in the entire world is in the ocean. In each molecule of water, waiting to be tapped for use.

http://witcombe.sbc.edu/water/chemistryelectrolysis.html - explanation

http://brownsgas.com/ - using water and electricity to make hydrogen (sort of)

Welding with water:

There is a ton of info on this all over the net.

Stop Making Cents
21st August 2010, 07:57 AM
I'm waiting for a dip on Palladium to buy more. It's my favorite PM. What pisses me off is that when Palladium was under $300 / oz a year or so ago, it was nowhere to be found. All the major PM retailers were mysteriously out of it :oo-->

$500 / oz seems a little steep, although i think it can go much higher. I'm hoping for a dip but won't be surprised if it doesn't come down.

16th April 2011, 09:28 PM
Intersting info, would be a safe purchase IMHO.

8th August 2011, 07:58 PM
how come they can't get pure hydrogen from doing hydrolysis ?

i always thought with hydrolysis, that Oxygen being a negatively charged molecule, goes to the positive electrode. & and that Hydrogen goes to the negative electrode.

but then again, i haven't done any hydrolysis recently.

so the Palladium/ Silver alloy is, sounds like, the best known way to separate the hydrogen, which MIGHT be generated by hydrolysis ?

is you invest in Palladium, is there a technology that would diminish its value by offering an alternative & cheaper way to separate hydrogen ?

14th January 2012, 02:11 AM
Continued Advances in Fuel Cell Technology

The New Year may well be the breakthrough year for fuel cells. The astonishing innovation and marketing locomotive of Apple Computers with the i – you name it – product list leading us into new uses for electronic devices, has let slip they will preview a fuel cell idea at this month’s Consumer Electronics Show.

Apple has gone so far as to file patent applications named “Fuel Cell System to Power a Portable Computing Device” and “Fuel Cell System Coupled to a Portable Computing Device” – ideas not to be taken lightly.

It not a great surprise to close Apple watchers, Apple has filed other patent applications for light weight hydrogen fuel cells. Those patents, which were brought to light this past October, described a building process where multiple fuel cells are connected by a power bus in a parallel pattern, and a voltage-multiplying circuit is added for additional voltage from the stack.

Apple hopes to utilize these lighter, more efficient fuel cells in its mobile products in an effort to promote renewable energy sources and offer devices with the ability to run for days or even weeks without refuelling, according to the patent applications. The devices will also be lighter and less bulky due to the lack of traditional batteries.

The interesting thing and idea to watch is Apple wants to integrate fuel cells right into their electronics. No fuel cartridge needed. But Apple allows creating a hydrogen fuel cell system that is cost-effective is a challenge.

The puzzle remains how hydrogen gas storage costs are going to make fuel cells economically viable, hydrogen is very difficult to store. The smallest atom making the smallest molecule in H2 form needs compressed or exotic materials to keep it in one place.

The more interesting fuel cells rely on low cost stores of hydrogen in methanol or ethanol, liquids that have very high hydrogen density and only need plastic tanks at atmospheric pressure.

Apple’s patent application isn’t clear on their choice of fuels, either hydrogen or a hydrocarbon. Apple states that alternative fuel cells may correspond to solid oxide fuel cells, molten carbonate fuel cells, direct methanol fuel cells, alkaline fuel cells, and/or other types of fuel cells.

Another part of the appeal is regulating a fuel cell’s operating parameter by directly charging an external battery with the fuel cell allowing the control process to be highly reliable.


Meanwhile the U.S. Department of Defense, with the world’s largest fuel bill and likely the largest buyer of batteries is hard at the Direct Methanol Fuel Cell. The U.S. Army is especially interested in hydrogen based fuel cell technology, says Maj. Mark Owens, which drastically reduces the amount of batteries that soldiers carry on dismounted missions. Owens’ shop, the PM Soldier Warrior, studied one three-day mission with a company-sized element and found that the fuel cell reduced the amount of batteries they carried by 600 pounds. The test was the 1st Battalion of the 1st Infantry Division deployed to Afghanistan in 2011 with their rucksacks full of experimental renewable energy equipment.

The fuels cells are powered by reformed methanol – meaning it’s slightly watered-down – and “get lighter as time goes on,” as the fuel is used Owens says, “and the case weighs almost nothing.” Still, the rucksack-packable fuel-cell generator weighs 36 lb., according to Army documents. “Obviously, we want to get the weight down as much as possible,” Owens says. Also under evaluation is a 4.6-lb. wearable fuel cell that generates 50 watts of continuous power for 10 hours.

The problem is the money – all the fuel cells from simple hydrogen to those reacting heavy petrochemicals like kerosene all rely in expensive and rare elements like platinum, palladium and even rhodium. And they run hot, 100s of degrees centigrade. While the Finns have come up with a much less costly way to use the metals platinum and palladium, the investment will still be very substantial and the growth of the industry will simply push the metal prices higher.

Still, there are glimmers of research looking for ways to build fuel cells without the precious metal component. One small break, in an industry building and selling fuel cells in specialized uses with great regularity, offers hope that mass markets can be addressed.

Bloom Energy can build fuel cells reacting with natural gas, or methane fuel for sensible prices. Bloom and many others can be expected to be looking for ways to downsize and use liquid fuels. There is intense interest and cash on the line for the market right now.

2012 might be the year a fuel cell comes out that runs under the temperature of boiling water, and runs on cheap, energy dense and abundant, natural gas, ethanol or methanol.

So far details are rare, but you can be sure there will news coming soon.