Carbon Nanotubes Could Replace Platinum and Lead to Affordable Hydrogen Cars

By Eliza Strickland | February 6, 2009 3:11 pm

carbon nanotubesThe joke about hydrogen-powered cars is that they’re about 10 years away–and always will be. The technology has been held up largely by the high cost of hydrogen fuel cells, but now researchers say they’ve found a way to bring down the cost dramatically by making a key component out of carbon nanotubes instead of platinum. More than half the cost of fuel-cell stacks comes from platinum, according to the Department of Energy. “Fuel cells haven’t been commercialized for larger-scale applications because platinum is too expensive,” says Liming Dai [Technology Review], the lead author of the new study.

Researcher found that tightly packed, vertically aligned carbon nanotubes doped with nitrogen were more effective as catalysts than platinum, which is usually used to help oxygen react within the fuel cell. That is a vital stage of the fuel cell cycle. Rather than burning fuel to create heat to power a turbine, fuel cells turn chemical energy directly into a flow of electricity. Hydrogen gas, for example, is pumped past one electrode (the anode), where it is split into its constituent electrons and protons. The electrons then flow out of the anode, providing electrical power, while the protons diffuse through the cell. Electrons and protons both end up at a second electrode (the cathode), where they combine with oxygen to form water [New Scientist].

That second reaction is very slow, so engineers have developed cathodes made out of materials that act as chemical catalysts and speed up the reaction. Until now, platinum was considered the best catalyst, but now carbon nanotubes with a trace of nitrogen (the critical ingredient) have left the precious metal in the dust.

In their experiments, reported in Science [subscription required], researchers found that the nanotube setup produced four times more electric current than a fuel cell that used platinum. Dai also says that carbon nanotubes, which are known to be electrically and mechanically robust, could overcome other issues that platinum faces. Carbon monoxide can stick to platinum’s surface and make it less effective, Dai says. Also, platinum is not very durable, and its properties degrade over time. “Carbon nanotubes have long-term operational stability and do not suffer from carbon-monoxide poisoning,” Dai says [Technology Review].

The lab tests were done with a type of highly efficient fuel cells known as alkaline fuel cells. These cells have so far been limited to use for power generation on spacecraft, but the new advance could open the doors for their entry into the vehicle market [Technology Review]. Prototypes of hydrogen-powered cars have used polymer electrolyte membrane (PEM) fuel cells, but Dai says the nanotube catalyst would work for those as well. And while carbon nanotubes are currently expensive to make, Dai believes it will soon be commercially viable to use them in fuel cells. “Since 1990 the cost of producing carbon nanotubes has fallen 100-fold and can be expected to fall further. Platinum on the other hand is a finite resource – there are limited reserves in nature” [Chemistry World], he says.

Related Content:
80beats: DARPA Wants a Biofuel Jet, While Germany Works on a Hydrogen Plane
80beats: Even With Public Funding, Hydrogen Cars Are at Least 15 Years Away
DISCOVER: Under the Hood of the First Real Fuel-Cell Car
DISCOVER: Future Tech test drives three hydrogen cars
DISCOVER: Lovin’ Hydrogen describes Amory Lovins’s vision of a hydrogen-powered future

Image: Science

CATEGORIZED UNDER: Technology
  • http://www.mazepath.com/uncleal/ Uncle Al

    My 1989 VW Golf gets 300 miles from its modest gas tank. Calculate how much hydrogen gets you 300 miles driven. How do you plan to store it on board, git? The densest hydrogen atoms/cm^3 storage available – well beyond any EPA-targetted bushwa goals – is an open bucket of diesel. You get to burn the carbon, too.

    Will housewives diddle 5000+ psi fittings or 23 K croygenic fills? If your car air conditioner leaked (real and virtual) CF_2Cl_2 mw = 120.92, how well do you think hydrogen containment will go with mw = 2.0159? LEL and UEL, hydrogen has the widest span.

    So we have 200 million H*Y*D*R*O*G*E*N cars on the road, each one drooling water out its tailpipe. Have you ever driven in the rain? Real clever for icing conditions in winter, too. Where do you plant to mine hydrogen? Pop a nuke under cubic miles of Colorado oil shale and Enviro-whiners will pop a cap up your butt. Great advertising slogan: “Buy it or walk”.

  • Bob Munck

    “How do you plan to store it on board, git?”

    Carbon nanotubes might help there as well, being used in light, ultra-strong pressure tanks. If they could manage pressures of 1,000 bars, they would be equivalent in size and vehicle range to a tank of gasoline.

    “So we have 200 million H*Y*D*R*O*G*E*N cars on the road, each one drooling water out its tailpipe. ”

    The water comes out as steam or hot moist air.

    “Where do you plant to mine hydrogen?”

    How about solar cells on rooftops, trickling out hydrogen by dissociating water while the sun shines? On the other end of the size spectrum, pebble-bed nuclear reactors underground out in the desert, delivering electricity and hydrogen to population centers through SuperGrid superconducting pipelines.

  • http://www.lousycanuck.ca Jason Thibeault

    Uncle Al, I have never met anyone, even the most ardent climate change skeptics, who did not agree that the industrialized world needs to stop burning fossil fuels to create energy. The man I debate climate change’s anthropogenic nature with the most, is also the one who turned me on to the idea of hydrogen as power generation. He however also felt that the water vapor entering the atmosphere from a fleet of hydrogen-powered cars would inevitably cause more of a greenhouse effect than the CO2 we’re putting out there now. Since there was little arguing with him on the science (as I had not researched anything on the idea prior to his introducing it), I suggested giant dehumidifiers, a joke to misdirect him while I went about researching further. He seemed to consider what I’d intended as a joke, plausible.

    The fact that someone who disbelieves AGW understood that the water wouldn’t go dribbling out the tailpipe, and you didn’t, leads me to believe that you’re either replying based solely on your gut reaction to this, throwing in what facts you have off the top of your head re: diesel, to misdirect us from the fact that you have no real argument against this article, as you have on a number of other science blogs, especially ones on discovermagazine.com. I strongly suspect you’re trolling to increase your site’s exposure, which by the by resembles something out of the Geocities days.

    Either that, or you’re one hell of a right-wing parodist. Can I call “maybe Poe?”

  • Uncle B

    GM is dead at the government’s teat, and with it, SUV’s and big cars in general! OPEC and the Saudis sit this week to raise oil to $70.00 bbl! and they want more, later! Big transport trucking is on the cusp, and about to be transferred back to rail, from whence it came, from cheap oil! The average American will take the bus or walk, very soon, a dictum of the oil price hikes during the (GRD) great republican depression, now underway! The highways are being cleared for better ideas as we speak, n’est pas? VW, Hyundai, Toyota, all know the facts concerning what is to come to Americans, regardless of what Obama does. Post GRD, the American psyche will be pummeled flat, no more ridiculous sense of entitlement, no more wallets full of good money, no more unending credit, no more cheap fuels, no more cheap foods, many living in shanty-towns on cities edge, monumental arrogance totally deflated, Military forces an oiless mockery, industries gone off-shore, unemployment at sickeningly high levels, streets lined with foreclosure signs, mobs in the streets, moments from Anarchy, and Post GRD, a poverty stricken few survivors, only able to piece together some semblance of the former civilization! The new, super economical, bio-diesel fuelable super light sane form of transport is for these gentle, environmentally conscientious thin, light bodied vegan folk, who will grow Algae based diesel fuels and live in garden communes, not for todays moron population anyway, so don’t get stressed out, fooling yourselves thinking you can afford one, check at the bank first, you are broke! Nanotubes and fuel cells, exotics in my small world may replace the bio-diesel’s batteries, making an interesting pulg-in, regenerative situation I applaud, may all good fossil fuel replacements come into fruition in their own place Post GRD, and may Americans and a new America rise like a Phoenix from the ashes of the pre-GRD era G d willing!

  • Uncle Salty

    Uncle B…

    Were any of those extremely long, run-on sentences, actually in English? I can’t make any sense out of anything you just said. Try speaking an intelligible language and you might get a better response.

  • Billy J.

    I appreciate this article for showing the human ingenuity. No longer does man depend fully on nature as its resources but has learned to manipulate nature as to reach a particular goal. Science is beautiful! That is why my major is physics.

  • kanimal

    I recently read where a scientist in the UK was able to get hydrogen by using sound waves on sea water. Anyone open to a sonic carburetor? Also, the hydrogen cars would not be allowed to spew water vapor unless it was in very tiny amounts. Water vapor is a greenhouse gas that is ten times worse than carbon dioxide.

  • Allen Ev.

    Will it take 10 years to commercialize these carbon nanotube fuel cells?

  • http://www.golfsbeststore.com/store Danielle

    Well said, finally a good report on this stuff

  • http://puregreencars.com Mike

    Hydrogen production takes a lot more energy input than the energy content of the hydrogen produced. This is why electric cars are in the long term more effective then hydrogen powered ones.

  • Louis

    the energy input source to produce the hydrogen is where the prohibitive cost comes from, we have an abundunt renewable source for that energy. using electricity generated from solar panels (themseleves made more efficient via carbon nanotech) hydrogen can be produced via electralysis cheaply. Ideally a combanation of technologies will be required to make a hydrogen vehicle the superior product. A self contained system that utilizes an onboard store of water as a fuel source, using stored (battery) power to split and compress it to provide a constant flow of fuel to the cell which then recycles the water. Charging the generating battery can be supplemented via regentive braking, an onboard solar charger and waste heat conversion. No, it will not be 100% efficient, it does not have to be, it will extend vehicle range. A maintianed loop system.

  • alan ward

    hydrogen pills inert ammonia, as compared to liquid not inert,ammonia, one a hydrogen casset can be renewed and because intert can be posted until large ammounts needed hydrogen economy, also there are many ways to extract hydrogen once platium is not needed to, , it should be easy to make, work,and to the size of conventional, tanks same distance, and there are still, more solutions, im willing to bet.

  • alan ward

    ther is not enough nickle and litium for long term unless sea is mine, for these types of batteries long term,

  • Ed Smith, Palm Springs, CA

    It seems as though “Uncle B” overdosed on the Obama Kool-Aid. Obama and Bush are two sides of the same corrupt “Republicrat” coin. It’s time to come back to reality and lose your “Obama can do no wrong” delusion.

  • Spuffler

    So where is this technology, today? Is it somewhere in the soup of energy ideas that are only 1/3rd developed and nobody wants to drop seed money on them (because we are in a tight economy)? So, instead of actually developing the technology, we will publish intricate details about it in public spaces and stand around to let the 3rd world read and develop these paradigm shifting developments. Any chance for an economic recovery clearly needs a risk taker for such shifts; keeping the money to yourself means you will sink with the ship, but you take no chance of making the needed life raft. Good show, old chap!

  • http://www.9foru7is.com Kermit Stonesifer

    this is real good cant wait to read more

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