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Cleantech News converting CO2 to CO to fuel

Published on December 3rd, 2013 | by Tina Casey


Carbon Nanofibers Offer Cheap Way to Convert CO2 To Fuel

December 3rd, 2013 by  

File this one under “I” for It takes a thief to catch a thief. A research team at the University of Illinois at Chicago is on track to developing a low-cost method for reducing carbon dioxide to carbon monoxide, which puts it one step away from creating synfuels including synthetic gasoline. The secret sauce is the use of carbon nanofibers in combination with another catalyst.

If the new UIC carbon reduction system bears out on a commercial scale, it would provide a direct financial incentive for carbon emitters to capture and reclaim carbon dioxide as a valuable byproduct, rather  than enabling it to enter the atmosphere as a greenhouse gas.

Using Carbon Nanotubes To Convert Carbon Dioxide

Reducing CO2 to CO is far from a new thing, but until now the process has been typically carried out using a single, expensive catalyst.

converting CO2 to CO to fuel

Gasoline can by Stu Horvath (Jack of Nothing).

The UIC team started with the idea that since CO2 reduction is a two-step reaction, it might be more efficient and less costly to develop different catalysts for each step.

They got the efficiency part right on an early try using an ionic liquid as a catalyst for the first step (ionic liquid refers to a salt in a liquid state) and silver for the second step, but that still left cost as an obstacle.

The next challenge was to find a cheap substitute for the silver catalyst, which the team achieved by doping carbon nanofibers with nitrogen.

That wasn’t exactly a stab in the the dark, since according to UIC writer Jeanne Galatzer-Levy the use of nitrogen-doped carbon nanofibers is fairly common.

With nitrogen-doped carbon fibers as a co-catalyst for the ionic liquid, the overall reaction exceeded expectations, achieving an efficiency greater than silver.

As for the reason behind the stellar performance, that turned out to be a bit of a surprise. When the reaction was analyzed, the UIC team discovered that the nitrogen dopant was not the critical factor, it was the carbon atom.

Wait For It…Graphene!

That discovery could turn out to be the eureka moment for the UIC team as described by UIC’s Bijandra Kumar, who co-first-authored the research paper (just published online in Nature Communications and slated for the print edition, too):

…one can imagine that using atomically-thin, two-dimensional graphene nano-sheets, which have extremely high surface area and can easily be designed with dopant atoms like nitrogen, we can develop even far more efficient catalyst systems.

Did he just say graphene? Yes, he did. Graphene, an atom-thin sheet of carbon with unique and powerful characteristics, has been popping up all over the clean tech field, including photovoltaic cells, so it wouldn’t be much of a stretch to put it to work in carbon dioxide reduction.

When Life Hands You Carbon Dioxide, Make Lemonade

The whole point of this is to get a cheap source for syngas as a precursor to creating fuels, with the co-aim of managing carbon emissions.

That’s just one strategy for reclaiming and re-using carbon dioxide. For a different angle, take a look at the sustainable winery at UC-Davis, which includes a system for converting CO2 to calcium carbonate, aka chalk.

As for carbon monoxide, one approach is illustrated by the New Zealand company LanzaTech, which has developed a microbe-based carbon conversion system that can yield fuels and plastics. The company recently won a $4 million U.S. Department of Energy grant to bump up development of the system into mainstream use.

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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.

  • Peter Gray

    The elephant-in-the-room missing piece of this article is energy. Unless someone finds a way to violate the 1st Law of Thermodynamics, we cannot convert CO2 into gasoline without using more energy than we got from the gasoline in the first place. If the gasoline was used to produce work, as it almost always is, we’d need to burn at least 4 liters of fuel to re-create one liter. Same thing holds at a fossil-fueled power plant, with a minimum loss factor of 2 or 3 instead of 4 or 5.

    This might be a step toward combining wind or solar with, say, a coal plant, and using the syngas or liquid fuel as a storage medium. Still, we’d need at least 2-3 times as much wind/solar output as the coal plant produces – at about the same time, since compressing and storing large volumes of hot exhaust would be quite costly – to capture all the CO2.

    Something about this doesn’t sound practical or efficient. Maybe it’s better than current CCS plans, but that’s a low bar to clear.

    Thinking a little further, if this works (kinda), why not cut out the fossil fuel entirely, and use it as closed-loop energy storage for solar and wind? If the fuel is combusted, there’s still a huge inefficiency problem – much greater losses than with batteries or compressed air – but if the equipment is cheap enough, maybe it’s worth that penalty? Only alternative would be some kind of fuel cell. But we can already use a hydrogen cycle for that, and we’re back to the age-old problem of fuel cells: fantastic idea … that might be available in 10 or 20 more years.

    To the author: would you consider doing a follow-up to put this technology in some practical perspective for us? Maybe with a little skepticism based on the energy balance problem? I’m just speculating here…

    • kos

      Energy will not be the problem in the future. http://www.iter.org/

    • Peter Gray

      I tried replying to “kos,” but it said the post was not active. This is in reply to kos…

      Saying “energy will not be a problem” because of ITER is a bit
      over-confident for my taste. As with the practical portable fuel cell,
      fusion has been just around the corner for many decades, and the corner
      doesn’t seem to be any closer.

      ITER is an extremely expensive
      project that might break even on energy within a couple decades. Or if
      it’s complicated parts don’t fit together quite right, it could be a
      total bust.

      I wish ITER the best, but I wouldn’t form an opinion
      just from the project’s own hype. Check this out as well:

      Here’s a constructive follow-up about ITER’s managment problems: http://www.newyorker.com/online/blogs/comment/2014/02/how-to-fix-iter.html

  • heinbloed

    ” Carbon Nanofibers ” are a proven carcinogen.

    So are the ” Carbon Nanotubes “.

    The idiocy to fix carbon in carbonate is seen in our oceans: the corals disolve nowadays ( this process is already non-reversable in human time scales!) because of the CO2 in the water which turns the water acetic.

    As long as it is legal to release CO2 into the atmosphere and military forces are employed to enhance this all available carbon will be turned into CO2.
    Including the old coral reefs which are since centuries kiln fired for the cement industry.

    ‘Greenwashing’ we call this UIC project.

    • Peter Gray

      Sigh… somehow it’s even worse when the tinfoil hats claim to be on our side…

  • beernotwar

    This should be seen not as a way to manage CO2 flue gasses from fossil fuel plants, but a way to turn large industrial breweries into fuel generation plants. Fermentation releases concentrated CO2 as a byproduct. There is so little air in the gas that microbes can’t survive in it (which helps fermenting beer protect itself from infection). Large industrial breweries probably off-gas enough CO2 to be interesting as a source of fuel. Right now some of them capture this gas to carbonate their beer, but often I believe it goes to waste and is returned to the atmosphere.

    The advantage of using CO2 from fermentation is that the greenhouse gasses being utilized are “new” gasses that were collected by the grain in the previous year, rather than just re-using fossil carbon from flue gasses. This is a closed CO2 cycle when the fuel is burned and no new net CO2 goes into the atmosphere.

  • JamesWimberley

    But the authors are a bunch of foreigners, one of them called Mohammed! It can’t be true! /irony

  • heinbloed

    Nanoparticles (Graphene) are a health hazard.

    Check the WHO warnings.

    • Bob_Wallace

      Don’t snort them.

      • Peter Gray

        😉 Can’t improve on that reply.

    • JamesWimberley

      Graphene isn’t inherently a nanoparticle. It’s a regular sheet of carbon atoms in a hexagonal mesh like chicken wire. It’s one atom thick, but of indefinite area. Plans to use graphene in catalysts, conduction layers in semiconductors, etc, all involve embedding it in larger structures – SOCs, batteries, reactors – not letting it loose in the environment. Where you are very likely to meet nanoparticles today and tomorrow is in diesel exhaust fumes and soot from coal power stations.

  • Marion Meads

    It is excellent advance, and can be used effectively where we have a point source of CO2 emissions. The main issue remains, how are we going to capture and concentrate the CO2 that is dispersed currently in the atmosphere so that it can be used to create fuel aside from using plants or algae grown in the open environment?

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