Nanospikes Convert Carbon Dioxide Back Into Ethanol

By Nathaniel Scharping | October 19, 2016 1:40 pm

A microscopic image of the carbon nanospikes created by the researchers. (Credit: ORNL)

A new chemical process turns carbon dioxide into ethanol using commonly-found catalysts and electricity. In a sense, they’ve figured out a way to put the genie back in the bottle.

The alchemic process of converting greenhouse gases into usable energy is an appealing means of both addressing climate change and providing sustainable sources of energy. Converting carbon dioxide into energy and other useful products has been done before, but the process isn’t efficient or cheap enough to implement at a large scale. Researchers from the Oak Ridge National Laboratory, however, say that they have found a chemical reaction that produces hydrocarbons using just copper as a catalyst, and they say it’s quite efficient.

A Pointed Solution

The key to their method is how the copper is arranged. First, the researchers create a scaffold made from carbon and nitrogen. The surface is covered in tiny spikes, each about 50 nanometers high. The researchers then deposit copper particles onto the surface, which acts as a catalyst for the reaction. When electricity is run through the material, the reactions are concentrated at the very tips of the spikes, they say, providing the energy required for carbon dioxide dissolved in water to break apart and reform as ethanol.

They liken to process to running a combustion reaction, where ethanol is broken up in the presence of oxygen to create CO2 and other molecules, backwards. The reaction achieved an efficiency of 63 percent when creating ethanol, using a power supply of just 1.2 volts at room temperature. The researchers published their work last month in Chemistry Select.

Copper is a common catalyst for these kinds of reactions, but it was usually only able to form lighter hydrocarbons, and the reactions usually yielded more than one product, making it difficult to use for large-scale processes. The Oak Ridge researchers’ process, however, yields mostly ethanol, thanks to the unique structure of their nanospikes. Still, it’s a technique that’s far from industrial scaling.

Just A Step

Turning carbon dioxide into ethanol won’t solve global warming, of course. When we burn the ethanol, it will turn into carbon dioxide again, leaving us right back where we started. Making our own ethanol is better than pulling it out of the ground though, and could help level off our net carbon emissions. The researchers also suggest that it could function as a kind of battery for electrical grids. If a grid is producing excess power at any time, the extra electricity could be used to fuel this process, creating ethanol. When power is needed, the ethanol could be used as fuel to again create electricity.

Even such a process still consumes electricity, though, and the researchers say more work needs to be done to further understand the process and make it even more efficient. It may not be nuclear fusion, but making our own hydrocarbons is an important step towards weaning us off the limited natural stores of fossil fuels that currently power our civilization.

CATEGORIZED UNDER: Environment, Technology, top posts
  • Chris H

    Good News!

    • Uncle Al

      Propagandistic swill. Don’t vote against kinetics and against thermodynamics. What neutralizes ten moles of hydroxide produced for every mole of ethanol?

      Will we have a massive national “moon shot” to increase acid mine drainage?

      • Chris H

        as usual, right over my head, Al.

        so it’s not good news?

        • Uncle Al

          Embrace engineering, ignore Enviro-whinerism. Stipulated: Somebody else in the tenebrous future deserves to have what you purchased now – and not them, either. No.

          Let’s reduce all levels of decreed toxicants to below their natural occurrence levels.

      • Peter Olins

        How about CO2? We have plenty to spare.

  • Uncle Al

    using commonly-found catalysts and electricity” Th only cheap electricity originates with burning fossil fuels. Plant forests not burn them.

    carbon dioxide dissolved in water to break apart and reform as ethanol” Hydrate CO_2 to carbonic acid (go ahead, look at the crappy equilibrium constant and the purely awful kinetic constant, hence carbonic anhydrase). One-carbon carbonic acid to one-carbon formic acid to…two-carbon ethanol? Free radical dimerization is notoriously unscaleable.

    highly textured nitrogen-doped, few-layer graphene electrode” cm^2? Maybe. Tens of thousands of square meters to process megatonnes of CO_2/year? More grant funding is needed.

    adheres well to the highly-doped silicon wafers” What could be cheaper and more sure than using single crystal silicon too expensive for solar cells? Here’s an idea! Don’t burn carbon to make the electricity needed to slightly recapture it

    • Scott Forschler

      “The only cheap electricity originates with burning fossil fuels.” Incorrect; wind power is now roughly equivalent in cost to coal at its source; it suffers from being non-dispatchable (not available on demand) but it is as cheap or sometimes cheaper when available. We have yet to see to what extent this problem can be diminished by having a network of widely dispersed wind farms interconnected by long-range power lines, which can reduce the statistical fluctuation of the variable source. But it is cost-competitive. Granted, natural gas is cheaper yet; but for how long? There’s not an infinite amount, and it’s good to have a plan for generating ethanol once it starts to run down in another generation or so. Plus you can burn ethanol in a car; natural gas has a lower energy density and so doesn’t take you so far.

      Some other non-fossil sources are also cheaper than any fossil fuels, and always have been: geothermal in selected places (e.g., Iceland) and hydroelectric. They suffer from geographical limitations, and the latter from basically being used up already, but they are cheaper. In short, then, if we find a relatively cheap way of using electricity to turn CO2 into ethanol, we can run this process next to these non-fossil power sources during off-peak hours, and save the ethanol to replace fossil fuel consumption. Whether this is economical remains to be seen, but it is not theoretically impossible.

    • Peter Olins

      Anyone who has successfully developed a new product or technology will know that there is always a host of people with dozens of reasons why something probably won’t work. Plus, the developer (who is intimately familiar with the topic) can probably think of a hundred more.

      The challenge is to find the path in the face of seemingly insurmountable obstacles. Let’s hope that these scientists (and the people that follow them) will have the skill and courage to turn this discovery into something practical—whatever it may be.

      Yes, Uncle Al, more grant or investment funding is needed.

  • CWilke

    This is interesting. 63% efficiency in direct conversion is impressive. I would not necessarily look at this as a “holy grail” per se, but if it CAN be scaled, this could be a viable alternative for gasoline and petrol. The engines and infrastructure would be VERY similar and would allow a similar level of convenience. And, as long as we’re pulling more CO_2 out than putting in (for the immediate future anyway), we SHOULD be able to create a negative carbon impression.

  • Marcelo Pacheco

    This is a new process that will take years to be developed commercially. Meanwhile solar PV costs are dropping. In 10 years solar PV is expected to cost half as much as today, while increasing efficiency to over 30%. Plants like sugar cane have just a few % efficiency (in total solar radiation received vs fuel produced). This process would allow dry desert to produce fuel, leaving coal/natural gas and oil on the ground.
    This process needs to be developed to commercial scale, ethanol is suitable both to be mixed with gasoline or used as a stand alone fuel. Brazil has a mass scale ethanol program since the 80s, all of our gasoline uses at least 15% ethanol, and most of our cars can be freely fuelled with either ethanol, gasoline or any mix of the two. If this process is developed in massive scale we can replace gasoline with ethanol worldwide !

    The problem is breaking the oil interests that shackle truly revolutionary alternate fuel technology.

    A few facts about large scale solar usage:
    Grid scale solar is already cheaper than coal in India (statement by India’s
    Prime Minister in 2016). Home solar+storage already cheaper than grid
    electricity in Australia. American Samoa running almost 100% on solar
    using Tesla batteries. Hawaii already runs over 10% on solar PV.
    A few easy to make predictions:
    In a few years all tropical/equatorial islands running on Diesel generators will be running 100% on solar+batteries, since the batteries last 10+ years and cost half as much as the Diesel used over those 10 years, and solar panels are already ultra cheap (most of the cost is the batteries).
    In a few years India will produce as much solar PV electricity as the largest hydro electric dam produces every year. China will do the same.
    In 3 years Solar PV in the US will need no subsidies in sunny areas. Solar+batteries will be cheaper than the grid.

  • Sana Zulfiqar

    indeed an amazing work!


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