Environment

Novel technique produces ethanol from carbon monoxide

Novel technique produces ethan...
Carbon monoxide gas could be a new main source of ethanol fuel (Photo: Shutterstock)
Carbon monoxide gas could be a new main source of ethanol fuel (Photo: Shutterstock)
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Carbon monoxide gas could be a new main source of ethanol fuel (Photo: Shutterstock)
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Carbon monoxide gas could be a new main source of ethanol fuel (Photo: Shutterstock)

Ethanol may be touted as a more eco-friendly alternative to fossil fuels, but it's not without its own drawbacks. Most importantly, the corn or other plants required as feedstock often take up field space that could otherwise be put to use growing food crops. Also, as with other plants, the feedstock crops require large amounts of water and fertilizer. Now, however, scientists at Stanford University have devised a method of producing liquid ethanol from carbon monoxide gas.

The technology was developed by assistant professor of chemistry Matthew Kanan and graduate student Christina Li. Whereas plant-based ethanol is obtained through a fermentation process, their technique involves taking water saturated with carbon monoxide gas, and placing it in an electrochemical cell at room temperature.

Like other fuel cells, theirs has two electrodes (an anode and a cathode), which an electrical current flows between. In the case of a hydrogen fuel cell, the application of that current would convert ordinary water contained within the cell into oxygen gas and hydrogen gas. By using a cathode made of oxide-derived copper, however, Kanan and Li were able to reduce the carbon monoxide in their water into ethanol and acetate.

While a cathode made from conventional copper could do the same thing to a limited extent, it would only have been about one tenth as efficient. "Conventional copper electrodes consist of individual nanoparticles that just sit on top of each other," Kanan explained. "Oxide-derived copper, on the other hand, is made of copper nanocrystals that are all linked together in a continuous network with well-defined grain boundaries." That structure allows it to use up to 57 percent of the electrical current for producing the ethanol and acetate – according to Stanford, that number is quite impressive.

What would be more impressive is if the electricity used in the process could be obtained from renewable sources, and if the carbon monoxide could be derived from something "greener" than the current source, fossil fuels. The researchers are working toward both of these goals, along with making the process more efficient. They're also looking at using the technology to produce fuels other than ethanol.

A paper on the research was published last week in the journal Nature.

Source: Stanford University

8 comments
Gavin Roe
I like it, however why not use waste gas from industry as a source of CO and how much energy is required to convert the solution
Reason
The author seems to have skipped over the most important bit of this paper. The paper describes the catalytic conversion of CO2 to CO as (in my words) 'the easy bit'. Therefore their paper "demonstrates the feasibility of a two-step conversion of CO2 to liquid fuel that could be powered by renewable electricity". If that is economically viable, it should be on the front page.
Slowburn
The big question is how much does it cost per BTU? Could use use the process to produce alcohol for human consumption? It could help with world hunger.
jerryd
Sounds doable to me. Though first CO is a fuel that has to be made. Luckily it's easily made from waste/yard biomass along with more H2. There is going to be extra O2 which could be used to make CO from other carbon matter. I wonder how much product is actually ethanol as acetate is more a chemical feedstock and maybe not as useful to many. I'm thinking of home, small size units so people can make their own fuels.
Ralf Biernacki
Liquid fuel, my donkey. These guys have made booze from nothing but water and air! This is the breakthrough of the century! Now where can I get my hands on some oxide-derived copper, so that I can build my own still?
Techjunkie88
Surely this is an alternative form of carbon capture from burning fossil fuels. If the CO2 and CO from power stations can be used as the feedstock for ethanol production you have a win win solution that deserves much greater fanfare. What are the costs?
Alex Cannara
What's missing here is the realization that we cannot burn any fuels for future energy production. www.mercurynews.com/__science/ci_25664175/climate-__change-pacific-ocean-acidity-__dissolving-shells-key#disqus___thread http://tinyurl.com/n2qnos6 We're ~1500 years behind the narttural carbon cycle. This means extinctions in seas before 2050. Stopping combustion isn't enough either. We must actively protect ocean chemistry before 2050 and only advanced, hi-temp nuclear can do that. -- Dr. A. Cannara 650 400 3071
npublici
Passing carbon dioxide over graphitic carbon nitride in sunlight produces methanol and ethanol.When it is doped it improves production.