Have scientists discovered an efficient process to turn CO2 into Ethanol?

[Tribble]

Scientists at the Oak Ridge National Laboratory in Tennessee have discovered a chemical reaction to turn CO2 into ethanol, potentially creating a new technology to help avert climate change. Their findings were published in the journal ChemistrySelect.

The researchers were attempting to find a series of chemical reactions that could turn CO2 into a useful fuel, when they realized the first step in their process managed to do it all by itself. The reaction turns CO2 into ethanol, which could in turn be used to power generators and vehicles.

The tech involves a new combination of copper and carbon arranged into nanospikes on a silicon surface. The nanotechnology allows the reactions to be very precise, with very few contaminants.

"By using common materials, but arranging them with nanotechnology, we figured out how to limit the side reactions and end up with the one thing that we want," said Adam Rondinone.

This process has several advantages when compared to other methods of converting CO2 into fuel. The reaction uses common materials like copper and carbon, and it converts the CO2 into ethanol, which is already widely used as a fuel.

Perhaps most importantly, it works at room temperature, which means that it can be started and stopped easily and with little energy cost. This means that this conversion process could be used as temporary energy storage during a lull in renewable energy generation, smoothing out fluctuations in a renewable energy grid.

"A process like this would allow you to consume extra electricity when it's available to make and store as ethanol," said Rondinone. "This could help to balance a grid supplied by intermittent renewable sources."

The researchers plan to further study this process and try and make it more efficient. If they're successful, we just might see large-scale carbon capture using this technique in the near future.

Source: Oak Ridge National Laboratory via New Atlas

http://www.popularmechanics.com/science ... o-ethanol/


Paper here:

http://onlinelibrary.wiley.com/doi/10.1 ... 01169/full

I obviously have no scientific background and cannot comment on this news in a meaningful way but it would be nice if it became economically viable to turn CO2 into Ethanol... for electricity use, of course

For those who have scientific backgrounds, does this appear to be a valid study? If so, do you think anything will come out of it, or will this be thrown on the "neat but not practical" pile heap?

[Simon_Jester]

One problem is that when you burn the ethanol you get the CO2 right back into the air... but at least you haven't increased the net amount of carbon in the atmosphere.

I don't know how practical this will turn out to be. A lot depends on production quantities.

I must also note that we already have a fairly effective way to make ethanol fuel from atmospheric carbon dioxide. They're called plants.

The main limiting factor on that is that plants we grow for fuel compete with plants we grow for food- an issue that artificial ethanol from atmospheric C02 would resolve.

[Jaepheth]

Well... could certainly give new meaning to the term "solar still"

[Zixinus]

The real question is how well can you scale this up. Can you create large plants that can produce millions of liters of the stuff cost-effectively?

I recall that Sea Skimmer also mentioend some similar kind of technology, with the potential for ships to replenish fuel supply by some machine.

[ndryden]

The paper itself seems fine, but some of the popular press coverage is--as usual--overhyped. This is a first step that needs a lot of follow-on work to be viable at scale. Let me quote from the conclusion (emphasis mine):

The overpotential (which might be lowered with the proper electrolyte, and by separating the hydrogen production to another catalyst) probably precludes economic viability for this catalyst, but the high selectivity for a 12-electron reaction suggests that nanostructured surfaces with multiple reactive sites in close proximity can yield novel reaction mechanisms.

Derek Lowe had a nice post on this yesterday, which summarizes in plain english what this means better than I can:

Basically, you have to use more electric power to get ethanol this way than the resulting ethanol can possibly be worth.

(I recommend reading his whole post for more discussion on the paper.)

[madd0ct0r]

I'd be prepared to pay a limited energy cost to dump spare electricity into a very long term stable* chemical form. In simplest form you've got a summer surplus being turned into winter heating fuel.

*oxidises badly but airtight tanks are easy.

[Simon_Jester]

I'd be prepared to pay a limited energy cost to dump spare electricity into a very long term stable* chemical form. In simplest form you've got a summer surplus being turned into winter heating fuel.

This is also how plants work.

[madd0ct0r]

Tries wiring his cactus into his laptop charger...


I'm talking about surplus joules of electricity in the grid, not purpose built solar panels strapped to one of these.
Looking into it, the ethanol production is very dilute, so there's a third energy cost there, but I'd still rather store ethanol than hydrogen any day of the week.

[Simon_Jester]

Sorry, I know I'm being silly.

But honestly, people have been using plants to dump spare energy (e.g. sunlight during summer) into long term stable chemical fuel (e.g. firewood) for a long time.

[Sea Skimmer]

That's really giving humans too much credit. Tree farming on an economically relevant scale is a very new thing, 1 century max on a relevant scale, though some forests were replanted in the 1400s for hunting preserves, and does not even begin to match the level of massive deforestation humanity already inflicted on the planet. Indeed such action has been going on for so long we don't even really know just how bad it was, because it predates all records. In places like Australia its seriously up in the air just what the human involvement in mass desertification was tens of thousands of years ago. Humans start fires....

Also for many traditional uses burning wood has efficiency that's like 2-4%, which IIRC is similar to the efficiency of human labor powered by grain fed cattle, in terms of sunlight -productive work conversion. So not exactly something we want to emulate if we can avoid it! Lots of crap will work at ultra low efficiency.

I recall that Sea Skimmer also mentioend some similar kind of technology, with the potential for ships to replenish fuel supply by some machine.

Yeah USN patented a bunch of tech to turn seawater into gasoline, from which it could be converted to jet fuel, but it was high temperature, and involved unspecified but possibly exotic catalysts, which made it unlikely to be useful outside of military applications where the main cost is not always the cost of fuel, but the cost of delivery. Such as by a large naval auxiliary to an aircraft carrier.

Low temperature process cannot help but be more efficient, and as a practical matter the equipment is likely to have a much longer service lifespan between overhauls. Which is pretty important, any pieces of oil refinery equipment go years between shutdowns when possible, because shutting them down basically always breaks stuff.

Also with catalysts, some of the ones that crop up often for advanced chemical processes are stuff the earth physically does not have a large supply of. That's been a huge factor in holding back fuel cells since the 1960s. Fuel cells worked back then, NASA used some for Apoll, but getting the cost down has been crippled by raw materials costs, while work on ones that use more common elements has only recently begun to pan out.

Interestingly sometimes the requirement has simply been very high purity of common element , like iron, but getting iron which is pure to the millionth of a percent is not easy! And you've got to keep up that purity while making it into the actual cell.

[LaCroix]

Yeah, forest management goes back far into bronze age, and maybe before. There is a point to be made that most modern 'natural' forrests are a result of industrialisation, for the reduction in charcoal production and the general movement into cities, leaving the forrests to revert into a more original state. That's why you get "national wild forrests" in Europe, which are defined as not having been modified for more tan a 100 years.

He has summed it up pretty well, for a different reason, but you get an idea.