Nanotube Tech Transforms CO2 into Fuel

[INRM]

http://dsc.discovery.com/news/2009/03/23/carbon-dioxide-fuel.html

March 23, 2009 -- Powered by sunlight, titanium oxide nanotubes can turn carbon dioxide into methane, which can be harnessed as an energy source, say scientists at Pennsylvania State University.
The nanotubes could dramatically reduce CO2 emissions into the atmosphere and reduce our need for fossil fuels.

The nanotubes are arranged vertically, almost like empty honeycomb. Over the top of the nanotubes sits a thin, reddish-brown layer of copper oxide. Both the copper and titanium oxide act as catalysts, speeding up reactions that take place naturally.

Opinions?

[joobz]

http://dsc.discovery.com/news/2009/03/23/carbon-dioxide-fuel.html





Opinions?
it's possible.

fouling is likely to be a major problem.

[Soapy Sam]

I can't open the link (company firewall).
Clearly it's impossible to "Turn" CO2 "into" CH4.

The hydrogen has to come from somewhere. I presume water?
The energy to dissociate the water is the problem. If it comes from a heat source, where does that come from?
If it's UV or solar in general, I'd doubt it's very efficient unless done on a huge scale.
I guess all the nano- bit does is provides a large area substrate for reactions to be catalysed on.

It doesn't seem impossible, but is it industrally feasible? Dunno.

[dropzone]

Dude, it's "nano." That fixes EVERYTHING. ;)

[Furcifer]

Opinions?
This will be recieved very skeptically by the AGW crowd. :D

I'm not sure fouling would be an issue at all, water is easily demineralized. It sounds interesting and feasible, but on what scake I'm not sure.

[Furcifer]

Clearly it's impossible to "Turn" CO2 "into" CH4.


It does in the atmosphere. I believe they measure CH4 in the air to get an idea of how much CO2 is in it. That's why it's called a greenhouse gas isn't it?

[Madalch]

Okay, so you're going to use nanotechnology to turn carbon dioxide and water into methane and (presumably) oxygen. And then burn the mixture of methane and oxygen to get ENERGY!! (and carbon dioxide and water).

Surely there is an easier way to collect and store solar energy?

[DogB]

Surely there is an easier way to collect and store solar energy?

I suspect once you take storage and transport into account ‘diesel from algae’ will beat this hands down.

As for the likelihood of either of them becoming commercially viable…

[Dave Rogers]

Okay, so you're going to use nanotechnology to turn carbon dioxide and water into methane and (presumably) oxygen. And then burn the mixture of methane and oxygen to get ENERGY!! (and carbon dioxide and water).

Surely there is an easier way to collect and store solar energy?

Collect, almost certainly. Store, maybe not. Chemical energy storage is likely to be a couple of orders of magnitude better than (for example) battery storage in terms of energy density, methane is far more durable than a rechargeable battery, and it's convenient to store, transport and use. Propane would be better - methane is a bit light for automotive use, for example - but it's probably a lot more convenient and efficient than storing the electrical output of a solar cell. I can see there may be some fairly large niche markets for this sort of thing.

Dave

[CORed]

It does in the atmosphere. I believe they measure CH4 in the air to get an idea of how much CO2 is in it. That's why it's called a greenhouse gas isn't it?

Backwards. Atmospheric CH4 oxidizes to CO2 AND H2O.

[Furcifer]

Backwards. Atmospheric CH4 oxidizes to CO2 AND H2O.

For the most part, but I think carbon monoxide and free OH from ozone will combine to form CH4 and oxygen.

[mhaze]

For the most part, but I think carbon monoxide and free OH from ozone will combine to form CH4 and oxygen.

Aw, maybe way up high where energy is provided by incoming cosmic rays etc, but not on the ground. As I recall carbon monoxide to CO2 is a combustion process so there we are moving toward releasing energy, not gaining it.

It's putting the Hs' on the C that takes energy input, in the question at hand.

Then, guess what? We can get the energy back out!

And at the end of this, we've done nothing more than create (basically) natural gas....

[Madalch]

It's putting the Hs' on the C that takes energy input, in the question at hand.

Actually, no- it's taking the oxygen off the carbon that requires energy.

Forming bonds always gives off energy, breaking them always requires energy. The oxygen-carbon bond is stronger than the hydrogen-carbon bonds.

[lomiller]

It does in the atmosphere. I believe they measure CH4 in the air to get an idea of how much CO2 is in it. That's why it's called a greenhouse gas isn't it?


CH4 decays to CO2, and each are measured separately.

As pointed out above the reason we emit CO2 to begin with is that
O2 + Hydrocarbons => CO2 + H2O + Energy

You can certainly reverse this, but even in the ideal case you need to put in at least as much energy as you got out. In practice it will be nowhere close to 100% efficient so the process takes more energy then you get from burning the hydrocarbon in the first place.

[ponderingturtle]

The thing is there is nothing remarkable about the chemical conversion, it is readily doable. The issue is how efficient it is, and how you can power it.

If it runs on sunlight, well how efficient is it compared to PV cells? It is certainly a more efficient way of storing the energy, of course there is issues of how you then use it, but lets say you run a fuel cell with it.

There is also the issue of were are you getting the CO2.

[Soapy Sam]

It does in the atmosphere. I believe they measure CH4 in the air to get an idea of how much CO2 is in it. That's why it's called a greenhouse gas isn't it?

You miss my point.
CO2 is CO2. It can no more "turn into" CH4 than it can turn into a pub.

To produce methane from CO2 you also require hydrogen. There is no* free hydrogen in the atmosphere- which is just as well. I presume (I can't read the link) the hydrogen comes from water or water vapour.

*For a practical definition of "no".

[Furcifer]

You miss my point.
CO2 is CO2. It can no more "turn into" CH4 than it can turn into a pub.

To produce methane from CO2 you also require hydrogen. There is no* free hydrogen in the atmosphere- which is just as well. I presume (I can't read the link) the hydrogen comes from water or water vapour.

*For a practical definition of "no".

I see, you meant in the absence of hydrogen, free or otherwise.

[Furcifer]

CH4 decays to CO2, and each are measured separately.

As pointed out above the reason we emit CO2 to begin with is that
O2 + Hydrocarbons => CO2 + H2O + Energy

You can certainly reverse this, but even in the ideal case you need to put in at least as much energy as you got out. In practice it will be nowhere close to 100% efficient so the process takes more energy then you get from burning the hydrocarbon in the first place.

Ahh, you're looking at it from an energy standpoint.

There's a surprising amount of heat wasted in generating electricity (depending on the plant approximately 25-50%). The right side of the above combustion equation is already what comes out the stack. There would be a substantial recovery of energy using a product like this in a "scrubber". I believe that's why the Professor in the refers to sequestering.