Catalyst could help turn CO2 into fuel

[Javaman]

http://www.newscientisttech.com/article/dn11390-catalyst-could-help-turn-cosub2sub-into-fuel.html

"Breaking open the very stable bonds in CO2 is one of the biggest challenges in synthetic chemistry," says Frederic Goettmann, a chemist at the Max Planck Institute for Colloids and Interfaces in Potsdam, Germany. "But plants have been doing it for millions of years."

Plants use the energy of sunlight to cleave the relatively stable chemical bonds between the carbon and oxygen atoms in a carbon dioxide molecule. In photosynthesis, the CO2 molecule is initially bonded to nitrogen atoms, making reactive compounds called carbamates. These less stable compounds can then be broken down, allowing the carbon to be used in the synthesis of other plant products, such as sugars and proteins.

In an attempt to emulate this natural process, Goettmann and colleagues Arne Thomas and Markus Antonietti developed their own nitrogen-based catalyst that can produce carbamates. The graphite-like compound is made from flat layers of carbon and nitrogen atoms arranged in hexagons.

[LiberalEsto]

1. Imagine if they could make diamonds

with all that carbon.

[eppur_se_muova]

2. Actually, *hydrogenation* of CO2 is pretty trivial.

I'm surprised by the claim that there is anything hard about reducing CO2. Doing it under milder conditions, promoted by light etc., might be a valid goal, but CO2 can be hydrogenated right down to methane -- Robert Zubrin even developed a simple reactor to do this on Mars.

http://en.wikipedia.org/wiki/Sabatier_reaction

Direct hydrogenation of CO2 down to methanol (CH3OH) is also quite well established:

http://www.google.com/search?q=methanol+hydrogenation+CO2&btnG=Search&hl=en

I particularly like this one, which makes dimethyl ether and methanol:

http://www3.interscience.wiley.com/cgi-bin/abstract/76507118/ABSTRACT?CRETRY=1&SRETRY=0

[Canuckistanian]

3. That's a brilliant use of hydrogen in the Sabatier Reaction case

Essentially, take 1/8th of the fuel you need to get back home and get the rest from Mars itself.

Is that right?

[eppur_se_muova]

5. Not quite sure about the 1/8th figure... he also suggests taking along a nuclear reactor

and using the energy from that to convert Martian H2O to H2 -- essentially making all the fuel you need to explore the planet using the energy from the nuclear fuel. But you need some H2 initially to get things going, explore for H2O, etc.

on edit: Of course the idea of using nuclear energy to convert CO2 to gas or liquid fuel is exactly the kind of thing that some have been suggesting needs to be done on Earth. CH4 would probably not be a good choice (GHG), nor a convenient one, but CH3OH and dimethyl ether are both in limited use with current technology. See NNadir's posts on George Olah's work, etc. Europeans seem to be focusing more effort on this than our own gov't (surprise!).

[NobleCynic]

4. It is far too easy to misread this article because of the title

It is talking about a method of energy storage, not energy generation. It is talking about a possible way to take energy and store it, using CO2, in the form of a hydrocarbon. But that energy has to come from somewhere. I see this as having potential use under the circumstance that you have excess energy production (from nuclear, solar, wind, or some other non-hydrocarbon source) and insufficient hydrocarbon fuels for chemical usage, transportation needs, etc. But as long as the seed energy comes from a hydrocarbon source, entropy dictates that this is likely an inefficient way of going about business.