I don't see that as a dumb question. In fact, if it could be done, it would definitely be the best possible thing to do. The logistics on the other hand would be very difficult. Like water, carbon dioxide is a burnt substence, the end result of an energy releasing reaction (not sure what the technical word is) Any effort to sperate the molocule would require considerable energy. I am not sure it would be practical to do this in smokestack. However with the right catalyst, this could be done in a lower energy environment. After all, plants do it.
While writing this, I searched the internet and I found this. http://technology.newscientist.com/a...into-fuel.html
Very fascinating, from what I understand of the temperatures involved it could be done on site, using waste heat for part of the reaction. On the other hand I would prefer a reaction that released oxygen. From what I understand about mini article it may be possible. http://cat.inist.fr/?aModele=afficheN&cpsidt=1944444
This is very exciting.

__________________