I've been reading some of the available liturature relating to dissolved gasses in water. The temperature of the water plays an important role. Gasses are more readily disolved in cold water, with an example being the carbonator pump used for soda fountains. On the other hand, gasses bubbled through hot water produces gas which is rich in water vapor. An example of this would be bubbling exhaust gases through hot water, to produce hot CO2 laden with water vapor. (If using at least some amount of petrol.)
I've also been wondering if anyone has tried using carbonated water in their Meyer cell? Siemens has recently developed a synthetic diesel process involving reacting CO2 with water, at 800 degrees.