Looking for cars that run on CO2, producing oxygen as result. 
That's not how physics works. Breaking up CO2 into carbon and oxygen requires energy, it is impossible to produce energy this way.But CO2/Methane reaction releases water, and only about half as efficient as gasoline/oxygen
Given the relatively cheap production and renewability of methane, might be a good idea. CO2 + CH4 → 2 H2 + 2 CO