I agree. CO2 is an oxide. It is a product, not a precursor of combustion. You put energy in, not take it out. Through a series of reactions, one could end up with something that would combust, but more useable energy must go into the process than comes out.
“more useable energy must go into the process than comes out.”
JUST LIKE growing corn to make ethanol to blend with gasoline. It’s a net energy loss.