You’re 100% correct. The whole point of burning a fuel is to release its energy and oops we have byproducts. Well the second law of thermodynamics explicitly states that if you want to put that CO2 back, you’ve got an energy cost which is *crunches numbers* roughly the same as that released when you burnt it in the first place.

That being said, if we had some purely green energy sources then it is a laudable goal that could help reduce the harmful effects of climate change.

Personally I think harvesting CO2 in the ocean is the way to go. It already absorbs tons (gigatons) each year. We just need to figure out a way to coax that dissolved CO2 to fall out of solution as lime without waiting on a geologic timescale for humanity to get murdered by sentient iguanas that love the heat.