What can I use as a fuel for an engine with carbon dioxide as the oxidizer?

On Mars carbon dioxide is abundant. It is plausible to utilize a fuel in an engine that can use carbon dioxide as an oxidizer? I know this is a strange inquiry, but could a engine be made to use $\ce{CO2}$ in the martian atmosphere the same way most engines consume $\ce{O2}$ on Earth?




Usually when we say something "burns", it's being oxidized. In the case of carbon dioxide only the oxygen can be oxidized, by displacing it as the element; that requires fluorine or a sufficiently powerful fluorinating agent.


Carbon dioxide *supports* combustion, acting as the oxidizer instead of being oxidized, with some active metals such as magnesium. Thus


$\ce{2 Mg + CO\_2 -> 2 MgO + C}$


Such reactivity is why special reagents are needed to extinguish burning active metals.


Addendum:


The comments indicate that the OP is interested in burning fuel on Mars. Absent any active metals like magnesium in the oxide-rich and still water-bearing environment on Mars, it is not practical to use carbon dioxide for combustion. Better is to bring some water along or extract it from underground, electrolyze it with solar power, and re-burn the hydrogen and oxygen.


 12