Titan, a moon of Saturn, has readily available water ice ($\ce{H2O}$) and methane ($\ce{CH4}$) on its surface, at a frigid $\pu{93.7 K}$.
It would be significant if these (or possibly, other available hydrocarbons) could be reacted in a self-sustaining way, releasing usable energy. I presume the best way of doing this would be to react by the simple following two step process:
- Split water into hydrogen and oxygen: $$\ce{2 H2O → 4 H2 + O2}$$
- Burn oxygen and methane: $$\ce{CH4 + 2 O2 → CO2 + 2 H2O}$$
Keeping in mind the starting temperature, does this sequence of reactions operate at a net energy release (that is, is it theoretically possible to use this reaction to power itself, with energy leftover)? If not, could other hydrocarbons* found on Titan fit the bill?
*Methane, ethane, propane, and benzene exist. Others may as well.