I agree with @coldandrich, the video does seem to violate the first law of thermodynamics. Hydrolysis requires energy to be put into the system to separate water into its consituents of hydrogen and oxygen which are in a higher energy state than water. Water, on its own, is not a fuel unless it is being transitioned into a lower energy state through a chemical reaction (where it will no longer be water) or if it is being used in other ways as @coldandrich has outlined. Without a more satisfactory explanation, I'm out.