One of the Tokyo Institute of Technology research group has developed an experimental prototype engine that generates a rotational force from the chemical reaction between water and magnesium.
The prototype consists of a cylindrical metal having a water inlet on the lower part and two outlets pointing in opposite directions on its upper part. The cylinder is filled with magnesium chips and heated at 600 degrees Celsius.
When water is added, it reacts with the magnesium to form magnesium oxide and hydrogen: Mg + H2O -> MgO + H2.
The propulsive force caused by the output of both the gas cylinder rotates it about its axis. The hydrogen then reacts with oxygen to form water vapor.
This engine does not use fossil fuel, it emits no carbon dioxide. In addition, magnesium oxide resulting from the reaction can be recycled.
Indeed, the Tokyo Institute of Technology works in collaboration with Mitsubishi Corp. a project called "Entropia Laser Initiative", whose objective is to recycle magnesium oxide by exposing it to a laser powered by solar energy.