Interesting concept water even in ppm as a catalyst:
http://www.sciencedaily.com/releases/2012/05/120517143506.htm
> Essentially, when water is present, hydrogen diffuses via a proton transfer, or proton "hopping," mechanism, in which hydrogen atoms from the oxide surface jump onto nearby water molecules and make hydronium ions, which then deliver their extra proton to the oxide surface and liberate a water molecule. That repeated process leads to rapid hydrogen atom diffusion on the oxide surface.
Maybe I'll go back to my hypothesis that Defkalion uses its spark plugs to burn a little Hydrogen .... (just kidding).
