I've seen some interesting Hydrogen generation using aluminium and gallium, the alloy they make oxidisers so well that it will pull the O2 out of water and rele

I've seen some interesting Hydrogen generation using aluminium and gallium, the alloy they make oxidisers so well that it will pull the O2 out of water and release hydrogen. Now how much energy is used to reclaim the aluminium/gallium alloy and rid of the extra oxygen is something I'm not sure of. But certainly pulling hydrogen from water efficiently is one area of interest.