joechip

Nickel and Cobalt are excellent H2 generation catalysts. Platinum, Ruthenim and Gold are better, but a ton more expensive. See any 'Volcano plot' of M-H bond energy vs. Exchange-Current Density in a good electrochemistry text to get an idea. The good catalytic metals are the ones at the top of the volcano. Catalysts, in this case, would lower the activation energy barrier to water hydrolysis resulting in lower voltage being needed to drive the cell. In the case of constant voltage, then the amperage needed would drop. Molybdenum is not an excellent M-H catalyst, Nickel is really the star in 316 stainless. In H2 fuel-cell research of oxidation of H2-emitting compounds (think metal hydrides) it seems a mix of Ni-Co works better than either Ni or Co, for reasons unknown. So, high Nickel alloys, or Ni-Co alloys would be the most affordable solutions and will not degrade in a near-neutral pH solution containing citrate or carbonate. I would not recommend hydroxide solutions. If/when I build one of these my electrolyte would be either citrate or borate depending on the temperature application. I hope this helps. BTW, I'm an electrochemist working on research in this area.