This comment was posted by Jamie Sibley in the Always Open thread.
Starting at room temperature, iron will combine with oxygen to form iron oxide, and by the time the reaction gets to LAH breakdown temperature, all the oxygen is bound to the iron.
As hydrogen is released from the LAH, it is absorbed into the nickel without having a change to react with the oxygen that is bound to the iron. As the temperature increases, starting at 350c iron oxide would normally start to be reduced by hydrogen into water and iron but the hydrogen is already absorbed into the nickel and cannot participate in this reaction.
The only remaining reaction possibility, is for iron oxide to be converted into carbon dioxide and iron. The beauty of this proposed reaction pathway is that it keeps oxygen bound away from hydrogen, during the hydrogen production and loading phases.
Iron and Carbon prevent the hydrogen in LAH from forming water inside the e-cat.