A composition is provided that can be used, for example, in a fuel
processor for a fuel cell system. The composition includes a first
material such as a catalyst, and a second material such as a desiccant.
The second material is capable of sorbing and desorbing a heat transfer
material such as water, and is present in an amount sufficient to sorb an
amount of the heat transfer material sufficient to remove a portion of
the heat generated when the first material undergoes an exothermic
reaction.