Abstract: 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.

Abstract: A fuel cell system includes a first reactant intake manifold, a first reactant output manifold, a second reactant intake manifold, a second reactant output manifold, a cooling gas intake manifold, a cooling gas output manifold, a liquid intake manifold, fuel cells and a cooling elements distributed among the fuel cells. Each cooling element defines a coolant passage. During operation, a cooling gas flows from the cooling gas intake manifold into the cooling gas output manifold through the coolant passage. Each cooling element also includes a water injection path. During operation water from the liquid intake manifold is injected into the coolant passage to mix with the cooling gas passing therethrough.