A combinatorial library of catalyst candidates, each consisting of a different metal element supported on γ-alumina, is screened for hydrogen oxidation catalytic activity. Heat liberated on the surface of active catalysts by the catalyzed reaction is detected by noninvasive IR thermography. A 16-candidate library identifies four distinctly active pellets, which correspond to active formulations known from the literature. A higher density library shows similar results, but heat and mass transport effects influence the pellet temperatures. This method may be used to screen and optimize catalyst formulations more efficiently and quickly than current methods and may also be useful for study of operational lifetime, resistance to poisons, and regenerability.