The effect of dilution on H-2/O-2/N-2 oxidation over platinum is studied in a stagnation flow geometry. Experimental catalytic autotherms are compared to simulations, for model validation and to extract a realistic heat loss parameter. The comparison shows good agreement between theory and experiments regarding the autothermal temperatures, the occurrence and location of the surface stoichiometric point, and the upper flammability limit. Upon model validation, operation regimes for catalytic oxidation are predicted as a function of N-2 dilution. In particular, dilution is proposed as a strategy to control catalytic autothermal temperatures at fixed H-2/O-2 ratios, and its effects on reactor safety such as reactor startup and flame flashback are discussed.