Evaluation of different zeolites in their parent and protonated forms for the catalytic combustion of hexane and benzene

Deep oxidation of benzene and n-hexane over NaX, CaA and ZSM-5 zeolites in their parent and protonated forms has been studied in the present work. Chemical composition was determined by ICP-MS, varying the Si/Al ratio between 1 and 11.38. Parent and protonated zeolites were characterized by X-ray diffraction (XRD), N2 physisorption, ammonia temperature-programmed desorption (NH3-TPD) and inverse gas chromatography (IGC). Catalytic activities were evaluated by recording the light-off curves in a pulsed flow microreactor. Reactivity (expressed in terms of ignition temperatures) was correlated with surface acidity (strength and concentration of acid sites), morphological parameters and adsorption properties. ZSM-5 and X Zeolites present the best catalytic performance for the catalytic oxidation of benzene and n-hexane, respectively. Results obtained indicate that the catalytic activity for n-hexane oxidation strongly depends on the strength of the interaction between the organic molecule and the catalyst, whereas in the case of benzene, the adsorption capacity of the material plays a key role on the catalytic activity.