Transition metal-exchanged LTA zeolites as novel catalysts for methane combustion

The performance of different transition metal-exchanged zeolites for catalytic combustion of lean methane–air mixtures was studied in this work. Transition metals (Fe, Co, Mn) were incorporated to the parent LTA zeolite by ion exchange, using metal nitrates as precursors. Catalytic performance of these materials was compared to the corresponding to the bulk metal oxides in terms of activity and stability. In general terms, Co-exchanged zeolites present very similar behavior to the parent metal oxide, whereas the Mn-exchanged present very poor performance, and the Fe-exchanged zeolite present markedly better performance than the parent bulk oxide. Characterization of the fresh and used catalysts suggests that the superior behavior of the iron-exchanged zeolite is caused by a change in the reducibility properties of the metal species caused by the interaction with the zeolite framework (observed in TPR and O2-TPD experiments).