Effect of exchanged lanthanum on the hydrothermal stability of the In-MOR structure

E. G. GIORIA, S. N. IBARLÍN, N. NAVASCUÉS, S. IRUSTA, H. P. DECOLATTI, E. E. MIRÓ, LAURA GUTIERREZ

Conferencia; 18th International Zeolite Conference; 2016

International Zeolite Association

It is well-known that zeolites as catalysts are complex materials formed by different components which give its characteristic properties to the zeolite. The different types of zeolitic structures together with the vast number of combinations of elements that can be associated to these matrices result in a vast array of catalysts that may be actives for many industrial reactions. The role of such components can be purely catalytic; they can act as stabilizing agents or just provide particular physical properties to the zeolitic support. For the catalytic goals the incorporation of active metals by different methods conduces to complex interactions between the guest components and the zeolitic matrix with the consequent improvement in the global catalytic performance of the modified zeolite. Nevertheless, in all cases the zeolitic catalysts undergo changes during its use under reaction conditions. The inside zeolite transformations can range from the loss of crystallinity, the migration of the metals from their original positions, the agglomeration of active particles sites, the changes on the strength and distribution of acid sites to pore blockage. By now, it is known that zeolites are not stable under rigorous conditions such as high temperature gas streams containing water, and it is for this reason that the use of zeolite-based catalysts is limited.In this vein, the main aim of this work is to perform a detailed characterization study of La and In co-exchanged mordenite, in order to investigate both the La species generated into the zeolite matrix and their influence on the exchanged Indium. To achieve this aim XRD, pyridine desorption, XPS, FTIR and TEM techniques were applied in order to understand better both surface and bulk properties of the La,In-MOR samples. In addition, taking into account that In-zeolites are active and selective catalysts for the SCR of NOx with CH4, and that lanthanum could improve the stability of the mordenite structure [8], this reaction was performed to evaluate probably stabilizing properties as well as possible synergic effects between La and In in a similar way with the La,Co-MOR catalytic system [1]. Nevertheless, this study could be of interest to be applied in other catalytic reactions.