Selective catalytic reduction of NO by NH3 on cerium modified faujasite zeolite prepared from aluminum scraps and industrial metasilicate

This work was devoted to the study of the selective catalytic reduction of NO by NH3 on calcined and hydrothermal treated cerium loaded zeolite catalysts. The parent faujasite zeolite Na-F (Si/Al = 1.32 and S-BET = 749 m(2)/g) used as support for the preparation of the catalysts was obtained from industrial sodium metasilicate and aluminum scraps. As expected, the NO conversion increases with increasing the percentage of cerium in the structure of the faujasite zeolite. Total NO conversion into N-2 is reached at 400 degrees C at a space velocity of 250 000 h(-1). The high conversion is due to the redox shift between Ce3+/Ce4+ and the strong acid sites related to the rare earth present in the framework that is the key in SCR of NO process. Moreover, the highest loaded cerium catalyst retains almost its activity after hydrothermal treatment at 850 degrees C. This higher loading is desirable for both activity and stability provided that two stages of preparation are used to put the Ce ions in the sodalite cages. (C) 2020 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.