NH3-SCR over Fe/SSZ-13 catalyst prepared by modification of natural chabazite

Abstract

Zeolites are crystalline microporous aluminosilicate materials used in millions of tons annually in petrochemical and environmental protection industries. Zeolites exist in both natural and synthetic variants, with the former primarily found in abundance in various geological formations, including volcanic and sedimentary rocks. The properties of these natural chabazite such as crystallinity, surface area, and composition can be tailored to enhance their catalytic properties. This work aims to transform low-grade natural chabazite into high-quality catalytic material and examine its activity in the selective catalytic reduction of nitrogen oxides with ammonia reaction. For this purpose, natural chabazite was modified by combining it with a synthetic mixture of silica, alumina, and organic template, followed by hydrothermal crystallization. The initial and modified samples were subjected to various characterization techniques, including XRD, N₂-physisorption, ICP-OES, and SEM, to measure their crystallinity, porosity, elemental composition, and morphology. The characterization results reveal that the modification of natural chabazite enhanced the crystallinity and surface area of the sample, resulting in the incorporation of iron within the micropores of SSZ-13 zeolite. Their catalytic activities were evaluated at varying temperatures, and the resulting Fe/SSZ-13 catalyst showed high activity in the NH₃-SCR reaction.