Preparation and application of honeycomb NH<sub>3</sub>-SCR catalyst based on small crystal-sized FeCu-ZSM-5 zeolite

The systematic characterizations indicate that the FeCu-ZSM-5 zeolite obtained under optimal conditions has an average crystal size of 0.61 μm. Compared with the conventional one (4.28 μm), FeCu-ZSM-5 zeolite with small crystal size exhibits a larger specific surface area (312 m2/g), a higher total acid amount (1.01 mmol/g), a higher proportion of isolated Cu2+ and Fe3+ active species, as well as better dispersion and stronger metal interactions, thus displaying superior catalytic performance in the NH3-SCR reaction.

The catalyst stability test conducted at 300 °C consistently maintained excellent denitrification performance. On this basis, the formulation and process parameters of the coating slurry were systematically optimized with small crystal-sized FeCu-ZSM-5 zeolite as the active component and natural mineral honeycomb as the support. The results show that when the solid content in the slurry is 18 wt%, the amount of inorganic binder is 3 wt%, and a two-step coating process is adopted, the obtained honeycomb catalyst has a coating loading of 131 g/L with a coating shedding rate of only 0.16%.