Selective catalytic reduction (SCR) of NO_x with NH₃ over the SSZ-13/ZSM-5 intergrowth zeolite

An intergrowth zeolite combining the SSZ-13 and ZSM-5 structure was synthesized using a dual-template method for application in selective catalytic reduction (SCR) of NO_x with NH₃. The intergrown structure was confirmed through detailed characterization. Compared to pure-phase zeolites, the intergrowth exhibited up to a 14 % enhancement in NO conversion at temperatures above 220 °C after hydrothermal aging (at 750 °C with 10 % H₂O for 16 h). Comprehensive characterization revealed that intergrowth zeolite promoted the transformation of hydrothermally less stable Cu species (ZCuOH, located at 8 MR) to hydrothermally more stable Cu species (Z₂Cu, located at 6 MR) during hydrothermal ageing. Additionally, copper leaching is hindered due to the well-preserved structural integrity of the intergrowth zeolite, with only a slight decrease in crystallinity (∼1.6 %). These findings suggest that intergrowth zeolites are promising candidates for mitigating NO_x emissions in stationary sources under harsh hydrothermal conditions, such as that found in thermal power generation and steel manufacturing.