Tailoring the local environment of silver in SSZ-13 zeolites for low-temperature catalytic oxidation of ammonia

• SSZ-13 zeolites with various acid site densities and particle sizes were prepared. • Impact of the local environment in SSZ-13 on the formation of Ag species was studied. • The engineering of active Ag species was achieved by tailoring SSZ-13 support. • Nanosized SSZ-13 (Si/Al = 31) highly disperses abundant stable and active Ag 0 species. • Ag/SSZ-13(31 s) shows excellent low-temperature activity in NH 3 -SCO reactions. Supported Ag catalysts have shown great potential in selective catalytic oxidation of ammonia (NH 3 -SCO) for the depletion of harmful ammonia emissions. However, the lack of effective ways to control the proportional population of active Ag species in/on the support has been the major limitation to their catalytic performance. Herein, the electronic properties, stability, and dispersion of Ag species were rationally tuned by tailoring the micro-environment of SSZ-13 zeolite supports. The influence of the local environment of Ag species in SSZ-13 on their catalytic behavior during NH 3 -SCO reaction was extensively investigated by comprehensive characterizations. Results obtained have shown that SSZ-13 (31s) with moderate ion-exchange sites, a large external surface area and abundantly accessible defect sites are beneficial to the stabilization and dispersion of the Ag active sites which trigger the formation of plentiful active Ag 0 species. The Ag 0 species are immobilized on SSZ-13(31s) with high metal dispersion which facilitates the activation of oxygen and the dehydrogenation of adsorbed NH 3 , thus exhibiting excellent low-temperature activity and hydrothermal stability in the NH 3 -SCO reaction. This work deepens the understanding on the effect of support towards the engineering of active metal species and provides a facile strategy for the preparation of highly efficient metal-based catalysts.