Understanding enhancement of strong Copper-Yttrium interactions on catalytic properties of Cu/Y-SSZ-13 for NH3-SCR

Abstract

Cu-SSZ-13 represents one of the most promising catalysts for selective catalytic reduction of NOx with ammonia (NH3-SCR), but it has remained challenging to gain superior low-temperature activity and hydrothermal stability for meeting the stringent emission regulations. Here, Cu/Yx-SSZ-13 have been prepared by in situ doping of Y and subsequent ion-exchanging with Cu ions. The combined analysis of various energy spectra techniques unveils that Y ions are mainly located in the six-membered rings (6MRs) of chabazite framework and have a strong interaction with Cu cations in 8MRs, resulting in the remarkable low-temperature NOx abatement efficiency and hydrothermal stability. Mechanism studies reveal that the interplay between Y and Cu not only enhances the electron transfer from Cu to Y ions that favors the ammonia solvation process and reduces the reaction barrier, but also inhibits the aggregation of Cu sites. This work paves the way for next generation of advanced NH3-SCR catalysts.