No abstract

We have used several techniques to characterize Cu-SSZ-13 before and after exposure to reaction conditions relevant for NO reduction by NH3–SCR to address the increase in NH3–SCR activity observed as a function of time on stream. Specifically, we focus on characterizing copper species in samples prepared with solid state ion exchange (SSIE) having varying Cu loadings from 0.7 to 5.2 wt %. X-ray diffraction shows that CuO species that likely remain from the SSIE synthesis on the outside of the zeolite crystallites are significantly reduced by exposure to reaction conditions. High-resolution X-ray diffraction (HR-XRD) further reveals a corresponding increase of Cu2O species. X-ray photoelectron, Auger electron, and ultraviolet–visible spectroscopy show an increase in both Cu­(II) and Cu­(I) species inside the zeolite pores, with a preserved long-range order of the zeolite structure as revealed by HR-XRD.

Hydrothermal synthesis of Na-SSZ-13 using a low concentration of the structure-directing agent N,N,N-trimethyl-1-adamantanimonium hydroxide and functionalization of the SSZ-13 framework through the introduction of Cu and Fe via ion exchange have been carried out.