Characterization of copper species over Cu/SAPO-34 in selective catalytic reduction of NOx with ammonia: Relationships between active Cu sites and de-NOx performance at low temperature

The isolated Cu2+ species associated with the six-ring window and displaced into the ellipsoidal cavity of SAPO-34 (Site (I)) are the active sites of the NH3 SCR reaction over Cu/SAPO-34 catalyst in the temperature range 100–200°C. [Display omitted] ► We prepare a series of Cu/SAPO-34 catalysts with varying Cu loadings. ► We identify and quantify four coexisting copper species in these samples. ► The isolated Cu2+ species are the active sites for NH3-SCR reaction at T