Fig. 1. (a) In situ FTIR spectra of Cu-CHA 0.1_5 (yellow), Cu-CHA 0.2_15 (red) and Cu-CHA 0.6_29 (blue) exposed to 1000 ppm NO/10% O2 at 200 °C, after pretreatment in O2. Illustration of (a) chelating bidentate Z[CuII(NO3)], atom colour code: Cu, green; H, white; O, red; N, blue; Si, grey. (b) Schematic representation of a zeolite Brønsted site involved in a strong hydrogen bond with a H2O molecule. Spectra were subtracted from the zeolite spectrum before NO/O2 admission and normalized to the sample “optical thickness” and Cu content.
