Fig. 4. Evolution of the in situ XAS spectra of Cu-CHA during exposure to 1000 ppm NO/10% O₂ at 200 °C (from grey to coloured curves). Main panels: Cu K-edge XANES spectra of Cu-CHA 0.1_5 (yellow), Cu-CHA 0.2_15 (red) and Cu-CHA 0.6_29 (blue); insets: k²-weighted k²χ(k) EXAFS curves.