Fig. 3: Transformation of N-contained species during adsorption and desorption stages.

In situ diffuse reflectance infrared Fourier transform spectrum (DRIFTS) in 20 min of NO + O2 adsorption and subsequent desorption for (a) Pd/0.75Ce and (b) Pd/0.25Ce between 100 and 500 °C. c In situ near ambient pressure X-ray photoelectronic spectroscopy (NAP-XPS) of N 1 s at 100 °C and 300 °C in NO atmosphere. d Binding energy shifts of O 1 s based on in situ NAP-XPS between 100 and 400 °C.