Reactivity of NO over K-deposited Pd(111) and surface structure of the catalyst

The reactivity of NO over K-deposited Pd(111) [K/Pd(111)] and the surface structure of K/Pd(111) were studied by infrared reflection absorption spectroscopy, temperature-programmed desorption, and low-energy electron diffraction. The p(2×2) and (√3×√3)R30° structures were observed for the K/Pd(111) surface at ΘK=0.38 and 0.56, respectively; no ordered structure was observed for the K/Pd(111) surface below ΘK=0.21. NO adsorbed on the K/Pd(111) surface decomposed to N2 at 530 and 610 K. N2 desorption at 530 K was due to NO dissociation on Pd–K sites. In contrast, N2 formation at 610 K was due to decomposition of a monodentate nitrito-type NO2− species. The amount of NO2− formation depended on K coverage over the K/Pd(111) surface.

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