NO and NO2 adsorption on a polycrystalline platinum surface was studied using temperature programmed desorption (TPD). NO adsorption is irreversible for NO exposures of less than 0.12 L at 120 K yielding only N2 and O2 upon heating. However, when the NO exposure is increased to 0.12 L and above, reversible NO adsorption is observed. Two NO desorption states occur with peaks at 470 and 300 K. No desorption of NO2 resulting from oxidation of NO was observed at any coverage. NO2 adsorption at 120 K is largely irreversible below monolayer saturation coverages. However, a small NO2 desorption peak is observed at 300 K at a monolayer coverage of NO2. NO and O2 TPD spectra following NO2 exposures are quite different from those spectra obtained following NO or O2 exposures. The differences in the NO TPD spectra are due to the influence of coadsorbed O atoms on the adsorption and decomposition of both NO and NO2. Changes in the O2 TPD spectra are due to the very high coverages of adsorbed O atoms that can be obtained from NO2 exposures.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry