The interaction of rhodium foil with nitrogen dioxide over a temperature range of 30–450°C at three NO2 pressures of 10–6, 10–5, and 10–4 mbar was studied using X-ray photoelectron spectroscopy (XPS). At all of the three pressures, a three-dimensional surface oxide film with the Rh2O3 stoichiometry was formed on the foil surface starting from a temperature of 150°C. As the interaction temperature was increased at an NO2 pressure of 10–6 mbar, the film thickness d initially increased to reach a maximum of ~2.0 nm at 350°C and then decreased due to the decomposition of Rh2O3 to the metal. At pressures of 10–5 and 10–4 mbar, a monotonic increase in d up to 3.0 or 4.7 nm, respectively, was observed in a temperature range of 150–450°C. In the case of the interaction with the participation of molecular oxygen at a pressure of 10–4 mbar and temperatures of 30–450°C, the Rh foil surface was not oxidized. The results of the study on the interaction of NO2 with Rh were compared with the data obtained earlier for Pd and Pt under comparable conditions.
- X-ray photoelectron spectroscopy (XPS)
- SYNTHESIS GAS
- CO OXIDATION
- PARTIAL OXIDATION