Examination of a Low-Temperature Rhodium Oxidation Mechanism
Kinetics and Catalysis
, E-ISSN: 1608-3210
Boreskov Institute of Catalysis, Siberian Division, Russian Academy of Sciences
The interaction of O2 with Rh(100) and polycrystalline rhodium at O2 pressures of 10(-5) - 10(3) Pa at 400 - 600 K is studied by thermodesorption and Auger electron spectroscopy. At P(O)2 = 10(-5) - 10(-1) Pa, a surface rhodium oxide is formed, whereas at P(O)2 greater-than-or-equal-to 10(-1) Pa, a bulk rhodium oxide (Rh2O3) is produced. The bulk oxide film grows by the Cabrera-Mott mechanism of low-temperature metal oxidation. The film growth is dependent on P(O)2 and the sample temperature. The data obtained indicates that the rhodium surface structure has a minor influence on the oxidation process.