An infrared spectroscopic study of the adsorption of NO2, NO, and N2O on α-Fe2O3 was carried out in order to identify chemisorbed species which could act as catalytic intermediates. Presorptions of pyridine and water were used in addition to usual pretreatments of the surface, in order to identify and discuss adsorption sites and mechanisms. Stable nitrate ions are formed on the surface, starting at beam temperature (b.t.) with NO and are predominant at 150 °C with NO2. Between b.t. and 150 °C, NO2 mainly chemisorbs as such or as its dimer N2O4. Depending on the pressure, NO chemisorbs at b.t. also as is or as NO- ions, as well as in the form of its dimer N2O2. N2O merely physisorbs on an "oxygen-rich" surface, but it strongly chemisorbs on an "evacuated" surface producing species which can be identified as N2O-. © 1981.
Infrared study of the adsorption of nitrogen dioxide, nitric oxide and nitrous oxide on hematite
BUSCA, GUIDO;
1981-01-01
Abstract
An infrared spectroscopic study of the adsorption of NO2, NO, and N2O on α-Fe2O3 was carried out in order to identify chemisorbed species which could act as catalytic intermediates. Presorptions of pyridine and water were used in addition to usual pretreatments of the surface, in order to identify and discuss adsorption sites and mechanisms. Stable nitrate ions are formed on the surface, starting at beam temperature (b.t.) with NO and are predominant at 150 °C with NO2. Between b.t. and 150 °C, NO2 mainly chemisorbs as such or as its dimer N2O4. Depending on the pressure, NO chemisorbs at b.t. also as is or as NO- ions, as well as in the form of its dimer N2O2. N2O merely physisorbs on an "oxygen-rich" surface, but it strongly chemisorbs on an "evacuated" surface producing species which can be identified as N2O-. © 1981.
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