Portal de Periódicos da CAPES

IR spectroscopy study of NO adsorption and NO + O2 co-adsorption on Al2O3

2002; Royal Society of Chemistry; Volume: 4; Issue: 11 Linguagem: Inglês

10.1039/b111396h

1463-9084

Tzvetomir Venkov, Konstantin Hadjiivanov, D. Klissurski,

Gas Sensing Nanomaterials and Sensors

Adsorption of NO on Al2O3 leads to the formation of small amounts of surface nitro–nitrito (1461, 1318, 1228, 1220 and 1074 cm−1) and nitrato (1652 cm−1) complexes. Introduction of oxygen into the system causes oxidation of the NO2− compounds to nitrates (1628, 1591, 1565, 1298, 1259 and 1042 cm−1) whose concentration increases with time and with the oxygen amount. The nitrates obtained in this way are stable up to 723 K. They increase the Lewis acidity of Al3+ sites in the vicinity, as a result of which mononitrosyls of the type Al3+(NO3−)-NO (1938 cm−1) are formed. In addition, weakly bound N2O3 (1895, 1565, 1298 cm−1) and N2O4 (1752 cm−1) are obtained. Analysis of the spectra in the 2900–2400 cm−1 region shows the presence of combination bands at 2883, 2624 and 2546–2526 cm−1, which can be useful for the spectral identification of the surface anionic nitrogen-oxo species.