FTIR studies of adsorption of NO, NO2 and N2O on layered V2O5/ZrO2

The adsorption of NO, NO2 and N2O at various temperatures on mono- and multi-layered V2O5/ZrO2 catalysts prepared by the gas-phase method has been investigated by IR spectroscopy. On the reduced samples of both mono- and multi-layer catalysts, NO is adsorbed giving mono- and di-nitrosylic species. On the oxidized form of the monolayer catalyst, only nitrite and nitrate species are formed and no nitrosylic species are formed. NO2 adsorbed on reduced multilayer catalysts exhibits IR bands due to nitrate species together with minor amounts of nitrosylic species. The surface nitrosylic species were less readily formed on the monolayer catalyst than on multilayer catalysts. Quantitative analysis of the VO band in the region 1100–900 cm–1 indicates that only the surface VO species in the top layer of the catalyst interacts with the adsorbed species. Both NO and NO2 reoxidize the catalyst surface at higher temperatures and the monolayer catalyst was less readily oxidized than the multilayer catalyst.