Ki. Hadjiivanov et al., IR SPECTROSCOPIC STUDY OF NO2 ADSORPTION ON CHROMIA, Journal of the Chemical Society. Faraday transactions, 91(1), 1995, pp. 149-153
Citations number
34
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
NO2 adsorption on cc-chromia leads to the formation of bridged and bid
entate nitrates as well as of nitro species. In an NO2 atmosphere the
latter are oxidized to nitrates. When NO2 is adsorbed with the partici
pation of the surface hydroxy groups on chromia, bridged nitrates and
water are among the reaction products. Adsorption of NO2 on reduced sa
mples leads to the oxidation of the surface and to the formation of th
e same species as observed on oxidized samples, but in different conce
ntrations. Preadsorbed water slightly affects NO2 adsorption. Ammonia
adsorption on a sample precovered with NO2 leads to the appearance of
NH4NO3-like surface species (with the participation of the bridged nit
rates). These species are supposed to be intermediates in the catalyti
c selective reduction of NO2 by ammonia. The mechanism of the process
is discussed.