INFRARED AND RAMAN-STUDY OF THE ADSORPTION OF NITROGEN-OXIDES ON TITANIA-SUPPORTED VANADIA CATALYSTS

Infrared and Raman spectra are reported of vanadia-anatase catalysts with three vanadia loadings exposed to nitric oxide and nitrogen dioxide at ambient temperature. Bridging, bidentate and monodentate nitrato species were identified. The surface species were less readily formed from nitric oxide than nitrogen dioxide and a smaller variety of adsorbed products was formed on catalysts with high rather than low vanadia loading. Reduced catalysts were reoxidised by nitrogen dioxide but not nitric oxide. The latter generated mono- and di-nitrosyl vanadium complexes on adsorption. Nitrous oxide failed to give adsorbed species on the catalyst surfaces.