STUDY OF TI-V-P-O CATALYSTS FOR THE SELECTIVE REDUCTION OF NITRIC-OXIDE IN THE PRESENCE OF OXYGEN

The influence of vanadium content on the catalytic activity of Ti-V-P-O cctalysts for the selective reduction of nitric oxide with ammonia in the presence of oxygen was studied in a pseudoadiabatic reactor. The catalytic activity is related to the presence of well dispersed vanadium-oxygen species interacting with the titanium dioxide surface. Other proportionally less active configurations of vanadium species were detected on the catalyst surface such as α- and β-VOPO4 (shown by X-ray diffraction). The vanadium species named "paracrystalline V2O5" revealed by (laser Raman spectroscopy) was not active and when selectively extracted the activity per gram of catalyst increased, probably owing to the cleaning of plugged pores. © 1990.