Collect. Czech. Chem. Commun. 1988, 53, 288-293

Reduction and oxidation of vanadium catalysts for the NO + NH3 reaction

Milan Čížek and Vladimír Pour

Institute of Inorganic Chemistry Czechoslovak Academy of Sciences, 160 00 Prague 6


The reduction of V2O5/Al2O3 (15 mass % V2O5) and V2O5 by ammonia, hydrogen, and a NO + NH3 mixture, and the oxidation of pre-reduced catalysts by oxygen and nitrogen oxide have been investigated. For both catalysts, the reduction rate increases in the sequence H2 < NH3 < NO + NH3. From the character of the temperature and concentration dependences of the oxidation state of vanadium, it has been concluded that in the temperature range 100 to 175 °C the catalysts are reduced by the NO + NH3 mixture within the surface layer only. The reaction of this mixture with oxidized surface of vanadium catalyst is of the same order with respect to NO and NH3 concentrations.