Nickel-ceric oxide catalysts - for redn. of nitrogen oxides in exhaust and waste gases, active over wide temp. range

摘要

Catalysts for the redn. of N oxides contain CeO2 and NiO in a molar ratio of 0.05-2.5:1, esp. 0.1-1.5:1. They can also contain 7.5-25, pref. 10-20 wt. % Rh or 10-50, pref. 20-30 wt. % Ru or 7.5-25, pref. 10-20 wt. % Rh and 15-50, pref. 20-30 wt. % Ru (w.r.t. 100 pts. NiO+CeO2) and also Cu, Ca, Ag, Zn, Cd, Co and/or Ce sulphides in an amt. of 0.1-2 mole/mole Ru or Mg, Ca, Sr, Ba, Al, Ti, Zr, Mn, Fe, Ni, La, Ce, Nd, Sm, Gd and/or Yb oxide(s) in an amt. of 0.5-2 mole/mole Ru. The catalysts are used for the redn. of N oxides at a temp. 500 degrees C, esp. in exhaust and waste gases from IC engines, power stations, chemical works etc. These catalysts have high activity over a wide temp. range, resistance to catalyst poisons and acceptable or low cost. They also minimise the formation of NH3 during redn.