CATALYST FOR EXHAUST GAS TREATMENT CAPABLE OF CARRYING OUT REDUCTION TREATMENT OF SO3, METHOD FOR PRODUCTION THEREOF, AND METHOD FOR TREATING EXHAUST GAS USING THE CATALYST

摘要

Provided are a catalyst for an exhaust gas treatment capable of carrying out a reduction treatment of SO₃ which can efficiently decrease SO₃ being co-present in an exhaust combustion gas and being a starting material for an S-containing substance, such as an acidic ammonium sulfate, causing the reduction of the performance capability of a catalyst and the corrosion of a device provided downstream from the catalyst and which inhibits the formation of SO₃ in the catalyst itself; a method for producing the catalyst; and a method for treating an exhaust gas using the above catalyst. A catalyst for treating an exhaust combustion gas containing nitrogen oxides, wherein 50 wt % or more of Ru and/or Ir being carried by a base material is contained in a region having a depth from the surface of the base material of 150 µm or less. The above catalyst can be produced by a method which comprises immersing the base material into a metal colloid solution of Ru and/or Ir to be carried or an aqueous solution containing at least one of the compounds of Ru and/or Ir to be carried.