To provide a method for cleaning exhaust by which NOx and PM can be continuously self-removed under ordinary burning conditions without requiring specified control and to provide an exhaust cleaning catalyst and an apparatus for cleaning exhaust.
In the method for cleaning exhaust, PM particles and NOx in exhaust are removed by converting the PM particles to HC by a reaction represented by the formula mC+nH2O→H2nCm+n/2.O2. The apparatus for cleaning exhaust has a filter obtained by carrying a noble metal and fine oxide particles of ≤1 μm average particle diameter on the inner walls of pores in a monolithic filer and disposed in an exhaust flue. In the method for cleaning exhaust, hydrogen generation reactions represented by the formulae C+H2 O→H2+CO and C+2H2O→2H2+CO2 are carried out at ≤500°C exhaust temperature. The exhaust cleaning catalyst contains an H2 generation catalyst and an NOx removal catalyst, the H2 generation catalyst contains Rh-carrying porous particles and metals such as Fe, Co, Mn and Ni, and these metals are contained at a ratio of 0.1-10 when Rh is represented by 1.
HANAKI YASUNARI
KAMIJO MOTOHISA
