Process and apparatus for cleaning a gas flow

A gas scrubbing device for removing nitrogen oxides from a gas, said device comprising an intermediate storage medium located at least partially in the gas stream, said intermediate storage medium comprising a mixture of:

• a nitrogen oxide storage material comprising one or more of the elements Cu, Ag, Au, Fe, Co, Ni, Ru, Rh, Pd, Re, Os, Ir, Pt and/or their oxides and/or their alloys;
• and
• a catalytically active supporting material having the chemical formula A1a1(1−x)A2a2(1−x)BbO4 where the A1 and A2 particles are selected from the group consisting of Mg, Ca, Mn, Fe, Ni, Co, Cu, Sn and Ti;
• B is Al and where a1+a2+b≦3 with a1, a2, b>0 and 0≦x<1,
• wherein said intermediate storage medium has a porous structure and has gas flow channels, and
• wherein the supporting material is catalytically active at a temperature of below about 200° C.

A gas scrubbing device for removing nitrogen oxides from a gas, said device comprising an intermediate storage medium located at least partially in the gas stream, said intermediate storage medium comprising a mixture of:

• a nitrogen oxide storage material comprising one or more of the elements Cu, Ag, Au, Fe, Co, Ni, Ru, Rh, Pd, Re, Os, Ir, Pt and/or their oxides and/or their alloys;
• and
• a catalytically active supporting material having the chemical formula Aa(1−x)BbO4 in a BbO3 matrix, wherein A is at least one of Ca, Mn, Fe, Ni, Co, Cu, Sn and Ti;
• B is Al;
• wherein a+b<3, with a, b>0, and 0≦x≦1,
• wherein said intermediate storage medium has a porous structure and has gas flow channels, and
• wherein the supporting material is catalytically active at a temperature of below about 200° C.