A composition for scr catalysts

A composition comprising:

• (i) a non-zeolitic oxidic material comprising alumina;
• and
• (ii) an 8-membered ring pore zeolitic material comprising one or more of copper and iron, wherein a framework structure of the zeolitic material comprises a tetravalent element Y, a trivalent element X and oxygen, wherein the molar ratio of Y:X, calculated as YO2:X2O3, ranges from 2:1 to 40:1;
• wherein at least part of the outer surface of the zeolitic material according to (ii) is covered by a layer comprising the non-zeolitic oxidic material according to (i);
• and
• wherein Y comprises one or more of Si, Sn, Ti, Zr and Ge and X comprises one or more of Al, B, In and Ga.

A process for preparing a composition, the process comprising:

• (a) providing an 8-membered ring pore zeolitic material, comprising one or more of copper and iron, wherein a framework structure of the zeolitic material comprises a tetravalent element Y, a trivalent element X and oxygen, wherein the molar ratio of Y:X, calculated as YO2:X2O3, ranges from 2:1 to 40:1, wherein the zeolitic material comprises crystals having an average crystal size in the range of from 0.05 micrometers to 5 micrometers;
• (b) providing a source of a non-zeolitic oxidic material comprising alumina, wherein the source of the non-zeolitic oxidic material is a colloid dispersion comprising particles of the non-zeolitic oxidic material, wherein the particles of the non-zeolitic oxidic material have a Dv50 ranging from 30 nm to 200 nm;
• (c) admixing the zeolitic material obtained in (a) with the source of the non-zeolitic oxidic material comprising alumina obtained in (b), forming a mixture;
• and
• (d) calcining the mixture obtained in (c) in a gas atmosphere having a temperature ranging from 400° C. to 800° C.