Abstract: The present invention relates to a catalyst comprising a support substrate having a length L extending between the ends a and b, and four material zones A, B, C and D, wherein material zone B comprises bismuth.

Abstract: The invention relates to an exhaust-gas aftertreatment system for selective catalytic reduction with a plurality of SCR catalytic converters, which exhaust-gas aftertreatment system is able to reduce NOx in a large temperature range and can store SOx. The invention further relates to a method for treating an exhaust gas flow, in which method the exhaust-gas aftertreatment system according to the invention is used. The system comprises a high-temperature SCR catalyst for temperature ranges between 250° C. and 750° C. and a low-temperature SCR catalyst arranged downstream thereof for temperature ranges between 60° C. and less than 250° C. There is a reductant supply system directly upstream of the high-temperature SCR catalyst. The high-temperature SCR catalyst is designed to reduce NOx in exhaust gas that has a temperature above a temperature threshold value and to store SOx in the temperature range below the threshold value.