Mixed metal large crystal molecular sieve catalyst compositions, catalytic articles, systems and methods

A catalytic article comprising a substrate having at least one washcoat thereon so as to contain both a first molecular sieve promoted with copper and a second molecular sieve promoted with iron, the first and second molecular sieves having a d6r unit and the first molecular sieve having cubic shaped crystals with an average crystal size of about 0.5 to about 2 microns, wherein the weight ratio of the copper-promoted molecular sieve to the iron-promoted molecular sieve is about 1:1 to about 4:1, the catalytic article effective to catalyze the reduction of nitrogen oxides in the presence of a reductant, wherein the catalytic article has an N2O make of about 7 ppm or less at 225° C. and an N2O make of about 4 ppm or less at 550° C. after hydrothermal aging in the presence of 10% H2O at 750° C. for 5 hours.