The present disclosure generally provides catalysts, catalytic articles and catalyst systems including such catalytic articles. In particular, the catalyst composition includes a zeolite having a chabazite (CHA) crystal structure ion-exchanged with iron and copper. Methods of making and using the catalyst composition are also provided, as well as emission treatment systems containing a catalyst article coated with the catalyst composition. The catalyst article present in such emission treatment systems is useful to catalyze the reduction of nitrogen oxides in gas exhaust in the presence of a reductant.