A catalytic converter includes a catalyst substrate including a body having a length and defining a plurality of zones along the length, with each zone having at least one cross-sectional structure defining a plurality of cells forming an exhaust gas flow path through the length via cells of adjacent zones, and the cells being more densely arranged within the at least one cross-sectional structure of an upstream zone than an adjacent downstream zone. The catalytic converter also includes a wash-coat layer deposited on surfaces of the cells forming active surface area configured to react with exhaust gas traveling along the length. The exhaust gas flows along the exhaust gas flow path through the cells such that more active surface area is available for reaction in each upstream zone than an adjacent downstream zone.