An exhaust system for an internal combustion engine includes an upstream segment and a downstream segment connecting with the upstream segment. The downstream segment is a NOx reducing segment having an exhaust gas outlet and a reductant inlet disposed between the exhaust gas outlet and an exhaust gas inlet for the downstream segment. The upstream segment further includes a coating having a catalyst configured to increase a ratio of NO2 to NO in exhaust gases passing through the upstream segment. The coating includes a catalyst distribution, which may be a catalyst coating length, which is linked to a target ratio of NO2 to NO for reducing NOx in the downstream segment. The catalyst distribution in the upstream segment is adapted to increase the ratio of NO2 to NO, while limiting the ratio of NO2 to NO to a ratio optimized for reduction of NOx in the downstream segment.