A device and method for catalytic reduction of NOx in gaseous products of combustion by directing the products of combustion through a particulate filter (32) and then into a mixing zone (28) through separate flow passages (34, 36) at respective velocities greater than that at which products of combustion leave the filter, by causing an injector (38) to introduce urea solution through a nozzle (40) aimed toward the mixing zone along a slant direction (42) to, and across, flow entering the mixing zone through a first (34) of the separate flow passages and ultimately toward a far wall (44) of the mixing zone relative to the nozzle while directing exhaust flow entering the mixing zone through a second (36) of the separate flow passages to enter the mixing zone between the first flow passage and far wall, and by directing flow leaving the mixing zone through an SCR catalyst (48).