A nitrous oxide (N.sub.2O) removal catalyst composite is provided, comprising a N.sub.2O removal catalytic material on a substrate, the catalytic material comprising a rhodium (Rh) component supported on a ceria-based support, wherein the catalyst composite has a H.sub.2-consumption peak of about 100° C. or less as measured by hydrogen temperature-programmed reduction (H.sub.2-TPR). Methods of making and using the same are also provided.

Disclosed herein are emission treatment systems, articles, and methods for selectively reducing NOx compounds. The systems include a hydrogen generator, a hydrogen selective catalytic reduction (H.sub.2-SCR) article, and one or more of a diesel oxidation catalyst (DOC) and/or a lean NOx trap (LNT) and/or a low temperature NOx adsorber (LTNA). Certain articles may comprise a zone coated substrate and/or a layered coated substrate and/or an intermingled coated substrate of one or more of the H.sub.2-SCR and/or DOC and/or LNT and/or LTNA catalytic compositions.

A catalysed filter system for treating particulate-containing exhaust gas from a stationary emission source comprises an elongate filter element comprising porous walls which define a hollow section and a substrate material supporting a catalyst component disposed within the hollow section, the arrangement being such that gas entering the hollow section of the elongate filter element from across the porous walls thereof must contact the substrate material supporting the catalyst component before exiting the hollow section of the elongate filter element.

A reductant dosing system includes an injector, a fixed displacement pump in fluid communication with the injector, a reductant source in fluid communication with the fixed displacement pump, a pressure sensor assembly that detects a pressure of a reductant and stores a calibration value, and a controller communicatively coupled to the fixed displacement pump and the pressure sensor assembly. The controller receives data that includes the detected pressure of the reductant and the calibration value. The controller, in response to the calibration value being within a predetermined calibration value range, calculates a flow rate of the fixed displacement pump based on at least the detected pressure and the calibration value, and, in response to the calibration value being outside the predetermined calibration value range, calculates the flow rate of the fixed displacement pump based on at least the detected pressure and a pre-determined calibration value different from the calibration value.

A nitrous oxide (N.sub.2O) removal catalyst composite is provided, comprising a N.sub.2O removal catalytic material on a substrate, the catalytic material comprising a rhodium (Rh) component supported on a ceria-based support, wherein the catalyst composite has a H.sub.2-consumption peak of about 100° C. or less as measured by hydrogen temperature-programmed reduction (H.sub.2-TPR). Methods of making and using the same are also provided.

A reductant dosing system includes: an injector; a fixed displacement pump in fluid communication with the injector; a reductant source in fluid communication with the fixed displacement pump; a pressure sensor assembly configured to detect a pressure of reductant in the reductant dosing system; and a controller communicatively coupled to the fixed displacement pump and to the pressure sensor assembly, wherein the controller is configured to calculate a flow rate of the fixed displacement pump based on at least a calibration value determined based on data received from the pressure sensor assembly.

A catalyst for the conversion of NO.sub.X and N.sub.2O comprising iron chabazite and iron beta zeolite. A method of simultaneously reducing the NO.sub.X and N.sub.2O concentration in a process gas stream comprising contacting the process gas stream with a catalyst comprising iron chabazite and iron beta zeolite under conversion conditions.

Catalyst material comprising a ternary spinel mixed oxide for treatment of an exhaust gas stream via direct decomposition removal of NOx to N.sub.2 and O.sub.2. The low temperature (from about 400 C. to about 650 C.), direct decomposition is accomplished without the need of a reductant molecule. In one example, Mn may be incorporated into metal oxide, such as Cu.sub.yCo.sub.3-yO.sub.4 spinel oxide, synthesized using co-precipitation techniques.

Catalyst and use of the catalyst comprising a molecular sieve belonging to the ABC-6 framework family with disorder in the ABC stacking sequence essentially composed of double-six-ring periodic building units and having a mole ratio of silicon oxide to aluminum oxide from about 8 to about 60.

A nitrous oxide (N.sub.2O) removal catalyst composition for treating an exhaust stream of an internal combustion engine is provided, containing a platinum group metal (PGM) component on a metal oxide-based support, wherein the N.sub.2O removal catalyst composition is in a substantially reduced form, such that it has an oxygen deficiency of about 0.05 mmol oxygen atoms/g or greater, and wherein the N.sub.2O removal catalyst composition provides effective removal of at least a portion of N.sub.2O from the exhaust stream under lean conditions at a temperature of about 350 C. or lower. N.sub.2O removal catalytic articles, systems, and methods are also provided for removing at least a portion of N.sub.2O from an exhaust stream under lean, low temperature conditions.