The present invention pertains to: a vanadium pentoxide-tungsten trioxide catalyst supported on an iron ion-exchanged titanium dioxide; and a method for removing nitrogen oxides using the same. More specifically, the present invention pertains to: a deNO.sub.xing catalyst in which the iron ion-exchanged titanium dioxide is utilized as a support for the vanadium pentoxide and tungsten trioxide to drastically reduce the generation and emission of nitrous oxide; and a method for removing nitrogen oxides using the same.

An aftertreatment system includes: a first exhaust gas path comprising a heater; a second exhaust gas path comprising a first decomposition chamber configured to receive reductant and a first selective catalytic reduction catalyst downstream of the first decomposition chamber; a combined exhaust gas path downstream of the first exhaust gas path and the second exhaust gas path, the combined exhaust gas path configured to receive exhaust gas from both the first exhaust gas path and the second exhaust gas path; a selector valve configured to divert the exhaust gas between the first exhaust gas path and the second exhaust gas path based on a temperature of the exhaust gas; and a controller programmed to control the selector valve.

It is an object to provide a regenerated denitration catalyst whose denitration performance is restored compared with a denitration catalyst before use, utilizing a spent denitration catalyst, and a method for manufacturing the same. In a regenerated denitration catalyst according to the present disclosure, a spent denitration catalyst including a first titanium oxide as a main component, and a second titanium oxide are mixed. The spent denitration catalyst is already used in a denitration reaction in which nitrogen oxides in a gas are decomposed into nitrogen and water using a reducing agent. The second titanium oxide has a larger specific surface area per unit weight than the first titanium oxide. A content of the second titanium oxide based on a total weight of the first titanium oxide and the second titanium oxide is preferably 10% by weight or more and 90% by weight or less.

An ammonia oxidation catalyst device, including a substrate, a first catalyst coat layer and a second catalyst coat layer, wherein: the first catalyst coat layer includes inorganic oxide particles and a catalytic noble metal supported on the inorganic oxide particles; the second catalyst coat layer includes an NO.sub.x selective reduction catalyst and a proton zeolite H-Zeolite; the first catalyst coat layer is present on the substrate; and the second catalyst coat layer is present on the first catalyst coat layer.

Improved systems and methods are disclosed for treating tail gas in a sulfuric acid production plant. A tail gas treatment system is employed which comprises a product stripper and a purge gas scrubber. The inventive arrangement provides an advantageous economical way to remove high levels of SO.sub.2 from the tail gas stream.

A catalytic reaction apparatus includes a coating composition for a catalyst and a catalyst portion to which the coating composition is applied, wherein the coating composition includes 1 to 15 parts by weight of tungsten, 1 to 15 parts by weight of vanadium, 35 to 55 parts by weight of titanium and 30 to 45 parts by weight of oxygen. This apparatus is configured to prevent a decrease in catalytic reaction efficiency in a specific temperature environment, thereby maximizing versatility.

Various aspects of the present disclosure are directed towards apparatuses, systems, and methods of preparing catalysts. In some embodiments, a catalyst includes a catalytically active component and a support material comprising TiO2 having a crystal structure comprising an anatase phase and a secondary material. In some embodiments, the support material includes a secondary material such as SiO.sub.2, MoO.sub.3, WO.sub.3, and Al.sub.2O.sub.3.

An emission treatment system for NOx abatement in an exhaust stream of an ammonia-fueled engine, the emission treatment system including a selective catalytic reduction (SCR) catalyst disposed on a substrate in fluid communication with the exhaust stream, an oxidation catalyst disposed on a substrate positioned either upstream or downstream of the SCR catalyst and in fluid communication with the exhaust stream and the SCR catalyst, and optionally, one or more adsorption components disposed on a substrate positioned upstream and/or downstream of the SCR catalyst and in fluid communication with the exhaust stream and the SCR catalyst, the adsorption component chosen from low temperature NOx adsorbers (LT-NA), low temperature ammonia adsorbers (LT-AA), low temperature water vapor adsorbers (LT-WA), and combinations thereof. The disclosure further provides a related method of treatment of an exhaust gas.

Embodiments relate to a metal vanadate catalyst for nitrogen oxide reduction functionalized with H.sub.3-APO.sub.4.sup.A (A=1, 2, or 3) and SO.sub.B.sup.2 (B=3 or 4) and a synthesis method thereof, and more particularly, to a solid-state catalyst for nitrogen oxide reduction, including a transition metal vanadate or a rare-earth metal vanadate as a catalytic site in a support, some of the catalytic sites being modified with H.sub.3-APO.sub.4.sup.A and SO.sub.B.sup.2 functional groups, and a synthesis method thereof.

A method for synthesizing functionalized porous cerium oxide nanoparticles and the resulting nanoparticles. The method involves preparing a synthesis mixture comprising a cerium source, two other metal sources, and an organic acid serving as a fuel. Volatile components are removed from the mixture, which is then subjected to thermal treatment in a static oven. The resulting nanoparticles have a three-dimensional structure with micropores and mesopores, oxygen-defects sites, 10 wt % of transition elements, and 1 wt % of tri-valent cations. The nanoparticles exhibit high photocatalytic activity and adsorption efficiency, and can be coated on a stainless steel substrate. The nanoparticles can be used for photocatalytic reactions, selective reduction and oxidation reactions, adsorption of specific compounds, and removal of toxic compounds from the air. The nanoparticles are coated on a chimney and allows for reduced hydrocarbons, carbon dioxide and carbon monoxide.