An oxidation catalyst composition is provided, the composition including a plurality of platinum group metal particles having a multi-modal distribution of particle sizes. The plurality of platinum group metal particles includes a first population of platinum group metal particles having a range of particle sizes of from about 0.5 nm to about 3 nm, and a second population of platinum group metal particles having a range of particle sizes of from about 4 nm to about 15 nm. Methods for the preparation and use of the catalyst composition are also provided, as well as catalyst articles and emission gas treatment systems employing such catalyst articles. The catalyst exhibits enhanced stability with respect to oxidation performance after degreening and/or aging, as compared to conventional oxidation catalysts, in particular less loss of NOx oxidation performance.

An object of the present invention is to increase the reduction performance of nitrogen oxides compared to existing three-way catalysts; simultaneously inhibit the emission of ammonia and nitrous oxide; simplify a process by means of a method of further doping an iridium-ruthenium catalyst into a commercial three-way catalyst; and expand the scope of application. The present invention provides a catalyst for simultaneously inhibiting the emission of ammonia and nitrous oxide by doping an iridium-ruthenium catalyst component into a three-way catalyst (TWC), a diesel oxidation catalyst, or a lean NOx trap supported on a honeycomb support.

A method of manufacturing a catalyst article, the method comprising: providing a complex of a humic acid or derivative thereof, and a PGM; providing a support material; applying the complex to the support material to form a loaded support material; disposing the loaded support material on a substrate; and heating the loaded support material to form nanoparticles of the PGM on the support material.

The devices, systems and techniques disclosed in this patent document include photocatalytic filter devices and can be used to provide a method for manufacturing a photocatalytic filter with improved adhesion. In addition, the present disclosure of this patent document includes technology to provide a method for reactivating a photocatalytic filter. Using the disclosed techniques, even if a photocatalytic filter is contaminated, the contaminated photocatalytic filter is easily reactivated while maintaining improved adhesion.

A layered catalyst structure for purifying an exhaust gas stream includes a catalyst support and a palladium catalyst layer including an atomic dispersion of palladium ions electrostatically adsorbed onto an exterior surface of the catalyst support. The catalyst support includes an alumina substrate, a first ceria layer disposed on and extending substantially continuously over the alumina substrate, and a second colloidal ceria layer formed directly on the first ceria layer over the alumina substrate. The palladium catalyst layer is formed on the exterior surface of the catalyst support by applying a palladium-containing precursor solution to the exterior surface of the catalyst support and then heating the catalyst support and the palladium-containing precursor solution. The palladium-containing precursor solution includes a positively charged palladium complex in an aqueous medium and has a pH greater than a point of zero charge of the second colloidal ceria layer.

Provided is a preparation method of a coating material. The method includes: using an aluminum salt and a silicon source as precursors; and performing hydrothermal crystallization and calcination treatments successively under an action of a template agent to obtain the coating material, wherein the template agent is used to cause the coating material to form a porous spherical structure. In the embodiments of the present disclosure, the preparation process of the coating material is simple and the cost is low, and the specific surface area of the prepared coating material is large.

Catalyst compositions to perform selective alkyl-demethylation of C2+-hydrocarbyl-substituted aromatic hydrocarbon may exhibit a hydrogen chemisorption of at least 15% and comprise an oxide support material selected from the group consisting of an alkaline earth metal oxide, silica, a composite of an alkaline earth metal oxide and Al.sub.2O.sub.3, a composite of ZnO and Al.sub.2O.sub.3, a lanthanide oxide, a composite of a lanthanide oxide and Al.sub.2O.sub.3, and combinations and mixtures of two or more thereof; and a transition metal element dispersed upon the oxide support material. Alkyl-demethylation processes of a C6+ aromatic hydrocarbon-containing stream comprising C2+-hydrocarbyl-substituted aromatic hydrocarbons may comprise contacting the catalyst compositions in an alkyl-demethylation zone under alkyl-demethylation conditions to form an alkyl-demethylated aromatic hydrocarbon as an effluent exiting the alkyl-demethylation zone.

This exhaust gas purifying catalyst is provided with a substrate and a catalyst layer formed on a surface of the substrate. The catalyst layer contains zeolite particles that support a metal, and a rare earth element-containing compound that contains a rare earth element. The rare earth element-containing compound is added in such an amount that the molar ratio of the rare earth element relative to Si contained in the zeolite is 0.001 to 0.014 in terms of oxides.

Systems for treating wastewater containing organic nitrogen compounds are disclosed. The systems include a wet air oxidation unit having an oxidation zone, a catalytic zone, and a metal-based catalyst. Methods of treating wastewater containing organic nitrogen compounds are also disclosed. The methods include contacting the wastewater with an oxidant to produce a mixed liquor, contacting the mixed liquor with a metal-based catalyst to catalyze ammonia and produce a gas containing nitrogen and a liquid effluent containing nitrogen. Methods of retrofitting a wet air oxidation unit including providing a metal-based catalyst are also disclosed. Methods of facilitating treatment of wastewater in a wet air oxidation unit including providing a metal-based catalyst are also disclosed.

A method for producing a crystalline film comprising zeolite and/or zeolite-like crystals on a porous substrate is described. The method has the steps of: providing a porous support; modifying at least a surface of the top-layer of said porous support by treatment with a composition having one or more cationic polymer(s); rendering at least the outer surface of said porous support hydrophobic by treatment with a composition having one or more hydrophobic agent(s); subjecting said treated porous support to a composition having zeolite and/or zeolite-like crystals thereby depositing and attaching zeolite and/or zeolite-like crystals on said treated porous support, and growing a crystalline film of zeolite and/or zeolite-like crystals on said treated porous support and calcination. Crystalline films find use in a variety of fields such as in the production of membranes, catalysts etc.