摘要:
Methods for synthesizing macroscale 3D heteroatom-doped carbon nanotube materials (such as boron doped carbon nanotube materials) and compositions thereof. Macroscopic quantities of three-dimensionally networked heteroatom-doped carbon nanotube materials are directly grown using an aerosol-assisted chemical vapor deposition method. The porous heteroatom-doped carbon nanotube material is created by doping of heteroatoms (such as boron) in the nanotube lattice during growth, which influences the creation of elbow joints and branching of nanotubes leading to the three dimensional super-structure. The super-hydrophobic heteroatom-doped carbon nanotube sponge is strongly oleophilic and an soak up large quantities of organic solvents and oil. The trapped oil can be burnt off and the heteroatom-doped carbon nanotube material can be used repeatedly as an oil removal scaffold. Optionally, the heteroatom-doped carbon nanotubes in the heteroatom-doped carbon nanotube materials can be welded to form one or more macroscale 3D carbon nanotubes.
摘要:
An apparatus is described, as including a reaction region for contacting a reactant gas with a reactive solid under conditions effective to form an intermediate product, and an opening for allowing an unreacted portion of the gaseous reagent and the intermediate product to exit the reaction region. The apparatus can be beneficially employed to form a final product as a reaction product of the intermediate product and the reactant gas. The reaction of the reactant gas and reactive solid can be conducted in a first reaction zone, with the reaction of the reactant gas and intermediate product conducted in a second reaction zone. In a specific implementation, the reaction of the reactant gas and intermediate product is reversible, and the reactant gas and intermediate product are flowed to the second reaction zone at a controlled rate or in a controlled manner, to suppress back reaction forming the reactive solid.
摘要:
An oxidation catalyst composite, methods, and systems for the treatment of exhaust gas emissions from a diesel engine are described. More particularly, an oxidation catalyst composite including a zoned diesel oxidation catalyst with a first washcoat zone with a Pt/Pd ratio that is less than 3:1 and a PGM loading at least twice that of a second washcoat zone.
摘要:
Described are catalyst compositions, catalytic articles, methods of manufacturing catalytic articles and exhaust gas treatment systems and methods that utilize the catalytic articles. The catalytic articles include a washcoat of platinum group metal on refractory oxide support particles, and further including a molecular sieve wherein greater than 90% of the molecular sieve particles have a particle size greater than 1 μm.
摘要:
The invention provides a composite catalyst containing a first component and a second component. The first component contains nanosized gold particles. The second component contains nanosized platinum group metals. The composite catalyst is useful for catalyzing the oxidation of carbon monoxide, hydrocarbons, oxides of nitrogen, and other pollutants at low temperatures.
摘要:
A CO slip catalyst, for treating an exhaust gas from a lean burn internal combustion engine, is disclosed. The CO slip catalyst comprises palladium and a ceria-containing material. The invention also includes a method for oxidizing excess CO in an exhaust gas, wherein the excess CO results from the periodic contact of an upstream catalyst under rich exhaust conditions. The method comprises contacting the excess CO in the exhaust gas with a CO slip catalyst at a temperature in the range of 100 to 700° C.
摘要:
A catalyst material for the oxidation of NO comprising a catalyst carrier including a ceria-alumina support having platinum and optionally palladium dispersed on the support is described. When palladium is present, the ratio of platinum to palladium by weight is at least 1:1. The amount of ceria in the support is in the range of 1% to 12% by weight. The catalyst material is useful for methods and systems of abating pollutants from automotive exhaust gas from lean burn engines.
摘要:
An oxidation catalyst for treating an exhaust gas produced by a combustion engine, wherein the oxidation catalyst comprises a substrate and a catalyst layer, wherein the catalyst layer comprises: a first support material; a first noble metal; and a second noble metal; wherein the catalyst layer is disposed on a surface of the substrate, and the catalyst layer has a non-uniform distribution of the first noble metal in a direction perpendicular to the surface of the substrate. The oxidation catalyst can be used to oxidize carbon monoxide (CO), hydrocarbons (HCs) and also oxides of nitrogen (NOx) in such an exhaust gas.
摘要:
A NOx absorber catalyst comprising a substrate monolith coated with one or more washcoat layers and comprising a first component comprising a nitrogen oxide storage component, at least one precious metal and a dispersed rare earth oxide supported on a refractory support material, and a second component comprising a precious metal supported on a bulk reducible oxide that is substantially free of nitrogen oxide storage material, wherein the precious metal present in the second component comprises Pt, Pd or a combination of both Pt and Pd and wherein the bulk reducible oxide is an oxide, a composite oxide or a mixed oxide comprising at least one of manganese, iron, cobalt, copper, tin or cerium.