Systems and methods of synthesizing nanoparticles on substrates using rapid, high temperature thermal shock. A method involves depositing micro-sized particles or salt precursors on a substrate, and applying a rapid, high temperature thermal pulse or shock to the micro-sized particles or the salt precursors and the substrate to cause the micro-sized particles or the salt precursors to become nanoparticles on the substrate. A system may include a rotatable member that receives a roll of a substrate sheet having micro-sized particles or salt precursors; a motor that rotates the rotatable member so as to unroll consecutive portions of the substrate sheet from the roll; and a thermal energy source that applies a short, high temperature thermal shock to consecutive portions of the substrate sheet that are unrolled from the roll by rotating the first rotatable member. Some systems and methods produce nanoparticles on existing substrate. The nanoparticles may be metallic, ceramic, inorganic, semiconductor, or compound nanoparticles. The substrate may be a carbon-based substrate, a conducting substrate, or a non-conducting substrate. The high temperature thermal shock process may be enabled by electrical Joule heating, microwave heating, thermal radiative heating, plasma heating, or laser heating.

An exhaust system for an internal combustion engine, the exhaust system comprising, a lean NO.sub.x trap (LNT), a wall flow monolithic substrate having a NO.sub.x storage and reduction zone thereon, the wall flow monolithic substrate having a pre-coated porosity of 40% or greater, the NO.sub.x storage and reduction zone comprising a platinum group metal loaded on a first support, the first support comprising one or more alkaline earth metal compounds, a mixed magnesium/aluminium oxide, cerium oxide, and at least one base metal oxide selected the group consisting of copper oxide, manganese oxide, iron oxide and zinc oxide.

An exhaust system for an internal combustion engine, the exhaust system comprising, a lean NO.sub.x trap (LNT), a wall flow monolithic substrate having a NO.sub.x storage and reduction zone thereon, the wall flow monolithic substrate having a pre-coated porosity of 40% or greater, the NO.sub.x storage and reduction zone comprising a platinum group metal loaded on a first support, the first support comprising one or more alkaline earth metal compounds, a mixed magnesium/aluminium oxide, cerium oxide, and at least one base metal oxide selected the group consisting of copper oxide, manganese oxide, iron oxide and zinc oxide.

A catalyst fibrous structure having a catalyst metal carried on a fibrous structure, wherein (a) a Log differential micropore volume distribution curve thereof obtained by measurement using a mercury intrusion technique has a peak having a maximum micropore diameter in the range of from 0.1 μm to 100 μm; (b) a Log differential micropore volume at the peak is 0.5 mL/g or more; and (c) an amount of a catalyst metal compound and a binder carried per unit volume is 0.05 g/mL or more. A production method for producing a catalyst fibrous structure having: (1) mixing a catalyst metal compound or a catalyst precursor, and an inorganic binder and a solvent; (2) grinding the mixture to obtain a coating material of the catalyst metal compound or the catalyst precursor having a median particle diameter of 2 μm or less and a viscosity of from 10 mPa.Math.s to 200 mPa.Math.s; (3) impregnating a fibrous structure with the coating material to fill up voids of the fibrous structure with the coating material of the catalyst metal compound or the catalyst precursor; (4) heating and drying the fibrous structure, directly as it is, at a temperature not lower than the boiling point of the solvent; and (5) heating and calcination the dried fibrous structure at a temperature not lower than the dehydration temperature of the inorganic binder to obtain a catalyst fibrous structure.

A catalyst fibrous structure having a catalyst metal carried on a fibrous structure, wherein (a) a Log differential micropore volume distribution curve thereof obtained by measurement using a mercury intrusion technique has a peak having a maximum micropore diameter in the range of from 0.1 μm to 100 μm; (b) a Log differential micropore volume at the peak is 0.5 mL/g or more; and (c) an amount of a catalyst metal compound and a binder carried per unit volume is 0.05 g/mL or more. A production method for producing a catalyst fibrous structure having: (1) mixing a catalyst metal compound or a catalyst precursor, and an inorganic binder and a solvent; (2) grinding the mixture to obtain a coating material of the catalyst metal compound or the catalyst precursor having a median particle diameter of 2 μm or less and a viscosity of from 10 mPa.Math.s to 200 mPa.Math.s; (3) impregnating a fibrous structure with the coating material to fill up voids of the fibrous structure with the coating material of the catalyst metal compound or the catalyst precursor; (4) heating and drying the fibrous structure, directly as it is, at a temperature not lower than the boiling point of the solvent; and (5) heating and calcination the dried fibrous structure at a temperature not lower than the dehydration temperature of the inorganic binder to obtain a catalyst fibrous structure.

An object of the present invention is to provide an exhaust gas purification catalyst for purifying exhaust gas, in particular, fine composite-metal particles contained therein, and a method for producing the same; the exhaust gas purification catalyst according to the present invention includes fine composite-metal particles containing Rh and Pd, wherein, when the fine composite-metal particles in the exhaust gas purification catalyst are analyzed by STEM-EDX, the average ratio of the amount of Pd with respect to the total amount of Rh and Pd in the fine composite-metal particles is 1.7 atomic % or more and 24.8 atomic % or less.

An object of the present invention is to provide an exhaust gas purification catalyst for purifying exhaust gas, in particular, fine composite-metal particles contained therein, and a method for producing the same; the exhaust gas purification catalyst according to the present invention includes fine composite-metal particles containing Rh and Pd, wherein, when the fine composite-metal particles in the exhaust gas purification catalyst are analyzed by STEM-EDX, the average ratio of the amount of Pd with respect to the total amount of Rh and Pd in the fine composite-metal particles is 1.7 atomic % or more and 24.8 atomic % or less.

An exhaust gas-purifying catalyst of the present invention comprises a substrate, and one or more catalytic layers provided on the substrate, wherein at least one of the catalytic layers (i) contains a precious metal, alumina, and an acidic oxide element, (ii) has a correlation coefficient ρ.sub.Al,AE of 0.70 or more, and (iii) has a correlation coefficient ρ.sub.PM,AE of 0.70 or more.

An exhaust gas-purifying catalyst of the present invention comprises a substrate, and one or more catalytic layers provided on the substrate, wherein at least one of the catalytic layers (i) contains a precious metal, alumina, and an acidic oxide element, (ii) has a correlation coefficient ρ.sub.Al,AE of 0.70 or more, and (iii) has a correlation coefficient ρ.sub.PM,AE of 0.70 or more.

Catalyst compositions, articles, systems and methods related to a three-way-catalyst composition comprising alumina doped with a transition metal.