Abstract:
In one aspect, compositions comprising copper-silica (Cu—SiO2) core-shell nanoparticles are described herein. The core-shell nanoparticles comprise copper (Cu) core components and silica (SiO2) shell components encapsulating the core components. In some embodiments, the nanoparticle compositions comprise a continuous aqueous phase and a population of copper-silica (Cu—SiO2) core-shell nanoparticles dispersed in the aqueous phase.
Abstract:
The present disclosure relates to micron-sized particle used for catalyzing and storing NOx gases, such as those found in vehicle exhaust emissions, washcoats employing micron-sized particle used for catalyzing and storing NOx gases, washcoat coated substrates, lean NOx trap (LNT) systems, and vehicles using such systems. Also provided are methods of preparing micron-sized particle used for catalyzing and storing NOx gases, as well as preparation of washcoats and coated substrates. More specifically, the present disclosure relates to a lean NOx trapping materials, wherein the materials include a NOx catalytic component attached to a micron-sized carrier particle and a NOx storage component, as well as washcoats and coated substrates useful in the treatment of exhaust gases. In some embodiments, a portion of the NOx storage component is attached to the micron-sized carrier particle.
Abstract:
Disclosed is a visible light responsive photocatalyst that simultaneously realizes high crystallinity and refinement of primary particles. Also disclosed is a photocatalyst composed of secondary particles that have a high porosity and are aggregates of fine primary particles. Rhodium-doped strontium titanate that is a visible light responsive photocatalyst of the present invention has a primary particle diameter of not more than 70 nm and has a absorbance at a wavelength of 570 nm of not less than 0.6 and a absorbance at a wavelength of 1800 nm of not more than 0.7, each absorbance determining by measuring a diffuse reflection spectrum, the rhodium-doped strontium titanate having a high water-splitting activity as a photocatalyst.
Abstract:
Disclosed is a photocatalyst, and methods for its use, that includes a photoactive material comprising a photonic band gap and an electronic band gap, wherein the photonic band gap at least partially overlaps with the electronic band gap, and an electrically conductive material deposited on the photoactive material.
Abstract:
Disclosed are a complex oxide catalyst for dehydrogenation, a method of preparing the same, and use thereof, wherein the catalyst includes a first transition metal selected from the group consisting of gallium, vanadium, chromium, manganese, molybdenum, and zinc, a hydrogen-activating metal including at least one selected from the group consisting of Groups 8, 9, 10, and 11 elements in a periodic table, and alumina, the amount of the first transition metal being 0.1 wt % to 20 wt %, the amount of the hydrogen-activating metal being 0.01 wt % to 2 wt %, based on the amount of the alumina, the first transition metal being loaded on the alumina, and the hydrogen-activating metal being surrounded by the alumina.
Abstract:
Disclosed are catalysts comprised of platinum and gold. The catalysts are generally useful for the selective oxidation of compositions comprised of a primary alcohol group and at least one secondary alcohol group wherein at least the primary alcohol group is converted to a carboxyl group. More particularly, the catalysts are supported catalysts including particles comprising gold and particles comprising platinum, wherein the molar ratio of platinum to gold is in the range of about 100:1 to about 1:4, the platinum is essentially present as Pt(0) and the platinum-containing particles are of a size in the range of about 2 to about 50 nm. Also disclosed are methods for the oxidative chemocatalytic conversion of carbohydrates to carboxylic acids or derivatives thereof. Additionally, methods are disclosed for the selective oxidation of glucose to glucaric acid or derivatives thereof using catalysts comprising platinum and gold. Further, methods are disclosed for the production of such catalysts.
Abstract:
Niobia- and tantala-doped ceria catalysts, their use in selective catalytic reduction (SCR) processes, and a compact after-treatment system for exhaust gases are disclosed. In some aspects, the catalyst comprises at least 91 wt. % of ceria and 0.1 to 9 wt. % of niobia or tantala doped on the ceria. While conventional SCR catalysts can deactivate at higher temperatures, the doped cerias, particularly ones having as little as 1 or 2 wt. % of Nb2O5 or Ta2O5, are activated toward NOx conversion by calcination. The doped cerias are also valuable for SCRF® catalyzed filter applications, including an after-treatment system that comprises a diesel particulate filter having inlets and outlets, and a dual-function catalyst coated on the inlets, outlets, or both. Compared with conventional SCR catalysts, the niobia or tantala-doped cerias enable a higher level of NO2 to be present.
Abstract translation:公知了氧化铌和钽铝氧化物催化剂,它们在选择性催化还原(SCR)工艺中的应用,以及用于废气的紧凑的后处理系统。 在一些方面,催化剂包含至少91wt。 %的二氧化铈和0.1〜9wt。 在氧化铈上掺杂的氧化铌或钽的百分比。 虽然常规SCR催化剂可以在较高温度下失活,但是掺杂的二氧化铈,特别是具有少至1或2wt。 Nb 2 O 5或Ta 2 O 5的%通过煅烧而被NOx活化。 掺杂的二氧化铈对于SCRF®催化过滤器应用也是有价值的,其包括后处理系统,其包括具有入口和出口的柴油微粒过滤器,以及涂覆在入口或出口上的双功能催化剂。 与传统的SCR催化剂相比,氧化铌或氧化钽掺杂的铈氧化物可以提供更高水平的NO2。
Abstract:
A promoted VPO catalyst for the oxidation of n-butane to maleic anhydride wherein the catalyst comprises the mixed oxides of vanadium and phosphorus, niobium and at least one of antimony and bismuth, wherein the catalyst may be produced in a process comprising impregnating a VPO catalyst with a metal source compound of niobium and a metal source compound of at least one of antimony and bismuth, to form a metal impregnated VPO catalyst, and then drying the metal impregnated VPO catalyst to form the promoted VPO catalyst.
Abstract:
In a method of preparing a ruthenium-containing catalyst on a non-conductive metal oxide support comprises dissolving one or more ruthenium precursor compounds in an liquid organic polyol, combining the thus obtained solution with (a) nano-powder(s) of one or more metal oxides in a ratio of moles metal oxide(s) to moles ruthenium atoms in the one or more ruthenium precursor compounds of about 0:1 to about 6:1, the metal oxide nano-powder(s) having a surface area of from about 5 to about 300 m2/g and a point of zero charge (PZC) of pH 5.5 or higher, agitating the thus obtained mixture, adding pre-shaped alumina support pellets to the agitated mixture, which is than heated at a temperature of about 50° C. to the boiling point of the organic polyol, until the reaction is finished, cooling the mixture and combining it with an aqueous solution of NaNO3 and/or KNO3, agitating the resultant mixture, separating the solvent and the solids, and drying the thus obtained solid pellets of alumina, or alumina and the metal oxide(s) of the nano-powder(s) coated with ruthenium and an additional amount Na and/or K ions. Also disclosed is the supported ruthenium-containing catalyst obtainable by the method and the use thereof in decomposing ammonia into nitrogen and oxygen.
Abstract:
To provide an exhaust gas catalyst using a fired aluminum phosphate body with more excellent performance, and a method for producing it. (1) An exhaust gas purification catalyst including at least one platinum-group metal selected from the group consisting of Pt, Rh and Pd having a mean particle diameter of between 0.50 nm and 2.0 nm, supported on a tridymite-type fired aluminum phosphate body. (2) A method for producing an exhaust gas purification catalyst, including the steps of: firing aluminum phosphate obtained from an aqueous solution prepared to a pH of 3.5 to 4.5, at a temperature of between 1000° C. and 1200° C. for 2 hours or longer, to obtain a fired aluminum phosphate body, and supporting at least one type of platinum-group metal selected from the group consisting of Pt, Rh and Pd on the fired aluminum phosphate body.