摘要:
Provided are exhaust systems and components suitable for use in conjunction with gasoline engines to treat gaseous emissions such as hydrocarbons, nitrogen oxides, and carbon monoxides. Layered three-way conversion (TWC) catalysts comprise an outer layer whose rhodium is supported by an oxygen storage component, such as a ceria-zirconia composite, and the outer layer is substantially free from alumina as a support. The rhodium-containing layer can be free of all other precious metals, such as platinum and palladium. A lower palladium layer is provided where the palladium is supported by a refractory metal oxide. The lower palladium layer can be free of rhodium and platinum and can contain an oxygen storage component that is the same or different from that in the rhodium-containing layer. Methods of making and using these catalysts are also provided.
摘要:
The invention relates to a catalyst for fuel cells which comprises a support, at least one catalytically active metal from the platinum group or an alloy comprising at least one metal of the platinum group and also at least one oxide of at least one metal selected from among Ti, Sn, Si, W, Mo, Zn, Ta, Nb, V, Cr and Zr. The invention further relates to a process for producing such a catalyst and its use.
摘要:
The invention relates to a process for producing a catalyst comprising a metal of the platinum group and a second metal selected from among the metals of the platinum group or the transition metals, in which a catalyst comprising the metal of the platinum group is mixed with a complex comprising the second metal to give a dry powder in a first step and the powder is subsequently heat treated to form a compound between the metal of the platinum group and the second metal. The invention further relates to the use of the catalyst produced according to the invention.
摘要:
A layered three-way conversion catalyst having the capability of simultaneously catalyzing the oxidation of hydrocarbons and carbon monoxide and the reduction of nitrogen oxides is disclosed. Engine exhaust treatment system and methods of using the same are also provided. The catalytic material can be provided in layers such that a larger amount of oxygen storage component is provided in a downstream zone as compared to an upstream zone. For example, the upstream zone can be configured to have one, two, or three layers, and the downstream zone can be independently configured to have one, two, or three layers. In one or more embodiments, the catalyst supported on a carrier has three layers, where at least two of the layers are zoned to have an oxygen storage component being present in an upstream zone in an amount that is less than the oxygen storage component present in the downstream zone.
摘要:
The invention relates to a catalyst for fuel cells which comprises a support, at least one catalytically active metal from the platinum group or an alloy comprising at least one metal of the platinum group and also at least one oxide of at least one metal selected from among Ti, Sn, Si, W, Mo, Zn, Ta, Nb, V, Cr and Zr. The invention further relates to a process for producing such a catalyst and its use.
摘要:
Process for preparing hydrocyanic acid by catalytic dehydration of gaseous formamide, wherein the dehydration of formamide is coupled with an exothermic reaction by the reactor used in the dehydration comprising two separate fluid paths which are separated by a common reactor wall, with one fluid path being provided for the dehydration of formamide and the second fluid path being provided for the exothermic reaction.
摘要:
Described is a process for the production of mixed oxide particles. The process comprises providing a mixture comprising a solvent, one or more precursor compounds of ceria, one or more precursor compounds of zirconia, and one or more precursor compounds of one or more rare earth oxides other than ceria and/or one or more precursor compounds of yttria; forming an aerosol of the mixture; and pyrolyzing the aerosol of to obtain mixed oxide particles. The content of the rare earth oxides other than ceria and/or of yttria in the mixed oxide particles is comprised in the range of from 0.1 to 4.9 wt.-% based on the total weight of the rare earth oxides, yttria, and zirconia contained in the mixed oxide particles. Also describes are mixed oxide particles obtained from flame spray pyrolysis and to their use as an oxygen storage component, a catalyst, and/or as a catalyst support.
摘要:
The present invention relates to a membrane-electrode assembly comprising at least one membrane, at least two electrode layers and at least one barrier layer, wherein the at least one barrier layer comprises at least one catalytically active species and/or at least one adsorbent material and the barrier layer is electronically nonconductive when a catalytically active species is present, the use of such a barrier layer in a membrane-electrode assembly and in a fuel cell, and also a gas-diffusion electrode and a fuel cell comprising such a membrane-electrode assembly.
摘要:
Provided are exhaust systems and components suitable for use in conjunction with gasoline engines to treat gaseous emissions such as hydrocarbons, nitrogen oxides, and carbon monoxides. Layered three-way conversion (TWC) catalysts comprise an outer layer whose rhodium is supported by an oxygen storage component, such as a ceria-zirconia composite, and the outer layer is substantially free from alumina as a support. The rhodium-containing layer can be free of all other precious metals, such as platinum and palladium. A lower palladium layer is provided where the palladium is supported by a refractory metal oxide. The lower palladium layer can be free of rhodium and platinum and can contain an oxygen storage component that is the same or different from that in the rhodium-containing layer. Methods of making and using these catalysts are also provided.
摘要:
The invention relates to a process for the continuous production of a catalyst comprising an alloy of a metal of the platinum group and at least a second metal as alloying metal selected from among the metals of the platinum group and the transition metals, in which a catalyst comprising the metal of the platinum group is mixed with at least one complex each comprising the alloying metal to give an alloy precursor and the alloy precursor is heated in a continuously operated furnace to produce the alloy.