Umicore

About: Umicore is a company organization based out in Brussels, Belgium. It is known for research contribution in the topics: Catalysis & Exhaust gas. The organization has 1253 authors who have published 1516 publications receiving 23358 citations. The organization is also known as: Union Miniere.

Structure characterization of switched Ag – metal oxide contact materials

Abstract: The structural changes of several Ag - metal oxide composites during switching operations were investigated During the switching operation the contact material is melting and for a short moment (ca10 ms) the metal oxide particles will be floating in the liquid silver resulting in structural changes These processes affect the switching performance of contact materials and shall be described in this work The low hardness of the Ag-matrix requires careful sample preparation in order to avoid preparation artifacts and to reveal the actual structural features This was achieved by a final step, in which the polished surface was ion beam etched The samples will be analyzed by stereography, light microscopy, field emission scanning electron microscopy (FE-SEM) and electron back scatter diffraction (EBSD) It was found that the structure of a switched material can be divided into four category regions: Firstly, the bulk material, secondly, a very small heat affected zone, thirdly, a broad fusion zone and finally, the surface layer The fusion zone is characterized by large columnar grains, increasing porosity and oxide agglomeration towards the surface These structural phenomena can only be revealed by ion beam etching, as will be illustrated by examples of selected contact material

Modeling and Optimization of Multi-functional Ammonia Slip Catalysts for Diesel Exhaust Aftertreatment

Abstract: Ammonia slip catalysts (ASC) are used downstream of the NH3-selective catalytic NOx reduction (SCR) system, to minimize ammonia slip from transport sector SCR units. The ASC may consist of an SCR active layer for NOx control, a layer with oxidation functionality for ammonia conversion, or a combination thereof, either as individual layers or as a single mixed layer. Mathematical models of such systems involve flow and mass transfer in the monolithic channels as well as coupled reaction/diffusion processes in the catalytic layers. In this work, we develop a single-channel 1D-1D (pseudo 2D) steady-state tank-in-series mathematical model for monolithic ammonia slip catalysts with up to two layers. Kinetics of relevant reactions over the Cu-Beta zeolite and the Pt/TiO2 layer, including SCR, ammonia oxidation, and the formation of N2O, were derived based on an extensive flow reactor study. The model was validated based on experiments using four different small-scale ASC monoliths, showing good agreement between the model predictions and the experimental results. Comparison of ten ASC configurations for the oxidation of 200 ppm NH3 at 300 °C shows that configurations with a pure layer of NH3 oxidation catalyst generate undesirable high N2O and NOx levels. The best ASC configurations feature fast diffusion in the catalytic layers (a high effective diffusion coefficient), a thin top layer loading with some ammonia oxidation catalyst, and a mixed layer of ammonia oxidation catalyst and the SCR catalyst to limit the formation of N2O and NOx.

Application of methyl cellulose on washcoats and precious metal solution

Abstract: The present invention relates to a novel washcoat composition, a method for coating substrates with the washcoat composition and a method for controlling the shelf life of washcoat.

Process for the manufacture of membrane-electrode-assemblies using catalyst-coated membranes and adhesives

Abstract: The invention relates to the field of electrochemical cells and fuel cells, more specifically to polymer-electrolyte-membrane (PEM) fuel cells and describes a process for the manufacture of membrane-electrode-assemblies (MEAs) containing five layers. The five-layer MEA is assembled together by means of a lamination process involving an adhesive component. The anode gas diffusion layer, the catalyst-coated membrane and the cathode gas diffusion layer are combined together by a low temperature / low pressure lamination process. Handling of the MEAs and assembly of the products into PEMFC and DMFC stacks is simplified. Less damage and perforation of the catalyst-coated membrane occurs and thus the performance of the five-layer MEAs is significantly improved.

Method and device for cleaning exhaust gases of a combustion motor

Abstract: The method involves processing exhaust gas with an oxidative effective particle filter (1) and with an oxidation catalyst (2). A selective catalytic reduction (SCR) catalyst (3c) is provided for processing the exhaust gas after causing a sufficient quantity of a reducing agent over a dosing device (3b) from a reducing agent source (3a). The particle filter or its coating has metals such as platinum, palladium or rhodium. The particle filter or the oxidation catalyst is contained as nitrogen oxide storage components of oxides of the cerium, barium or strontium. An independent claim is included for an exhaust gas cleaning device with a selective catalytic reduction layer.