Methods for Identification of Materials Causing Corrosion on Metallic Substrates within ZPGM Catalyst Systems
First Claim
1. A method for detecting corrosion in a catalytic system, comprising:
- aging at least one catalyst system in communication with a substrate;
determining at least one color change on a surface of the at least one catalyst system, wherein the surface of the at least one catalyst system comprises a zero platinum group metal catalyst,analyzing at least one portion of the surface using a method selected from the group consisting of X-ray diffraction analysis (XRD), X-Ray Fluorescence (XRF), X-ray Photoelectron Spectroscopy (XPS), and combinations thereof;
wherein at least one corrosive material is identified in the at least one catalyst system according to said analyzing.
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Abstract
The present disclosure provides an identification process which may employ various identification techniques on Zero platinum group metal (ZPGM) catalyst systems, in order to identify responsible materials for the formation of corrosion material, such as hexavalent chromium compounds. Identification analysis, such as X-ray diffraction analysis (XRD), X-ray fluorescence (XRF), and X-ray Photoelectron Spectroscopy (XPS) may be performed on various thermally treated ZPGM catalyst systems, such as in bare substrate, substrate with one type of ZPGM in washcoat, a substrate with one type of ZPGM in overcoat and substrate combination of ZPGM metals in both washcoat and overcoat. Results of identification analysis may show that regardless of metal catalyst (for example Ag, Cu, Ce), hexavalent chromium (Cr6+) may be formed on aged catalysts systems, which may be due to the high concentration of chromium in substrate. Therefore, corrosion and production of hexavalent chromium may initiate from elements found in the substrate and not from elements within the ZPGM metal catalysts.
36 Citations
16 Claims
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1. A method for detecting corrosion in a catalytic system, comprising:
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aging at least one catalyst system in communication with a substrate; determining at least one color change on a surface of the at least one catalyst system, wherein the surface of the at least one catalyst system comprises a zero platinum group metal catalyst, analyzing at least one portion of the surface using a method selected from the group consisting of X-ray diffraction analysis (XRD), X-Ray Fluorescence (XRF), X-ray Photoelectron Spectroscopy (XPS), and combinations thereof; wherein at least one corrosive material is identified in the at least one catalyst system according to said analyzing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification