| 摘要 |
<p>The present disclosure provides identification techniques on platinum group metal (PGM) and zero platinum group metal (ZPGM) catalyst systems, in order to identify responsible materials for the formation of corrosion products, such as hexavalent chromium compounds. Identification analyses, such as X-ray diffraction analysis (XRD) and X-ray fluorescence (XRF) may be performed on various thermally treated PGM and ZPGM catalyst systems. Results of identification analyses may show that for both PGM and ZPGM catalysts, hexavalent chromium (Cr6+) may be formed during thermal aging at range of 600C to 900C. This may be due to the high concentration of chromium in substrate alloys. Therefore, occurrence of corrosion and production of hexavalent chromium may initiate from elements found in the substrate and not from elements within the PGM and ZPGM catalysts. Additionally, tests regarding washcoat adhesion and back pressure performed on disclosed PGM and ZPGM catalyst systems show that presence of corrosion products does not affect the quality of ZPGM and PGM catalyst systems.</p> |
