| 摘要 |
Three-way precious metal catalysts useful for conversion treatment of gas emissions, for example, pollutants in fuel combustion gases from automotive exhausts, or gas emissions from stationary fuel combustion sources; have chemical activity and thermal stability of the catalysts appreciably enhanced by utilizing a composite oxygen-ion conducting support material. Such composite supports are composed of zirconia stabilized by yttria, calcia, magnesia or scandia, and at least 40 wt.% inert support material such as alumina or titania, and have surface area of 20300 m2/gm. The catalysts can be supported by composites of yttria-stabilized-zirconia (YSZ) and alumina, and contain 0.01-3.0 wt.% total active metals, which may consist of major metals platinum or palladium and minor metals rhodium or ruthenium dispersed on the support. Such three-way catalysts are thermally stable, achieve a high level of pollutants (CO, NOX, H2 and hydrocarbons) removal, and have long catalyst life without requiring undesirably high loading of expensive precious active metals on the catalyst support material.
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