Process for elimination of hexavalent chromium compounds on metallic substrates within zero-PGM catalyst systems
AssigneeClean Diesel Technologies, Inc.
InventorZahra Nazarpoor
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Abstract
Systems and Methods for manufacturing ZPGM catalysts systems that may allow the prevention of formation or the conversion of corrosion causing compounds, such as hexavalent chromium compounds, within ZPGM catalyst systems are disclosed. ZPGM catalysts systems, may include metallic substrate, which may include alloys of iron and chromium, a washcoat and an overcoat. Disclosed manufacturing processes may include a thermal decomposition of hexavalent chromium compounds which may allow the decomposition of such compounds into trivalent chromium compounds, and may also produce metallic catalyst, such as silver.
Claims17
A method for reducing corrosion of a catalytic system, comprising:
- providing a catalyst system, comprising:
- a substrate;
- a washcoat suitable for deposition on the substrate, comprising at least one first oxide solid selected from the group consisting of a first carrier material oxide, at least one first catalyst, and a mixture thereof;
- and
- an overcoat suitable for deposition on the substrate, comprising at least one second oxide solid selected from the group consisting of a second carrier material oxide, at least one second catalyst, and a mixture thereof;
- wherein at least one of the washcoat and the overcoat is aged;
- and
- providing an exhaust stream at a temperature of greater than 400° C. having one selected from the group consisting of hydrogen, carbon monoxide, ammonia and combinations thereof;
- wherein at least one hexavalent chromium compound is reduced.
Dependencies are inferred from the claim text.