Catalyst for change
Palladium and gold replace platinum in diesel catalysts
- Published in Technology.
Core issue: Nanostellar uses a palladium outer structure with a gold core in its catalyst technology
Nanostellar has developed a diesel catalyst that replaces platinum with palladium and gold, reducing cost and lowering carbon monoxide and hydrocarbon emissions by 30%, according to the firm.
Current catalytic converters use precious metals, such as platinum, to catalyse the oxidation of harmful by-products in the engine exhaust, reducing noxious emissions. Development work to replace those expensive materials has long been considered by the industry, but the technical challenges concerning catalyst durability prevented alternatives being used.
Nanostellar's CEO, Pankaj Dhingra said: "The catalyst material is palladium, the role of the gold is to prevent the palladium oxidizing. Diesel catalysts cycle between ambient temperatures of -20°C to 800°C, so the material has to be thermally stable in this temperature regime. Gold isn't thermally stable and so can't be used by itself. We have used a core-shell structure made from palladium with gold at the core. The palladium keeps the gold confined during high temperature cycles."
The cost of platinum is heavily influenced by the automotive industry, which accounts for 60% of its use. The material can cost up to $1,800 per troy ounce - gold costs $700 - $1,500, while palladium costs $700.
The technology could be adapted for use in gasoline engines, as well as fuel cell vehicles, though more testing would be required.
The palladium and gold catalyst technology is currently in production with a European OEM.
