(Nanowerk News) Platinum is the most expensive component of the diesel oxidation catalysts (DOCs) that are required to meet the new, stringent emission regulations for the 14 million light-duty and 2 million heavy-duty diesel vehicles produced annually worldwide.
In recent years, producers of catalyst materials have introduced the use of palladium to partially replace the four-times more expensive platinum. Now, to further reduce the amount of platinum needed and the overall cost of the catalysts, one catalyst producer, Nanostellar, has pioneered the use of gold – which is currently about half the price of platinum – for diesel emission control.
Independent testing of Nanostellar’s NS Gold™, in comparison with today’s pure-platinum catalysts, has shown that the gold catalyst increases hydrocarbon oxidation activity by as much as 40 percent at equal precious-metal cost. When compared to emerging platinum-palladium catalysts, gold promises to increase hydrocarbon oxidation activity by 15-20 percent at equal precious-metal cost.
A tri-metal formulation of gold, platinum, and palladium, the new catalyst material allows the proportions of each metal to be adjusted to help catalyst systems engineers meet engine-specific performance targets and stabilize the overall cost of diesel catalysts, despite fluctuations in the price of precious metals.