[Supplementary information]

In almost all of the catalysts applied to gasoline-powered automobiles today, three kinds of precious metals — palladium, platinum and rhodium — are used to purify the exhaust gas.

Automotive catalysts are continuously exposed to high operating temperatures of 800°C or more. In addition, because the fuel injection rate is controlled by using an oxygen sensor, an oxidation-reduction fluctuation (an alternating state of oxygen surplus and oxygen shortage) is constantly taking place. These harsh conditions deteriorate the activity of a catalyst by growing precious metal particles into a huge lump.

When the metal particles grow huge, their surface area becomes smaller and their purifying performance drops. In anticipation of this degradation, a large amount of precious metal is generally used when producing automotive catalysts. In other words, an extra portion of precious metals is used to compensate for the reduction of the working surface areas of the metals in order to maintain their catalytic performance for a longer time.

The amount of precious metals used in catalyst production began to increase in the early 1990s when automotive emission standards were strengthened all over the world. This has resulted in higher prices for precious metals. Super Intelligent Catalyst technology makes it possible to reduce the amount of precious metals used in catalysts, which should, in turn, normalise the market prices of the metals.
Change in precious metal demand*
 
Change in precious metal prices*
The graph is based on data from Platinum Metals Review, published by Johnson Matthey PLC.