|Mazda’s new catalyst structure. Click to enlarge.
Mazda Motor Corporation has developed a new catalyst structure for automotive exhaust systems that substantially reduces the amount of precious metals such as platinum and palladium that are required.
The new development enables Mazda to reduce the amount of platinum and palladium used in automotive three-way catalysts by 70 to 90%. It does not result in any changes in the performance of purifying gas emissions and maintains the high durability of conventional catalysts.
In conventional catalysts, the precious metals that promote the chemical reactions that treat exhaust gases are adhered to a base material. Exposure to exhaust gas heat causes the precious metal to agglomerate into larger particles. This reduces the catalyst’s effective surface area and catalytic activity, which requires the use of a significant amount of precious metals to counter and maintain an efficient purification performance.
Mazda developed a new catalyst using its proprietary catalyst material structure and precious metal particles that are less than 5 nanometers (nm) in diameter. This is the first time that a catalyst material has been achieved that features single, nanosized precious metal particles embedded in fixed positions.
As a result, there is no agglomeration of the precious metal particles, and the amount of high-priced precious metals used in three-way catalytic converters can be reduced by 70 to 90%. Moreover, the new catalyst material will maintain the same level of purifying efficiency, with minimal deterioration over time even under the harshest operating conditions.