Platinum fuel-borne catalysts

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Category: Emissions Control

Subject: Platinum fuel-borne catalysts

Question

Do platinum fuel-borne catalysts work by heterogeneous or homogeneous catalysis?

Answer

The platinum starts off in an organometallic form which is soluble in fuel, but in the engine it is converted into metallic and ionic particles. The fuel additive is always used on a vehicle fitted with a soot filter, so the particles end up there (and very few are emitted).

The platinum acts as a heterogeneous catalyst, either as particles in the exhaust stream or (more likely) as immobilised particles in the filter, or deposited on surfaces within the cylinders.

Answer posted 31 July 2006

Submitted by: Ms Sara Coles

Affiliation: Platinum Metals Review

Answered by: Dr Stan Golunski

Affiliation: Technology Manager of Gas Phase Catalysis, Johnson Matthey Technology Centre