Three-way catalysts (TWC)

Gasoline fuelled vehicles utilise a three-way catalyst that can reduce carbon monoxide (CO), hydrocarbon (HC) and oxides of nitrogen (NOx) emissions by over 99%  –  if the air-to-fuel ratio (AFR) is accurately controlled. Optimised conversion is achieved with an AFR of 14.7:1. 

[CO] + O2 → CO2

[HC] + O2 → CO2 + H2O

[NOx] + H2 → N2 + H2O


Composition: Typically, precious metals (Pd, Pt or Rh) with alumina and rare earth oxide, coated on a flow-through monolith.

Our three-way catalysts…

  • Are the product of our long-established expertise developing a portfolio of catalyst solutions for various engines and vehicle platforms

  • Are tailored for a variety of needs in terms of back pressure, cost, oxygen storage levels and precious metal

  • Are designed using materials to help our customers meet demanding global durability targets.

Get in touch

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John Goodwin