What rare metals are contained in a three-way catalytic converter?
2 Answers
A three-way catalytic converter can extract precious metals such as platinum (Pt), rhodium (Rh), and palladium (Pd), while the substances used in the catalyst coating are rhodium nitrate, palladium nitrate, and platinum nitrate. Composition of a three-way catalytic converter: A three-way catalytic converter generally consists of four parts: the shell, damping layer, substrate, and catalyst coating. Shell: Made of stainless steel to prevent oxide scale from falling off, which could clog the substrate. Damping layer: Composed of a gasket or wire mesh pad, it serves to seal, insulate, and secure the substrate. To protect the substrate from damage caused by vibration, thermal deformation, and other factors, the gasket is made of expanded mica and aluminum silicate fibers, bonded together with an adhesive. Substrate: Made of honeycomb-shaped ceramic material, though many also use metal (including stainless steel) materials. Catalyst: Composed of precious metals such as platinum, rhodium, and palladium, sprayed onto the substrate to form the purifying agent. Lifespan of a three-way catalytic converter: The lifespan of a three-way catalytic converter is generally between 80,000 to 100,000 kilometers. The actual lifespan depends on the vehicle's usage conditions, and it is also influenced by the quality of fuel used and the driving environment.
I've been repairing cars for decades and frequently dismantle catalytic converters, which primarily contain three precious metals: platinum, palladium, and rhodium. Platinum is responsible for oxidizing carbon monoxide emissions, palladium handles hydrocarbon residues, and rhodium targets nitrogen oxides for reduction, cleaning up the exhaust. These metals are extremely valuable due to their scarcity on Earth and high extraction costs—rhodium, for instance, has very limited global reserves, driving up recycling prices. The interior of the converter features a honeycomb structure where the metal coatings react at high temperatures with remarkable efficiency. During vehicle maintenance, engine issues like carbon buildup or oil leaks can accelerate wear on these metals. I recommend car owners regularly inspect their exhaust systems to prevent catalytic converter failure and resource wastage. Recycling old converters can fetch a good price since these metals can be reused in new components, making it both practical and eco-friendly.
