Platinum, palladium and rhodium: how the metals move converter prices
What each platinum-group metal does in a catalytic converter, why rhodium matters so much, and how daily market prices feed into the price per piece.
· Catalytic Price
- Platinum, palladium and rhodium are the three metals that give a converter its value.
- Petrol-car units lean on palladium and rhodium; diesel units on platinum.
- Rhodium is scarce and by far the most expensive per gram, so a little of it moves the price a lot.
- Catalytic Price records the three market prices daily and recalculates converter prices from them.
Three metals, three jobs
Platinum and palladium turn unburnt fuel and carbon monoxide into water and carbon dioxide; rhodium breaks down nitrogen oxides. A petrol three-way catalyst needs all three, with palladium doing most of the oxidation work in modern units. Diesel catalysts and filters rely more on platinum because it tolerates the cooler, oxygen-rich diesel exhaust.
Why rhodium matters so much
Rhodium is mined in tiny quantities, mostly as a by-product of platinum in South Africa, and nothing replaces it for nitrogen-oxide control. Its price per gram has for years been far above platinum and palladium, and it swings hard. A converter with a modest rhodium load can owe most of its value to that one metal, which is why two references with similar total metal can be worth very different amounts.
From market to price per piece
Metals trade in US dollars per troy ounce. We record the three prices every day – see metal prices – convert them to a price per gram, apply the assayed content and weight of each reference, deduct refining and handling, and publish the result as a price per piece. When the markets move, every converter price moves with them.
Reading the trend
Metal prices respond to car production (demand), mine output and strikes (supply), investment flows and exchange rates. A rising rhodium price lifts petrol-car converters first; a rising platinum price lifts diesel units. Members on Gold and Platinum plans can set price alerts on a metal or on a converter and be e-mailed when it crosses a level they choose.
What this means when you sell
Because the price is tied to the market of the day, a quote is valid for a limited time. If you hold stock, watch the metals: the same units can be worth noticeably more or less a few weeks apart.
Questions & answers
Which metal is worth the most?
Per gram, rhodium – usually by a wide margin – followed by palladium and platinum, although the order of platinum and palladium changes with the market.
Do petrol and diesel converters contain the same metals?
No. Petrol units lean on palladium and rhodium; diesel catalysts and filters contain mostly platinum.