# Autocatalysts: Overview

How petrol, diesel and truck catalysts each clean exhaust

Source page: https://www.materialinsights.org/chemicals/autocatalysts/overview/

What this tab covers What the chemical is, how big its market is, what it is used for (with shares, volumes, why it wins and what could replace it), and its chain from raw material to end user. Ends with three things to remember.

An autocatalyst is a ceramic or metal honeycomb coated with a washcoat of alumina, ceria and zirconia that carries a few grams of platinum, palladium and rhodium. It turns carbon monoxide, unburnt fuel and nitrogen oxides into CO2, water and nitrogen. Diesel systems add particulate filters and urea-based SCR catalysts on copper zeolite or vanadia. In 2025 cars and trucks took about 378 t of PGMs, worth roughly $18 billion at 2025 prices. Three firms, Johnson Matthey, Umicore and BASF, dominate coating. Battery cars need none, so this market has peaked.
 Volume about 378 t of PGMs a year in vehicle catalysts (2025): palladium 256 t, platinum 95 t, rhodium 28 t Market value about $18 billion of contained metal (2025, indicative: tonnages x 2025 average prices of about $1,100/oz Pd, $1,200/oz Pt and $5,800/oz Rh); coating and fabrication value excluding metal perhaps $6-9 billion (indicative, basis: JM Clean Air £2.1 billion and Umicore Catalysis €1.7 billion plus BASF and Asian makers) Growth flat to declining: JM assumes a 3% fall in global light-duty vehicle production in 2026/27; Umicore says combustion-engine output has peaked Johnson Matthey PGM Market Report May 2026 (Pd, Rh demand); WPIC Platinum Quarterly Q2 2026 (Pt automotive 3,039 koz); USGS MCS 2026 (2025 average price changes); JM FY2025/26 results; Umicore FY2025 results

#### Key uses

| Use | Share | Annual volume | Why this commodity | Alternatives |
|---|---|---|---|---|
| **Light-duty petrol and hybrid three-way catalysts (TWC) and petrol particulate filters** | n/a | most of the 256 t palladium and 28 t rhodiumbasis | A three-way catalyst cleans all three regulated gases at once when the engine runs at the right air-fuel ratio. Palladium oxidises CO and hydrocarbons, rhodium reduces NOx, and ceria stores oxygen. Hybrids still need a full catalyst and cold starts are harder, so loadings per hybrid can be higher. Johnson Matthey PGM Market Report 2026; palladium and rhodium tiles | Platinum substituting for palladium (rising since 2023) Battery electric vehicles (no catalyst) |
| **Light-duty diesel (oxidation catalysts, filters, SCR, NOx traps)** | 47% | JM light-duty diesel sales £991 millionbasis | Diesel exhaust is lean, so a three-way catalyst does not work. A platinum-rich oxidation catalyst, a particulate filter and urea SCR or a NOx trap are combined. European diesel car share has fallen since 2015, but JM still earns most from diesel. JM FY2025/26 results presentation | Petrol and hybrid powertrains Battery electric cars |
| **Heavy-duty diesel (trucks, buses, off-road)** | 34% | JM heavy-duty sales £729 millionbasis | Truck systems are large: oxidation catalyst, filter, SCR and ammonia slip catalyst. Euro VI, China VI, US EPA 2027 and India BS-VI rules lifted content per truck. Platinum is the main PGM; SCR uses copper zeolite or vanadia, not PGM. JM FY2025/26 results presentation | Battery and fuel-cell trucks Natural gas trucks (three-way catalyst) |
| **Light-duty petrol at JM** | 19% | JM light-duty gasoline sales £403 millionbasis | JM is smaller in petrol, where Umicore says it has a strong position. The world petrol market is larger than the JM split suggests. JM FY2025/26 results presentation; Umicore FY2025 results | Battery electric vehicles |
| **Two- and three-wheelers** | n/a | not publishedbasis | Small catalysts on scooters and motorcycles became standard with BS-VI in India in 2020; small per unit but large in number in India. indicative | Electric two-wheelers |

 No public source splits the global autocatalyst market by segment. Shares shown are JM's Clean Air sales mix for FY2025/26 (LDD 47%, HDD 34%, LDG 19%; sum 100%) and describe JM, not the world. Metal volumes from JM (palladium, rhodium) and WPIC (platinum).

#### From raw material to user

1. **PGM mining and refining** South Africa supplies about 70% of mined platinum and about 81% of rhodium; Russia's Nornickel about 2.7 Moz of palladium (2025 guidance) (PGM tiles).
2. **Substrate** Cordierite honeycombs with 400-900 cells per square inch, or silicon carbide filters, from Corning and NGK (indicative).
3. **Washcoat and coating** Alumina, ceria-zirconia and zeolite slurries carrying PGM salts are coated on the substrate and calcined; a car typically carries 2-7 g of PGM (indicative).
4. **Canning and fitting** Exhaust system makers such as Forvia and Tenneco can the bricks and supply carmakers.
5. **Recycling** Spent converters are collected by scrap dealers and smelted; recycled rhodium met about 29% of 2025 demand (rhodium tile); recycled metal emits about 98-99% less than primary (IPA).

#### Made from (commodity table)
[Pt Platinum](https://www.materialinsights.org/commodities/platinum/)[Pd Palladium](https://www.materialinsights.org/commodities/palladium/)[Rh Rhodium](https://www.materialinsights.org/commodities/rhodium/)

#### Three things to know

- Vehicle catalysts used about 378 t of platinum, palladium and rhodium in 2025, worth roughly $18 billion (indicative).
- Johnson Matthey's Clean Air margin rose from 11.8% to 14.5% in FY2025/26 even as sales fell 7%, as the business is run for cash in a shrinking market.
- Primary platinum emits about 36,828 t CO2e per t, recycled about 477 t, so recycling decides the footprint (IPA, 2022 production year).

#### Read the tabs
[Production route](https://www.materialinsights.org/chemicals/autocatalysts/routes/)[Production](https://www.materialinsights.org/chemicals/autocatalysts/production/)[Feedstocks](https://www.materialinsights.org/chemicals/autocatalysts/feedstocks/)[Cycles](https://www.materialinsights.org/chemicals/autocatalysts/cycles/)[Trading](https://www.materialinsights.org/chemicals/autocatalysts/trading/)[Movement](https://www.materialinsights.org/chemicals/autocatalysts/movement/)[Regulation](https://www.materialinsights.org/chemicals/autocatalysts/regulation/)[Characteristics](https://www.materialinsights.org/chemicals/autocatalysts/characteristics/)[Emissions](https://www.materialinsights.org/chemicals/autocatalysts/emissions/)

## Other sections

- [Summary](https://www.materialinsights.org/chemicals/autocatalysts/index.md)
- [Correlation](https://www.materialinsights.org/chemicals/autocatalysts/correlation/index.md)
- [Production route](https://www.materialinsights.org/chemicals/autocatalysts/routes/index.md)
- [Production](https://www.materialinsights.org/chemicals/autocatalysts/production/index.md)
- [Feedstocks](https://www.materialinsights.org/chemicals/autocatalysts/feedstocks/index.md)
- [Cycles](https://www.materialinsights.org/chemicals/autocatalysts/cycles/index.md)
- [Trading](https://www.materialinsights.org/chemicals/autocatalysts/trading/index.md)
- [Movement](https://www.materialinsights.org/chemicals/autocatalysts/movement/index.md)
- [Regulation](https://www.materialinsights.org/chemicals/autocatalysts/regulation/index.md)
- [Characteristics](https://www.materialinsights.org/chemicals/autocatalysts/characteristics/index.md)
- [Emissions](https://www.materialinsights.org/chemicals/autocatalysts/emissions/index.md)
- [Relationships](https://www.materialinsights.org/chemicals/autocatalysts/links/index.md)