Autocatalyst demand is the platinum, palladium and rhodium consumed in vehicle emissions catalysts, the largest single demand sector for the three metals combined, at 11,911 koz (Pt+Pd+Rh) forecast for 2026 by Johnson Matthey's PGM Market Report (May 2026). Which metal does which job, and why can none of the three simply stand in for another? A gasoline three-way catalyst runs on palladium and rhodium, a diesel system runs mostly on platinum, and the sections below set out the gram-level loadings, the Euro 7, China 7 and US Tier 4 rules that drive them, and the platinum-for-palladium substitution that ties the two metal markets together.
What Is Autocatalyst Demand?#
Autocatalyst demand is PGM consumed by catalytic converters and diesel aftertreatment systems fitted to internal combustion engines, tracked separately by metal because each plays a different chemical role. Platinum, palladium and rhodium each convert a different tailpipe pollutant, which is why demand for the three metals can move in opposite directions even though a single catalytic converter often carries all three at once.
Global Automotive PGM Demand, 2021-2026#
Global automotive platinum demand is forecast at 3,226 koz for 2026, palladium at 7,829 koz and rhodium at 856 koz, each down from 2025 on Johnson Matthey's basis (May 2026). The combined total of 11,911 koz sits 9.4% below the sector's 2023 peak of 13,141 koz, and Johnson Matthey attributes the forecast 4 to 5% fall in 2026 to a matching decline in internal-combustion vehicle production.
| Metal | 2024 (koz) | 2025 (koz) | 2026f (koz) |
|---|---|---|---|
| Platinum | 3,389 | 3,329 | 3,226 |
| Palladium | 8,329 | 8,227 | 7,829 |
| Rhodium | 915 | 899 | 856 |
| Pt+Pd+Rh total | 12,633 | 12,455 | 11,911 |
Source: Johnson Matthey, PGM Market Report, May 2026.
Automotive Share of Each Metal's Total Demand#
Automotive uses 43.6% of total platinum demand, 84.7% of palladium demand and 85.2% of rhodium demand in Johnson Matthey's 2026 forecast. Rhodium's ten-year band runs 85 to 95%, a range Johnson Matthey quotes unaltered even though 2025's 84.6% share fell just below it, while WPIC frames platinum's exposure lower, at 36 to 44% of total demand over the last five years on its own Metals Focus basis.
| Metal | 2025 automotive share | 2026f automotive share |
|---|---|---|
| Platinum | 41.5% | 43.6% |
| Palladium | 81.1% | 84.7% |
| Rhodium | 84.6% | 85.2% |
Source: author-derived from Johnson Matthey, PGM Market Report, May 2026.
How a Catalytic Converter Uses Platinum, Palladium and Rhodium#
A catalytic converter uses different platinum group metals for different jobs: palladium and rhodium in the gasoline three-way catalyst, platinum in the diesel oxidation catalyst, and no PGM at all in the urea-SCR system.
| Device | PGMs used | Function |
|---|---|---|
| Three-way catalyst (TWC) | Palladium + rhodium (platinum where substituted) | Oxidizes CO and hydrocarbons and reduces NOx simultaneously, near stoichiometric air-fuel ratio |
| Close-coupled catalyst | Palladium-rich, plus rhodium | Reaches light-off fastest near the manifold; sees the highest operating temperature |
| Gasoline particulate filter (GPF) | Palladium, rhodium (TWC washcoat) or uncoated | Traps sub-23 nm and sub-10 nm particulates |
| Diesel oxidation catalyst (DOC) | Platinum-dominant, plus palladium | Oxidizes CO and hydrocarbons; converts NO to NO2 to feed the DPF and SCR downstream |
| Diesel particulate filter (DPF) | Platinum + palladium | Traps soot; the PGM coating assists passive regeneration |
| Selective catalytic reduction (SCR) | None | Urea injection reduces NOx to nitrogen, using a vanadium or zeolite catalyst |
| Ammonia slip catalyst (ASC) | Platinum, low loading | Oxidizes unreacted ammonia that slips past the SCR |
| Lean NOx trap (LNT) | Platinum + rhodium | Stores NOx while running lean, reduces it during brief rich excursions |
Source: US DOE EERE Program Record 16006, 17 February 2016.
Three-Way Catalyst, DOC, DPF, SCR, ASC and LNT: Which Metal Does What#
The eight aftertreatment devices in production use are the three-way catalyst, close-coupled catalyst, gasoline particulate filter, diesel oxidation catalyst, diesel particulate filter, selective catalytic reduction unit, ammonia slip catalyst and lean NOx trap, each named for the pollutant it targets.
- Three-way catalyst (TWC): the core gasoline device, running palladium and rhodium together.
- Close-coupled catalyst: mounted at the manifold, palladium-rich for thermal durability.
- Gasoline particulate filter (GPF): traps particulates, often carrying the TWC washcoat.
- Diesel oxidation catalyst (DOC): platinum-dominant, oxidizes CO and hydrocarbons.
- Diesel particulate filter (DPF): platinum and palladium coated, traps soot.
- Selective catalytic reduction (SCR): carries no platinum group metal at all, using injected urea.
- Ammonia slip catalyst (ASC): a low-loading platinum guard catalyst downstream of the SCR.
- Lean NOx trap (LNT): platinum and rhodium, fitted to smaller diesel engines instead of SCR.
Only platinum, palladium and rhodium appear in this list. Ruthenium and iridium carry no automotive line in Johnson Matthey's demand tables, and osmium is not tracked by the major analysts at all. The chemistry behind each device's metal choice, from three-way stoichiometry to lean-NOx-trap storage cycles, is set out in full on how catalytic converters use PGMs; this page tracks the demand volumes and regulation those devices create, not their internal engineering.
PGM Loadings per Vehicle: How Many Grams of Platinum, Palladium and Rhodium#
A US gasoline light-duty vehicle carries a modeled 6.21 grams of total PGM and a diesel light-duty vehicle 8.51 grams, per the US DOE's 2016 medium-case projection to 2025. That per-vehicle figure is what the industry calls the vehicle's PGM loading, and it is the hardest number in this sector to source because catalyst formulations are commercially confidential.
Gasoline vs Diesel Loadings (US DOE)#
US DOE's 2016 projection splits the gasoline vehicle's 6.21 g as 0.35 g platinum, 5.52 g palladium and 0.35 g rhodium, and the diesel vehicle's 8.51 g as 6.32 g platinum, 1.86 g palladium and 0.32 g rhodium.
| Vehicle type | Platinum (g) | Palladium (g) | Rhodium (g) | Total PGM (g) |
|---|---|---|---|---|
| Gasoline LDV | 0.35 | 5.52 | 0.35 | 6.21 |
| Diesel LDV | 6.32 | 1.86 | 0.32 | 8.51 |
Source: US DOE EERE Program Record 16006, 17 February 2016, medium-case 2025 projection.
The split flips by fuel type: gasoline vehicles carry 89% of their PGM as palladium, while diesel vehicles carry 74% as platinum, because platinum is the more efficient oxidation metal in oxygen-rich diesel exhaust.
Why SCR vs LNT Changes Rhodium Content by 2.2x#
Choosing SCR instead of a lean NOx trap on a 3.0-liter diesel catalyst removes rhodium from the system entirely, cutting total PGM content from 17.3 g to 7.93 g, a 2.2-fold swing (US DOE 2016, adjusted from Sanchez et al. 2012).
The LNT route carries 13.3 g platinum, 2.14 g palladium and 1.88 g rhodium; the SCR route carries 5.79 g platinum, 2.14 g palladium and 0.00 g rhodium, because a urea-based SCR system needs no reduction catalyst at all.
Why Chinese Domestic Loadings Are the Lowest in the World#
Chinese domestic vehicles carry the lowest PGM loadings in the world because China 6b's real-driving-emissions test uses a lenient conformity factor and excludes the cold-start phase, the most PGM-intensive part of the drive cycle (Johnson Matthey, May 2026). China 6b's RDE conformity factor of 2.1 lets a car exceed the laboratory NOx limit by more than double under real-world testing, and Chinese carmakers additionally run milder catalyst ageing cycles during durability testing, according to Johnson Matthey. The result is a form of engineered thrifting: Chinese domestic loadings keep falling even as the country's vehicle output rises, the opposite of the loading increases that tighter real-driving-emissions rules have produced in Europe and North America.
Emissions Legislation Driving PGM Loadings (Euro 7, China 7, US Tier 4)#
Three regional emissions standards set most of the world's PGM loading: Euro 7 in Europe, China 7 in China and Tier 4 in the United States, each tightening durability or particulate rules rather than the core pollutant limits.
Europe: Euro 6 to Euro 7#
Euro 7 keeps Euro 6's tailpipe limits for cars but extends the compliance lifetime to 8 years/160,000 km and applies from 29 November 2026 for new type approvals (Regulation (EU) 2024/1257).
| Pollutant | Euro 6 gasoline | Euro 6 diesel | Euro 7 gasoline | Euro 7 diesel |
|---|---|---|---|---|
| CO (g/km) | 1.0 | 0.50 | 1.0 | 0.50 |
| NOx (g/km) | 0.06 | 0.08 | 0.06 | 0.08 |
| PM (g/km) | 0.005 | 0.005 | 0.0045 | 0.0045 |
Source: DieselNet, Europe: Cars and Light Trucks; Regulation (EU) 2024/1257, Annex I (M1 and N1 Class I).
Because the tailpipe limits barely move, Johnson Matthey expects only a limited PGM uplift from Euro 7 on light vehicles, with scope to thrift some of it back out once early catalyst designs bed in.
China: China 6a, 6b and the China 7 Outlook#
China 6b, in force since 1 July 2023, cut the NOx limit to 35 mg/km from China 6a's 60 mg/km, while China 7 remains a draft delayed to end-2026, with Johnson Matthey assuming 2029 implementation and WPIC assuming 2028.
| Pollutant | China 6a (mg/km) | China 6b (mg/km) | Change |
|---|---|---|---|
| CO | 700 | 500 | -29% |
| NOx | 60 | 35 | -42% |
| PM | 4.5 | 3.0 | -33% |
Source: TransportPolicy.net, China: Light-duty: Emissions.
North America: Tier 3, Tier 4 and the EPA Low-NOx Rule#
US Tier 4, finalized in March 2024, cuts the light-duty NMOG+NOx fleet average to 15 mg/mi by 2033, half of Tier 3's 30 mg/mi endpoint, though the EPA proposed on 18 May 2026 delaying its start from model year 2027 to 2029.
| Model year | LDV NMOG+NOx (mg/mi) | MDV NMOG+NOx (mg/mi) |
|---|---|---|
| 2027 | 25 | 175 |
| 2030 | 19 | 120 |
| 2033+ | 15 | 75 |
Source: DieselNet, US: Cars and Light-Duty Trucks, Tier 4.
Regulation Timing by Region#
Each major market is moving from its current standard to a named successor on a different, sometimes contested, timeline.
| Region | Current standard | Next standard | Date |
|---|---|---|---|
| Europe | Euro 6e | Euro 7 | 29 Nov 2026 (new types); 29 Nov 2027 (all) |
| China | China 6b | China 7 | Draft expected end-2026; JM estimates 2029, WPIC assumes 2028f |
| North America | Federal Tier 3 | Federal Tier 4 | MY2027 per the 2024 rule; EPA proposed MY2029 on 18 May 2026 |
Source: Johnson Matthey, PGM Market Report, May 2026, Figure 25.
Platinum-for-Palladium Substitution#
Platinum-for-palladium substitution is the near 1:1 gram-for-gram exchange of platinum for palladium in gasoline three-way catalysts, made economic when platinum trades at a sustained discount to palladium. The exchange works because platinum-palladium substitution rests on thermal durability, not chemistry: palladium tolerates the high temperatures of a close-coupled catalyst better than platinum, so substitution is easiest in cooler-running underfloor positions.
How Far Substitution Went, and Why It Is Slow to Reverse#
Substitution added an estimated 720 koz of incremental platinum demand in 2024 (Metals Focus, via WPIC), but locks in for around seven years once designed into a vehicle platform, so it cannot respond to a single quarter's price move. WPIC describes substitution as occurring almost exclusively on new vehicle models, representing about 15% of the market in any given year, and it expects reverse substitution, palladium going back into platinum's place, to reach 250 koz by 2029.
Rhodium: The Irreplaceable NOx Metal#
Rhodium has no commercial substitute in the three-way catalyst's NOx-reduction step, which is why it survives at only 5-7% of TWC PGM mass despite trading at several times the platinum price. That structural role concentrates risk in the rhodium market: automotive demand took 85.2% of Johnson Matthey's 1,005 koz 2026 forecast for total rhodium demand, and South Africa supplies 82% of the primary metal that feeds it.
Powertrain Mix: Why Hybrids Still Need Autocatalysts#
Hybrid and plug-in hybrid vehicles still need a catalytic converter because their engines still burn fuel, and Heraeus's Precious Appraisal (Edition 28, 3 August 2026) states that "hybrids still require autocatalysts, while intermittent engine operation and lower exhaust temperatures can require higher PGM loadings than petrol and diesel powertrains." Hybridisation is therefore PGM-positive per vehicle, and only PGM-negative relative to a scenario where a pure battery-electric vehicle would otherwise have been built instead; the demand consequence of that substitution is covered on electric vehicles and PGM demand.
China illustrates the scale of that shift: the country produced more than 10 million light-duty battery-electric vehicles in 2025, up a third on 2024 and nearly 70% of the global total, according to Johnson Matthey's May 2026 report.
Autocatalyst Demand and PGM Prices#
Autocatalyst demand is one of the four demand pillars tracked on today's live platinum and palladium prices. Automotive, jewelry, industrial and investment demand together set the balance behind platinum price today and palladium price today, and the automotive pillar is the largest of the four for all three metals covered on this page.
Related PGM Market Pages#
Related PGM market pages cover substitution, rhodium, the hydrogen economy and scrap converter value in more depth.
- Platinum-for-palladium substitution, its scale and its slow reversal.
- The rhodium market's supply concentration and price volatility.
- Platinum and the hydrogen economy: fuel cells and electrolyzers.
- How much platinum, palladium and rhodium a scrap catalytic converter contains.
This page does not forecast where the platinum price is headed; DailyPlatinum's platinum price forecast page compiles the named WPIC and Johnson Matthey outlooks instead.
Autocatalyst Demand FAQ#
Is platinum in high demand from automakers?#
Automotive is platinum's second-largest demand sector by Johnson Matthey's count, using 43.6% of total 2026f demand, though Johnson Matthey forecasts automotive PGM demand overall falling 4 to 5% in 2026 with ICE vehicle production.
Which platinum group metal is used most in catalytic converters?#
By tonnage, palladium is the platinum group metal used most in catalytic converters: 243.5 t forecast for 2026, more than platinum (100.3 t) and rhodium (26.6 t) combined (Johnson Matthey, May 2026).
Why can't rhodium be replaced in a catalytic converter?#
Rhodium cannot be replaced because platinum and palladium are effective oxidation catalysts but inadequate NOx-reduction catalysts under three-way-catalyst conditions (US DOE 16006).
Do hybrid and plug-in hybrid cars need catalytic converters?#
Hybrid and plug-in hybrid vehicles need a catalytic converter because their internal combustion engine still produces regulated tailpipe emissions whenever it runs.