Platinum in Fuel Cells
Platinum loading in PEM fuel cells: why the cathode needs it, how it fell 100-fold since the 1960s, and why heavy-duty trucks use more platinum, not less.
Guide
Uses of Platinum Group Metals: 22 Industrial Applications
Where platinum, palladium, rhodium, iridium, ruthenium and osmium are used: 22 applications from autocatalysts and fuel cells to electronics, glass and medicine.
Platinum group metals, platinum, palladium, rhodium, iridium, ruthenium and osmium, are used in 22 industrial, energy, electronic and medical applications because of their catalytic activity, corrosion resistance and high melting points. Catalysis dominates the tonnage: automotive catalysts took 41.5% of platinum's 8,019 koz (249.4 t) of 2025 demand on Johnson Matthey's basis. The six platinum group metals (PGMs) each lead in a different use, so this directory sorts the 22 applications into six sectors, each with its own page.
Browse Applications
PGMs in Energy and Hydrogen
Iridium and Platinum in PEM Electrolyzers
How PEM water electrolyzers use iridium and platinum, current and DOE-target loadings in kg per gigawatt, and whether iridium supply limits green hydrogen scale-up.
PGMs in Electronics and Data Storage
PGMs in Electronics
How palladium, ruthenium, platinum and iridium are used in electronics: capacitors, connectors, hard disks, semiconductor interconnects and where to find palladium in scrap boards.
Platinum Sensors
How platinum works inside a Pt100 RTD and a lambda oxygen sensor, why IEC 60751 makes it the reference thermometry metal, and why oxygen-sensor demand is a live driver of platinum's "Other" industrial category.
PGMs in Jewelry, Dental and Medical Applications
Rhodium Plating
How rhodium plating works, its thickness in microns, how long it lasts, what re-plating costs and the US rule requiring dealers to disclose it.
Platinum in Medicine
How platinum, iridium and osmium are used in medicine: chemotherapy compound identities, Pt-Ir and Pt-Os implant alloys, dental alloys and PGM radiotherapy isotopes.
More in Applications
PGMs in Autocatalysts
How platinum, palladium and rhodium work inside a three-way catalyst, gram by gram and device by device, and why ruthenium, iridium and osmium are never used in one.
Platinum-Cured Silicone
How platinum catalyzes silicone curing through hydrosilylation, Speier's and Karstedt's catalysts, typical ppm loading, and why platinum-cured silicone is one of the few dissipative platinum uses.
What Are Platinum Group Metals Used For?#
Platinum group metals are used as catalysts, electrical contacts, corrosion-resistant coatings and high-temperature components, spanning automotive, energy, chemical, electronic and medical industries. The five functional roles are listed below with named examples.
- Catalysts, such as autocatalysts, nitric acid gauzes and fuel cell electrodes
- Electronic materials, such as capacitor electrodes, thick-film resistor pastes and hard disk recording layers
- Electrode coatings, such as chlor-alkali anodes and PEM electrolyzer anodes
- High-temperature hardware, such as glass-fiber bushings, crystal-growth crucibles and thermocouple wire
- Medical materials, such as platinum-iridium implant electrodes and platinum anticancer compounds
Why do six metals serve such different industries? Their melting points run from 1,555 °C (palladium) to 3,033 °C (osmium) on CRC handbook values, and platinum alloys keep "high resistance to corrosion, erosion, and chemical contamination" at very high temperatures (SFA Oxford for the IPA, May 2026). Metal in glass tooling, refinery catalysts and nitric acid gauzes is recovered and refined again, so Johnson Matthey reports industrial demand net of closed-loop recycling.
The Six Platinum Group Metals and Their Primary Uses#
Each platinum group metal has its own symbol, atomic number and CAS Registry Number: platinum (Pt, 78, CAS 7440-06-4), palladium (Pd, 46, CAS 7440-05-3), rhodium (Rh, 45, CAS 7440-16-6), iridium (Ir, 77, CAS 7439-88-5), ruthenium (Ru, 44, CAS 7440-18-8) and osmium (Os, 76, CAS 7440-04-2). The table adds each metal's largest 2025 end use (Johnson Matthey, May 2026).
| Metal | Symbol | Atomic number | CAS | Melting point | Largest end use, 2025 (JM basis) |
|---|---|---|---|---|---|
| Platinum | Pt | 78 | 7440-06-4 | 1,768 °C | Automotive catalysts, 41.5% of 8,019 koz demand |
| Palladium | Pd | 46 | 7440-05-3 | 1,555 °C | Automotive catalysts, 81.1% of 10,140 koz demand (derived) |
| Rhodium | Rh | 45 | 7440-16-6 | 1,964 °C | Automotive catalysts, 84.6% of 1,063 koz demand |
| Iridium | Ir | 77 | 7439-88-5 | 2,446 °C | Electrochemical anodes, 42.4% of 236 koz demand |
| Ruthenium | Ru | 44 | 7440-18-8 | 2,334 °C | Chemical catalysts, 44.8% of 1,265 koz demand |
| Osmium | Os | 76 | 7440-04-2 | 3,033 °C | Osmium tetroxide oxidant for fine chemicals (no published demand series) |
Iridium and ruthenium carry no automotive line at all in Johnson Matthey's tables. Platinum has the widest spread of uses, covered on platinum (Pt), element 78.
PGMs in Automotive and Aerospace#
Automotive and aerospace applications use PGMs as autocatalysts, spark plug tips and turbine coatings, the largest single demand category for platinum and palladium. Johnson Matthey counts 3,329 koz (103.5 t) of platinum, 8,227 koz (255.9 t) of palladium and 899 koz (28.0 t) of rhodium in 2025 automotive demand. Rhodium's 84.6% automotive share fell just below the 85-95% band Johnson Matthey usually quotes.
How much metal does one car carry? US DOE Program Record 16006 (February 2016) projected 6.21 g of PGMs per US gasoline light-duty vehicle for 2025: 5.52 g palladium, 0.35 g platinum and 0.35 g rhodium.
Spark plugs use heat resistance instead: iridium melts at 2,446 °C against platinum's 1,768 °C, which lets DENSO draw its iridium center electrode down to 0.4 mm. In aerospace, iridium-coated rhenium thruster chambers run up to 2,200 °C (NASA technical report).
| Application page | Metals used | Use |
|---|---|---|
| PGMs in autocatalysts | Pt, Pd, Rh | Three-way and diesel catalysts that convert CO, hydrocarbons and NOx |
| Platinum and iridium in spark plugs | Ir, Pt, Ru | Fine-wire electrodes that lower spark voltage |
| Platinum, iridium and rhodium in aerospace | Pt, Ir, Rh | Turbine blade bond coats, Ir/Re thruster chambers, Pt-Rh test-stand thermocouples |
PGMs in Energy and Hydrogen#
Energy applications use platinum in fuel cell catalysts and iridium in PEM electrolyzer anodes, the fastest-growing PGM demand category tied to the hydrogen economy. WPIC's hydrogen line rose 63% to 65 koz (2.0 t) of platinum in 2025, the fastest growth of any platinum industrial segment.
In fuel cells, a 3M and GM short stack reached 0.19 g PGM per kW in 2011, beating the US DOE 2010 target of 0.2 g/kW (DOE Record 11013). Heavy-duty trucks keep loadings near 0.3 mg/cm², against below 0.125 mg/cm² for cars (Cullen et al., US national laboratories, 2021), for durability.
PEM electrolyzers need iridium on the anode at about 400 kg/GW today (US DOE, 2022), with a published thrifting ladder to 80 kg/GW by 2030 (WPIC). The cathode uses about 260 kg of platinum per GW (0.26 g/kW, US DOE 2022). At 400 kg/GW, iridium supply becomes binding only at about 15-25 GW of PEM installations per year.
| Application page | Metals used | Use |
|---|---|---|
| Platinum in fuel cells | Pt (Ru in some anodes) | Cathode catalyst for the oxygen reduction reaction |
| Iridium and platinum in PEM electrolyzers | Ir, Pt | Iridium oxide anode, platinum cathode for water splitting |
PGMs in Chemical and Industrial Catalysis#
Chemical and industrial catalysis uses PGM gauzes and complexes to make nitric acid, refine petroleum, cure silicone and drive cross-coupling and metathesis reactions. Nitric acid plants oxidize ammonia over Pt-10% Rh gauze, an alloy first patented by DuPont in 1929, losing 50 to 400 mg of platinum per metric ton of acid depending on pressure (PMC10756977 study). Refinery reforming catalysts carry 0.24-0.26 wt% platinum in one granted US patent (5198404A). Platinum-cured silicone uses about 10 ppm platinum as Karstedt's catalyst, left unrecovered in the rubber.
Which metals lead chemistry by volume? Platinum and ruthenium do: Johnson Matthey puts 2025 chemical demand at 614 koz for platinum and 567 koz (17.6 t) for ruthenium, the ruthenium mostly for Chinese caprolactam and adipic acid. Ruthenium's 1,265 koz of total demand makes it the third-largest industrial PGM, behind platinum (2,627 koz) and palladium (1,448 koz). Palladium complexes drive cross-coupling, ruthenium Grubbs catalysts drive metathesis, and ruthenium oxide coatings, typically with iridium, form the chlor-alkali anodes.
| Application page | Metals used | Use |
|---|---|---|
| Platinum-rhodium gauzes in nitric acid production | Pt, Rh, Pd | Ammonia oxidation gauze and palladium catchment gauze |
| Platinum reforming catalysts in petroleum refining | Pt, Pd | Naphtha reforming, isomerization and hydrocracking |
| Platinum-cured silicone | Pt | Hydrosilylation cure of addition-cure silicone |
| PGM catalysts in chemistry | Pd, Ru, Rh, Ir, Os, Pt | Hydrogenation, cross-coupling, metathesis, carbonylation, dihydroxylation |
| Ruthenium and iridium anodes in chlor-alkali electrolysis | Ru, Ir | Dimensionally stable anodes on titanium for chlorine production |
PGMs in Electronics and Data Storage#
Electronics and data-storage applications use PGMs as electrical contacts, capacitor electrodes, magnetic-layer sputtering targets and OLED emitters. Johnson Matthey reports that total PGM use in electrical and electronics applications rose about 8% to 1.25 Moz (38.9 t) in 2025, lifted by hard disk demand from AI data centers.
Hard disks move two metals in opposite directions: HAMR media use iron-platinum, which raises platinum loadings per drive (WPIC), while the SFA (Oxford) factsheet for the IPA expects lower ruthenium content per unit. Palladium has been displaced in many mainstream MLCC capacitors by nickel and copper electrodes (SFA/IPA, May 2026). Iridium complexes such as Ir(ppy)3 serve as OLED emitters at about 5% doping, and Pt100 platinum sensors read 100 Ω at 0 °C under IEC 60751.
| Application page | Metals used | Use |
|---|---|---|
| PGMs in electronics | Pd, Ru, Pt, Rh | Contacts, connector plating, thick-film resistors, sputtering targets |
| Palladium in MLCC capacitors | Pd, Ag-Pd | Internal electrodes in high-reliability capacitors |
| Ruthenium and platinum in hard disk drives | Pt, Ru | CoCrPt and FePt recording layers, ruthenium interlayers |
| Iridium complexes in OLED displays | Ir, Pt | Phosphorescent emitter dopants |
| Platinum sensors | Pt | Pt100 resistance thermometers and oxygen sensor electrodes |
PGMs in Precision Instruments and Glass#
Precision instruments and glass manufacturing use PGMs' high melting points and corrosion resistance in crucibles, thermocouples, glass-fiber bushings and pen nib tips. Glass fiber is drawn through platinum-rhodium bushings, usually Pt-10% Rh or Pt-20% Rh, at 1,100-1,450 °C (MDPI Materials study), and Heraeus reports modern bushings with 4,000 tips or more. Platinum in glass manufacturing is capital stock, so WPIC even recorded net glass demand of minus 71 koz in Q1 2025.
Platinum thermocouples follow IEC 60584: Type S (Pt-10% Rh against pure platinum) and Type R (Pt-13% Rh) read to 1,600 °C, and Type B (Pt-30% Rh against Pt-6% Rh) reads to 1,800 °C. Heraeus rates iridium crucibles to about 2,300 °C for growing sapphire and spinel crystals. Osmium's hard, wear-resistant alloys tip fountain pen nibs (SFA Oxford osmium factsheet).
| Application page | Metals used | Use |
|---|---|---|
| Platinum in glass manufacturing | Pt, Rh | Glass-fiber bushings and LCD glass melting and delivery systems |
| Platinum thermocouples | Pt, Rh | Type S, R and B high-temperature measurement |
| Iridium and platinum crucibles for crystal growth | Ir, Pt | Czochralski growth of sapphire, YAG and oxide crystals |
| Iridium and osmium in pen nibs | Ir, Os | Wear-resistant nib tipping alloys |
PGMs in Jewelry, Dental and Medical Applications#
Jewelry, dental and medical applications use rhodium for plating white-metal jewelry, palladium and platinum for dental alloys, and platinum compounds for chemotherapy drugs, always described here at the metal and compound level, never as medical dosing advice. Rhodium plating has no separate demand line: Johnson Matthey books it inside rhodium "Other" demand of 26 koz (0.8 t) in 2025, an upper bound rather than a measurement.
Dental use is shrinking: Johnson Matthey's palladium dental and biomedical demand fell from 208 koz in 2021 to 163 koz in 2025 as all-ceramic crowns replaced metal alloys. Under the ADA classification, a high-noble dental alloy holds at least 60 wt% noble metal, including at least 40 wt% gold.
Medical use is growing. WPIC's platinum medical demand reached 320 koz (9.95 t) in 2025, mostly for implantable devices such as Pt-10% Ir pacemaker and neurostimulator electrodes. Platinum in medicine also covers anticancer compounds, a use from which no metal returns.
| Application page | Metals used | Use |
|---|---|---|
| Rhodium plating | Rh | Electroplated finish on white gold, platinum and silver: process, thickness and durability |
| Palladium and platinum in dental alloys | Pd, Pt | Porcelain-fused-to-metal crown and bridge alloys |
| Platinum in medicine | Pt, Ir, Os | Platinum anticancer compounds, implant electrodes, Pt-10% Os implant parts |
Where PGM Application Demand Comes From#
PGM application demand is tracked by sector: automotive, industrial, electronics, jewelry, investment and medical, with automotive the largest for platinum and palladium. The platinum group metals market has two sector series, Johnson Matthey and WPIC with Metals Focus, with different definitions that are never combined.
WPIC's Platinum Quarterly Q2 2026 (9 September 2026) gives these full-year 2026 forecasts by sector:
- Automotive: down 4% year on year
- Industrial: up 5%, including electronics and medical
- Jewelry: down 15%
- Investment: net disinvestment of 83 koz
Together they leave WPIC forecasting a 265 koz platinum surplus for 2026; the yearly koz values sit on PGM application demand.
Palladium's 8,227 koz automotive line exceeds all other palladium uses combined, as the autocatalyst demand for platinum and palladium series shows.
Johnson Matthey reports that China's share of global industrial PGM demand fell to a six-year low of 36% in 2025, as Chinese glassmakers halved platinum purchases.
Hydrogen's long-run demand path is tracked on platinum and the hydrogen economy.
PGM Applications FAQ#
What are 5 uses of platinum group metals?#
The five most common uses of platinum group metals are autocatalysts, jewelry, electronics, dental alloys and industrial catalysis. The five are listed below with their lead metals.
- Autocatalysts: palladium, platinum and rhodium
- Jewelry: platinum, with rhodium plating
- Electronics: ruthenium, palladium and platinum
- Dental alloys: palladium and platinum
- Industrial catalysis: platinum, rhodium, ruthenium and iridium
Which platinum group metal is used the most in industry?#
Platinum is used most by tonnage in automotive catalysts, which took 41.5% of platinum's 8,019,000-ounce total demand in 2025 on Johnson Matthey's basis. Platinum also leads Johnson Matthey's industrial line at 2,627 koz, ahead of palladium at 1,448 koz. Prices for all six metals are listed on platinum group metal prices today.
Do all six platinum group metals have industrial uses?#
Not equally: platinum and palladium have the largest industrial footprint, while osmium's world production of only 500-550 kg a year (SFA/IPA, May 2026) limits it to a handful of specialist uses. Osmium tetroxide in stereoselective synthesis is the main one. Fabricated wire, powder and foil of the other metals are listed under PGM products.