Rhodium

Overview

Rhodium is a hard, silvery platinum-group metal (PGM) isolated by William Hyde Wollaston in 1803 from platinum ore. It resists corrosion and has low electrical resistance.¹

Its dominant use is in vehicle catalytic converters, where it reduces nitrogen oxides (NOx) in exhaust gases.¹ The automotive sector accounts for more than 80% of rhodium demand.²

Rhodium is critical because supply is very small and geographically concentrated, and because it cannot be mined on its own. The United States lists it as a critical mineral, classed as a by-product of nickel and platinum, and the EU covers it through its "Platinum Group Metals" entry on both the critical and the strategic raw materials lists.³⁴

Where it comes from

Rhodium is always a by-product of mining the PGM basket, which is dominated by platinum and palladium. Platinum and palladium make up 86% of PGM production by mass, and rhodium just 5%, although rhodium's share by value is generally much higher.² The UG2 chromitite reef of South Africa's Bushveld Complex carries a relatively high proportion of the minor PGMs, including rhodium.²

Primary supply has been about 22 t a year for the past three years. South Africa supplied 17.6 t of the 21.8 t estimated for 2025, followed by Russia, Zimbabwe and North America. There is essentially no primary supply from Europe.⁵²

• South Africa17.6 t · 81%
• Russia2.1 t · 10%
• Zimbabwe1.4 t · 6%
• North America0.5 t · 2%
• Other countries0.2 t · <1%

Johnson Matthey estimates of primary sales, allocated to the region where mining took place. Source: PGM Market Report May 2026

Refining is integrated with platinum and palladium refining, mostly in the producing countries. Separating rhodium from the other PGMs takes aggressive chloride-based or oxidative leaching followed by selective precipitation, solvent extraction or ion exchange, and making refined metal can take up to six months from mining.²

What it is used for

Global rhodium demand was 33.1 t in 2025, of which automotive catalysts took 28.0 t.⁵ Rhodium is needed in gasoline three-way catalysts to meet NOx limits over a vehicle's legislated lifetime. Total demand fell by about 4 t between 2019 and 2025, and high prices have encouraged automakers to thrift loadings.²

{{chart:end-uses}}

In chemicals, platinum-rhodium gauzes catalyze the oxidation of ammonia to make nitric acid, and homogeneous rhodium catalysts are used in hydroformylation ("oxo" synthesis of aldehydes) and in the Monsanto acetic acid process.² Platinum-rhodium alloys are also used in equipment for making glass fiber and display glass, and in thermocouples for measuring temperatures up to about 1,700 °C.² After four years of selling surplus metal, Chinese glassmakers returned to net rhodium buying in 2025, because rhodium remains essential for some specialist glass fibers and for display glass.⁵

The market was in deficit by 1.6 t in 2025, partly because rhodium exchange-traded funds saw active buying for the first time in nearly a decade. Johnson Matthey forecasts a small surplus of 0.5 t in 2026 as gasoline vehicle output falls and recycling rises.⁵

Grades and forms

Rhodium is marketed as refined metal, mostly sponge and powder, or as rhodium salts for catalyst and plating manufacturers. Alloys with platinum typically contain 3–10% rhodium for nitric acid gauzes and 5–20% for glassmaking equipment.²

Trade and policy

The United States imported about 14,000 kg of rhodium in 2025 and exported about 340 kg; unwrought and semi-manufactured PGMs enter duty free under normal trade relations.⁶ The EU's demand has averaged about 5 t a year since 2020. About 2 t of that is met by recycling autocatalysts, so the EU imports around 3 t a year, mainly from South Africa and the United States.²

Rhodium is one of five platinum-group metals named individually on the final 2025 US List of Critical Minerals, published in November 2025.³

Recycling and substitution

Spent autocatalysts are the only significant open-loop source of secondary rhodium. They yielded 9.7 t in 2025, nearly a third of total supply, and Johnson Matthey expects recoveries to reach a four-year high in 2026.⁵

Substitution is limited. After an earlier price spike in 2008, automakers cut rhodium use as far as possible until tighter emission rules required more of it again. In nitric acid production platinum-rhodium gauzes are still regarded as the best option. Glassmakers can vary the rhodium content of their alloys, and rhodium contact coatings can be replaced by gold in less demanding environments.² The main long-term risk to demand is the shift from combustion engines to battery electric vehicles.²

Sources

1. Rhodium: element information, properties and uses. Royal Society of Chemistry, accessed 2026-10-03. ↩ ↩²

2. PGM Fact Sheet: Rhodium (May 2026). International Platinum Group Metals Association, accessed 2026-10-03. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹²

3. Final 2025 List of Critical Minerals (90 FR, 7 November 2025). Federal Register, accessed 2026-10-03. ↩ ↩²

4. EU critical raw materials. European Commission Joint Research Centre (RMIS), accessed 2026-10-03. ↩

5. PGM Market Report May 2026. Johnson Matthey, accessed 2026-10-03. ↩ ↩² ↩³ ↩⁴ ↩⁵

6. Mineral Commodity Summaries 2026: Platinum-Group Metals. U.S. Geological Survey, accessed 2026-10-03. ↩