Cerium (Ce) accounts for around 50% of the rare earth content in bastnäsite ore by weight, yet it trades at just $1–3/kg — making it the most abundant and least valuable rare earth by price. Every major REE producer, from MP Materials (NYSE: MP) to Lynas Rare Earths (ASX: LYC), generates cerium as an unavoidable byproduct of neodymium-praseodymium (NdPr) separation. The result is a chronic oversupply problem: cerium is stockpiled because demand does not match production. Understanding where cerium uses are growing — and where new applications could absorb that surplus — matters for the economics of the entire REE supply chain.
How We Ranked the Top 10 Cerium Uses
Entries are ranked by estimated global commercial volume consumed annually. Established applications with large-scale industrial consumption rank above emerging uses regardless of growth rate. Data draws on USGS Mineral Resources reporting and publicly available market analysis. Where volume data is estimated rather than confirmed, this is noted.
Top 10 Cerium Uses in Industry
1. Fluid Catalytic Cracking (FCC) Catalysts — Petroleum Refining
Fluid catalytic cracking is the largest single cerium use by volume globally. Refineries use cerium-containing zeolite catalysts to break heavy crude oil fractions into gasoline and diesel. Cerium acts as a rare earth promoter within the FCC catalyst matrix, improving selectivity and resistance to metal poisoning from vanadium and nickel in crude feedstocks. Demand is tied directly to global refinery throughput; with petroleum refining remaining a high-volume industry through the 2020s and into the 2030s, this application continues to consume the largest share of cerium oxide output. The application is not growing rapidly, but its sheer scale keeps it at the top of any cerium uses ranking.
2. Glass Polishing Compounds (CeO₂)
Cerium oxide polishing powder is the preferred abrasive for precision glass finishing across optics, flat panel displays, semiconductor wafers, smartphone screens, and automotive glass. Its chemical-mechanical action removes surface micro-roughness without scratching, outperforming traditional iron oxide (rouge) polishing compounds. Demand from semiconductor fabrication and LCD panel manufacturing has driven cerium oxide glass polishing to be the fastest-growing established application by revenue. According to the China Rare Earth Industry Association, cerium oxide used in glass polishing rose by 34% in 2023 alone, driven by high-resolution display and optical lens production growth. This is among the clearest cases where new technology demand is expanding a traditional cerium use.
3. Automotive Catalytic Converters
Cerium oxide serves as an oxygen storage component in three-way catalytic converters for gasoline and hybrid vehicles, cycling between Ce³⁺ and Ce⁴⁺ oxidation states to buffer oxygen levels during combustion. This buffering function allows the catalytic converter to reduce nitrogen oxides (NOx), carbon monoxide (CO), and hydrocarbons simultaneously across varying engine conditions. Stricter emission standards — Euro 6 in Europe, BS-VI in India, China 6b — are sustaining cerium demand in catalytic converters even as battery electric vehicle (BEV) market share rises. Hybrid vehicles, which retain internal combustion engines and therefore require catalytic converters, represent a sustained demand source through at least the 2030s.
4. UV-Absorbing and Decolourising Glass Additives
Cerium is added directly to glass melts as a UV-absorbing additive, blocking ultraviolet radiation in optical lenses, windshields, aerospace glazing, and specialist protective eyewear. It also acts as a decolouriser, counteracting the green tint introduced by iron impurities in glass batch materials — a function critical for high-clarity optical and flat glass production. Unlike polishing (a surface process), this is a bulk glass application consuming cerium at the melting stage. Architectural glass, aircraft windows, and medical imaging equipment all rely on cerium-doped glass formulations.
5. Metallurgical Alloying — Misch Metal
Misch metal is a cerium-dominant rare earth alloy (typically 50% Ce, 25% La, 15% Nd, 10% Pr) used in steel and cast iron production as a desulfurising and deoxidising additive, and in magnesium alloys to improve high-temperature strength. Its most familiar consumer application is the pyrophoric alloy used in lighter flints — the spark produced when misch metal is struck against a steel file ignites butane gas. In metallurgical applications at scale, cerium improves the mechanical properties and corrosion resistance of steel by modifying sulphide inclusion morphology. REE processing companies that separate LREE streams typically produce misch metal as a lower-value consolidated product when individual element prices do not justify full separation.
6. Steel Desulfurisation
Beyond misch metal additions, refined cerium compounds are used directly in steel desulfurisation as a standalone treatment in specialty steel production. Cerium has a strong affinity for sulfur and oxygen at steelmaking temperatures, forming stable cerium oxysulfides that modify inclusion shape and distribution. The result is improved toughness, ductility, and fatigue resistance in high-specification steel grades used in aerospace, pipeline, and automotive structural applications. This is a relatively niche cerium use by volume compared to catalysts and glass, but it serves high-value end markets where premium pricing for specialty steel justifies the additive cost.
7. Diesel Fuel Additives — Nano-CeO₂
Nano-scale cerium oxide particles added to diesel fuel act as a combustion catalyst, reducing particulate emissions and improving fuel economy by lowering the ignition temperature of soot particles in diesel exhaust aftertreatment systems. Commercial diesel additives containing nano-CeO₂ have been deployed in fleet vehicle programmes, marine applications, and power generation equipment. The application remains commercially constrained: regulatory approval pathways for fuel additives vary by jurisdiction, and the environmental fate of nano-CeO₂ particles emitted in exhaust is subject to ongoing regulatory scrutiny in the EU and UK. Volume consumed is modest relative to the top three applications, but potential scale is significant if regulatory barriers are resolved.
8. Rare Earth Phosphors (Legacy Application)
Cerium is used as a dopant in phosphor materials for fluorescent lighting, cathode ray tube (CRT) displays, and — increasingly — white LED lighting. In LED phosphors, cerium-doped yttrium aluminium garnet (Ce:YAG) converts blue LED emission to the broad yellow spectrum that, combined with residual blue, produces white light. This is one of the few cerium applications in high-performance electronics where cerium is not a bulk commodity but a precisely specified dopant. CRT demand has collapsed with the death of that display technology, but LED phosphor demand is partially offsetting this decline. Overall, phosphor applications represent a declining share of total cerium use as CRT legacy volumes exit the market faster than LED demand grows.
9. Solid Oxide Fuel Cells (SOFC) — Emerging
Solid oxide fuel cells use cerium oxide — typically gadolinium-doped ceria (GDC) — as an electrolyte or buffer layer material, exploiting cerium’s high ionic conductivity and thermal stability at operating temperatures of 500–800°C. SOFCs generate electricity through electrochemical oxidation of hydrogen or hydrocarbon fuels with near-zero direct emissions. The application is commercially early-stage: SOFC systems are deployed in stationary power generation, data centre backup power, and military applications, with commercial aviation and marine propulsion under active development. According to the US Department of Energy, cerium-based catalysts were involved in 28% of SOFC R&D projects in 2023. Volume consumed remains small relative to catalysts and glass, but long-term growth potential is meaningful if SOFC deployment scales.
10. Water Treatment Applications — Emerging
Cerium oxide’s redox properties — its ability to cycle between oxidation states — make it an active research target for water treatment applications, including oxidative degradation of organic pollutants, heavy metal remediation, and antibacterial water purification. Nano-CeO₂ has demonstrated efficacy in laboratory settings for removing dyes, pharmaceutical compounds, and heavy metals from wastewater streams. Commercial deployment remains limited; most applications are at pilot or demonstration scale rather than industrial volume. Water treatment represents the most speculative entry on this list, included because it is the most credible emerging application beyond SOFCs that could absorb cerium at meaningful scale if technology and cost conditions develop favourably.
Cerium Uses — Summary Comparison
| Rank | Application | Key Form | Volume Scale | Growth Outlook |
|---|---|---|---|---|
| 1 | FCC Catalysts — Petroleum Refining | Cerium oxide / REE promoter | Very large | Stable / gradual decline long-term |
| 2 | Glass Polishing Compounds | CeO₂ powder | Large | Strong growth — display, optics, semiconductors |
| 3 | Automotive Catalytic Converters | CeO₂ oxygen storage | Large | Stable — hybrid demand offsets BEV decline |
| 4 | UV-Absorbing Glass Additives | Cerium compounds in melt | Medium | Steady — architectural, aerospace, medical glass |
| 5 | Metallurgical Alloying (Misch Metal) | Ce-dominant alloy | Medium | Stable |
| 6 | Steel Desulfurisation | Cerium compounds | Small-medium | Stable — niche, high-value steel grades |
| 7 | Diesel Fuel Additives | Nano-CeO₂ | Small | Regulatory-dependent |
| 8 | Rare Earth Phosphors | Ce:YAG dopant | Small | Declining (CRT exit) / partial LED offset |
| 9 | Solid Oxide Fuel Cells | GDC electrolyte | Nascent | High potential — early commercial stage |
| 10 | Water Treatment | Nano-CeO₂ | Nascent | Speculative — pilot stage only |
The Cerium Oversupply Problem — And Why New Cerium Uses Matter
The commercial reality of cerium is unlike any other rare earth: it is produced whether demand exists for it or not. Every tonne of NdPr oxide separated from bastnäsite or monazite ore generates cerium as a co-product. China Northern Rare Earth (SHA: 600111), the world’s largest LREE producer, processes ore from Bayan Obo — a deposit where cerium constitutes approximately half of total rare earth content by weight. The same structural dynamic applies to Western producers building out supply chains outside China: MP Materials at Mountain Pass and Lynas at its Australian and Malaysian operations all face the same cerium surplus challenge.
The price consequence is stark. While dysprosium trades above $200/kg and terbium has crossed $970/kg on SMM benchmarks, cerium oxide trades at approximately $1–3/kg — a fraction of the cost of processing and separating it. Producers often find it more economical to stockpile cerium oxide than to sell it below cost. New cerium uses — particularly in solid oxide fuel cells, water treatment, and next-generation catalysts — represent a genuine commercial opportunity: unlocking value in a material the industry already produces in abundance. For more on how supply chain structure shapes REE economics, see our geopolitics coverage.
According to the USGS Mineral Resources Program, rare earth end-use in the US has historically directed 74% of consumption to catalysts — with cerium the dominant element in that category. Developing applications that absorb cerium at scale would reduce oversupply pressure and improve the economics of the Western REE projects currently in development. For an overview of where cerium is produced alongside other REEs, see our ranking of the top 10 rare earth producing countries.
What is cerium most commonly used for?
Cerium’s largest use by volume is as a rare earth promoter in fluid catalytic cracking (FCC) catalysts for petroleum refining. It is also widely used as cerium oxide (CeO₂) in glass polishing compounds and as an oxygen storage component in automotive catalytic converters.
Why is cerium so cheap compared to other rare earths?
Cerium is the most abundant rare earth element and constitutes around 50% of the rare earth content in most ore bodies by weight. It is produced as an unavoidable co-product whenever neodymium and praseodymium are separated, resulting in chronic oversupply. With demand not matching production volumes, cerium oxide typically trades at just $1–3/kg versus hundreds of dollars per kilogram for heavy rare earths such as dysprosium and terbium.
Is cerium used in electric vehicles?
Cerium’s direct role in battery EVs is limited — it is not used in NdFeB permanent magnets, which use neodymium, dysprosium, and praseodymium. However, hybrid vehicles retain internal combustion engines and require cerium-containing catalytic converters. Cerium is also being researched for use in solid oxide fuel cell systems and, in nano-oxide form, as a combustion improver in diesel and hydrogen fuel blends.
What is cerium oxide used for?
Cerium oxide (CeO₂) is used in glass and semiconductor polishing compounds, as the active oxygen-storage material in automotive catalytic converters, as a UV-absorbing additive in glass melts, and as the electrolyte material in solid oxide fuel cells. Nano-scale CeO₂ is used in diesel fuel additives and is being researched for water treatment applications.
Who are the main producers of cerium?
China Northern Rare Earth (SHA: 600111) is the world’s dominant cerium producer, processing bastnäsite ore from the Bayan Obo deposit in Inner Mongolia. MP Materials (NYSE: MP) at Mountain Pass, California and Lynas Rare Earths (ASX: LYC) in Australia and Malaysia are the principal Western producers. All three generate cerium as a co-product of their primary NdPr separation operations.
