Cerium(III) oxide
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| Names | |
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| IUPAC name
Cerium(III) oxide
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| Other names
Cerium sesquioxide
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.014.289 |
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PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| Ce2O3 | |
| Molar mass | 328.229 g·mol−1 |
| Appearance | yellow-green dust[citation needed] |
| Density | 6.2 g/cm3 |
| Melting point | 2,177 °C (3,951 °F; 2,450 K) |
| Boiling point | 3,730 °C (6,750 °F; 4,000 K) |
| insoluble | |
| Solubility in sulfuric acid | soluble |
| Solubility in hydrochloric acid | insoluble |
| Structure | |
| Hexagonal, hP5 | |
| P3m1, No. 164 | |
| Hazards | |
| GHS labelling: | |
 
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| Related compounds | |
Other anions
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Cerium(III) chloride |
Other cations
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Lanthanum(III) oxide, Praseodymium(III) oxide |
Related compounds
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Cerium(IV) oxide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Cerium(III) oxide, also known as cerium oxide, cerium trioxide, cerium sesquioxide, cerous oxide or dicerium trioxide, is an oxide of the rare-earth metal cerium. It has chemical formula Ce2O3 and is gold-yellow in color.
Applications
[edit]Engine and exhaust catalysts
[edit]Cerium oxide is used as a catalytic converter for the minimisation of CO emissions in the exhaust gases from motor vehicles.
When there is a shortage of oxygen, cerium(IV) oxide is reduced by carbon monoxide to cerium(III) oxide:
- 2 CeO2 + CO → Ce2O3 + CO2
When there is an oxygen surplus, the process is reversed and cerium(III) oxide is oxidized to cerium(IV) oxide:
- 2 Ce2O3 + O2 → 4 CeO2
Major automotive applications for cerium(III) oxide are as a catalytic converter for the oxidation of CO and NOx emissions in the exhaust gases from motor vehicles,[1][2] and secondly, cerium oxide finds use as a fuel additive to diesel fuels, which results in increased fuel efficiency and decreased hydrocarbon derived particulate matter emissions,[3] however the health effects of the cerium oxide bearing engine exhaust is a point of study and dispute.[4][5][6]
Water splitting
[edit]The cerium(IV) oxide–cerium(III) oxide cycle or CeO2/Ce2O3 cycle is a two step thermochemical water splitting process based on cerium(IV) oxide and cerium(III) oxide for hydrogen production.[7]
Photoluminescence
[edit]Cerium(III) oxide combined with tin(II) oxide (SnO) in ceramic form is used for illumination with UV light. It absorbs light with a wavelength of 320 nm and emits light with a wavelength of 412 nm.[8] This combination of cerium(III) oxide and tin(II) oxide is rare, and obtained only with difficulty on a laboratory scale.[citation needed]
Production
[edit]Cerium(III) oxide is produced by the reduction of cerium(IV) oxide with hydrogen at approximately 1,400 °C (2,550 °F). Samples produced in this way are only slowly air-oxidized back to the dioxide at room temperature.[9]
References
[edit]- ^ Bleiwas, D.I. (2013). Potential for Recovery of Cerium Contained in Automotive Catalytic Converters. Reston, Va.: U.S. Department of the Interior, U.S. Geological Survey.
- ^ "Argonne's deNOx Catalyst Begins Extensive Diesel Engine Exhaust Testing". Archived from the original on 2015-09-07. Retrieved 2014-06-02.
- ^ "Exploring Nano-sized Fuel Additives EPA scientists examine nanoparticle impacts on vehicle emissions and air pollution".
- ^ "Nanoparticles used as additives in diesel fuels can travel from lungs to liver, November 18, 2011. Marshall University Research Corporation".
- ^ Park, B.; Donaldson, K.; Duffin, R.; Tran, L.; Kelly, F.; Mudway, I.; Morin, J. P.; Guest, R.; Jenkinson, P.; Samaras, Z.; Giannouli, M.; Kouridis, H.; Martin, P. (Apr 2008). "Hazard and risk assessment of a nanoparticulate cerium oxide-based diesel fuel additive - a case study". Inhal Toxicol. 20 (6): 547–66. doi:10.1080/08958370801915309. PMID 18444008.
- ^ "Exploring Nano-sized Fuel Additives EPA scientists examine nanoparticle impacts on vehicle emissions and air pollution".
- ^ Hydrogen production from solar thermochemical water splitting cycles Archived August 30, 2009, at the Wayback Machine
- ^ Peplinski, D.R.; Wozniak, W. T.; Moser, J. B. (1980). "Spectral Studies of New Luminophors for Dental Porcelain". Journal of Dental Research. 59 (9): 1501–1509. doi:10.1177/00220345800590090801. PMID 6931128.
- ^ Y. Wetzel (1963). "Scandium, Yttrium, Rare Earths". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 1. NY, NY: Academic Press. p. 1151.