Cerium(III) oxide
 | |
| Names | |
|---|---|
| IUPAC name
Cerium(III) oxide | |
| Other names
Cerium sesquioxide | |
| Identifiers | |
| ECHA InfoCard | 100.014.289 |
| Properties | |
| Ce2O3 | |
| Molar mass | 328.24 g/mol |
| Appearance | yellow-green dust |
| 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 | |
| P-3m1, No. 164 | |
| Related compounds | |
| Other anions |
Cerium(III) chloride |
| Other cations |
Lanthanum oxide, Praseodymium(III) oxide |
| Related compounds |
CeO2 |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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| Infobox references | |
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
Engine and exhaust catalysts
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 CeO
2 + CO → Ce
2O
3 + CO
2
When there is an oxygen surplus, the process is reversed and cerium(III) oxide is oxidized to cerium(IV) oxide:
- 2 Ce
2O
3 + O
2 → 4 CeO
2
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
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]
Illumination
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.
Production
Cerium(III) oxide is produced by the reduction of cerium(IV) oxide with hydrogen at approximately 1,400 °C (2,550 °F) to make air stable cerium(III) oxide.
References
- ↑ 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".
- ↑ "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".
- ↑ "Hazard and risk assessment of a nanoparticulate cerium oxide-based diesel fuel additive - a case study.". Inhal Toxicol. 20: 547–66. Apr 2008. PMID 18444008. doi:10.1080/08958370801915309.
- ↑ "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.
- ↑ Spectral Studies of New Luminophors for Dental Porcelain