:Cerium(III) oxide

Cerium oxide is of commercial interest as a catalyst for oxidation of carbon monoxide and reduction of {{NOx|link=yes}}. These applications exploit the facility of the Ce(III)/Ce(IV) redox couple. It is used in catalytic converters ("three-way 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 oxidizes carbon monoxide to the benign dioxide:Bleiwas, D.I. (2013). [https://purl.fdlp.gov/GPO/gpo36871 Potential for Recovery of Cerium Contained in Automotive Catalytic Converters.] Reston, Va.: U.S. Department of the Interior, U.S. Geological Survey.{{cite web |url=http://www.transportation.anl.gov/engines/cerium-oxide_catalyst.html |title=Argonne's deNOx Catalyst Begins Extensive Diesel Engine Exhaust Testing |access-date=2014-06-02 |archive-url=https://web.archive.org/web/20150907191148/http://www.transportation.anl.gov/engines/cerium-oxide_catalyst.html |archive-date=2015-09-07 |url-status=dead }}

:{{chem2|2 CeO2 + CO → Ce2O3 + CO2}}

When oxygen is in surplus, the process is reversed and cerium(III) oxide is oxidized to cerium(IV) oxide:

:{{chem2|2 Ce2O3 + O2 → 4 CeO2}}

Cerium oxide-based catalysts have been intensively investigated for selective catalytic reduction (SCR) of {{NOx}}. Such technologies, which tend to use vanadium oxide-based catalysts rather than ceria, are associated with power plants, foundries, cement factories and other energy-intensive facilities.{{cite journal |doi=10.1021/acs.chemrev.9b00202 |title=Selective Catalytic Reduction of NO _x with NH₃ by Using Novel Catalysts: State of the Art and Future Prospects |date=2019 |last1=Han |first1=Lupeng |last2=Cai |first2=Sixiang |last3=Gao |first3=Min |last4=Hasegawa |first4=Jun-ya |last5=Wang |first5=Penglu |last6=Zhang |first6=Jianping |last7=Shi |first7=Liyi |last8=Zhang |first8=Dengsong |journal=Chemical Reviews |volume=119 |issue=19 |pages=10916–10976 |pmid=31415159 }}

Cerium oxide finds use as a fuel additive to diesel fuels,{{huh?|date=January 2025}} which results in increased fuel efficiency and decreased hydrocarbon derived particulate matter emissions,{{cite web |url=http://www.epa.gov/sciencematters/april2011/nano.htm |title=Exploring Nano-sized Fuel Additives EPA scientists examine nanoparticle impacts on vehicle emissions and air pollution.}} however the health effects of the cerium oxide bearing engine exhaust is a point of study and dispute.{{cite web |url=https://www.sciencedaily.com/releases/2011/11/111117141157.htm |title=Nanoparticles used as additives in diesel fuels can travel from lungs to liver, November 18, 2011. Marshall University Research Corporation}}{{cite journal |title=Hazard and risk assessment of a nanoparticulate cerium oxide-based diesel fuel additive - a case study. | pmid=18444008 | doi=10.1080/08958370801915309 | volume=20 | issue=6 | date=Apr 2008 | journal=Inhal Toxicol | pages=547–66| last1=Park | first1=B. | last2=Donaldson | first2=K. | last3=Duffin | first3=R. | last4=Tran | first4=L. | last5=Kelly | first5=F. | last6=Mudway | first6=I. | last7=Morin | first7=J. P. | last8=Guest | first8=R. | last9=Jenkinson | first9=P. | last10=Samaras | first10=Z. | last11=Giannouli | first11=M. | last12=Kouridis | first12=H. | last13=Martin | first13=P. | bibcode=2008InhTx..20..547P }}{{cite web |url=http://www.epa.gov/sciencematters/april2011/nano.htm |title=Exploring Nano-sized Fuel Additives EPA scientists examine nanoparticle impacts on vehicle emissions and air pollution.}}

The cerium(IV) oxide–cerium(III) oxide cycle or {{chem2|CeO2/Ce2O3}} cycle is a two step thermochemical water splitting process based on cerium(IV) oxide and cerium(III) oxide for hydrogen production.[http://www.solarpaces.org/Tasks/Task2/HPST.HTM Hydrogen production from solar thermochemical water splitting cycles] {{webarchive|url=https://web.archive.org/web/20090830011704/http://www.solarpaces.org/Tasks/Task2/HPST.HTM |date=August 30, 2009}}{{cite journal |doi=10.1021/acs.chemrev.5b00603 |title=Fundamentals and Catalytic Applications of CeO₂-Based Materials |date=2016 |last1=Montini |first1=Tiziano |last2=Melchionna |first2=Michele |last3=Monai |first3=Matteo |last4=Fornasiero |first4=Paolo |journal=Chemical Reviews |volume=116 |issue=10 |pages=5987–6041 |pmid=27120134 |hdl=11368/2890051 |hdl-access=free }}

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.{{Cite journal|last1=Peplinski|first1=D.R.|last2=Wozniak|first2=W. T.|last3=Moser|first3=J. B.|title=Spectral Studies of New Luminophors for Dental Porcelain|journal=Journal of Dental Research|volume=59|issue=9|pages=1501–1509|doi=10.1177/00220345800590090801|pmid=6931128|year=1980}} This combination of cerium(III) oxide and tin(II) oxide is rare, and obtained only with difficulty on a laboratory scale.{{citation needed|date=October 2019}}

Cerium(III) oxide is produced by the reduction of cerium(IV) oxide with hydrogen at approximately {{convert|1400|°C|°F}}. Samples produced in this way are only slowly air-oxidized back to the dioxide at room temperature.{{cite book|author=Y. Wetzel|chapter=Scandium, Yttrium, Rare Earths|title=Handbook of Preparative Inorganic Chemistry, 2nd Ed. |editor=G. Brauer|publisher=Academic Press|year=1963|place=NY, NY|volume=1|pages=1151}}

{{reflist}}

• [https://archive.today/20121209035919/http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFN-47RJ7JP-2&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=044eb8aef1bd8613029859416f8bfead Transformation of CeO2(1 1 1) to Ce2O3(0 0 0 1) films]

{{Cerium compounds}}

{{Oxides}}

{{DEFAULTSORT:Cerium(Iii) Oxide}}

Category:Cerium(III) compounds

Category:Sesquioxides