Molecular Oxygen Activation on Suspended Doped Cerium(IV) Oxide Particles in Molten Chloride Salts

• Published in: Catalysis letters Vol. 150; no. 1; pp. 273 - 280
• Main Authors: Tangeysh, Behzad, Metiu, Horia, Gordon, Michael J., McFarland, Eric W.
• Format: Journal Article
• Language: English
• Published: New York Springer US 2020; Springer; Springer Nature B.V
• Subjects: Activation; Catalysis; Cerium; Cerium oxides; Chemistry; Chemistry and Materials Science; Gadolinium; Industrial Chemistry/Chemical Engineering; Lanthanides; Liquid phases; Lithium chloride; Magnesium chloride; Organometallic Chemistry; Oxidation; Oxygen; Physical Chemistry; Potassium chloride; Praseodymium; Samarium; Surface tension; Vapor phases; Cl; Oxygen activation; Molten chloride salts; CO oxidation; production; Doped ceria catalyst
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-019-02942-0

Suspensions of cerium(IV) oxide (CeO
2
) particles in molten chloride salts were found to be active for molecular oxygen activation when doped with the larger Lanthanides, gadolinium (Gd), praseodymium, (Pr), and samarium, (Sm). The activity for O
2
oxidation of gas phase CO on suspended doped ceria in molten mixtures of LiCl–LiBr–KBr and NaCl–KCl is significantly higher than undoped ceria or the salt mixtures alone in the temperature ranges of 350–600 °C, and 700–800 °C, respectively. Surface tension measurements show that the solid doped ceria particles suspended in the melt are contacting the gas–liquid interface of the bubbles. The activity for O
2
oxidation of liquid phase MgCl
2
in molten MgCl
2
–KCl to produce Cl
2
and solid MgO was also observed to be significantly increased on suspended CeO
2
doped with 5 wt% or 10 wt% Gd. The rates of oxidation were observed to increase with catalyst loading.
Graphic Abstract