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The hidden properties of cerium: How do oxygen defects affect its conductivity?
Cerium dioxide (CeO2), also known as cerium ash, has important applications in various fields due to its unique chemical properties. Especially in terms of electronic conductivity, the presence of oxygen defects can significantly affect the conductive properties of cerium. This article will take a closer look at cerium's properties, structure, and how oxygen defects change its conductivity.
Characteristics and structure of cerium
Cerium usually appears in the natural state in the form of oxides, and the main ores are basnerite and monoclinic stone. Cerium dioxide is a pale yellow white powder with a unique reversible conversion property, which can be converted into non-stoichiometric oxides.
The fluorite structure has 8-coordinated cerium (Ce4+) and 4-coordinated oxygen (O2−). At high temperatures, cerium dioxide releases oxygen to form a non-stoichiometric form with oxygen deficiency.
Defect Chemistry
In the most stable cerium spider phase, cerium oxide displays a variety of defects that depend mainly on the partial pressure of oxygen or the stress state of the material. Oxygen vacancies and small polarons (electrons localized in the cerium cation) are the most prominent presences. At a high concentration of oxygen vacancies, the diffusion rate of oxide anions in the lattice increases.
This property makes cerium oxides excellent for applications in solid oxide fuel cells, and both undoped and doped cerium show high electronic conductivity at low oxygen partial pressures. sex.
Application Areas
Cerium dioxide is mainly used in two areas: chemical polishing and glass decolorization. Especially in chemical mechanical polishing, the superiority of cerium has made it replace many other oxides and become an important material in the industry.
Cerium oxides also perform well in a number of emerging applications such as catalysis, energy and fuels, especially in the generation of hydrogen energy, using cerium's oxygen defect properties to decompose water.
Security Issues
In the field of nanotechnology, cerium dioxide nanoparticles (nanocerium) have been widely studied for their antibacterial and antioxidant properties. This makes it a promising candidate for use in sunscreens, especially when compared to zinc oxide and titanium dioxide.
ConclusionIn summary, cerium oxide is widely used in many industries due to its unique conductive properties. Oxygen defects play a particularly significant role in improving its conductivity and have also promoted the advancement of many technologies. In the future, will cerium dioxide unleash more potential and value in a wider range of applications?
