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Hydrothermal synthesis and sintering of ultrafine CeO2 powders

What is CeO2?

Nanocrystalline cerium(IV) oxide (CeO2) powders were prepared by heating solutions of cerium(IV) salts in the presence of urea under hydrothermal conditions at 120° to 180°C. The effects of urea concentration and hydrothermal treatment temperature on the morphology and crystallite size of the synthesized particles were investigated. The synthesized particles were angular, ultrafine CeO2 with a cubic fluorite structure. Their crystallite size decreased from 20 to 10 nm with increasing urea concentration from 2 times to 8 times that of the Ce4+ ion. The size only slightly changed by calcining at temperatures below 600°C.

 

Hydrothermal synthesis and sintering of ultrafine CeO2 powders

Undoped CeO2 and Y2O3-doped CeO2 powders, with  10–15 nm particle sizes, were prepared under hydrothermal conditions of 10 MPa at 300 °C for four h. The compacted powders were sintered freely in air or O2 at constant heating rates of 1–10 °C/min up to 1350 °C. The undoped CeO2 started to sinter at 800–900 °C and reached a maximum density of 0.95 of the theoretical at 1200 °C, after which the density decreased slightly. Isothermal sintering at 1150 °C produced a sample with a relative density  of 0.98 and an average grain size of 100 nm. The samples sintered above 1200 °C exhibited microcracking. The decrease in density and the microcracking above 1200 °C are attributed to a redox reaction leading to the formation of oxygen vacancies and the evolution of O2 gas. Doping with Y2O3 increased the temperature at which measurable sintering commenced and increased the sintering rate compared with the undoped CeO2. Sintered samples of the doped CeO2 showed no microcracks. The CeO2 doped with up to 3 mol% Y2O3 was sintered to almost full density and with a grain size of 200 nm at 1400 °C.

 

This work reports on the investigation of nanosized CeO2-ZnO systems

This work reports on investigating nanosized CeO2-ZnO systems prepared by Pechini's method. The structural and morphological characterization of CeO2-ZnO systems as well as the characterization of CeO2 and ZnO separately, showed that the employed method resulted in powders with spheroidal particles whose sizes are in the range of 30 – 200 nm, which is appropriate to provide homogeneous suspensions. The ZnO present in the prepared mixed oxides seems to increase particle size distribution and influence particle arrangement after powder dispersion. This work reports on investigating nanosized CeO2-ZnO systems prepared by Pechini's method. The structural and morphological characterization of CeO2-ZnO systems as well as the characterization of CeO2 and ZnO separately, showed that the employed method resulted in powders with spheroidal particles whose sizes are in the range of 30 – 200 nm, which is appropriate to provide homogeneous suspensions. The ZnO present in the prepared mixed oxides seems to increase particle size distribution and influence particle arrangement after powder dispersion. Ultrafine nm-sized particles have attracted much attention since they often exhibit physical and chemical properties significantly different from those of bulk materials. In particular, materials with high surface area have importance in two major fields: ceramic science and catalysis. In recent years, nanotechnology has created excitement in a wide array of scientific and financial sectors. Cosmetic chemists may not have realized that their industry has been leading the way in nanotechnology for the last ten years with the use of one of the first nanotechnological products, nanoscaled (<100 nm) inorganic UV absorbers or "nanopowders." Cerium oxide is a major compound in the useful rare earth family and has been applied as a useful glass-polishing material, ultraviolet absorbent, and automotive exhaust promoter. Fine particles of cerium oxide of very small size can become potential new materials that may be useful for fine UV absorbent and high-activity catalysts. Many studies have reported the synthesis of nanosized particles of ceria for various purposes. However, because of its high catalytic activity for the oxidation of organic material, CeO2 has seldom been used commercially as a sunscreen material. So, introducing ZnO should reduce the oxidation catalytic activity of cerium oxide.

 

Price of CeO2

CeO2 particle size and purity will affect the product's Price, and the purchase volume can also affect the cost of CeO2. A large amount of large amount will be lower. The Price of CeO2 is on our company's official website.

 

CeO2 supplier

Mis-Asia is a reliable and high-quality global chemical material supplier and manufacturer. It has over 12 years of experience providing ultra-high quality chemicals and nanotechnology materials, including CeO2, nitride powder, graphite powder, sulfide powder, and 3D printing powder. If you are looking for high-quality and cost-effective CeO2, you are welcome to contact us or inquire any time.

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