Proposed are cerium oxide composite powder and a dispersion composition containing the same powder. The powder includes two types of cerium oxide particles satisfying different specific particle size ranges. When the average density of the cerium oxide composite powder in a dispersion composition solution is controlled to be in a specific range, the dispersion composition can provide a high polishing rate without causing damage to a substrate and has good storage stability.

The present invention is polishing particles for polishing a synthetic quartz glass substrate. The polishing particles contain cerium-based polishing particles and have a breaking strength, which is measured by a compression tester, of 30 MPa or more. This provides polishing particles for polishing a synthetic quartz glass substrate while sufficiently reducing generation of defects due to polishing.

A method of manufacturing a cerium dioxide powder is provided. The method includes mixing a cerium salt, an amine and solvent to form a mixed solution, in which the amine includes a secondary amine, a tertiary amine or a combination thereof, and the tertiary amine is selected from the group consisting of hexamethylenetetramine, triethylenediamine and a combination thereof. A solvothermal reaction of the mixed solution is performed to form the cerium dioxide powder. The cerium dioxide powder manufactured by the method is also provided herein.

A method of manufacturing a cerium dioxide powder is provided. The method includes mixing a cerium salt, an amine and solvent to form a mixed solution, in which the amine includes a secondary amine, a tertiary amine or a combination thereof, and the tertiary amine is selected from the group consisting of hexamethylenetetramine, triethylenediamine and a combination thereof. A solvothermal reaction of the mixed solution is performed to form the cerium dioxide powder. The cerium dioxide powder manufactured by the method is also provided herein.

The present disclosure relates to a dissimilar metal-doped cerium oxide including cerium oxide and a dissimilar metal other than the cerium oxide, in which a relationship of the following formula (1) is satisfied:

0.8≤|(D90)−(D10)|/D50≤2.0  (1) (in the formula (1), D10, D50, and D90 respectively represent the following: D10: particle diameter at which cumulative volume fraction is 10% D50: particle diameter at which cumulative volume fraction is 50% D90: particle diameter at which cumulative volume fraction is 90%).

The present disclosure relates to a dissimilar metal-doped cerium oxide including cerium oxide and a dissimilar metal other than the cerium oxide, in which a relationship of the following formula (1) is satisfied:

0.8≤|(D90)−(D10)|/D50≤2.0  (1) (in the formula (1), D10, D50, and D90 respectively represent the following: D10: particle diameter at which cumulative volume fraction is 10% D50: particle diameter at which cumulative volume fraction is 50% D90: particle diameter at which cumulative volume fraction is 90%).

A reducing agent for use in production of a product gas containing carbon monoxide, the reducing agent being brought into contact with a raw material gas containing carbon dioxide to reduce the carbon dioxide to produce the product gas; the reducing agent containing an oxygen carrier having oxygen ionic conductivity, and a basic oxide supported on the oxygen carrier. In addition, the basic oxide preferably contains at least one selected from the group consisting of lithium (Li), sodium (Na), potassium (K), magnesium (Mg), manganese (Mn), cobalt (Co), strontium (Sr), and rubidium (Rb). The reducing agent has a high conversion efficiency of carbon dioxide to carbon monoxide, and can be used, for example, in a chemical looping method, and a method for producing a gas using such a reducing agent.

In order to use less cerium oxide and achieve higher durability and polishing speeds, these abrasive particles used in an abrasive have: a shell layer (3) which is the outermost shell layer of the abrasive particles and is formed with cerium oxide as the main component; and a middle layer (2) which contains cerium oxide and an oxide of at least one element selected from Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, Th, and the alkali earth metals, and which is formed closer to the center of the abrasive particles than the shell layer (3).

The object of the present invention is to provide an exhaust gas purifying catalyst that can achieve high purification performance while suppressing H.sub.2S emissions. The object is solved by an exhaust gas purifying catalyst in which the top layer of a catalyst coating layer comprises a ceria-zirconia composite oxide having a pyrochlore-type ordered array structure, in which the ceria-zirconia composite oxide contains at least one additional element selected from the group consisting of praseodymium, lanthanum, and yttrium at 0.5 to 5.0 mol % in relation to the total cation amount, and the molar ratio of (cerium+additional element):(zirconium) is within the range from 43:57 to 48:52.

Cerium oxide nanoparticles (CNPs) have been proven to exhibit antioxidant properties attributed to its surface oxidation states (Ce4+ to Ce3+ and vice versa) mediated at the oxygen vacancies on the surface of CNPs. Different anions in precursor cerium salts were used to prepare CNPs resulting in disclosed CNPs with varying physicochemical properties such as dispersion stability, hydrodynamic size, and the signature surface chemistry. The antioxidant catalytic activity and oxidation potentials of different CNPs have been significantly altered with the change of anions in the precursor salts. For one, CNPs prepared using precursor salts containing NO.sub.3.sup.− and Cl.sup.− ions exhibited increased antioxidant activity than previously thought possible. The change in oxidation potentials of CNPs with the change in concentration of the nitrate and chloride ions indicates the disclosed CNP's have different surface chemistry and antioxidant properties. These compositions and methods of their synthesis are disclosed.