A method of producing ceria nanocrystals is provided. The method includes providing a gas that includes ozone to a solution that includes a cerium salt, and obtaining ceria nanocrystals from the solution after the gas is provided to the first solution. A method of producing nanoparticles is provided. The method includes providing a gas that includes ozone to a solution that includes a metal salt that includes at least one of a transition metal or a lanthanide, and producing at least one of metal oxide nanoparticles, metal oxynitrate nanoparticles, or metal oxyhydroxide nanoparticles from the solution after the gas is provided to the solution.

A method of producing ceria nanocrystals is provided. The method includes providing a gas that includes ozone to a solution that includes a cerium salt, and obtaining ceria nanocrystals from the solution after the gas is provided to the first solution. A method of producing nanoparticles is provided. The method includes providing a gas that includes ozone to a solution that includes a metal salt that includes at least one of a transition metal or a lanthanide, and producing at least one of metal oxide nanoparticles, metal oxynitrate nanoparticles, or metal oxyhydroxide nanoparticles from the solution after the gas is provided to the solution.

Dy.sub.2O.sub.3 particles of a nanoparticle scale have beneficial properties for ceramic and electronic uses. Disclosed herein are moderately dispersed Dy.sub.2O.sub.3 particles having regular morphology and lateral size ranging from about 10 nm to 1 μm. The Dy.sub.2O.sub.3 particles may exhibit a narrow particle size distribution such that the difference between D.sub.10 and D.sub.90 is about 0.1 μm to 1 μm. Further disclosed are processes of producing these moderately dispersed Dy.sub.2O.sub.3 particles. These processes do not include grinding to obtain the particles. Also disclosed herein are uses for these Dy.sub.2O.sub.3μ particles.

The present disclosure provides for compositions, methods of making compositions, and methods of using the composition. In an aspect, the composition can be a reactive material that can be used to split a gas such as water or carbon dioxide.

The present disclosure provides for compositions, methods of making compositions, and methods of using the composition. In an aspect, the composition can be a reactive material that can be used to split a gas such as water or carbon dioxide.

The present application relates to a technical filed of energy sources and illumination, and discloses a rare earth oxide nanosheet composite modified by an organic ligand, a preparation method and an organic light-emitting diode (OLED) luminescent film. The rare earth oxide nanosheet composite modified by the organic ligand is obtained by adding the organic ligand in the rare earth nanosheet sol for ultrasonic coordination; and a mole ratio of the rare earth nanosheet sol to the organic ligand is 1:(3-9).

Novel hybrid nanoparticles, useful for inhibiting or slowing down the formation of sulfur deposits or minerals in a well during the extraction of gas or oil. Specifically, the nanoparticles each include (i) a polyorganosiloxane (POS) matrix; and, optionally as a coating over a lanthanide oxide core, (iii) at least one polymeric scale inhibitor during the extraction of gas or oil. The invention also relates to the method for obtaining the nanoinhibitors and the application of same.

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.

The present invention provides a crystal of a europium compound containing europium. The present invention enables the preparation of a crystal of a europium compound having a powder X-ray diffraction pattern having a first diffraction peak in diffraction angle (2θ) range of 34.3° to 36.1° in which a half width of the first diffraction peak is 1.8° or less, and/or having a second diffraction peak in diffraction angle (2θ) range of 28.6° to 29.6° and a third diffraction peak in diffraction angle (2θ) range of 36.8° to 38.4° in which a half width of the second diffraction peak is 1.0° or less and a half width of the third diffraction peak is 1.6° or less, and being at least one compound selected from compounds represented by formulae (1) to (4):

EuCl.sub.x  (1)

Eu(OH).sub.2  (2)

Eu(OH).sub.2Cl  (3)

EuOCl  (4) x is 0.05 or more and 5 or less.

Rare earth compound particles are prepared by a step of heating an aqueous solution containing rare earth metal ions and urea to form a rare earth compound by a reaction of a hydrolysis product of urea, and the rare earth metal ions. In the heating step, heating the aqueous solution into which an acetylene glycol-ethylene oxide adduct is added.