Abstract: Disclosed are a grain boundary and surface-doped rare earth manganese-zirconium composite compound as well as a preparation method and use thereof. A rare earth manganese oxide with a special structure is formed at grain boundary and surface of a rare earth zirconium-based oxide by a grain boundary doping method so as to increase oxygen defects at the grain boundary and the surface, thereby increasing the amount of active oxygen, improving the catalytic activity of the rare earth manganese-zirconium composite compound, inhibiting high-temperature sintering of the rare earth manganese-zirconium composite compound, and improving the NO catalytic oxidation capability. When the rare earth manganese-zirconium composite compound is applied to a catalyst, the consumption of noble metal can be greatly reduced.

Abstract: Disclosed are a grain boundary and surface-loaded noble metal catalyst, a preparation method and an application thereof. The noble metal is dispersed at the grain boundary and surface of alumina and/or a rare earth manganese-zirconium composite oxide to form a multiphase interface, which achieves the following beneficial technical effects: firstly, the multiphase interface has a larger steric hindrance and a stronger anchoring effect, which can inhibit the migration, agglomeration, and growth of the noble metal at high temperatures, increase the high-temperature stability and catalytic performance of the noble metal, and reduce the usage of the noble metal; secondly, the multiphase interface exhibits a synergistic catalytic effect, which can reduce the activation energy of lattice oxygen and increase the quantity of active oxygen, thereby enhancing the NO oxidation and low-temperature catalytic activity.

Abstract: The present invention discloses a rare-earth-manganese/cerium-zirconium-based composite compound, a method for preparing the same, and a use thereof. The composite compound is of a core-shell structure with a general formula expressed as: A REcBaOb-(1-A)CexZr(1-x-y)MyO2-z, wherein 0.1?A?0.3, preferably 0.1?A?0.2; a shell layer has a main component of rare-earth manganese oxide with a general formula of REcMnaOb, wherein RE is a rare-earth element or a combination of more than one rare-earth elements, and B is Mn or a combination of Mn and a transition metal element, 1?a?8, 2?b?18, and 0.25?c?4; and a core has a main component of cerium-zirconium composite oxide with a general formula of CexZr(1-x-y)MyO2-z, wherein M is one or more non-cerium rare-earth elements, 0.1?x?0.9, 0?y?0.3, and 0.01?z?0.3. The composite compound enhances an oxygen storage capacity of a cerium-zirconium material through an interface effect, thereby increasing a conversion rate of a nitrogen oxide.

Abstract: The present disclosure provides a cerium-zirconium-based composite oxide with a core-shell structure and a preparation method thereof, a catalyst system using the cerium-zirconium-based composite oxide, a catalytic converter for purifying tail gas by using the catalyst system, and application of the catalyst system or the catalytic converter in motor vehicle exhaust purification, industrial waste gas treatment or catalytic combustion. In the present invention, the cerium-zirconium-based composite oxide with a core-shell structure oxygen storage material is prepared by a step-by-step precipitation method. On the one hand, yttrium and a part of zirconium and cerium are precipitated on a cerium-zirconium surface, where the post-precipitation of yttrium is to segregate yttrium ions (Y3+) on a grain boundary surface, thus reducing lattice surface energy, pinning the grain boundary surface, making the migration of the grain boundary surface difficult, controlling the growth of grains.

Abstract: The present disclosure relates to a cerium-zirconium-based composite oxide having gradient element distribution and a preparation method therefor. According to the present disclosure, the cerium-zirconium-based composite oxide having gradient element distribution is prepared by a step-by-step precipitation method. First, a zirconium-rich component is precipitated to form a crystal structure and a crystal grain stack structure which have high thermal stability, slow down the segregation of zirconium on a surface after high-temperature treatment, and reduce element migration among crystal grains; second, a cerium-rich component is precipitated to improve the cerium content of the surface layers of the crystal grains, improve the utilization rate of the cerium element, and improve the oxygen storage amount and the oxygen storage rate.

Abstract: The present invention discloses a rare-earth-manganese/cerium-zirconium-based composite compound, a method for preparing the same, and a use thereof. The composite compound is of a core-shell structure with a general formula expressed as: A REcBaOb-(1-A)CexZr(1-x-y)MyO2-z, wherein 0.1?A?0.3, preferably 0.1?A?0.2; a shell layer has a main component of rare-earth manganese oxide with a general formula of REcMnaOb, wherein RE is a rare-earth element or a combination of more than one rare-earth elements, and B is Mn or a combination of Mn and a transition metal element, 1?a?8, 2?b?18, and 0.25?c?4; and a core has a main component of cerium-zirconium composite oxide with a general formula of CexZr(1-x-y)MyO2-z, wherein M is one or more non-cerium rare-earth elements, 0.1?x?0.9, 0?y?0.3, and 0.01?z?0.3. The composite compound enhances an oxygen storage capacity of a cerium-zirconium material through an interface effect, thereby increasing a conversion rate of a nitrogen oxide.

Abstract: Provided are a cerium-zirconium composite oxide, a preparation method therefor and application of a catalyst. The cerium-zirconium composite oxide has a composite phase structure, and comprises a cerium oxide phase and a cerium-zirconium solid solution phase, or consists of two or more cerium-zirconium solid solution phases with different crystal structures and different chemical compositions, wherein the chemical formula of the cerium-zirconium solid solution phase is CexZr1-x-yMyO2, where M is at least one selected from the group consisting of a rare earth element other than cerium, a transition metal element and an alkaline earth metal element, x is 15-85 mol %, and y is 0-20 mol %.

Abstract: Provided are a cerium-zirconium composite oxide, a preparation method therefor and application of a catalyst. The cerium-zirconium composite oxide has a composite phase structure, and comprises a cerium oxide phase and a cerium-zirconium solid solution phase, or consists of two or more cerium-zirconium solid solution phases with different crystal structures and different chemical compositions, wherein the chemical formula of the cerium-zirconium solid solution phase is CexZr1-x-yMyO2, where M is at least one selected from the group consisting of a rare earth element other than cerium, a transition metal element and an alkaline earth metal element, x is 15-85 mol %, and y is 0-20 mol %.

Abstract: The present invention provides a cerium oxide based composite polishing powder and a preparation method thereof. The polishing powder contains the element magnesium in an amount of 0.005 wt %-5 wt % to magnesium oxide meter. The preparation method includes: (1) uniformly mixing a salt solution containing cerium serving as the main component of the polishing powder; (2) uniformly mixing a precipitating agent of an aqueous magnesium bicarbonate solution with the mixed solution prepared in step (1) to obtain a slurry; (3) aging the slurry prepared in step (2) for 0-48 h while the temperature of the slurry is kept at 30-90 degrees centigrade, and filtering the aged slurry to obtain the precursor powder of the polishing powder; (4) calcinating the precursor powder at 600-1000 degrees centigrade, then dispersing and separating the calcinated precursor powder to obtain the polishing powder. The present invention improves the polishing performance and the suspension performance of polishing powder.

Abstract: The present invention provides a cerium oxide based composite polishing powder and a preparation method thereof. The polishing powder contains the element magnesium in an amount of 0.005 wt %-5 wt % to magnesium oxide meter. The preparation method includes: (1) uniformly mixing a salt solution containing cerium serving as the main component of the polishing powder; (2) uniformly mixing a precipitating agent of an aqueous magnesium bicarbonate solution with the mixed solution prepared in step (1) to obtain a slurry; (3) aging the slurry prepared in step (2) for 0-48 h while the temperature of the slurry is kept at 30-90 degrees centigrade, and filtering the aged slurry to obtain the precursor powder of the polishing powder; (4) calcinating the precursor powder at 600-1000 degrees centigrade, then dispersing and separating the calcinated precursor powder to obtain the polishing powder. The present invention improves the polishing performance and the suspension performance of polishing powder.

Abstract: The present invention relates to a method of precipitation of metal ions. Mineral(s), oxide(s), hydroxide(s) of magnesium and/or calcium are adopted as raw materials, and the raw material(s) is processed through at least one step of calcination, slaking, or carbonization to produce aqueous solution(s) of magnesium bicarbonate and/or calcium bicarbonate, and then the solution(s) is used as precipitant(s) to deposit rare earth, such as nickel, cobalt, iron, aluminum, gallium, indium, manganese, cadmium, zirconium, hafnium, strontium, barium, copper and zinc ions. And at least one of metal carbonates, hydroxides or basic carbonates is obtained, or furthermore the obtained products are calcined to produce metal oxides. The invention takes the cheap calcium and/or magnesium minerals or their oxides, hydroxides with low purity as raw materials to instead common precipitants such as ammonium bicarbonate and sodium carbonate etc.

Abstract: The present invention relates to a method of precipitation of metal ions. Mineral(s), oxide(s), hydroxide(s) of magnesium and/or calcium are adopted as raw materials, and the raw material(s) is processed through at least one step of calcination, slaking, or carbonization to produce aqueous solution(s) of magnesium bicarbonate and/or calcium bicarbonate, and then the solution(s) is used as precipitant(s) to deposit rare earth, such as nickel, cobalt, iron, aluminum, gallium, indium, manganese, cadmium, zirconium, hafnium, strontium, barium, copper and zinc ions. And at least one of metal carbonates, hydroxides or basic carbonates is obtained, or furthermore the obtained products are calcined to produce metal oxides. The invention takes the cheap calcium and/or magnesium minerals or their oxides, hydroxides with low purity as raw materials to instead common precipitants such as ammonium bicarbonate and sodium carbonate etc.