Materials, methods, and techniques for producing doped cerium oxide

Abstract

To provide doped cerium oxide having a large oxygen storage capacity, enabling not only its use as a co-catalyst in exhaust gas catalysts but also the removal of nitrous oxide and the conversion of carbon dioxide to nitrous oxide.SOLUTION: Doped cerium oxide particles may comprise about 90 weight percent (wt.%) to about 99.9 wt.% cerium oxide (CeO2) and up to about 10 wt.% dopant. Exemplary doped cerium oxide particles may have a BET specific surface area of more than 150 m2 / g after calcination at 500°C for 8 hours. Exemplary doped cerium oxide particles may have an oxygen storage capacity (OSC) of more than 900 μmol O2 / g after calcination at 500°C for 8 hours.SELECTED DRAWING: None

Description

[Technical Field]

[0001] Cross-reference of related applications This application, which is incorporated in its entirety herein, was filed on November 24, 2020. We claim priority from U.S. Provisional Patent Application No. 63 / 117,558.

[0002] The materials, methods, and techniques disclosed herein relate to doped cerium oxide. More specifically, this disclosure relates to the generation and properties of doped cerium oxide particles. [Background technology]

[0003] Cerium (Ce) is a trivalent cerium, also known as ceria or cerium. Cerium oxide is a rare earth element that can exist in any of the tetravalent (cerium) states. Materials containing this compound have been used in a variety of applications, including catalytic effects such as purifying exhaust gases from vehicles. Cerium oxide materials typically absorb oxygen in an oxidizing atmosphere and desorb oxygen in a reducing atmosphere. It possesses the property of absorbing / desorbing oxygen. Due to this oxygen absorption / desorption capability, cerium oxide material is a process gas. It will be possible to use it for various purposes, such as purifying harmful components inside. [Overview of the project]

[0004] In one embodiment, doped cerium oxide particles are disclosed. Exemplary doped cerium oxide particles It contains approximately 90 wt% to 99.9 wt% cerium oxide (CeO2). It may contain dopants of approximately 10 wt% or less. An example of doped cerium oxide particles is 5 After baking at 0°C for 8 hours, 150m 2 It may have a BET specific surface area exceeding / g. - After calcination at 500°C for 8 hours, the cerium oxide particles exceeded 900 μmol·O2 / g. It may possess oxygen storage capacity (OSC).

[0005] In another embodiment, a method for producing doped cerium oxide particles is disclosed. An exemplary method is The solvent has a rare earth oxide concentration of 10 to 50 grams of CeO2 per liter. The steps include adding at least one dopant to the Ce(NO3)4 solution; After adding at least one type of dopant, the Ce(NO3)4 solution containing the dopant is heated. The steps are: to induce hydrolysis; to cool the resulting mixture; and The steps are: neutralizing the mixture to pH 8-9; and filtering the neutralized mixture to remove the residue. ) and the step of generating a permeate; the step of burning the residue; and the step of drying. It can include this.

[0006] To gain some benefit from this disclosure, we have provided information on materials and technologies related to doped cerium oxide. There is no specific requirement that the method include all of the details characterized herein. The specific examples characterized herein mean exemplary applications of the described technology, and alternatively, Substitutions are possible. [Modes for carrying out the invention]

[0007] The materials, methods, and techniques disclosed and intended herein relate to the production of doped cerium oxide. Regarding this, exemplary doped cerium oxide can be used in a variety of applications, especially ceria and By comparison, improved oxygen mobility properties can be observed. For example, disclosed herein Doped cerium oxide is used in processes such as hydrogen gas (H2) generation and diacitic acid production. The process of converting carbon dioxide (CO2) to methane (CH4), as well as nitric acid (HNO3) Remove nitrous oxide (N2O) from adipic acid (CH2)4(COOH)2. It can be used as a catalyst in processes such as those described herein. Exemplary doped cerium oxide particles exhibit high performance in a temperature range of approximately 300°C to 800°C. It may be particularly suitable. Exemplary doped cerium oxide is intended for other applications.

[0008] definition Unless otherwise defined, all technical and scientific terms used herein are understood by those skilled in the art. This has the same meaning as it is generally understood. In case of any conflict, this document, which includes the definition, takes precedence. Exemplary methods and materials are described below, but are similar to those described herein. Equivalent methods and materials can be used in the implementation or testing of the present disclosure. The materials, methods, and examples disclosed herein are illustrative and not intended to limit the scope of this document.

[0009] The terms "comprise," "include," and "have" as used herein ) ”, has ”, can ”, contain ) The terms and their variations are non-restrictive and do not preclude the possibility of additional acts or structures. It is intended to be a transitional phrase, term, or word. Singular form: "one (a)" "An" and "the" refer to the plural unless the context clearly indicates otherwise. This includes references to the following. This disclosure also includes, whether expressly or otherwise, the following references to the foregoing. Other examples of embodiments or elements shown include "includes," "consists of," and "essentially consists of." We also intend to implement it in a specific form.

[0010] The definitions of specific functional groups and chemical terms are described in more detail below. Therefore, chemical elements are found in the periodic table, CAS version, and Handbook of Chemistry and Physics. Identified according to the inside cover of ICS 75th edition, specific functional groups are as described therein. It is generally defined as follows.

[0011] In this specification, when describing numerical ranges, each number falling within that range must be explicitly specified with the same degree of precision. This is intended to be the case. For example, for the range of 6 to 9, the numbers 7 and 8 in addition to 6 and 9 are intended to be the case. It is assumed that for the range 6.0-7.0, the values ​​will be 6.0, 6.1, 6.2, 6.3, 6.4, The numbers 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are explicitly assumed.

[0012] The modifier "approximately," used in relation to quantity, includes the value being described and is determined by the context. To have meaning (for example, including the degree of error related to the measurement of at least a certain quantity). Modification The word "approximately" should also be considered as disclosing a range defined by the absolute values ​​of two endpoints. Yes, it does. For example, the expression "approximately 2 to approximately 4" also discloses the range "2 to 4". The term can refer to plus or minus 10% of the given number. For example, "approximately 1 "0%" could represent a range of 9% to 11%, and "approximately 1" could represent 0.9 to 1.1. Other meanings of "approximately" can be obvious from the context, such as rounded numbers; therefore, for example, "approximately 1" is 0 0.5 to 1.4 could also mean something else.

[0013] I. Exemplary doped cerium oxide particles Exemplary doped cerium oxide particles can have a variety of chemical compositions and physical properties. Various aspects will be discussed below.

[0014] Exemplary doped cerium oxide particles contain a large proportion of cerium oxide (CeO2). In terms of type, exemplary doped cerium oxide particles are approximately 90.0 wt%~ It may contain approximately 99.9 wt% cerium oxide (CeO2). In various implementation forms, exemplary These doped cerium oxide particles contain approximately 90.0 wt% to 99.9 wt% cerium oxide (C) eO2); approximately 90 wt% to approximately 95 wt% cerium oxide (CeO2); approximately 95 wt% to approximately 99.9 wt% cerium oxide (CeO2); approximately 90 wt% to approximately 92 wt% cerium oxide Cerium oxide (CeO2); 92 wt%~94 wt% 6 wt% cerium oxide (CeO2); 96 wt%~98 wt% cerium oxide (CeO2) 2); Acids with a concentration of 97wt%~99wt%; 95wt%~96wt%; 96wt%~97wt% Cerium oxide (CeO2); 97 wt%~98 wt% cerium oxide (CeO2); or It may contain 98-99.9 wt% cerium oxide (CeO2). In various implementation forms, for example... Typical doped cerium oxide particles contain 90 wt% or more cerium oxide (CeO2); 91 wt% t% or more of cerium oxide (CeO2); 92 wt% or more of cerium oxide (CeO2); 9 3 wt% or more of cerium oxide (CeO2); 94 wt% or more of cerium oxide (CeO2) ;95 wt% or more cerium oxide (CeO2);96 wt% or more cerium oxide (CeO 2); 97 wt% or more cerium oxide (CeO2); 98 wt% or more cerium oxide (C eO2); or may contain 99 wt% or more of cerium oxide (CeO2). Various implementation forms In this state, exemplary doped cerium oxide particles contain less than 99.9 wt% cerium oxide (Ce O2); less than 98 wt% cerium oxide (CeO2); less than 97 wt% cerium oxide ( CeO2); less than 96 wt% cerium oxide (CeO2); less than 95 wt% cerium oxide Cerium oxide (CeO2) less than 94 wt%; less than 93 wt% cerium oxide Cerium oxide (CeO2); less than 92 wt% cerium oxide (CeO2); or less than 91 wt% It may contain a full amount of cerium oxide (CeO2).

[0015] Exemplary doped cerium oxide particles contain approximately 0.1 wt% to 10 wt% of dopant. It is possible. In various implementations, doped cerium oxide particles can be present in concentrations of 0.1 wt% to 10.0 wt%. % dopant; 0wt%~5wt% dopant; 0.1wt%~5wt% dopant T; 5wt%~10wt% dopant; 0.1wt%~3.0wt% dopant; 3 Dopants of 0.0 wt% to 6.0 wt%; dopants of 6.0 wt% to 9.0 wt%; 7 0.0 wt% to 10.0 wt% dopant; 0.1 wt% to 1 wt% dopant; 1 w t%~2wt% dopant; 2wt%~3wt% dopant; 3wt%~4wt% Dopant; 4wt%~5wt% dopant; 5wt%~6wt% dopant; 6w t%~7wt% dopant; 7wt%~8wt% dopant; 8wt%~9wt% Dopant; or may have 9 wt% to 10 wt% dopant. In various implementations Exemplary doped cerium oxide particles contain dopants of 10 wt% or less; and dopants of 9 wt% or less. Dopant; Dopant with 8 wt% or less; Dopant with 7 wt% or less; Dopant with 6 wt% or less Pant; Dopant of 5 wt% or less; Dopant of 4 wt% or less; Dopant of 3 wt% or less Dopant; Dopant of 2 wt% or less; Dopant of 1 wt% or less; Dopant of 0.5 wt% or less Pant; or having less than 0.1 wt% dopant. In various implementations, exemplary Doped cerium oxide particles: dopant exceeding 0.1 wt%; dopant exceeding 0.5 wt% ; Dopant exceeding 1 wt%; Dopant exceeding 2 wt%; Dopant exceeding 3 wt%; 4 wt Dopant exceeding %; Dopant exceeding 5 wt%; Dopant exceeding 6 wt%; Dopant exceeding 7 wt% -Pant; having more than 8 wt% dopant; or having more than 9 wt% dopant.

[0016] Exemplary doped cerium oxide particles may contain one or more dopants. The selection can be made considering one or more end uses for the doped cerium oxide particles. Yes, it is possible. Exemplary components that can be doped into exemplary cerium oxide particles include silicon dioxide. Silicon (SiO2) powder, silicon dioxide (SiO2) gel, tetraethyl orthosilicate (TE) OS), white carbon black (precipitated silica), aluminum oxide (Al2O3) powder The end of the solution contains rare substances such as lanthanum oxide (La2O3) and neodymium(III) oxide (Nd2O3). Examples include earth oxides, zeolites, or combinations thereof. Exemplary zeolites include... This is Zeolite Socony Mobil-5 (H-ZSM-5), HY Zeolite Examples include iodine and H-β zeolite.

[0017] Exemplary doped cerium oxide particles exhibit BET specific surface area, oxygen storage capacity, total pore volume, and It can be described in terms of physical properties such as crystal size and TPR profile. The BET specific surface area measurement device is manufactured by Micromeritics Company. Using N2 physical adsorption and desorption measurements performed with the ASAP2020 automated physical adsorption system. This can be done. The specific surface area of ​​the sample is BET in the range P / P0 = 0.05 to 0.35. It can be calculated using the (Brunauer-Emmett-Teller) multipoint method. The total pore volume is calculated using single-point adsorption at P / P0 = 0.99. The pore volume distribution can be calculated using the BJH method of desorption isotherms.

[0018] X-ray diffraction (XRD) was performed using a D / max 2550VB / manufactured by Rigaku Corporation. Using a PC X-ray diffractometer, with a CuKα radiation source (40kV, 40mA) and a scanning range of 2θ=10°, the measurement was taken. This can be performed using a scanning speed of 6° / min at ~80°. The crystal size (nm) is... Feller's equation d = kλ / βcosθ [where d is the crystal size (nm) and λ is the X-ray wave] The length is (0.15418 nm), β is the half-width of the diffraction peak (degrees), and θ is the diffraction angle ( It can be calculated by [the formula, where K is Scherrer's constant (0.89)].

[0019] Hydrogen temperature-programmed reduction (H2-TPR) measurement AUTOChem, manufactured by Micromeritics Company II. Using a 2920 type chemical adsorption device, 90% argon and 10% hydrogen are used. Using the available carrier gas, the temperature is raised from 100°C to 800°C at a gas flow rate of 50 ml / min. This can be performed using 0.1 g of sample at a heating rate of °C / min.

[0020] The oxygen storage capacity (OSC) of a sample can be determined by a thermal conductivity detector (TCD). The hydrogen consumption of the sample can be converted by the reduction peak area of ​​a certain amount of copper oxide powder. can be achieved. In the H2-TPR curve, the baseline in the temperature range of 200 to 600 °C and the area (S1) between the TPR curve and the area between the baseline in the temperature range of 600 to 800 °C and the TPR curve (S2), the ratio of S1 / S2 was defined.

[0021] The doped cerium oxide particles can be characterized from the perspective of the BET specific surface area. In some cases, exemplary doped cerium oxide particles, after calcination at 300 °C for 10 hours, 20 0 m<00,00002> / g or more, more than 210 m<00,00003> / g or more, more than 220 m<00,00004> / g or more; more than 230 m<00,00005> / g or more; or more than 240 m<00,00006> / g may have a BET specific surface area. In some cases, exemplary doped cerium oxide particles, after calcination at 300 °C for 10 hours, 250 m<00,00007> / g or less; 240 m<00,00008> / g or less; 2 30 m<00,00009> / g or less; or 220 m<00,00010> / g or less; or 210 m<00,00011> / g or less may have a BET specific surface area. In various embodiments, exemplary doped cerium oxide particles, after calcination at 300 °C for 10 hours, about 200 m<00,00012> / g to about 250 m<00,00013> / g; 200 m<00,00014> / g to 225 m<00,00015> / g ; 225 m<00,00016> / g to 250 m 2 / g; 200 m<00,00018> / g to 210 m<00,00019> / g; 210 m<00,00020> / g ~ 220 m<00,00021> / g; 220 m<00,00022> / g to 230 m<00,00023> / g; 230 m 2 / g to 240 m<00,00025> / g ; or 240m 2 / g~250m 2 It may have a BET specific surface area of ​​ / g.

[0022] In some cases, exemplary doped cerium oxide particles, after being calcined at 500°C for 8 hours, 150m 2 / g over;160m 2 / g over;170m 2 / g over;180m 2 / g greater than; or 1 90m 2 It may have a BET specific surface area greater than / g. In some cases, exemplary doped ceryl oxide The um particles were fired at 500°C for 8 hours, then 200m 2 / g or less; 190m 2 / g or less; 180m 2 / g or less; 170m 2 / g or less; or 160m 2 BET specific surface area less than / g It may have. In various implementation forms, exemplary doped cerium oxide particles are heated at 500°C for 8 hours. After the grilling in between, about 150m 2 / g~about 200m 2 / g;150m 2 / g~175m 2 / g ;175m 2 / g~200m 2 / g;150m 2 / g~160m 2 / g;160m 2 / g ~170m 2 / g;170m 2 / g~180m 2 / g;180m 2 / g~190m 2 / g ; or 190m 2 / g~200m 2 It may have a BET specific surface area of ​​ / g.

[0023] In some cases, exemplary doped cerium oxide particles, after being calcined at 700°C for 5 hours, 100m 2 / g over;110m 2 / g over;120m 2 / g over;130m 2 / g greater than; or 1 40m 2 It may have a BET specific surface area greater than / g. In some cases, exemplary doped ceryl oxide The um particles were fired at 700°C for 5 hours, then 150m 2 / g or less; 140m 2 / g or less; 130m 2 / g or less; 120m 2 / g or less; or 110m 2 BET specific surface area less than / g It may have. In various implementation forms, exemplary doped cerium oxide particles are heated at 700°C for 5 hours. After the grilling in between, about 100m 2 / g~about 150m 2 / g;100m 2 / g~125m 2 / g ;125m 2 / g~150m 2 / g;100m 2 / g~110m 2 / g;110m 2 / g ~120m 2 / g;120m 2 / g~130m 2 / g;130m 2 / g~140m 2 / g ; or 140m 2 / g~150m 2 It may have a BET specific surface area of ​​ / g.

[0024] In some cases, exemplary doped cerium oxide particles, after being calcined at 900°C for 5 hours, 55m 2 / g over;65m 2 / g over;75m 2 / g over;85m 2 / g or more; or 90m 2 / It may have a BET specific surface area of g super. In some cases, exemplary doped cerium oxide particles , after calcination at 900 °C for 5 hours, 100 m 2 / g or less; 90 m 2 / g or less; 80 m 2 / g or less; 70 m 2 / g or less; or may have a BET specific surface area of less than 60 m 2 / g. In various implementation forms, exemplary doped cerium oxide particles, after calcination at 900 °C for 5 hours, are about 5 5 m 2 / g to about 100 m 2 / g; 55 m 2 / g to 80 m 2 / g; 75 m 2 / g to 100 m 2 / g; 55 m 2 / g to 65 m 2 / g; 65 m 2 / g to 75 m 2 / g; 75 m 2 / g to 8 5 m 2 / g; 85 m 2 / g to 95 m 2 / g; or may have a BET specific surface area of 90 m 2 / g to 100 m 2 / g. T specific surface area.

[0025] Doped cerium oxide particles can be characterized from the perspective of oxygen storage capacity (OSC). Exemplary doped cerium oxide particles, after calcination at 500 °C for 8 hours, are more than 900 μmol ·O2 / g; more than 1000 μmol·O2 / g; or may have an OSC of more than 1100 μmol·O2 / g. Exemplary doped cerium oxide particles, after calcination at 500 °C for 8 hours, may have an OSC of 1200 μmol·O2 / g or less; 1100 μmol·O2 / g or less; or 1000 μ mol·O2 / g or less. In various implementation forms, exemplary doped cerium oxide The lium particles were calcined at 500°C for 8 hours, resulting in a concentration of 900 μmol·O2 / g ~ 1200 μm. ol·O2 / g;900μmol·O2 / g~1050μmol·O2 / g;1050μ mol·O2 / g~1200μmol·O2 / g;900μmol·O2 / g~1000 μmol·O2 / g; 1000μmol·O2 / g to 1100μmol·O2 / g; also It may have an OSC of 1100 μmol·O2 / g to 1200 μmol·O2 / g.

[0026] Exemplary doped cerium oxide particles were calcined at 700°C for 5 hours, resulting in 800 μmol. O2 / g greater than 900 μmol·O2 / g; or OS greater than 1000 μmol·O2 / g It may contain C. Exemplary doped cerium oxide particles were calcined at 700°C for 5 hours, and then 11 00 μmol·O2 / g or less; 1000 μmol·O2 / g or less; or 900 μmol • May have an OSC of O2 / g or less. In various implementation forms, exemplary doped cerium oxide The particles were calcined at 700°C for 5 hours, resulting in a concentration of 800 μmol·O2 / g to 1100 μmol· O2 / g;800μmol·O2 / g~950μmol·O2 / g;950μmol·O 2 / g~1100μmol·O2 / g;800μmol·O2 / g~900μmol·O 2 / g; 900 μmol·O2 / g ~ 1000 μmol·O2 / g; or 1000 μm It may have an OSC of ol·O2 / g to 1100 μmol·O2 / g.

[0027] Exemplary doped cerium oxide particles were calcined at 900°C for 5 hours, resulting in a volume of 700 μmol. OSC greater than O2 / g; greater than 800 μmol·O2 / g; or greater than 900 μmol·O2 / g It may have. Exemplary doped cerium oxide particles are calcined at 900°C for 5 hours, then 100 0 μmol·O2 / g or less; 900 μmol·O2 / g or less; or 800 μmol·O It may have OSCs of 2 / g or less. In various implementation forms, exemplary doped cerium oxide particles After baking at 900°C for 5 hours, the concentration is 700 μmol·O2 / g to 1000 μmol·O2. / g;700μmol·O2 / g~850μmol·O2 / g;850μmol·O2 / g~1000μmol·O2 / g;700μmol·O2 / g~800μmol·O2 / g; 800 μmol·O2 / g ~ 900 μmol·O2 / g; or 900 μmol·O It may have an OSC of 2 / g to 1000 μmol·O2 / g.

[0028] Doped cerium oxide particles can be characterized in terms of total pore volume. Doped cerium oxide particles, after calcination at 300°C for 10 hours, were larger than 0.40 mL / g. i; greater than 0.50 mL / g; greater than 0.60 mL / g; or 0.70 mL / It may have a total pore volume greater than g. Exemplary doped cerium oxide particles can be heated at 300°C. After 0 hours of heating, the levels were 0.80 mL / g or less; 0.70 mL / g or less; 0.60 mL / g or less. It may have a total pore volume that is larger than or greater than 0.70 mL / g. Exemplary doped cerium oxide particles were subjected to calcination at 300°C for 10 hours, then 0.4 mL / g~0.8mL / g;0.4mL / g~0.6mL / g;0.6mL / g~0.8mL / g;0.4mL / g~0.5mL / g;0.5mL / g~0.6mL / g;0.6mL / It may have a total pore volume of 0.7 mL / g or 0.7 mL / g to 0.8 mL / g.

[0029] Doped cerium oxide particles can be characterized in terms of total pore volume. Doped cerium oxide particles were greater than 0.40 mL / g after calcination at 500°C for 8 hours. ; greater than 0.50 mL / g; greater than 0.60 mL / g; or 0.70 mL / g It may have a larger total pore volume. Exemplary doped cerium oxide particles were subjected to 8 hours at 500°C. After intermediate roasting, levels below 0.80 mL / g; below 0.70 mL / g; greater than 0.60 mL / g. It may have a total pore volume greater than 0.70 mL / g; or 0.70 mL / g. In various implementations, Exemplary doped cerium oxide particles, after calcination at 500°C for 8 hours, yielded a concentration of 0.4 mL / g ~ 0 .8mL / g;0.4mL / g~0.6mL / g;0.6mL / g~0.8mL / g;0 .4mL / g~0.5mL / g;0.5mL / g~0.6mL / g;0.6mL / g~0 It may have a total pore volume of 0.7 mL / g or 0.7 mL / g to 0.8 mL / g.

[0030] Doped cerium oxide particles can be characterized in terms of total pore volume. Doped cerium oxide particles were greater than 0.35 mL / g after calcination at 700°C for 5 hours. ; greater than 0.45 mL / g; greater than 0.55 mL / g; or 0.65 mL / g It may have a larger total pore volume. Exemplary doped cerium oxide particles were fermented at 700°C for 5 hours. After intermittent roasting, levels below 0.70 mL / g; below 0.60 mL / g; greater than 0.50 mL / g. It may have a total pore volume greater than 0.40 mL / g; or 0.40 mL / g. In various implementations, Exemplary doped cerium oxide particles, after calcination at 700°C for 5 hours, have a concentration of 0.35 mL / g. 0.7mL / g;0.35mL / g~0.53mL / g;0.52mL / g~0.7mL / g; 0.35mL / g~0.45mL / g; 0.45mL / g~0.55mL / g; 0 Total pore volume of 0.55 mL / g to 0.65 mL / g; or 0.6 mL / g to 0.7 mL / g It may have a product.

[0031] Doped cerium oxide particles can be characterized in terms of total pore volume. Doped cerium oxide particles were greater than 0.35 mL / g after calcination at 900°C for 5 hours. ; greater than 0.45 mL / g; greater than 0.55 mL / g; or 0.65 mL / g It may have a larger total pore volume. Exemplary doped cerium oxide particles were heated at 900°C for 5 hours. After intermittent roasting, levels below 0.70 mL / g; below 0.60 mL / g; greater than 0.50 mL / g. It may have a total pore volume greater than 0.40 mL / g; or 0.40 mL / g. In various implementations, Exemplary doped cerium oxide particles, after calcination at 900°C for 5 hours, have a concentration of 0.35 mL / g. 0.7mL / g;0.35mL / g~0.53mL / g;0.52mL / g~0.7mL / g; 0.35mL / g~0.45mL / g; 0.45mL / g~0.55mL / g; 0 Total pore volume of 0.55 mL / g to 0.65 mL / g; or 0.6 mL / g to 0.7 mL / g It may have a product.

[0032] Doped cerium oxide particles are particularly noteworthy in terms of pore volume divided by total pore volume (d > 3 nm). This can be marked. Exemplary doped cerium oxide particles were calcined at 300°C for 10 hours. Afterwards, it may have at least 98% pore volume (d>3nm) / total pore volume. Exemplary d - After calcination at 500°C for 8 hours, the cerium oxide particles have a pore volume of at least 98%. d > 3 nm) / total pore volume may be present. Exemplary doped cerium oxide particles can be heated at 700°C. After 5 hours of calcination, it may have at least 98% pore volume (d>3nm) / total pore volume. Exemplary doped cerium oxide particles, after calcination at 900°C for 8 hours, show at least 98% It may have a pore volume (d>3nm) / total pore volume.

[0033] Doped cerium oxide particles can be characterized in terms of crystal size. After calcination at 500°C for 8 hours, the doped cerium oxide particles have a crystal size of less than approximately 10 nm. It may have. In various implementation forms, exemplary doped cerium oxide particles are heated at 500°C for 8 hours. After the intermediate burning, 6nm~10nm; 6nm~8nm; 8nm~10nm; 6nm~7nm The crystal size may be 7nm-8nm; 8nm-9nm; or 9nm-10nm. In various implementations, exemplary doped cerium oxide particles are subjected to calcination at 500°C for 8 hours. It may have a crystal size of 6 nm or larger; 7 nm or larger; 8 nm or larger; or 9 nm or larger. In various implementations, exemplary doped cerium oxide particles are calcined at 500°C for 8 hours, The crystal size may be 10 nm or less; 9 nm or less; 8 nm or less; or 7 nm or less.

[0034] Doped cerium oxide particles are considered to have a hydrogen (H2)-temperature-reducing (TPR) profile. It can be characterized by the H2-TPR profile generated Rough presented (A1) H2-TPR curves and baselines in the temperature range of 200°C to 600°C. The area defined by (A2) the H2-TPR curve in the temperature range of 600°C to 800°C. and the ratio of areas defined by the baseline, defined in terms of A1 / A2. Yes, it is possible. Exemplary doped cerium oxide particles, after calcination at 500°C for 8 hours, yielded 1.0-1. It may have an A1 / A2 ratio of 0.5. Exemplary doped cerium oxide particles are fermented at 700°C for 5 hours. After intermediate calcination, it may have an A1 / A2 ratio of 0.7 to 1.0. Exemplary doped cerium oxide. After firing at 900°C for 5 hours, the particles may have an A1 / A2 ratio of 0.35 to 0.7. Doped cerium oxide particles, after being calcined at 500°C for 8 hours, have a pH of 1.5 or less and 1.25 or less. or may have an A1 / A2 ratio of 1.0 or less. Doped cerium oxide particles can be used at 500°C After 8 hours of baking, it may have an A1 / A2 ratio greater than 0.7, greater than 1.0, or greater than 1.3. .

[0035] II. Exemplary Methods for Producing Cerium(IV) Hydroxide Using exemplary methods, cerium(IV)(Ce(OH)4) hydroxide precipitate and nitrate A cerium(IV) oxide solution can be produced. Now, during the synthesis of doped cerium oxide... Then, using the generated cerium(IV) hydroxide precipitate and cerium(IV) nitrate solution This is also acceptable. Embodiments other than those discussed below may include more or fewer operations. stomach.

[0036] The exemplary method can be started with a basic solution. The exemplary basic solution is 1.0 It can be prepared to have a base concentration of mol / L to 4.0 mol / L, at 20°C~ Temperatures below 30°C, such as 30°C, are also acceptable. An exemplary basic solution is NaOH. While preparing the basic solution, stir at approximately 800 rpm to 1200 rpm. can.

[0037] Next, the raw materials are added to the basic solution. In some cases, the raw materials are added in batches. It is possible. Typically, the temperature of the basic solution is 20-30°C. Exemplary raw materials are, It may be cerium chloride (CeCl3). In some cases, it is a raw material added to a basic solution. It contains 50-200g of CeO2 / L and free [H + ] is 0.05~0.5 mol / L In some cases, the exemplary starting material can be diluted before being added to the NaOH solution. For example, by diluting 300-500g of CeO2 / L initial solution, 50-200 A solution of 1g CeO2 / L CeCl3 can be prepared. Deionized water is used for dilution. It is possible.

[0038] The resulting mixture of raw materials and basic solution is subjected to air bubbling and / or stirring. It is possible. In some cases, the basic solution is air-bubbled before adding the raw materials. It can be used for various purposes. For example, air bubbling can produce 150-300 L-air / hour. It can be supplied at a speed of 100°C or faster. Air bubbling and / or stirring This can be carried out for a predetermined time, such as 1 to 5 hours. During that time, reverse precipitation can occur. A precipitation may occur.

[0039] After back precipitation, the solution is prepared at a constant temperature of typically 20°C to 30°C for a set period of time, such as 2 to 6 hours. The mixture can be aged. Typically, the resulting mixture has a pH of 12.0-13. It has a pH of at least 12, such as 0.5. During aging, the resulting mixture changes from a purple hue to yellow. It has the potential to change the hue of a color.

[0040] Filtration can be used to remove various ions. For example, NaOH is basic When used as a solution, Na during filtration + and Cl - It can remove ions. To achieve filtration of target ions, various filtration methods known in the art are selected. This can be done. To further remove the target ions, once or multiple times The cleaning operation can be performed.

[0041] After removing the target ions, the base concentration should be 0.01 to 0.1 mol per liter. The precipitate can be re-pulped in a basic solution containing [some]. In some cases, NaOH can be used in the basic solution. Repulping is, for example, 80 It can be performed with stirring at 0 rpm to 1200 rpm and at room temperature such as 20°C to 30°C. It is possible.

[0042] Solution aging can be accompanied by air bubbling through a porous air distributor. Bubbling can be provided at an airflow rate of 150-300 L per hour. Aging is, Perform the process at a temperature of 20°C to 30°C for a specified period of time, such as at least 30 minutes or 1 to 6 hours. This is then performed. The resulting mixture is then subjected to a second filtration process.

[0043] After filtration, the mixture can be washed. The first wash is performed with high-temperature deionized water (40°C). This can be done using a temperature of ~80°C, or possibly 50°C to 65°C. First wash This can be done multiple times, such as 2, 3, 4, 5, or up to 10 times.

[0044] The second wash is performed with high-temperature deionized water (which can be 40°C to 80°C or 50°C to 65°C). This can be done using a mixture of a strong acid such as nitric acid (HNO3). Used for the second wash. The resulting mixture may have a pH of approximately 4 to 5. The resulting residue may have a pH of 8 to 10. The resulting residue can have an electrical conductivity (EC) of less than 20 μS / cm. The washing in step 2 may be performed multiple times, such as two, three, four, five, or up to ten times.

[0045] After washing, a wet cake of cerium(IV) hydroxide remains. In some cases, cerium hydroxide Um(IV) moist cakes exhibit a loss of ignition (LOI) of 55% to 65%. It may have. In some cases, the total cerium in the cerium(IV) hydroxide-moistened cake At least 95% or at least 97% of the um chemical species is cerium(IV)(Ce 4+ ) may be. In some cases, CeO2 / total in a cerium(IV) hydroxide wetted cake. The ratio of rare earth oxides (TREOs) is at least 99% or at least 99.5%. Obtain. In some cases, the proportion of cerium oxide in a cerium(IV) hydroxide-moistened cake is It could be between 35% and 60%.

[0046] Cerium(IV) hydroxide-moistened cakes may contain one or more impurities. For example, an exemplary cerium(IV) hydroxide wetted cake is aluminum oxide (Al2O 3), Cl - na + Iron oxide (Fe2O3), zinc oxide (ZnO), and silicon dioxide The material contains one or more of the following impurities: 0.01 wt% or less of each impurity. It is possible.

[0047] Cerium(IV) hydroxide wetted cake can be dissolved in strong acid solutions such as HNO3. It is possible. In some implementations, the weight percentage of the strong acid in a strong acid solution is approximately 65%~ The concentration can be as high as approximately 65%, such as around 68%. Strong acid solutions should be prepared at high temperatures, such as approximately 65°C to 100°C. It can be warm. The molar ratio of strong acid to CeO2 can be 4.1 to 5.5. In the mixture, the weight percentage of the wet cake is approximately 42%. The resulting slurry is 65 It can be stirred at ~100°C for 5 to 30 minutes. In some cases, the slurry is clear red. When a certain hue is present, stirring can be terminated.

[0048] The resulting Ce(NO3)4 solution has a CeO2 concentration of 250-300 g per liter. It can contain, and more than 97% of all cerium chemical species is cerium(IV)(Ce 4+ ) It is possible. The resulting Ce(NO3)4 solution contains 0.1-0.5 [H + ] / Total Cerium Chemistry It may have a molar ratio of species.

[0049] III. Exemplary Methods for Synthesizing Doped Cerium Oxide Particles Doped cerium oxide particles can be synthesized using exemplary methods. Embodiments other than those discussed may include more or fewer operations. An exemplary method for generating lium particles is typically before hydrolysis, but after precipitation. The process includes the step of adding a dopant. In some cases, the dopant added before hydrolysis. In addition to the pant, a dopant may be added after hydrolysis.

[0050] An exemplary method involves using 10 to 50 grams of rare earth elements, such as CeO2, per liter of solvent. This can be initiated by preparing a Ce(NO3)4 solution with an oxide concentration. It is possible. In some implementations, cerium nitrate (I) produced using the method described above is used. V) (Ce(NO3)4) solution is diluted, for example, 10 grams per liter of solvent. 50 grams of CeO2; 10 to 30 grams of CeO2 per liter of solvent; solvent 15 to 25 grams of CeO2 per liter; or 20 grams per liter of solvent It is possible to achieve rare earth oxide concentrations of gram to 40 grams of CeO2. The prepared Ce(NO3)4 solution contains at least 10 grams of Ce per liter of solvent. O2; at least 20 grams of CeO2 per liter of solvent; small amount per liter of solvent At least 30 grams of CeO2; or at least 40 grams of C per liter of solvent May contain eO2. Deionized water can be used as a diluent.

[0051] Next, one or more dopants can be added to the Ce(NO3)4 solution. Various dopants can be added at this stage. An example dopant is shown above. We are discussing in more detail silicon dioxide (SiO2) powder and silicon dioxide (SiO2) gel. Tetraethyl orthosilicate (TEOS), white carbon black, aluminum oxide Examples include al(Al2O3) powder, lanthanum (La), and zeolite. Typically, The amount of dopant to be added is 0.1 wt% to 10 wt% of the Ce(NO3)4 solution. An example of silicon dioxide (SiO2) powder is 200-250 ml. 2 BET surface area per g It may have. An example of aluminum dioxide (Al2O3) powder is 200-250m 2 / It may have a BET surface area of ​​g.

[0052] After adding the dopant, the mixture is heated to a predetermined temperature. Typically, the predetermined temperature is It can be 120°C to 150°C. In various mounting configurations, the specified temperature is 120°C to 130°C. °C; 130°C to 140°C; or 140°C to 150°C. Heating to a predetermined temperature is This can take 30 minutes to 2 hours. After reaching the predetermined temperature, maintain the mixture at the predetermined temperature for approximately 6 hours. It can be maintained for approximately 12 hours. During this time, hydrolysis may occur.

[0053] After the hydrolysis operation, the resulting mixture can be cooled. In some cases, the obtained Lower the temperature of the mixture to below 50°C.

[0054] At this point, one or more dopants may be added at will. (Example) Typical dopants are discussed in more detail above, such as silicon dioxide (SiO2) powder, diacityl Silicon (SiO2) gel, tetraethyl orthosilicate (TEOS), white carbon Black, aluminum oxide (Al2O3) powder, lanthanum (La), zeolite, also These combinations can be listed. Typically, the amount of dopant added is Ce (NO3)4 solution is 0.1 wt% to 10 wt%. Dopants are added at this stage. In that case, the specified time, usually 30 minutes, 60 minutes, or 90 minutes, is obtained between 30 and 90 minutes. The mixture can be stirred.

[0055] Next, the resulting mixture, usually a slurry, is neutralized to pH 8-9. Typically, The slurry precipitates when neutralized. In some cases, hydroxide is used to neutralize the pH. A weak base such as ammonium (NH4OH) can be used. When used, the concentration may be greater than 25%. Neutralization of the resulting mixture takes 10 minutes to 3 minutes. This may involve stirring for a predetermined period of time, such as 0 minutes.

[0056] After neutralization, one or more dopants may be added as an option. (Example) The dopants discussed above in more detail include silicon dioxide (SiO2) powder and silicon dioxide. Silicon (SiO2) gel, tetraethyl orthosilicate (TEOS), white carbon Examples include lac, aluminum oxide (Al2O3) powder, lanthanum (La), and zeolite. This is possible. Typically, the amount of dopant added is 0.1% of the Ce(NO3)4 solution. The concentration is wt% to 10 wt%. If a dopant is added at this stage, it is usually added for a specified time. The resulting mixture is stirred for 30 to 90 minutes, such as 30 minutes, 60 minutes, or 90 minutes. can.

[0057] Next, the obtained precipitate is subjected to filtration. By exemplary filtration procedures, the residue, typically This produces a wet cake and a permeate. In order to produce a wet cake as a residue, Any type of filtration known in the technical field can be used.

[0058] The moist cake residue can be dried and baked at a given temperature for a predetermined time. The product is typically doped cerium oxide powder. For example, wet cake residue, 30 It can be baked at 0°C for 10 hours. For example, moist cake residue can be baked at 500°C for 8 hours. It can be baked. For example, a moist cake residue can be baked at 700°C for 5 hours. Yes, it is possible. In a certain implementation, the wet cake residue is baked at 300°C for 10 hours, and then C Bake the eO2 powder at 900°C for 5 hours.

[0059] In some cases, one or more dopants are added to the calcined residue (typically a powder). It can be impregnated with, for example, silicon dioxide (SiO2) gel or orthosilicic acid. Tetraethyl (TEOS) can be doped into the calcined residue. These implementations In terms of form, doping is followed by drying, and then baking at a predetermined temperature for a predetermined time. For example, the impregnated powder can be baked at 500°C for 5 hours.

[0060] IV. Exemplary Uses Exemplary embodiments of doped cerium oxide can be used in a variety of applications. In this case, doped cerium oxide can be particularly useful when using particles as a catalyst. It has improved oxygen transport properties. For example, exemplary doped cerium oxide particles are , exhaust gas purification, oxidation of carbon monoxide (CO), hydrogenation of carbon dioxide (CO2), aqueous gas Production of hydrogen gas (H2) and methane (CH4) by water-gas shift reaction. It can also be used to modify alcohol.

[0061] In some cases, exemplary methods for generating hydrogen gas (H2) are described herein. The process includes contacting a precursor raw material with an exemplary doped cerium oxide. In some cases, An exemplary method for converting carbon dioxide (CO2) to methane (CH4) is described herein. The process includes the step of contacting exemplary doped cerium oxide with carbon dioxide (CO2). In this case, exemplary methods for removing nitrous oxide (N2O) from the raw materials are described herein. Exemplary doped cerium oxide with nitric acid (HNO3) and / or adipic acid (CH2) The process includes a step of bringing the raw material containing 4(COOH)2 into contact with the raw material.

[0062] V. Experimental Examples Without limiting the scope of this disclosure, various experimental examples of the embodiments discussed above have been prepared and concluded The results will be discussed below.

[0063] A. Preparation of Ce(OH)4 raw materials and Ce(NO3)4 solution An experimental example of the Ce(OH)4 starting material was prepared using the following procedure. Initially, 2.5 mol / L A 0.5 L NaOH solution with the specified concentration was added to a 2 L beaker. The resulting mixture The mixture was stirred at 25-30°C with a stirring speed of 800-1,000 rpm.

[0064] Next, 200-250 L of air is added to the above NaOH solution through a porous air distributor. Air was blown in at a flow rate over time. Then 0.5L with a concentration of 100g-CeO2 / L was added. Place the CeCl3 solution into the NaOH solution in which air has been blown in, and soak at 25-30°C for 2 hours. It was slowly added dropwise. The above 100g-CeO2 / L CeCl3 solution contains approximately 300g-CeO 2 / L initial CeCl3 solution (free [H + A concentration of 0.1 mol / L ( ) is prepared using deionized water. It was prepared by dilution.

[0065] After 2 hours of back precipitation, the slurry was continuously aged at 25-30°C for 2 hours, and the slurry was... The color changed from purple to yellow, and the final pH was 12.5-13.5. The precipitate was first It is subjected to filtration, and then washed for the first time with deionized water, and Na + and Cl - Impurities were removed.

[0066] The precipitate that underwent the first wash was placed in a 1 L solution of 0.025 mol / L NaOH. Repulping, vigorously stirring at 25-30°C with a stirring speed of 800-1,000 rpm, simultaneously Next, air is blown into the above repulped slurry at a flow rate of 200-250 L-air / hour. Yes. After aging at 25-30°C for one hour, the slurry changed to a more vivid yellow color.

[0067] The precipitate is subjected to a second filtration, and then filtration is performed five times with 1 L of deionized water (60-65°C), and then with 1 L of Wash once with an HNO3 solution diluted with deionized water (pH=4.5-5, 60-65°C). The final residue had a pH of 8-9 and an electrical conductivity (EC) of less than 20 μS / cm. After a second wash and filtration, a Ce(OH)4 wet cake was obtained. Properties of 4 tatami mats or less: Ce 4+ / ΣCe=98.5%;CeO2 / TREO=99.8 It contained %;TREO=42.0% (TREO is total rare earth oxides).

[0068] An exemplary Ce(NO3)4 solution was prepared as follows. The moist cake (TREO=42.0%) was prepared at a concentration of 65-68%, with an HNO3 / CeO2 molar ratio. It was added to an HNO3 solution containing 4.5, resulting in a concentration of approximately 300 g-CeO2 / L. Stir the slurry until a clear red solution is formed, and dissolve at 65-100°C for several minutes. Ta.

[0069] B. Preparation of experimental powders

[0070] [Example 1] A specific amount of Ce(NO3)4 initial solution (approximately 300g-CeO2 / L) is added to deionized water. Dilute to prepare a 0.5 L Ce(NO3)4 solution with a concentration of 20 g-CeO2 / L. . 5 wt% SiO2 powder (BET surface area = 200~250 m²) 2 ( / g) diluted C It was added to the e(NO3)4 solution.

[0071] Add the mixed solution to a 1 L autoclave, then stir and heat from room temperature to 125°C. The temperature was raised in 0.5 hours. The hydrolysis reaction was carried out at 125°C for 6 hours. 6 hours of hydrolysis reaction Afterward, the slurry was cooled to below 50°C.

[0072] Neutralize the slurry with NH4OH solution (>25%) until pH=8.5 is achieved, then precipitate. Next, it was stirred for 10 minutes. Then, the precipitate was filtered.

[0073] Dry the moist cake, then bake at 300°C / 10 hours, 500°C / 8 hours, and 700°C Each was baked at 300°C for 5 hours. The CeO2 powder baked at 300°C for 10 hours was then baked at 900°C / I baked it again for 5 hours.

[0074] [Example 2] Except for changing the amount of added SiO2 powder to 10 wt%, the preparation method of Example 1 was followed. That's it.

[0075] [Example 3] After a 6-hour hydrolysis reaction, 10 wt% SiO2 powder was added to the cooled slurry. The preparation method of Example 1 was followed, except for the addition of [ingredient].

[0076] [Example 4] After the neutralization step with NH4OH solution, 10 wt% Si is added to the precipitated slurry. The preparation method of Example 1 was followed, except that O2 powder was added and then stirred for 30 minutes. .

[0077] [Example 5] The dopant is 10 wt% of conventional Al2O3 powder (BET surface area = 200-250 m²). 2 The preparation method of Example 3 was followed, except that it was changed to / g).

[0078] C. Physical properties of the experimental powder Various physical properties of an exemplary powder were measured, and the results are shown in Table 1 below. BET surface area, The test procedures for X-ray diffraction (XRD) and hydrogen thermal reduction (H2-TPR) are described in more detail above. It is described there.

[0079] [Table 1]

[0080] Exemplary Embodiments For reasons of completeness, various aspects of the technology are described below in numbered embodiments.

[0081] Embodiment 1. Approximately 90 wt% to approximately 99.9 wt% cerium oxide (C) doped cerium oxide particles containing eO2 and a dopant of approximately 10 wt% or less. , After baking at 500℃ for 8 hours, 150m 2 Having a BET specific surface area greater than / g; After calcination at 500°C for 8 hours, it exhibits an oxygen storage capacity (OSC) exceeding 900 μmol·O2 / g. Having, Doped cerium oxide particles.

[0082] Embodiment 2. The dopant is present in an amount of 0.1 wt% to 5 wt%; The dopant is silicon dioxide (SiO2) powder, silicon dioxide (SiO2) gel, ortho Tetraethyl silicate (TEOS), white carbon black, aluminum oxide (Al 2O3) powder, La2O3, Nd2O3, zeolite, or combinations thereof, Doped cerium oxide particles as described in Embodiment 1.

[0083] Embodiment 3. After calcination at 500°C for 8 hours, the total amount of 0.40 mL / g to 0.8 mL / g is measured. Doped cerium oxide particles according to Embodiment 1 or Embodiment 2, having pore volume.

[0084] Embodiment 4. After calcination at 500°C for 8 hours, at least 98% of the pore volume (d > 3 nm) is obtained. ) / Doped cerium oxide according to any one of Embodiments 1 to 3, having total pore volume particle.

[0085] Embodiment 5. After calcination at 700°C for 5 hours, approximately 800 μmol·O2 / g to approximately 1100 Having an oxygen storage capacity (OSC) of μmol·O2 / g, any one of Embodiments 1 to 4 Doped cerium oxide particles as described above.

[0086] Embodiment 6. After calcination at 500°C for 8 hours, the crystal has a size of less than 10 nm. Doped cerium oxide particles as described in any one of Forms 1 to 5.

[0087] Embodiment 7. After baking at 900°C for 5 hours, approximately 55m 2 / g~about 100m 2 / g BE Doped cerium oxide particles according to any one of Embodiments 1 to 6, having a specific surface area T .

[0088] Embodiment 8. Doped cerium oxide as described in any one of Embodiments 1 to 7 as a precursor A method for generating hydrogen gas (H2), comprising the step of bringing it into contact with a material.

[0089] Embodiment 9. Doped cerium oxide according to any one of Embodiments 1 to 7 is used with carbon dioxide. A step of bringing carbon dioxide (CO2) into contact with methane (CH4) How to convert it.

[0090] Embodiment 10. A method for removing nitrous oxide (N2O) from a raw material, wherein Embodiment 1 Doped cerium oxide as described in any one of 7, nitric acid (HNO3) and / or A method comprising the step of contacting a raw material containing adipic acid (CH2)4(COOH)2.

[0091] Embodiment 11. A method for producing doped cerium oxide particles, The solvent has a rare earth oxide concentration of 10 to 50 grams of CeO2 per liter. The steps include adding at least one dopant to a Ce(NO3)4 solution; After the step of adding at least one dopant, Ce(N) having the dopant The steps involve heating the O3)4 solution to induce hydrolysis; The steps include: cooling the resulting mixture; The step of neutralizing the resulting mixture to pH 8-9; The neutralized mixture is filtered to produce a residue and permeate; The step of burning the residue; Drying step and A method that includes this.

[0092] Embodiment 12. The step of burning the residue is performed in an environment at 300°C for at least 10 hours. The method according to Embodiment 11, which is carried out.

[0093] Embodiment 13. The step of burning the residue is carried out in an environment at 500°C for at least 5 hours. The method according to Embodiment 11 or Embodiment 12.

[0094] Embodiment 14. A solvent having 250 to 300 grams of CeO2 equivalent per liter. Embodiments 11 to 13 further include the step of diluting the Ce(NO3)4 solution. Either one of the methods.

[0095] Embodiment 15. The method according to Embodiment 14, wherein deionized water is used for dilution.

[0096] Embodiment 16. The method according to any one of Embodiments 11 to 15, wherein the Ce(NO3)4 solution is heated to about 120°C to about 150°C.

[0097] Embodiment 17. The method according to Embodiment 16, wherein the Ce(NO3)4 solution is heated for about 6 hours to about 12 hours.

[0098] Embodiment 18. The method according to any one of Embodiments 11 to 17, wherein the cooling step reduces the temperature of the resulting mixture to less than 50°C.

[0099] Embodiment 19. The method according to any one of Embodiments 11 to 18, further comprising a step of adding a second dopant after the cooling step and before the neutralization step.

[0100] Embodiment 20. The method according to any one of Embodiments 11 to 19, further comprising a step of adding a third dopant and stirring after the neutralization step and before the filtration step.

[0101] Embodiment 21. The method according to any one of Embodiments 11 to 20, further comprising a step of impregnating the calcined residue with TEOS or SiO2 gel.

[0102] Embodiment 22. The method according to Embodiment 上記の方法による方法であって、含浸した残渣を500℃で少なくとも5時間か焼するステップをさらに含む。

[0103] Embodiment 23. The method according to any one of Embodiments 1 to 22, wherein ammonium hydroxide (NH4OH) is used during neutralization.

[0104] Embodiment 24. Neutralization includes stirring; the concentration of the NH4OH solution is at least 25%. ​​​​​​​​​The method according to Embodiment 23.

[0105] Embodiment 25. The method according to any one of Embodiments 11 to 24, wherein the dopant contains silicon dioxide (SiO2) powder, silicon dioxide (SiO2 ) gel, tetraethyl orthosilicate (TEOS), white carbon black, aluminum oxide (Al2O3) powder, lanthanum (La), zeolite, or a combination thereof.

[0106] The foregoing detailed description and the accompanying examples are merely illustrative and should not be construed as limiting the scope of the present disclosure. Various changes and modifications to the embodiments of the present disclosure will be apparent to those skilled in the art. Without being limited thereto, such changes and modifications, including those related to chemical structures, substituents, derivatives, intermediates, syntheses, compositions, formulations, or methods of use, can be made without departing from the spirit and scope of the present disclosure. The invention described in the original claims of this application is listed below. [1] Approximately 90 wt% to 99.9 wt% cerium oxide (CeO 2 ); and doped cerium oxide particles containing approximately 10 wt% or less of dopant, The doped cerium oxide particles were calcined at 500°C for 8 hours, and then processed to 150m 2 Having a BET specific surface area greater than / g; The doped cerium oxide particles were calcined at 500°C for 8 hours, resulting in 900 μmol·O 2 Having an oxygen storage capacity (OSC) of more than / g, Doped cerium oxide particles. [2] The dopant is present in an amount of 0.1 wt% to 5 wt%; The aforementioned dopant is silicon dioxide (SiO 2 ) powder, silicon dioxide (SiO 2 ) Gel, tetraethyl orthosilicate (TEOS), white carbon black, aluminum oxide (Al 2 O 3 ) powder, La 2 O 3 , Nd 2 O 3 , zeolite, or combinations thereof [1] Doped cerium oxide particles as described above. [3] The doped cerium oxide particles, after calcination at 500°C for 8 hours, have a total pore volume of 0.40 mL / g to 0.8 mL / g as described in [1]. [4] The doped cerium oxide particles according to [1], wherein after calcination at 500°C for 8 hours, the particles have at least 98% pore volume (d>3nm) / total pore volume. [5] The doped cerium oxide particles were calcined at 700°C for 5 hours, yielding approximately 800 μmol·O 2 / g ~ approx. 1100 μmol O 2 Doped cerium oxide particles according to [1], having an oxygen storage capacity (OSC) of 1 / g. [6] The doped cerium oxide particles are the same as those described in [1], having a crystal size of less than 10 nm after calcination at 500°C for 8 hours. [7] The doped cerium oxide particles were calcined at 900°C for 5 hours, then approximately 55m 2 / g~about 100m 2 Doped cerium oxide particles according to [1], having a BET specific surface area of ​​1 / g. [8] [1] The method includes contacting the doped cerium oxide particles described above with a precursor raw material, and hydrogen gas (H 2 ) Method of generating. [9] [1] Doped cerium oxide particles as described above are used with carbon dioxide (CO 2 This includes contact with carbon dioxide (CO2). 2 ) to methane (CH 4 How to convert to ).

[10] Nitrous oxide (N) from raw materials 2 A method for removing O), wherein the doped cerium oxide particles described in [1] are subjected to nitric acid (HNO 3 ) and / or adipic acid (CH 2 ) 4 (COOH) 2 A method comprising contacting a raw material containing the above.

[11] A method for producing doped cerium oxide particles: 10 to 50 grams of CeO per liter of solvent 2 Ce(NO) has a rare earth oxide concentration. 3 ) 4 Adding at least one dopant to the solution; After the step of adding at least one dopant, the Ce(NO) containing the dopant is added. 3 ) 4 Heating the solution to induce hydrolysis; The resulting mixture is cooled; The mixture obtained above is neutralized to a pH of 8-9; The neutralized mixture is filtered to produce a residue and a permeate; The aforementioned residue is to be burned; Drying and A method that includes this.

[12] The method according to

[11] , wherein the step of burning the residue is performed in an environment of 300°C for at least 10 hours.

[13] The method according to

[11] , wherein the step of burning the residue is carried out in an environment of 500°C for at least 5 hours.

[14] 250 to 300 grams of CeO per liter of solvent 2 Ce(NO) 3 ) 4 The method according to

[11] , further comprising diluting the solution.

[15] The method according to

[14] , wherein deionized water is used for dilution.

[16] The Ce(NO 3 ) 4 The method according to

[11] , wherein the solution is heated to approximately 120°C to approximately 150°C.

[17] The aforementioned Ce(NO 3 ) 4 The method described in

[16] , wherein the solution is heated for approximately 6 to 12 hours.

[18] The method according to

[11] , wherein the cooling step reduces the temperature of the obtained mixture to less than 50°C.

[19] The method according to

[18] , further comprising the step of adding a second dopant after the cooling step and before the neutralizing step.

[20] The method according to

[19] , further comprising adding a third dopant and stirring after the neutralization step and before the filtration step.

[21] Add TEOS or SiO to the calcined residue 2 The method according to

[11] , further comprising impregnating with a gel.

[22] The method according to

[21] , further comprising baking the impregnated residue at 500°C for at least 5 hours.

[23] In neutralization, ammonium hydroxide (NH₃) 4 The method described in

[11] , in which OH) is used.

[24] Neutralization includes stirring; the NH 4 The method according to

[23] , wherein the concentration of the OH solution is at least 25%.

[25] The dopant is silicon dioxide (SiO 2 ) powder, silicon dioxide (SiO 2 ) Gel, tetraethyl orthosilicate (TEOS), white carbon black, aluminum oxide (Al 2 O 3 The method according to

[11] , comprising ) powder, lanthanum (La), zeolite, or a combination thereof.

Claims

1. 90 wt% to 95 wt% cerium oxide (CeO ２ ); and doped cerium oxide particles containing 5-10 wt% of a dopant, The dopant is SiO₂ or Al₂O₃, The doped cerium oxide particles were calcined at 500°C for 8 hours, and then processed to 150 m ２ Having a BET specific surface area greater than / g; The doped cerium oxide particles were calcined at 500°C for 8 hours, and then reduced to 900 μmol·O. ２ Having an oxygen storage capacity (OSC) of more than / g, Doped cerium oxide particles.

2. The dopant is silicon dioxide (SiO ２ ) powder, silicon dioxide (SiO ２ ) Gel, aluminum oxide (Al ２ O ３ ) Powder, or combination thereof, Doped cerium oxide particles according to claim 1.

3. The doped cerium oxide particles according to claim 1, wherein the doped cerium oxide particles have a total pore volume of 0.40 mL / g to 0.8 mL / g after calcination at 500°C for 8 hours.

4. The doped cerium oxide particles according to claim 1, wherein after calcination at 500°C for 8 hours, the particles have at least 98% pore volume (d > 3 nm) / total pore volume.

5. The doped cerium oxide particles have an oxygen storage capacity (OSC) of 800 μmol·O ２ / g to 1100 μmol·O ２ / g after calcination at 700°C for 5 hours. The doped cerium oxide particles according to claim 1.

6. The doped cerium oxide particles according to claim 1, wherein the doped cerium oxide particles have a crystal size of less than 10 nm after being calcined at 500°C for 8 hours.

7. The doped cerium oxide particles were calcined at 900°C for 5 hours, and then processed to 55m ２ / g to 100m ２ Doped cerium oxide particles according to claim 1, having a BET specific surface area of ​​1 / g.

8. A hydrogen gas (H) gas comprising contacting the doped cerium oxide particles described in claim 1 with a precursor raw material. ２ ) Method of generating.

9. The doped cerium oxide particles according to claim 1 are used with carbon dioxide (CO2). ２ This includes contact with carbon dioxide (CO2). ２ ) to methane (CH ４ How to convert to ).

10. Nitrous oxide (N) from raw materials ２ A method for removing O), wherein the doped cerium oxide particles described in claim 1 are subjected to nitric acid (HNO ３ ) and / or adipic acid (CH ２ ) ４ (COOH) ２ A method comprising contacting a raw material containing the above.

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