KR101987534B1 - Catalyst composite having high oxygen storage capacity and method of forming the catalyst composite - Google Patents

Abstract

In a catalyst composite having a high oxygen storage capacity and a method for producing the same, the catalyst composite includes a plurality of ceria nanocrystals precipitated on the surface of the core particles formed of an amorphous metal oxide.

Description

TECHNICAL FIELD The present invention relates to a catalyst composite having a high oxygen storage capacity and a method for producing the catalyst composite.

The present invention relates to a catalyst composite having a high oxygen storage capacity and a production method thereof, and more particularly to a catalyst composite having a high oxygen storage capacity, which is used in various fields such as a catalyst, a fuel cell, a coating, a gas sensor, And a method for producing the same.

Cerium oxide is used in various fields such as catalyst, fuel cell, coating, gas sensor and oxygen membrane. Especially, three-way catalysts (TWCs) and selective catalytic reduction Which is an oxide that plays an important role as an enhancer in a catalyst such as Al2O3. In the cerium oxide having the fluorite cubic structure, the lattice oxygen located at the center of the tetrahedral site is easily removed or regenerated along with the change of the cerium. Due to such oxygen storage characteristics, it is used as a material for supplying and removing active oxygen required for oxidation or reduction catalytic reaction according to the oxygen partial pressure of the system. The oxygen atoms desorbed from the lattice induce a Ce ⁴⁺ → Ce ³⁺ transition and form oxygen vacancies by providing two electrons in the Ce 4f0 state. The lattice oxygen desorption and regeneration reactions mainly occur in the surface lattice oxygen of cerium oxide, and the use of nano-sized particles or amorphization to obtain excellent oxygen storage ability leads to surface unstabilization of cerium oxide Are actively being carried out.

Recently, it has been reported that the oxygen storage capacity of cerium oxide increases linearly with decrease of particle size (particle size), and rapidly increases below particle size of 10 nm or less. Although it is required to reduce the size in order to maximize the catalytic activity of the cerium oxide, it is pointed out as a limit point that it is difficult to control the coagulation naturally due to the thermally unstable nature or the growth of the particles in a high temperature environment.

To overcome these limitations, various manufacturing methods have been studied and used. Powders that are easy to nanoize can be prepared by mechanical pulverization or by the general liquid method (sol-gel method, impregnation method), but for materials that are thermally unstable or agglutination-sensitive, such as cerium oxide, advanced synthesis methods are needed. As a typical method of producing nano powder, there are known vapor phase synthesis method, gas phase condensation method, hydrothermal synthesis method, high frequency plasma method, electric explosion method, microemulsion method and the like. However, Or devices or facilities have complex thresholds.

It is an object of the present invention to provide a catalyst composite having a high oxygen storage ability which is nano-sized to maximize the oxygen storage capacity of cerium oxide.

Another object of the present invention is to provide a method for producing the catalyst composite.

The catalyst composite with high oxygen storage capacity for one purpose of the present invention comprises a plurality of ceria nanocrystals deposited on the surface of core particles formed of amorphous metal oxide.

In one embodiment, the core particle is comprised of a metal oxide comprising cerium and titanium.

In one embodiment, the core particle includes a non-forming region of ceria nanocrystals, and at least a part of the surface of the core particle is exposed to the outside in the non-forming region.

In one embodiment, the size of the core particles is greater than 100 nm, and the size of each of the ceria nanocrystals may be between 1 and 10 nm.

In one embodiment, the atomic ratio of cerium and titanium in the catalyst composite may be from 3: 7 to 5: 5.

A method for preparing a catalyst composite for another purpose of the present invention comprises nucleating a titania precursor; Mixing the nuclear product with a ceria precursor to effect a sol-gel reaction; And a step of subjecting the sol-gel reaction product to heat treatment to precipitate a plurality of ceria nanocrystals on the surface of the core particles formed of amorphous cerium-titanium oxide.

In one embodiment, the titania precursor and the ceria precursor can be mixed and reacted such that the atomic ratio of titanium to cerium is 3: 7 to 5: 5.

In one embodiment, the nucleating comprises reacting the titania precursor primarily with an alcohol and reacting; And mixing the water with the mixed state of the titania precursor and the alcohol to react them. At this time, the volume of the solution containing the titania precursor may be 4 to 6 times the volume of the alcohol. In addition, in the step of secondary mixing and reacting the water, 4 to 6 times the volume of the mixed solution of the titania precursor and the alcohol may be used.

In one embodiment, the step of precipitating the ceria nanocrystals may be heat treated at 500 to 700 < 0 > C.

In one embodiment, the step of precipitating the ceria nanocrystals may be such that the core particles formed of cerium-titanium oxide retain the amorphous phase and the ceria precursor precipitates at the surface of the core particles to form ceria nanocrystals.

According to the catalyst composite having high oxygen storage capability and the method of producing the same of the present invention, the amorphous phase of the amorphous metal oxide serving as the support and the ceria nanocrystals precipitated (eluted) on the surface thereof can simultaneously improve the catalytic activity As compared with the case where the ceria nanoparticles are used alone as a catalyst, or when ceria is used as a catalyst, the metal oxide and the amorphous substance constituting the carrier are not agglomerated and can exhibit remarkably improved catalytic activity.

1 is a view for explaining the structure of a catalyst composite according to the present invention.
2 is a graph showing the XRD analysis results of the complexes 1 and 2 (C3T7-p, C5T5-p) and Comparative Samples 1 and 2 (C3T7-c and C5T5-c) according to the embodiment of the present invention.
Fig. 3 shows XRD analysis results of composites obtained by different contents of Ce and Ti.
4 is a diagram showing TEM images, SAED patterns and EDS mapping results of composite 1 (C3T7-p) and Comparative Sample 1 (C3T7-c) according to an embodiment of the present invention.
5 is a graph showing the results of EXAFS analysis of Composites 1 and 2 (C3T7-p, C5T5-p) and Comparative Samples 1 and 2 (C3T7-c, C5T5-c) and commercial ceria.
6 is a graph showing the nitrogen monoxide removal efficiency according to the temperatures of the complexes 1 and 2 (C3T7-p, C5T5-p) and Comparative Samples 1 and 2 (C3T7-c and C5T5-c).

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the term "comprises" or "having ", etc. is intended to specify that there is a feature, step, operation, element, part or combination thereof described in the specification, , &Quot; an ", " an ", " an "

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

1 is a view for explaining the structure of a catalyst composite according to the present invention.

Referring to FIG. 1, the catalyst composite includes core particles formed of an amorphous metal oxide and a plurality of ceria nanocrystals precipitated on the surfaces of the core particles.

The ceria nanocrystals do not completely cover the surface of the core particle but are disposed on the surface of the core particle so that at least a part of the surface of the core particle is exposed to the outside.

The amorphous metal oxide constituting the core particle is composed of an oxide whose phase is amorphous (amorphous) and contains cerium and titanium. For example, the amorphous metal oxide constituting the core particle may be represented by CeTiO _x (where 1 <x <2).

Since the catalyst composite according to the present invention has a structure in which a large number of ceria nanocrystals are supported on the surface of the core particles, the core particles become a supporter which is a target on which ceria nanocrystals, , And the core particle itself also contains an amorphous ceria, so that the catalyst composite according to the present invention can simultaneously enhance the catalytic activity. That is, it is possible to provide a catalyst composite having both an amorphous phase and an effect of nano size.

Each of the ceria nanocrystals is made of a ceria crystal represented by the formula CeO ₂ , and the size thereof is only nano-sized. Since such ceria nanocrystals are precipitated from the amorphous metal oxide constituting the core particles in the process of producing the catalyst composite and dispersed and disposed on the surface of the core particles and the ceria nanocrystals do not completely cover the surface of the core particles, The amorphous metal oxide constituting the core particles is exposed in the non-formed regions. The ceria nanocrystals are formed directly on the surface of the core particles, and thus the core particles and the precipitated nanoceria are dispersed while retaining the bond. As a result, the ceria nanocrystals cohere to each other, resulting in loss of nano-sized nanoparticles Can be prevented.

The catalyst composite according to the present invention includes a step of nucleating using a titania precursor, a sol-gel reaction by mixing a ceria precursor with a nucleus product, and a step of subjecting the sol-gel reaction product to heat treatment to form ceria nanocrystals And the core particles are amorphous oxides comprising cerium and titanium.

The titania precursor may be titanium isopropoxide (TTIP), and the ceria precursor may be cerium (III) nitrate hexahydrate.

The step of nucleating the titania precursor can be carried out, for example, by reacting the mixture by mixing with an alcohol and stirring the mixture, and reacting the mixture by reacting with an alcohol and then mixing and stirring the water. At this time, ethanol can be used as the alcohol.

The advantage of reacting the titania precursor with an alcohol and reacting it with water is to delay the rate at which the titania precursor crystallizes to titania. The alcohol may be added 4 to 6 times the volume of the titania precursor solution. When the amount of alcohol is less than 4 times, the rate of crystallization of the titania precursor can not be controlled. When the amount of alcohol is more than 6 times, coagulation of titania tends to occur. Therefore, the amount of alcohol is preferably 4 to 6 times , And more preferably about 5 times.

Further, water may be added at 4 to 6 times the volume of the mixed solution of the titania precursor and the alcohol. If the amount of water is less than 4 times, formation of sufficient titania core may be difficult. If the amount of water exceeds 6 times, there is a problem that sufficient reaction with ceria precursor added in the next step is not performed. Therefore, And more preferably about 5 times.

Ethanol and water, and then mixing the ceria precursor to produce a ceria precursor adsorbed on the surface of the nuclear product. At this time, the content of the ceria precursor is mixed so that the atomic ratio of the prepared titania precursor and cerium and titanium is 3: 7 to 5: 5, thereby performing sol-gel reaction. As a result of the sol-gel reaction, an amorphous titanium-cerium oxide is formed.

The heat treatment is performed at a temperature lower than the crystallization temperature of the titanium-cerium oxide so that the core particles are crystallized into nano-sized crystals while the amorphous state is maintained.

The size of the core particle is 100 nm or more, and the size of each of the ceria nanocrystals may be 1 to 10 nm. Preferably, the size of each of the ceria nanocrystals may be 5 nm or less.

Hereinafter, examples of the preparation of the catalyst composite according to one embodiment of the present invention and the catalytic performance of the catalyst composite structure produced through the same will be described in detail.

Preparation Example-1: Preparation of catalyst complex (C3T7-p)

Titanium isopropoxide (TTIP) is first mixed with ethanol at a volume ratio of 5 times, and then the water is mixed with 5 times the volume of ethanol, and the reaction is carried out by secondary stirring to perform the nucleation process Respectively. Cerium (III) nitrate hexahydrate was added to the nucleated product to effect a sol-gel reaction of the nucleated product with the cerium precursor. At this time, the ceria precursor and the titania precursor were mixed so that the atomic ratio of Ce and Ti became 3: 7. Each step of adding ethanol or adding precursors was stirred for at least 30 minutes and had a retention time and induced enough reaction to occur. The final solution was kept at room temperature for more than 12 hours. Vacuum filtering was applied to obtain the powder. The above powder was dried at 80 DEG C for at least 12 hours to remove all of the solute.

Then, a catalyst composite (C3T7-p) according to an embodiment of the present invention was prepared by performing heat treatment at a temperature of 550 DEG C for 6 hours.

Production Example 2

(C5T5-p) according to an embodiment of the present invention was prepared using Ce and Ti molar ratio of 5: 5 by preparing substantially the same process as the preparation of the catalyst composite (C3T7-p) Respectively.

Preparation of Comparative Examples 1 and 2

Titania (TiO ₂ ) particles (having a size of ~ 10 nm) as crystal grains were prepared, and the titania particles were mixed with cerium (III) nitrate hexahydrate and heat-treated at 550 ° C. for 6 hours to obtain a comparative sample 1 (C3T7-c). At this time, the ceria precursor was mixed and reacted with the titania particles such that the atomic ratio of Ce and Ti was 3: 7.

Further, except that the ceria precursor was mixed and reacted with the titania particles so that the atomic ratio of Ce and Ti was 5: 5 in the production process of the comparative sample 1 (C3T7-c), the comparative sample 2 (C5T5-c) was prepared.

Structural Analysis-1

XRD (X-ray diffraction) analysis was performed on each of the prepared complexes 1 and 2 (C3T7-p, C5T5-p) and Comparative Samples 1 and 2 (C3T7-c, C5T5-c). The results are shown in Fig.

2 is a graph showing the XRD analysis results of the complexes 1 and 2 (C3T7-p, C5T5-p) and Comparative Samples 1 and 2 (C3T7-c and C5T5-c) according to the embodiment of the present invention.

2, in the case of Comparative Samples 1 and 2 (C3T7-c and C5T5-c) synthesized using TiO ₂ crystal, CeO ₂ peak near the diffraction angle 25 ° (2θ) and near 28 ° of TiO ₂ it can confirm the peak. On the other hand, in the case of Composites 1 and 2 (C3T7-p, C5T5-p) prepared according to the present invention, no diffraction pattern attributable to TiO ₂ was observed at all and it was confirmed that a broadband diffraction peak due to CeO ₂ appears.

The resultant product was prepared in substantially the same process as the preparation of the complexes 1 and 2 (C3T7-p and C5T5-p) in various compositions with different atomic ratios of Ce and Ti, and XRD analysis was performed on each of them . The results are shown in Fig.

Fig. 3 shows XRD analysis results of composites obtained by different contents of Ce and Ti.

Referring to FIG. 3 together with FIG. 2, the same phenomenon as in the XRD analysis results shown in FIG. 2 is shown over a wide composition range. In the composition where the CeO ₂ ratio is designed to be 22 mol% or less, crystallization of TiO ₂ occurs rapidly, The core particles can not be maintained in an amorphous state, resulting in a crystalline state.

With this structure, CeO ₂ is at least 23 mol%, and the composite is designed to include the 30 mol% cerium 1 (C3T7-p) in ~ 7 mol% amount of CeO ₂ is excessive at the critical composition of CeO ₂ is TiO ₂ does not crystallize Lt; / RTI &gt; Diffraction peaks for the CeO ₂ crystal in the transient mapping of CeO ₂ shows a broad form until it was confirmed that the sharp diffraction peak appearing when more than 50 mol% CeO ₂ doped.

These results show that the broad peaks of CeO ₂ in composites 1 and 2 (C3T7-p, C5T5-p) are predicted by (i) amorphous CeO ₂ and (ii) In an amorphous state in which crystal grains of 10 nm or less exist, not only the crystal plane is not sufficient for the occurrence of diffraction phenomena but also the nonuniformity of the crystal plane spacing is increased as the ratio of the unstable surfaces increases, This can be seen as a factor.

Structural Analysis-2

Analysis was performed for each of the complex 1 (C3T7-p) and the comparative sample 1 (C3T7-c), and the results are shown in Fig.

4 is a diagram showing TEM images, SAED patterns and EDS mapping results of composite 1 (C3T7-p) and Comparative Sample 1 (C3T7-c) according to an embodiment of the present invention.

Referring to FIG. 4, the TEM image of the complex 1 (C3T7-p) confirmed in (a) confirms the presence of particles having a size of 100 to 200 nm, nm or less in size. The electron pattern of the selected region was obtained by using a 50 nm aperture, and as a result, a broad ring pattern was confirmed as a whole.

From the SAED results shown in FIG. 4 (b), it can be seen that the ring pattern for the CeO ₂ (111), (110) plane is discernible and the diffraction pattern for TiO ₂ is not confirmed, The distance is ~ 3.1 Å, which indicates that the nano-sized particles formed on the surface are actually CeO ₂ .

Referring to the EDS mapping results of Ce and Ti shown in FIG. 4 (c), it can be confirmed that the catalyst composite actually produced has a well dispersed state without aggregation of each element.

On the other hand, the comparative sample 1 (C3T7-c) in FIG. 4 (d) shows a particle size of about 200 nm, but no substance can be identified on the surface of CeO ₂ . As shown in FIG. 4 (f), Ce and Ti elements can be segregated separately to confirm the presence of minute particles. In particular, although TiO ₂ crystal grains are directly used as cores, agglomerated CeO ₂ And TiO ₂ nanoparticles are covered with a complex, which is attributed to the low thermal stability of CeO ₂ .

Precipitate analysis and results

X-ray photoelectron spectroscopy analysis of the complexes 1 and 2 (C3T7-p, C5T5-p) and Comparative Samples 1 and 2 (C3T7-c and C5T5-c) And the ratio to the element was calculated. The results are shown in Table 1 below.

Element name Binding Energy (eV) Peak Area Composition (%) Comp. except
for C and O (%) C3T7-p C1s 284.60 4132.5 34.19 - Ce3d5 883.39 22258.9 7.33 48.54 O1s 529.94 16986.1 50.72 - Ti2p 458.36 7154.23 7.77 51.46 C5T5-p C1s 284.60 3545.38 32.89 - Ce3d5 883.38 24157.3 8.92 68.56 O1s 529.84 16161.6 54.11 - Ti2p 458.39 3358.62 4.09 31.44 C3T7-c C1s 284.60 2994.12 27.61 - Ce3d5 883.00 14644.9 5.37 29.93 O1s 529.73 16360.6 54.45 - Ti2p 458.49 10384.0 12.57 70.07 C5T5-c C1s 284.60 2834.18 31.86 - Ce3d5 882.93 17123.1 7.66 48.24 O1s 529.74 12881.7 52.27 - Ti2p 458.66 5568.39 8.22 51.76

Since the detection of photoelectron by X-ray irradiation is limited to the surface in order to obtain the results shown in Table 1, it is an appropriate analysis method for quantifying the composition of the crystal-covered surface of 10 nm or less. (atomic composition%) except for carbon (C) added for calibration and oxygen (O) forming ceria and titania.

As shown in Table 1, the analysis results of the complexes 1 and 2 (C3T7-p, C5T5-p) and Comparative Samples 1 and 2 (C3T7-c and C5T5-c) It can be confirmed that there is a large difference. That is, there is almost no difference between the composition designed at 48.24 at.% For Comparative Sample 1 (C3T7-c) designed at 30 at.% And Comparative Sample 2 (C5T5-c) designed at 29.9 at. Can be confirmed. On the other hand, in composite 1 (C3T7-p) designed at 30 at.%, 48.54 at.% And 50 at. % In the composite 2 (C5T5-c), which is designed at a ratio of 68.56 at.%.

Through the above results, the composite 1 and 2 (C3T7-p, C5T5- p) the surface precipitation phase CeO ₂ was a HREM can be confirmed that the matching result, the surface by the precipitation both surfaces completely covered with the ceria nanocrystals in And the surface of the amorphous core particle is exposed together. Therefore, it can be confirmed that not only the amorphous phase of the amorphous core particles but also the ceria nanocrystals precipitated from the surface thereof participate in the reaction at the same time, thereby maximizing the catalytic activity.

Phase analysis of core particles

X-ray absorption spectroscopy (XAS) analysis using a synchrotron radiation beam was performed to confirm that the phase of the core particles was amorphous. Using this XAS analysis, the X-ray generated in the synchrotron radiation beam passes through the entire sample, so that it is possible to evaluate not only the crystalline phase but also the amorphous phase located in the core.

In order to investigate the amorphous phase, information about the atomic bonding around it can be obtained due to the electron excitation and the interaction of the photoelectrons in the band gap of the target component. _3- edge and the results of EXAFS analysis of commercial CeO ₂ for comparison of Composites 1 and 2 (C3T7-p, C5T5-p) and Comparative Samples 1 and 2 (C3T7-c and C5T5-c) 5.

5 is a graph showing the results of EXAFS analysis of Composites 1 and 2 (C3T7-p, C5T5-p) and Comparative Samples 1 and 2 (C3T7-c, C5T5-c) and commercial ceria.

CeO ₂ is a quartz crystal in which the cerium atom (Ce) has a face centered cubic structure and the oxygen atom (O) is located at the center of the tetrahedral site formed by the cerium atoms (Ce) And forms a fluorite cubic structure. Based on the cerium atom (Ce), the oxygen atom (O) has the closest bond (1 ^st shell) and the cerium atom (Ce) located at the center of the cube is bound (2 ^nd shell).

Referring to FIG. 5, the peaks near 1.8 Å and 3.6 Å in the Fourier-transformed space indicate the bond between Ce-O (1 ^st shell) and Ce-Ce (2 ^nd shell) ) Is a bond formed by the interaction of cerium and titanium by the strong metal-support interaction effect of titanium (Ti). These chemical bonds induce the crystallization temperature to be higher than that of TiO ₂ and CeO ₂ , and as a result, the amorphous phase can be maintained even at the heat treatment temperature of 550 ° C.

In EXAFS for amorphous phase, only a peak for 1 ^st shell bond is generally observed. In complex 1 (C3T7-p) according to the present invention, since the signal due to the ceria nanocrystals precipitated on the surface together with the amorphous phase is included, we can observe the peak of Ce-Ce (2 ^nd shell) which means range order.

On the other hand, in each of Comparative Samples 1 and 2 (C3T7-c, C5T5-c), the peak shows a position and intensity similar to the reference CeO ₂ . The intensity of each peak is the _2nd I / I _1st means a coordination number of bond and 1 ^st and 2 ^nd peak intensity ratio (intensity ratio) of the can give important information about the amorphous degree of the entire material. The results are shown in Table 2 below.

1 ^st shell
PeakIntensity
(Å ^-3 ) 2 ^nd shell
PeakIntensity
(Å ^-3 ) Intensity Ratio
(I _2nd / I _1st ) Reference CeO ₂ 1.25 0.68 0.54 C5T5-c 1.21 0.65 0.53 C3T7-c 1.14 0.6 0.52 C5T5-p 0.91 0.42 0.46 C3T7-p 0.75 0.23 0.37

Referring to Table 2, Comparative Samples 1 and 2 (C3T7-c, C5T5-c) had similar values to the reffered CeO2. Confirmed that the value is significantly reduced while the complex 2 and 1 (p-C5T5, C3T7-p) order, it can be confirmed that a referece than 0.54 CeO ₂ representing the value of the reduced level of 0.37 31.4%. The oxygen storage capacity is expressed by eliminating the lattice oxygen closest to cerium and reducing it by cerium. Therefore, the decrease in binding to Ce-O (1 ^st shell) implies that the ease of lattice oxygen desorption is improved. This long-range order reduction of amorphization leads to destabilization of the bond and leads to an increase in the reactivity of the surface catalytic reaction.

Evaluation of catalytic performance

The removal efficiency of nitrogen monoxide (NO) was confirmed for each of the complexes 1 and 2 (C3T7-p, C5T5-p) and Comparative Samples 1 and 2 (C3T7-c and C5T5-c). The results are shown in Fig.

6 is a graph showing the nitrogen monoxide removal efficiency according to the temperatures of the complexes 1 and 2 (C3T7-p, C5T5-p) and Comparative Samples 1 and 2 (C3T7-c and C5T5-c).

Referring to FIG. 6, it can be seen that the catalytic efficiency of Comparative Sample 1 (C3T3-c) is higher than that of Comparative Samples 1 and 2 which are synthesized using the titania particles as it is. The difference between Comparative Examples 1 and 2 (C3T7-c and C5T5-c) is that the efficiency is increased according to the loading amount of Ce on the TiO ₂ support and the efficiency is decreased when the loading amount exceeds a certain amount The result is a match. It can be seen that the efficiency of the complex 1 (C3T3-p) is higher than that of the complexes 1 and 2 (C3T7-p, C5T5-p) ) Than the difference in efficiency between the two. This is presumably because the ceria nanocrystals exposed on the surface and the amorphous CeTiO _x phase were covered by CeO ₂ agglomerated with the employment and lost the reaction point.

Compared to Comparative Sample 2 (C5T5-c), which showed the lowest efficiency, the efficiency of the composite 1 (C3T7-p) was improved by ~ 50%. In addition, the efficiency of the complex 2 (C3T7-p) at 200 ° C was 90% or more, which is not significantly different from that of the noble metal catalyst used as a NOx removal catalyst for low temperature (150 to 250 ° C).

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. It can be understood that it is possible.

Claims (12)

Core particles formed of an amorphous metal oxide; And a plurality of ceria nanocrystals precipitated on the surface thereof,
Wherein the core particles formed of the amorphous metal oxide are TiCeOx (1 < x < 2)
Catalyst complex with high oxygen storage capacity.
delete The method according to claim 1,
Wherein the core particles comprise a non-forming region of ceria nanocrystals,
Characterized in that at least a part of the surface of the core particle is exposed to the outside in the non-
Catalyst complex with high oxygen storage capacity.
The method according to claim 1,
The size of the core particles is 100 nm or more,
Wherein each of the ceria nanocrystals has a size of 1 to 10 nm.
Catalyst complex with high oxygen storage capacity.
delete Nucleating the titania precursor;
Mixing the nuclear product with a ceria precursor to effect a sol-gel reaction; And
Gel reaction product to precipitate a plurality of ceria nanocrystals on the surface of the core particle formed of amorphous cerium-titanium oxide,
The step of nucleating the titania precursor
Mixing the titania precursor with alcohol first and reacting; And
And mixing and reacting water in a mixed state of the titania precursor and the alcohol,
Wherein the core particles formed of amorphous cerium-titanium oxide are TiCeOx (1 < x < 2)
A method for producing a catalyst composite having a high oxygen storage capacity comprising an amorphous cerium-titanium oxide core and ceria nanocrystals precipitated on the core surface.
The method according to claim 6,
Wherein the titania precursor and the ceria precursor are mixed and reacted so that the atomic ratio of titanium to cerium is 3: 7 to 5: 5.
A method for producing a catalyst composite having a high oxygen storage capacity comprising an amorphous cerium-titanium oxide core and ceria nanocrystals precipitated on the core surface.
delete The method according to claim 6,
Characterized in that the volume of the solution containing the titania precursor is 4 to 6 times the volume of the alcohol.
A method for producing a catalyst composite having a high oxygen storage capacity comprising an amorphous cerium-titanium oxide core and ceria nanocrystals precipitated on the core surface.
The method according to claim 6,
In the step of secondary mixing and reacting the water
Characterized in that water is used four to six times as much as the total volume of the solution containing the titania precursor to which the alcohol is added.
A method for producing a catalyst composite having a high oxygen storage capacity comprising an amorphous cerium-titanium oxide core and ceria nanocrystals precipitated on the core surface.
The method according to claim 6,
Wherein the step of precipitating the ceria nanocrystals is a heat treatment at a temperature lower than the crystallization temperature of the titanium-cerium oxide.
A method for producing a catalyst composite having a high oxygen storage capacity comprising an amorphous cerium-titanium oxide core and ceria nanocrystals precipitated on the core surface.
The method according to claim 6,
The step of precipitating the ceria nanocrystals
Characterized in that the core particles formed of cerium-titanium oxide retain the amorphous phase and the ceria precursor precipitates on the surface of the core particles to form ceria nanocrystals.
A method for producing a catalyst composite having a high oxygen storage capacity comprising an amorphous cerium-titanium oxide core and ceria nanocrystals precipitated on the core surface.

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