Particle

Abstract

The present specification discloses particles. The particles can be applied to a reaction for forming hydrocarbons from raw materials containing Co2 and / or Co. The present specification aims to disclose, as the particles, particles that enable the production of a desired product with excellent selectivity and conversion rate and is designed to avoid an undesirable aggregation or sintering phenomenon and a decrease in catalytic activity during a reaction progressing process. For example, the particles allow for the production of hydrocarbons of 5 or more carbon atoms with high selectivity and conversion rate in the reaction of obtaining hydrocarbons from raw materials containing CO2 and / or CO. The present specification also discloses a use of the particles.

Description

particle

[0001] This application claims the benefit of priority to Republic of Korea Patent Application No. 10-2023-0123492, filed September 15, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present specification discloses a particle. In one example, the particle may be a catalyst used in a reaction to form a hydrocarbon using CO2 as a raw material.

[0003] CO2, released during fossil fuel-based energy production, is considered a major contributor to climate change, including global warming. Various attempts exist to capture and utilize CO2, and the catalytic CO2 hydrogenation reaction disclosed in Non-Patent Document 1 is one such attempt. This reaction utilizes methods such as Fischer-Tropsch (FTS) and methanol-to-olefin (MTO), and the methods reported to date can be broadly classified into two types.

[0004] The first type is a method that produces hydrocarbons such as liquid fuels, olefins, and aromatic compounds through the Fischer-Tropsch (FTS) reaction followed by the Reverse Water-Gas Shift (RWGS) reaction that converts CO2 to CO using an Fe catalyst (Non-patent Document 2). The second type is a method that converts CO2 to methanol using a catalyst (In2O3 or Cu / ZnO / Al2O3 series) and produces high value-added products (e.g., gasoline, etc.) through additional reactions (Non-patent Document 3).

[0005] In the first type, the RWGS reaction is endothermic, while the FTS reaction is exothermic. Therefore, for the RWGS reaction to proceed efficiently, a large amount of energy must be supplied, and to prevent the deterioration of the catalyst activity in the FTS reaction, the reaction must proceed while effectively removing the heat of reaction.

[0006] However, continuously performing this type of energy supply and removal is challenging. In particular, the low efficiency of energy removal generated during the FTS reaction frequently leads to undesirable agglomeration of catalyst particles, decreased catalyst activity, and / or deterioration. These problems, in turn, lead to low selectivity and conversion rates for hydrocarbons.

[0007] For example, in order for the above product to be applied as so-called aviation fuel, etc., hydrocarbons with a certain number of carbon atoms must be present in the product. However, if the selectivity and conversion rate are low, the product does not contain the desired hydrocarbon or the ratio of the hydrocarbon is low.

[0008] <Prior Art Literature>

[0009] <Non-patent literature>

[0010] (Non-patent Document 1) Ra, EC; Kim, Ky.; Kim, E.H.; Lee, H.; An, K.; Lee, JS Recycling Carbon Dioxide through Catalytic Hydrogenation: Recent Key Developments and Perspectives. ACS Catal. 2020, 10 (19), 11318-11345. DOI: 10.1021 / acscatal.0c02930

[0011] (Non-patent Document 2) Choi, YH; Jang, Y.J.; Park, H.; Kim, W.Y.; Lee, Y.H.; Choi, SH; Lee, J.S. Carbon Dioxide Fischer-Tropsch Synthesis: A New Path to Carbon-Neutral Fuels. Appl. Catal., B 2017, 202, 605-610, DOI: 10.1016 / j.apcatb.2016.09.072

[0012] (Non-patent Document 3) Sharma, P.; Sebastian, J.; Ghosh, S.; Creaser, D.; Olsson, L. Recent Advances in Hydrogenation of CO2 into Hydrocarbons via Methanol Intermediate over Heterogeneous Catalysts. Catal. Sci. Technol. 2021, 11 (5), 1665-1697, DOI: 10.1039 / D0CY01913E

[0013] The present specification discloses particles. The particles can be applied to a reaction for forming hydrocarbons from raw materials containing CO2 and / or CO. The present specification aims to disclose particles capable of obtaining a desired product with excellent selectivity and conversion without causing undesirable agglomeration or sintering phenomena and deterioration of catalytic activity during the reaction process. For example, the particles can obtain hydrocarbons having 5 or more carbon atoms with high selectivity and conversion in a reaction for obtaining hydrocarbons from raw materials containing CO2 and / or CO. The present specification also discloses uses of the particles.

[0014] Among the properties described in this specification, properties that are affected by the measurement temperature are properties measured at room temperature, unless otherwise specified.

[0015] The term room temperature means the natural temperature that has not been artificially heated or cooled, and can mean, for example, any temperature within the range of 10°C to 30°C, or a temperature of about 23°C or about 25°C.

[0016] In this specification, the unit of temperature is Celsius (℃) unless otherwise specified.

[0017] Among the properties mentioned in this specification, properties that are affected by the measurement pressure are properties measured at atmospheric pressure, unless otherwise specified.

[0018] The term atmospheric pressure refers to natural pressure that has not been artificially pressurized or depressurized, and can usually mean any pressure within the range of about 730 mmHg to 790 mmHg.

[0019] Among the properties mentioned in this specification, the properties affected by the measured humidity are properties measured at a standard humidity, unless otherwise specified. The standard humidity is a relative humidity (RH%) within a range of 40% to 60%, and for example, a relative humidity (RH%) of approximately 55% or 60%.

[0020] The term center of mass or center of gravity as used herein means the center of mass unless otherwise specified.

[0021] The present specification discloses a particle.

[0022] The particles may be catalyst particles, and in one example, may be CO2 or CO conversion catalyst or hydrogenation catalyst particles. Such catalysts may be applied to a reaction that produces hydrocarbon compounds using a raw material containing CO2 and / or CO. In this case, the reaction may be the so-called RWGS (Reverse Water-Gas Shift) reaction and / or FTS (Fischer-Tropsch) reaction.

[0023] The above particles may be in the form of secondary particles formed by agglomeration of multiple primary particles. The desired effect can be obtained by adjusting the form of the secondary particles.

[0024] For example, in the secondary particle form as described above, the primary particle may be a particle of any metal (hereinafter, referred to as the first metal), or may be a particle including the first metal. In addition, at least some of the primary particles among the plurality of primary particles forming the secondary particles may include a metal (hereinafter, referred to as the second metal) different from the first metal on the surface. That is, the second metal may be present on the surface of at least some of the primary particles, and the second metal may form a continuous or discontinuous layer on the surface of the primary particles, or may be included in the layer.

[0025] Figure 1 is an exemplary representation of a cross-section of the particle.

[0026] As shown in the drawing, the particles may be in the form of secondary particles formed by agglomeration of a plurality of primary particles (100), and a second metal may be present on the surface of at least some of the primary particles (100) among the plurality of primary particles (100).

[0027] In the drawing, the shape of the primary particle (100) is shown as being roughly circular, but the actual shape of the primary particle may be a shape other than circular, such as an irregular shape. In addition, although the drawing shows a case where the second metal forms a continuous layer (200) on the surface of the primary particle (100), the second metal may form a discontinuous layer on the surface of the primary particle (100) or may exist only on a part of the surface of the primary particle (100). In addition, although the drawing shows a form in which only the primary particles (100) are aggregated, other elements (for example, a support or a mold, etc.) may exist within the secondary particle, and empty spaces in which the primary particles or other elements do not exist may exist within the secondary particle.

[0028] As exemplarily shown in Fig. 1, the second metal may be present on the surface of at least the primary particles distributed on the surface of the secondary particles among the plurality of primary particles forming the secondary particles. Additionally, in the drawing, the layer (200) by the second metal exists only on the primary particles present on the surface side of the secondary particles, but in some cases, the layer by the second metal may form a layer on the surface of most of the primary particles.

[0029] By controlling the shape of the secondary particles in the following manner, the secondary particles can exhibit the desired catalytic activity, and such catalytic activity can be stably maintained during the reaction process.

[0030] For example, the ratio B / A of the area B of the second metal region to the area A of the first metal region in the cross-section of the secondary particle may be within a predetermined range.

[0031] In the above, the area A of the first metal region and the area B of the second metal region refer to regions identified by the first metal and the second metal in a cross-sectional image of the secondary particle, such as, for example, a Scanning Electron Microscope (SEM) image or a Transmission Electron Microscope (TEM) image. These regions can be displayed based on the DBSCAN (Density-based spatial clustering of applications with noise) algorithm for the cross-sectional image. Specific details for designating these regions are summarized in “Test Example 1” of this specification.

[0032] In the following specification, for convenience of explanation, it is assumed that the circular shape in FIGS. 1 and 2 is an area of ​​the first metal, and an area existing outside some of the circular shapes is an area of ​​the second metal.

[0033] The lower limit of the above ratio B / A may be about 0, 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95 or 1, and the upper limit may be about 10, 8, 6, 4, 2, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2 or 0.15. The above ratio B / A may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above, and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. By designing the catalyst to satisfy this range, the desired catalytic activity can be obtained, and such catalytic activity can be stably maintained throughout the reaction.

[0034] In the above ratio B / A, the lower limit of the area A may be about 200, 400, 600, 800, 850, 900, 1,000, 5,000, 10,000, 50,000, 100,000 or 150,000, and the upper limit may be about 1,000,000, 500,000, 100,000, 50,000, 10,000, 5,000, 1,000 or 950. The area A may be in a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. By designing the catalyst to satisfy this range, the desired catalytic activity can be obtained, and such catalytic activity can be stably maintained during the course of the reaction. The unit of the above area A is μm 2 am.

[0035] The above catalyst is R of the following formula 3 v It can be designed to be within a certain range.

[0036] [Formula 3]

[0037]

[0038] L in Equation 3 s may be the average distance from the center of the first metal region to the second metal region of the cross-section of the secondary particle. Such L s The unit of may be μm when applying Equation 3.

[0039] In Equation 3, A is A in the above ratio B / A, and B is B in the above ratio B / A. When applying Equation 3, the units of the above ratios A and B are each μm. 2 am.

[0040] Above L s can be verified in the following way.

[0041] First, the center of the cross-section of the above secondary particle is specified.

[0042] The center of the cross-section of the above secondary particle is C in the following equation 1 x And C in Equation 2 y can be regulated by

[0043] [Formula 1]

[0044]

[0045] [Formula 2]

[0046]

[0047] C above x and C y is the coordinate specified in the cross-section of the above secondary particle.

[0048] C above x and C y In order to specify, first, as exemplarily shown in FIG. 2, the cross-section of the secondary particle is positioned on the xy coordinates. Then, the first metal region (a portion of the cross-section of the secondary particle occupied by the first metal) and the second metal region (a portion of the cross-section of the secondary particle occupied by the second metal) are distinguished and marked within each of the plurality of primary particles forming the secondary particle. After this operation, the region of the first metal appears in the form of a plurality of primary particles in the drawing, and the region of the second metal is confirmed outside some of the regions of the first metal. The method of specifying these regions is as described above, and is specifically described in “Test Example 1” of the present specification.

[0049] Next, the center coordinates of the area of ​​the individual first metal are recorded in the x-coordinate and y-coordinate. For example, the center coordinates of the area 1001 of the first metal in Fig. 2 are (x i1 , y i1 ) is indicated, and the center coordinates of the area 1002 of the second metal are (x i3 , y i3) is indicated. In the above, the center coordinate is the coordinate where the center of mass of the corresponding first metal area exists.

[0050] For all areas of the first metal identified in the drawing, the center coordinates are indicated in the above manner, and the area of ​​the area of ​​the first metal having each center coordinate is also obtained.

[0051] This operation is performed on all regions of the first metal in the form of primary particles.

[0052] After that, as shown in the above equation 1, the value of the x-coordinate of the region of the first metal in the form of primary particles and the product of the area of ​​the region of the first metal are obtained for all regions of the first metal, and the obtained values ​​are added up, and then the value is divided by the sum of the areas of the regions of the individual first metals (C x ) becomes the x-coordinate of the center of the cross-section of the secondary particle.

[0053] As shown in Equation 2, the value of the y-coordinate of the region of the first metal in the form of primary particles and the product of the area of ​​the region of the first metal are obtained for all regions of the first metal, and the obtained values ​​are added up, and then the value is divided by the sum of the areas of the regions of the individual first metals (C y ) becomes the y-coordinate of the center of the secondary particle cross-section.

[0054] In Fig. 2, the coordinates of these centers (C x , C y ) is displayed.

[0055] Therefore, in the above equations 1 and 2, x i is the x-coordinate of the center of the region of the first metal in the cross-section of the secondary particle, respectively, and y i is the y-coordinate of the center of the region of the first metal within the cross-section of each primary particle in the cross-section of the secondary particle.

[0056] Also, in equations 1 and 2, Ai is the above coordinate x i and y i is the area of ​​the region of the first metal within the cross-section of the primary particle having .

[0057] These center coordinates x i and y i and area A i For example, it can be obtained using a Python program, and for example, it can be obtained using a library such as scipy or numpy in the Python program. In such a program, the area of ​​the first metal is divided into a plurality of polygons such as small triangles or squares, and the area and center coordinates of the area of ​​each divided polygon are used to obtain the center coordinate x through an operation process corresponding to Equations 1 and 2. i and y i and area A i is saved.

[0058] In addition, in Equations 1 and 2, n is the number of regions of the first metal, which corresponds to the number of primary particles forming the secondary particles. When the first and second metal regions are divided into the plurality of polygons, n may be the number of the divided polygons. Typically, an appropriate number of polygons that can produce optimal results are formed according to an algorithm such as a Python program, and therefore, the range of n is not particularly limited and is determined according to the Python program.

[0059] The center coordinates of the above secondary particle cross-section (C x , C y ) is obtained, the shortest distance from the center coordinates to the area where the second metal exists is obtained. In Fig. 2, the shortest distance is L s1 , L s2 and L s3 is indicated. In Fig. 2, the distance is divided into three (L s1 , L s2 , Ls3 ) is only displayed, but in reality, the center coordinates (C x , C y ) to find the shortest distance by scanning in all directions of 360 degrees. Then, the shortest distances found are arithmetic averaged and the result is L s can be done with L. At this time, L s The unit of can be μm. This average distance L s It can also be obtained using the above Python program, and for example, it can be obtained using a library such as scipy or numpy in the above Python program.

[0060] R of the above formula 3 obtained through the value obtained in this way v The lower limit of R may be about 0.01, 0.03, 0.05, 0.07, 0.09, 0.1, 0.2, 0.3, 0.4 or 0.5, and the upper limit may be about 1.5, 1.3, 1.1, 1.0, 0.5, 0.1, 0.08, 0.06, 0.05 or 0.04. v It can be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. By designing the catalyst to satisfy this range, the desired catalytic activity can be obtained, and such catalytic activity can be stably maintained during the course of the reaction.

[0061] In the above, the lower limit of Ls may be about 0, 30, 45, 50, 70, 90, 100, 150, 200, 300 or 400, and the upper limit may be about 1,000, 900, 800, 700, 600, 500, 450, 400, 300, 250, 200, 150, 100, 80 or 70. The above L sIt can be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. By designing the catalyst to satisfy this range, the desired catalytic activity can be obtained, and such catalytic activity can be stably maintained during the course of the reaction. The unit of the above Ls is μm.

[0062] The above catalyst is R of the following formula 4 g It can be designed to have a certain range.

[0063] [Formula 4]

[0064]

[0065] L in Equation 4 s is L in the above equation 3 s , and its unit is μm. In addition, B in Equation 4 is B in the above ratio B / A. When applying Equation 4, the unit of the area B is μm. 2 am.

[0066] In Equation 4, r is a value obtained by Equation 5 below.

[0067] [Formula 5]

[0068]

[0069] A in Equation 5 avg is the arithmetic mean of the area of ​​the first metal region belonging to each primary particle in the cross-section of the secondary particle. The method of obtaining this arithmetic mean is described in Test Example 1 of this specification, and when obtaining r in Equation 5, A avg The unit is μm 2 Apply the value of .

[0070] In Equation 4, a is the average distance between the centers of the first metal regions within the primary particle cross-section. In Fig. 4, the spacing between the centers of the first metal regions (100) is indicated as a1, a2, and a3. The spacing between the centers can be obtained for all the first metal regions (100), and the arithmetic mean of the obtained values ​​can be used as a in Equation 4. When applying Equation 4, the value of a in μm is applied. This a can be obtained using the k-Nearest Neighbors algorithm.

[0071] The lower limit of Rg in Equation 4 may be about 100, 200, 250, 300, 350, 400, 500, 550, 600, 650, 700, 750, 800, 850, 900, or 950, and the upper limit may be about 2,000, 1,500, 1,000, 800, 600, 400, or 300. The Rg may be in a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. By designing the catalyst to satisfy this range, the desired catalytic activity can be obtained, and such catalytic activity can be stably maintained during the course of the reaction.

[0072] The range of the ratio a / r of a to r in Equation 4 can be adjusted.

[0073] The lower limit of the above ratio a / r may be about 0.1, 0.3, 0.5, 0.7, 0.9, 1.1, or 1.3, and the upper limit may be about 2, 1.8, 1.6, 1.5, 1.4, or 1.3. The a / r may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. By designing the catalyst to satisfy this range, the desired catalytic activity can be obtained, and such catalytic activity can be stably maintained during the course of the reaction.

[0074] The lower limit of r in Equation 4 may be about 1, 3, 5, 7, 9, 10, 15, 20, 25, or 27, and the upper limit may be about 500, 450, 400, 350, 300, 250, 200, 150, 100, 80, 60, 40, 35, 30, 25, or 20. The r may be in a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. By designing the catalyst to satisfy this range, the desired catalytic activity can be obtained, and such catalytic activity can be stably maintained during the course of the reaction. The unit of the r is nm. The r corresponds to the average diameter of the primary particles.

[0075] The above catalyst is R of the following formula 6 l It can be designed to be within this range.

[0076] [Formula 6]

[0077]

[0078] L in Equation 6 s is L in the above equation 3 s , and the value in the unit is μm.

[0079] In addition, in Equation 6, l is a value obtained by Equation 9 below, and a value in μm is applied.

[0080] [Formula 9]

[0081]

[0082] In Equation 9, a and r are the same as a and r in Equation 4, respectively.

[0083] In Equation 6, R is a value obtained by Equation 8 below, and a value in μm is applied.

[0084] [Formula 8]

[0085]

[0086] In Equation 8, A is the area A in the above ratio B / A, and the unit is μm. 2 The value of is applied.

[0087] R in Equation 6 l The lower limit of R may be about 0, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 0.7 or 0.1, and the upper limit may be about 2, 1.5, 1, 0.8, 0.6, 0.4, 0.2, 0.1, 0.08, 0.06, 0.04 or 0.02. l It can be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. By designing the catalyst to satisfy this range, the desired catalytic activity can be obtained, and such catalytic activity can be stably maintained during the course of the reaction.

[0088] The lower limit of l in Equation 6 may be about 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, or 4.5, and the upper limit may be about 7.5, 7, 6.5, 6, 5.5, 5, 4.5, 4, or 3.5. The l may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. By designing a catalyst to satisfy these ranges, the desired catalytic activity can be obtained, and such catalytic activity can be stably maintained during the course of the reaction. The unit of the l is nm.

[0089] The above catalyst is R of the following formula 7 p It can be designed to have a certain range.

[0090] [Formula 7]

[0091]

[0092] L in equation 7 s and R is L in Equation 6 s and R, and the values ​​in the unit of μm are applied respectively.

[0093] R in Equation 7 p The lower limit of R may be about 0, 0.3, 0.4, 0.5, 1, 1.5, and the upper limit may be about 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1, or 0.5. pIt can be within a range that is less than or equal to an upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to an lower limit arbitrarily selected from the lower limits listed above and less than or equal to an upper limit arbitrarily selected from the upper limits listed above. By designing the catalyst to satisfy these ranges, the desired catalytic activity can be obtained, and such catalytic activity can be stably maintained during the course of the reaction.

[0094] The center coordinate (C) in the cross section of the above catalyst particle according to one example x , C y ) as the center, and the radius is L s When a virtual circle is drawn, the area B of the region of the second metal existing inside the virtual circle in and the area B of the region of the second metal existing outside the above circle out The ratio of B in / (B in +B out ) can be adjusted.

[0095] Figure 3 shows the center coordinates of the cross-section of the secondary particle (C x , C y ) and the radius is L s This is an example of a virtual circle, and in this way, the area of ​​the second metal is divided into an area (2001) within the virtual circle and an area (2002) within the virtual circle. In this state, the area of ​​the area of ​​the second metal within the virtual circle is B in , and the area of ​​the second metal area outside the above virtual circle is B out can be done with this area B in and B outFor example, it can be obtained using a Python program, and for example, it can be obtained using a library such as scipy or numpy in the Python program. In such a program, the area of ​​the second metal is divided into a plurality of small triangles or squares, such as polygons, and the area of ​​each divided polygon is used to obtain the B in and B out Find the area B above. in and B out The units are μm each 2 It could be.

[0096] The ratio of the area B obtained in the same way as above in / (B in +B out ) may be about 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35 or 0.4, and its upper limit may be about 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1 or 0.05. The above ratio B in / (B in +B out ) may be any number within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0097] The above ratio B in / (B in +B out ) is within the above range means that the catalyst particles are in the form of secondary particles formed by agglomeration of a plurality of primary particles, and the second metal is mainly present on the surface of the primary particles present on the surface of the secondary particles. By controlling the form of the catalyst particles in this way, a catalyst exhibiting the desired catalytic activity and stably maintaining the catalytic activity during the reaction process can be provided.

[0098] However, the above is only one example of a catalyst form, and the catalyst may have various forms as long as the catalyst is designed according to the above-described content.

[0099] The specific type of the above catalyst is not particularly limited as long as it satisfies the above-described design parameters. In particular, a catalyst satisfying the above-described parameters is effective as a CO2 or CO conversion catalyst or hydrogenation catalyst particle, as described above.

[0100] Accordingly, the catalyst may include a component included in the CO2 or CO conversion catalyst or hydrogenation catalyst particles.

[0101] A representative example of such catalysts is an Fe-based catalyst. Therefore, the first metal may be Fe. In this case, the primary particles may be Fe-based catalyst particles.

[0102] As these Fe-based catalyst particles, particles known as CO2 or CO conversion catalysts or hydrogenation catalyst particles can be applied.

[0103] For example, the primary particles may be Fe bulk catalyst particles or catalyst particles in which Fe is supported as an active ingredient on a support. The Fe bulk catalyst particles are catalysts composed only of an Fe-based component as an active ingredient without a separate support, and for example, Fe metal or a compound containing Fe can be used as the bulk catalyst. In another example, the primary particles may be catalyst particles in which Fe is supported as an active ingredient on a support. In this case, alumina or silica can typically be used as the support. Such supports have a large specific surface area, which is advantageous for supporting the active ingredient, and when Fe is supported, they can be excellent in terms of catalytic activity and durability.

[0104] The above primary particles may contain additional components in addition to the Fe. These components may be components commonly known as co-catalyst components, and may be, for example, one or more selected from the group consisting of Na, K, and Cu.

[0105] In the above catalyst, it is necessary to introduce the second metal so as to satisfy the parameters described above. This second metal protects the primary particles and suppresses undesirable sintering of the catalyst during the reaction process, thereby improving the conversion rate of CO2 and the selectivity for higher hydrocarbons (e.g., hydrocarbons having 5 or more, 6 or more, 7 or more, or 8 or more carbon atoms).

[0106] Such a second metal may include, for example, one or more selected from the group consisting of Al, Ce, Cu, Co, and Mo. Such a second metal may be included in the particles as a metal itself or in the form of an oxide, nitride, or oxynitride.

[0107] Such a second metal can improve heat resistance and mechanical stability without lowering the catalytic activity of the primary particles by being included so that the above parameters are satisfied.

[0108] A catalyst satisfying these above parameters can be prepared in the following manner.

[0109] For example, the catalyst can be manufactured by first manufacturing catalyst particles (which may be called precursor catalysts) including the primary particles (these precursor catalysts may be in the form of primary particles or secondary particles) and then introducing the second metal into such catalyst particles.

[0110] The above precursor catalyst can be manufactured by a known method, for example, by applying a precipitation method such as an incipient wetness impregnation method. In this process, the manufacturing process can be controlled so as to satisfy the above parameters. For example, if the size of the primary particles and / or secondary particles of the precursor catalyst is increased in the above process, the values ​​of A and r among the parameters can be increased, and the variable R can also be increased, and by controlling the number of primary particles in the catalyst, A avg The value can be controlled. In addition, the a value can also be controlled by adjusting the size of the primary particles. Methods for controlling the size of the primary particles and / or secondary particles or the number of primary particles are known.

[0111] A catalyst can be prepared by introducing a second metal into such a precursor catalyst. The method for introducing the second metal is not specific, and for example, the second metal can be introduced by applying a known deposition method and / or supporting method.

[0112] For example, among the deposition methods, the so-called ALD (Atomic Layer Deposition) method can precisely control the amount of the second metal introduced at the atomic level, and the amount of the second metal introduced can be controlled by adjusting the number of deposition cycles of the ALD method. In addition, by introducing a supporting method, a larger amount of the second metal can be introduced compared to deposition methods such as ALD. In this process, the amount of the second metal introduced is large, but the L s The value of tends to decrease, and even when applying the same method, L becomes smaller as the size of the precursor catalyst decreases. s The value tends to decrease.

[0113] In this way, L is controlled by controlling the shape of the precursor catalyst and / or the amount of the second metal introduced. s , r, a, and B can be controlled.

[0114] The lower limit of the size of the catalyst particles manufactured in this way is not particularly limited and may be, for example, about 1, 10, 30, 50, 70 or 100, and the upper limit may be about 1,000, 800, 600 or 500. The size may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. The size of the catalyst may be the so-called D50 particle size (volume basis) measured by a known laser diffraction method.

[0115] The present specification also discloses a method for producing a hydrocarbon mixture using the catalyst. This method may include a step of reacting a feedstock comprising at least one selected from the group consisting of CO and CO2 in the presence of the catalyst to obtain a hydrocarbon mixture. This reaction may be a so-called reverse water-gas shift (RWGS) reaction and / or a Fischer-Tropsch Synthesis (FTS) reaction.

[0116] There is no particular limitation on the method for carrying out the above reaction, and any known method can be applied as long as the above catalyst is applied.

[0117] The above reaction can be performed with high conversion and selectivity. These conversion and selectivity are values ​​measured using the method described in Test Example 2 of this specification.

[0118] For example, the lower limit of the selectivity may be about 40%, 45%, 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66% or 68%, and the upper limit may be about 100%, 90%, 80% or 70%. The selectivity may be within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0119] For example, the lower limit of the conversion rate may be about 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, or 58%, and the upper limit may be about 100%, 90%, 80%, 70%, or 60%. The selectivity may be within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0120] The above reaction can be performed without any special restrictions under conditions applicable to thermochemical conversion reactions such as CO2, and any known reactor can be used as the reactor. The conditions, such as the temperature at which the reaction is performed, are also not particularly restricted.

[0121] The present specification discloses particles. The particles can be applied to a reaction for forming hydrocarbons from raw materials containing CO2 and / or CO. The present specification aims to disclose particles capable of obtaining a desired product with excellent selectivity and conversion without causing undesirable agglomeration or sintering phenomena and deterioration of catalytic activity during the reaction process. For example, the particles can obtain hydrocarbons having 5 or more carbon atoms with high selectivity and conversion in a reaction for obtaining hydrocarbons from raw materials containing CO2 and / or CO. The present specification also discloses uses of the particles.

[0122] Figures 1 to 4 are exemplary drawings for explaining the shape of the catalyst.

[0123] Figures 5 and 6 are SEM images of the catalyst of the example.

[0124] Figure 7 is a TEM image of the catalyst of the embodiment.

[0125] Figure 8 is an SEM image of a catalyst of a comparative example.

[0126] Figure 9 is a TEM image of a catalyst of a comparative example.

[0127] The particles and the like are specifically described through the following examples, but the scope of the particles and the like is not limited to the following examples.

[0128]

[0129] Example 1.

[0130] A catalyst containing iron (Fe) as the first metal and aluminum (Al) as the second metal was prepared in the following manner. Iron nitrate hydrate (Fe(NO3)) was added to a precipitation reaction vessel. 3·A solution (200 mL) of iron nitrate (A), silica (B), and distilled water (C) was added. The solution was prepared by mixing the iron nitrate hydrate (A), silica (B), and distilled water (C) in a weight ratio of 222:1:200 (A:B:C). Subsequently, the temperature of the solution was raised to approximately 60°C while stirring at approximately 400 rpm. When the temperature reached approximately 60°C, an aqueous ammonium carbonate solution (180 g / L) was added to the precipitation reaction vessel at a rate of approximately 2 mL / min until the pH became approximately 7, and after the addition, the reaction vessel was stirred at 400 rpm for approximately 2 hours while maintaining the temperature at approximately 60°C to generate a precipitate. After collecting the precipitate through filtration, the precipitate was washed with distilled water, and dried at 110°C for approximately 12 hours.

[0131] The dried precipitate was ground using a mortar and pestle and sieved to obtain a powder. Separately, a solution was prepared by mixing distilled water (D), copper (II) nitrate trihydrate (E), and potassium nitrate (F) in a weight ratio of 4:3:50 (D:E:F). 13 g of the powder was added to 250 mL of the above solution, stirred, and then the precipitate was recovered. The recovered precipitate was then dried at 110°C until the solvent was completely removed, and then calcined at 400°C for about 3 hours to obtain secondary particles.

[0132] The obtained secondary particles were separated through a sieve to obtain particles having a particle size in the range of approximately 300 μm to 500 μm.

[0133] The obtained secondary particles were loaded onto a square tray, and the tray was placed into the chamber of an ALD (Atomic Layer Deposition) device. The temperature inside the chamber was set to approximately 150°C, the process pressure to approximately 1 Torr, and the processes (1) to (3) below were sequentially performed as one cycle, and the cycle was repeated 16 times (16 cycles) to introduce a second metal (aluminum) onto the surface of the particles.

[0134] (1) Pulse inject TMA (trimethyl aluminum) at approximately 20°C into the chamber together with a carrier gas (nitrogen gas) for 3 seconds (injection speed: approximately 100 sccm), maintain for 100 seconds, and then purge with nitrogen gas for 20 seconds. This process is repeated 3 times.

[0135] (2) (1) Purging with nitrogen gas for 600 seconds

[0136] (3) In the process of (1) above, the process of injecting steam in pulses for 3 seconds instead of TMA, maintaining it for 100 seconds, and then purging with nitrogen gas for 20 seconds is repeated 3 times.

[0137] The desired catalyst particles were manufactured through the above process. Figures 5 and 6 are SEM (Scanning electron microscope) images obtained for the particles, and Figure 7 is a TEM (Transmission Electron Microscope) image obtained for the particles.

[0138] In Figure 6, the first metal region, the Fe region, is identified in green, and the second metal region, the Al region, is identified in blue.

[0139] The above cross-sectional image was obtained by cutting the catalyst particles (I) after mixing them with epoxy molding liquid to obtain a cross-section, and then analyzing them using a scanning electron microscope (SEM), energy dispersive x-ray spectrometer (EDS), and electron probe micro-analysis (EPMA).

[0140] The above SEM images were taken using JEOL's JSM-7800F, and images were obtained at an acceleration voltage of 5 kV in composition mode. To obtain clear images of the first metal (Fe) and the second metal (Al), EDS mapping analysis was used to expose the corresponding spectra for more than 4 hours.

[0141] To obtain the above TEM image, the catalyst was cut with a FIB (Focused Ion Beam) (HELIOS 5 UX, Ga ion gun), and a TEM image was obtained for the cross-section. The TEM image was obtained using a Spectra 300 S equipment and an acceleration voltage of 200 kV. A clear image of the Fe region was obtained by EDS mapping with a Super-X EDS detector.

[0142] It can be confirmed from the above SEM and TEM images that the catalyst obtained is in the form of secondary particles in which a plurality of Fe-based primary particles are aggregated, and that the second metal (Al) is introduced to the surface of the primary particles present in the surface region among the plurality of primary particles by the ALD.

[0143]

[0144] Example 2.

[0145] A catalyst was obtained in the same manner as in Example 1, except that a powder having a size of 53 to 100 μm was used as a powder for applying the ALD process by changing the body, and SEM and TEM images were obtained in the same manner. The obtained catalyst was in the form of secondary particles in which a plurality of Fe-based primary particles were aggregated, and a second metal (Al) was introduced to the surface of the primary particles present in the surface region among the plurality of primary particles by the ALD.

[0146]

[0147] Example 3.

[0148] A catalyst was obtained in the same manner as in Example 1, except that a powder having a size of 45 to 53 μm was used as a powder for applying the ALD process by changing the body, and SEM and TEM images were obtained in the same manner. The obtained catalyst was in the form of secondary particles in which a plurality of Fe-based primary particles were aggregated, and a second metal (Al) was introduced to the surface of the primary particles present in the surface region among the plurality of primary particles by the ALD.

[0149]

[0150] Example 4.

[0151] A catalyst was obtained in the same manner as in Example 1, except that a powder having a size of 30 μm was used as a powder for applying the ALD process by changing the body, and SEM and TEM images were obtained in the same manner. The obtained catalyst was in the form of secondary particles in which a plurality of Fe-based primary particles were aggregated, and a second metal (Al) was introduced to the surfaces of the plurality of primary particles by the ALD.

[0152]

[0153] Example 4.

[0154] A catalyst was obtained in the same manner as in Example 1, except that a powder having a size of 30 μm was used as a powder for applying the ALD process by changing the body, and SEM and TEM images were obtained in the same manner. The obtained catalyst was in the form of secondary particles in which a plurality of Fe-based primary particles were aggregated, and a second metal (Al) was introduced to the surfaces of the plurality of primary particles by the ALD.

[0155]

[0156] Example 5.

[0157] The catalyst manufactured in Example 4 was further pulverized to a size of 45 μm or less, and mixed with distilled water in a weight ratio of 1:2 (catalyst:distilled water) to prepare a mixture. Thereafter, the mixture was mixed with alpha alumina (mold, molded body) having a diameter of about 4.8 mm, stirred at 120°C, dried, and then calcined at 400°C for 3 hours to prepare a catalyst including a molded body. The content of the catalyst in the mixture of the catalyst and the molded body was set to be about 10 wt%.

[0158]

[0159] Example 6.

[0160] A catalyst was prepared in the same manner as in Example 5, except that the content of the catalyst in the mixture of the catalyst and the molded body was lowered to about 7 to 8 wt%.

[0161]

[0162] Comparative Example 1.

[0163] Catalyst particles were obtained in the same manner as in Example 1, except that the ALD process was not performed. Fig. 8 is an SEM image obtained for the particles, and Fig. 9 is a TEM image obtained for the particles. The method for obtaining the SEM and TEM images is the same as in Example 1. It can be confirmed from the SEM and TEM images that the obtained catalyst is in the form of secondary particles in which a plurality of Fe-based primary particles are aggregated, but in a form in which the second metal (Al) is not present.

[0164]

[0165] Test Example 1.

[0166] Analysis was performed on the obtained SEM and TEM images. First, the DBSCAN (Density-based spatial clustering of applications with noise) algorithm was used to define the region where Fe exists (the first metal region) and the region where Al exists (the second metal region) in the image by drawing a closed curve. At this time, if there was an empty space or a molded body containing an element other than the first and second metals in the image, the region where the empty space or the molded body existed was excluded. For this definition, the radius for clustering was set, and DBSCAN was applied by specifying the minimum number of objects within the radius as an appropriate condition (4 to 10).

[0167] After that, the image was analyzed using the scipy or numpy library of the Python program.

[0168] Using the above program, the image defined by the closed curve corresponding to the first metal region (Fe region) in the SEM image is divided into a plurality of polygons such as small triangles or squares, and the center coordinates and area are calculated for each polygon, and then the center coordinates (C) are defined by Equations 1 and 2 below. x , C y) was obtained (see Fig. 2).

[0169] [Formula 1]

[0170]

[0171] [Formula 2]

[0172]

[0173] x in equations 1 and 2 i and y i are the x and y coordinates of the centers of the above-described individual polygons, and A i is the above coordinate x i and y i is the area of ​​a polygon whose center is at the coordinates.

[0174] n in equations 1 and 2 is the number of the divided polygons.

[0175] In addition, the total area A of the first metal (Fe) region was obtained by adding up the areas of the plurality of polygons. In addition, the number of each primary particle to which the first metal (Fe) region belongs was confirmed from the TEM image, and the arithmetic mean A of the area of ​​the first metal (Fe) region within each primary particle was obtained through the area of ​​the first metal (Fe) region and the number of particles. avg was saved.

[0176] In addition, the area B of the second metal (Al) region was obtained by adding the areas of multiple polygons in the same manner as the method for obtaining the above A.

[0177] After that, the above center coordinates (C x , C y ) to the area where the second metal (Al) exists, the shortest distance is determined by the center coordinate (C x , C y ) is calculated at 1-degree intervals in a 360-degree direction, and then the arithmetic mean is taken to obtain L. s was saved.

[0178] Next, the area A obtained above was substituted into Equation 8 below to obtain R of Equation 8 below, and the area Aavg was substituted into Equation 5 below to obtain r.

[0179] [Formula 5]

[0180]

[0181] [Formula 8]

[0182]

[0183] In addition, the average distance a between the centers of the first metal (Fe) regions within each primary particle defined by a closed curve in the image was also obtained from the TEM image using the k-Nearest Neighbors algorithm. That is, the center coordinates of the first metal (Fe) region within each primary particle were obtained from a plurality of small polygons divided into the first metal (Fe) region within each primary particle, and the arithmetic average of the distances between the center coordinates was taken as a.

[0184] Next, l of Equation 9 below was obtained by applying the above average distance a and r of Equation 5 above.

[0185] [Formula 9]

[0186]

[0187] Table 1 below summarizes the results obtained above.

[0188] R in Table 1 below v is the result obtained by Equation 3 below (L in calculation) s applies values ​​in μm, and A and B are each μm 2 (applying the value of the unit) and R g is the result obtained by Equation 4 below (L in calculation) s , r and a are each applied with values ​​in μm, and B is μm 2 (applying the value of the unit) and R l is the result obtained from Equation 6 below (L in calculation) s, l and R are applied with values ​​in μm), and R p is the result obtained from Equation 6 below (L in calculation) s and R is applied with values ​​in μm).

[0189] [Formula 3]

[0190]

[0191] [Formula 4]

[0192]

[0193] [Formula 6]

[0194]

[0195] [Formula 7]

[0196]

[0197] In Table 1, the units of A and B are μm each. 2 , the units of R and Ls are μm each, and the units of a, r, and l are nm each.

[0198] Example Comparative Example 1234561A180864477618099076287038340141791B24115357616089071067851627780B / A0.1330.7490.88911.6994.2460Rv0.0330.2180.3330.50.1840.2710Rg363.6377.7400.1369.5852.5983.60Rl0.010. 0530.0710.1370.0170.0180.01Rp0.4830.3210.16701.0641.8190R480784834283221425Ls232258030140 20a25252226333229r19201820282924l4.614.113.424.674.623.564.37a / r1.321.251.221.31.181.11.21

[0199] Test Example 2.

[0200] A hydrocarbon mixture was prepared from CO2 using the catalyst of the above example or comparative example. 0.5 g of the catalyst was placed in a fixed-bed tubular reactor (stainless steel, diameter 3 / 8 inch), and the catalyst was activated by reduction treatment for 8 hours under a CO atmosphere (>99.9 volume%) at 400°C.

[0201] Next, a mixed gas containing H2, CO2, and N2 in a volume ratio of 54:18:3 (H2:CO2:N2) was injected into the reactor at a flow rate of 75 ml / min, and the reaction was carried out under the conditions of 340°C and 20 bar. After the reaction, the product was passed through a constant-temperature water bath trap at 0°C to collect liquid hydrocarbons with 5 or more carbon atoms among the products, and the gaseous products were analyzed in real time by GC (Gas Chromatography). The reaction was performed continuously for more than 48 hours.

[0202] The conversion rate of CO2 and the selectivity for hydrocarbons with carbon number of 5 or more were confirmed by the following methods.

[0203] Conversion rate

[0204] CO2 conversion rate = 100 × (input CO2 flow rate - exhaust CO2 flow rate) / (input CO2 flow rate)

[0205] <Selectivity>

[0206] C 5+ Selectivity = 100% - (sum of selectivities of gaseous products)

[0207] Selectivity of gaseous products = 100 × (C A H B Flow rate × A) / (input CO2 flow rate - exhaust CO2 flow rate)

[0208] The evaluation results (conversion rate (%) and selectivity (%)) for each catalyst are summarized and shown in Table 2 below.

[0209] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Conversion rate 52.5 50.65 655.95 5.3 55.64 4.4 Selectivity 60.1 67.96 868.168.66 8.84 6.5

Claims

1. A secondary particle that is a condensation of multiple primary particles. The above primary particle comprises a first metal, A second metal is present on the surface of at least some of the primary particles among the above primary particles, The first metal and the second metal are different metals, Particles having Rl in the following formula 6 within the range of 0 to 2: [Formula 6] In Equation 6, Ls is the average distance from the center of the first metal region of the cross-section of the secondary particle to the second metal region, R is R in Equation 8 below, and l is l in Equation 9 below: [Formula 8] In Equation 8, A is the area of ​​the first metal region in the cross-section of the secondary particle: [Formula 9] In Equation 9, r is r of Equation 5 below, and a is the average distance between the centers of the first metal regions within the primary particle cross-section: [Formula 5] A in Equation 5 avg is the arithmetic mean of the area of ​​the first metal region belonging to each primary particle in the cross-section of the secondary particle.

2. In the first paragraph, a particle having Rp of the following formula 7 within a range of 0 to 5: [Formula 7] In Equation 7, Ls and R are the same as Ls and R in Equation 6, respectively.

3. In the first paragraph, a particle in which the ratio B / A of the area B of the second metal region to the area A of the first metal region in the cross-section of the secondary particle is within a range of more than 0 and less than or equal to 10.

4. In the third paragraph, the area A is 200 to 1,000,000 μm 2 Particles within the range of .

5. In the first paragraph, a particle having Rv of the following formula 3 within a range of 0.01 to 1.5: [Formula 3] In Equation 3, Ls is the average distance from the center of the first metal region of the cross-section of the secondary particle to the second metal region, A is the area of ​​the first metal region in the cross-section of the secondary particle, and B is the area of ​​the second metal region in the cross-section of the secondary particle.

6. In the fifth paragraph, a particle having Ls in the range of 0 to 1,000 μm.

7. In the first paragraph, a particle having Rg of the following formula 4 within a range of 100 to 2,000: [Formula 4] In Equation 4, Ls is the average distance from the center of the first metal region of the cross-section of the secondary particle to the second metal region, A is the area of ​​the first metal region in the cross-section of the secondary particle, B is the area of ​​the second metal region in the cross-section of the secondary particle, r is r of Equation 5, and a is the average spacing between the first metal regions in each primary particle in the cross-section of the secondary particle.

8. In the 7th paragraph, a particle in which the ratio a / r of a to r in Equation 4 is within the range of 0.1 to 2.

9. In the 7th paragraph, a particle in which r in formula 4 is within a range of 1 to 500 nm.

10. A particle in the first paragraph, wherein the first metal is Fe.

11. In the 10th paragraph, the particle further comprises at least one selected from the group consisting of Na, K and Cu.

12. A particle in the first paragraph, wherein the second metal is at least one selected from the group consisting of Al, Ce, Cu, Co, and Mo.

13. A method comprising the step of obtaining a hydrocarbon mixture by reacting a raw material comprising at least one selected from the group consisting of CO and CO2 in the presence of a catalyst according to any one of claims 1 to 12.

14. A method according to claim 13, wherein the reaction is at least one reaction selected from the group consisting of a reverse water-gas shift (RWGS) reaction and a Fischer-Tropsch Synthesis (FTS) reaction.

15. A method according to claim 13, wherein the selectivity is 40% or more.

16. A method according to claim 13, wherein the conversion rate is 40% or higher.

Images