Catalyst for methane reforming and method for preparing the same

Abstract

A catalyst for methane reforming according to an exemplary embodiment of the present application includes: a porous metal support; a first coating layer disposed on the porous metal support and including a perovskite-based compound represented by Chemical Formula 1; and a second coating layer disposed on the first coating layer and including a perovskite-based compound represented by Chemical Formula 2.

Description

Technical Field

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2021-0159456, filed in the Korean Intellectual Property Office on November 18, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to a catalyst for methane reforming and a method for preparing the catalyst. Background Art

[0003] As part of efforts to reduce greenhouse gases that contribute to global warming, extensive research has been conducted on carbon dioxide conversion technologies. One of these technologies is carbon dioxide reforming, which is a process for reacting methane with carbon dioxide to produce synthesis gas consisting of hydrogen and carbon monoxide.

[0004] Synthesis gas (syngas) is a material with high development value derived from a variety of downstream feedstocks. Industrially, natural gas reforming reactions for producing syngas (H2 / CO) can be broadly categorized into steam reforming, carbon dioxide (CO2) reforming, catalytic partial oxidation, autothermal reforming, and tertiary reforming, as shown in reaction schemes 1 through 5 below.

[0005] [Reaction Scheme 1]

[0006] CH4+H2O→3H2+COΔH=226kJ / mol

[0007] [Reaction Scheme 2]

[0008] CH4+CO2→2H2+2COΔH=261kJ / mol

[0009] [Reaction Scheme 3]

[0010] CH4+0.5O2→2H2+COΔH=-44kJ / mol

[0011] [Reaction Scheme 4]

[0012] Autothermal reforming: Reaction Scheme 1 + Reaction Scheme 3

[0013] [Reaction Scheme 5]

[0014] Triple Reaction: Reaction Scheme 1 + Reaction Scheme 2 + Reaction Scheme 3

[0015] Meanwhile, various catalysts can be used for reforming activity in the reforming process. Among them, when noble metal catalysts are used in the reforming process, there is an advantage in high efficiency in converting natural gas into hydrogen, but there is a problem of poor economic feasibility due to the high price of noble metal catalysts.

[0016] Therefore, nickel catalysts, which have high hydrogen conversion efficiency and are relatively inexpensive, are generally used in reforming processes. However, in this case, there is a problem of deactivation of the nickel catalyst due to the inevitable generation of carbon on the surface of the nickel catalyst.

[0017] Therefore, there is a need in the art to develop a catalyst that is resistant to carbon deposition and can be effectively applied to a methane reforming process. Summary of the Invention

[0018] Technical issues

[0019] The present application is directed to providing a catalyst for methane reforming and a method for preparing the catalyst.

[0020] Technical Solution

[0021] An exemplary embodiment of the present application provides a catalyst for methane reforming, comprising:

[0022] porous metal support;

[0023] A first coating layer disposed on the porous metal support and comprising a perovskite-based compound represented by the following Chemical Formula 1; and

[0024] The second coating layer is disposed on the first coating layer and includes a perovskite-based compound represented by the following Chemical Formula 2.

[0025] [Chemical Formula 1]

[0026] SrTiO3

[0027] [Chemical Formula 2]

[0028] Sr 1-x A x Ti α B y O 3-δ

[0029] In Chemical Formula 2,

[0030] A is selected from Y, Sc, La and lanthanides,

[0031] B is Ni, Co, Fe, Mn, Cr, Mo, Ru or Rh,

[0032] x is a real number greater than 0 and less than 1,

[0033] y is a real number greater than 0 and less than 0.3,

[0034] δ is a real number greater than 0 and less than 1,

[0035] α is a real number greater than 0.7 and less than 1, and

[0036] Satisfies (x+y)>0.

[0037] In addition, another exemplary embodiment of the present application provides a method for preparing a methane reforming catalyst, the method comprising:

[0038] preparing a first solution each containing a precursor of a perovskite-based compound represented by Chemical Formula 1; and a second solution each containing a precursor of a perovskite-based compound represented by Chemical Formula 2;

[0039] preparing a catalyst precursor provided with a first coating layer by coating a porous metal support with the first solution, and then performing a first heat treatment process; and

[0040] The catalyst provided with the second coating layer is prepared by coating the catalyst precursor provided with the first coating layer with the second solution, and then performing a second heat treatment process.

[0041] Beneficial effects

[0042] The catalyst for methane reforming according to an exemplary embodiment of the present application can not only improve the adhesion between the porous metal support and the second coating layer containing the perovskite-based compound represented by Chemical Formula 2, but also prevent the side reaction of the porous metal support by forming the first coating layer containing the perovskite-based compound represented by Chemical Formula 1 without a catalyst component.

[0043] In addition, the catalyst for methane reforming according to an exemplary embodiment of the present application is characterized in that, since the perovskite-based compound is supported on a porous metal support having high thermal conductivity, it is easy to control the reaction heat compared to pellet-type or powder-type catalysts in the prior art.

[0044] In addition, the catalyst for methane reforming according to an exemplary embodiment of the present application may exhibit high activity even at a high space velocity during the methane reforming reaction because the active surface area of ​​the catalyst may be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 are a set of electron microscope photographs showing the surface of the catalyst for methane reforming according to Example 1 of the present application. DETAILED DESCRIPTION

[0046] Hereinafter, this specification will be described in more detail.

[0047] In this specification, when one member is disposed “on” another member, this includes not only a case where one member is in contact with another member but also a case where another member exists between the two members.

[0048] In this specification, when a part “comprises” one constituent element, unless otherwise specifically stated, it does not mean that another constituent element is excluded but that another constituent element may be further included.

[0049] Currently, among the catalysts widely used in the field of reformers, powdered catalysts and pellet-type supported catalysts are generally used. Although powdered catalysts can have excellent performance due to their excellent dispersion, it is difficult to use them directly in industry. For example, when a powdered catalyst is used to drive a reformer, the catalyst is discharged along with the substances produced after the reaction. In this case, the powdered catalyst gradually accumulates in the material flow pipe at the outlet portion, eventually clogging the entire pipe. Therefore, there is a disadvantage that powdered catalysts cannot be used in reformers used in industry.

[0050] In addition, pellet-type supported catalysts are currently commonly used in industrial reformers. Due to the limitation of mass transfer rate, compared with powdered catalysts, their performance deteriorates only in terms of catalyst performance, but there is an advantage that pellet-type supported catalysts can be used for a long time due to the use of a carrier. However, the γ-Al2O3 pellets commonly used as pellet-type supported catalysts have weak structural strength and are therefore prone to breakage, which has the disadvantage of generating a pressure difference in the reactor. In addition, due to the characteristics of pellet-type supported catalysts, they are bulky, so when pellet-type supported catalysts are used in large-capacity reformers, their volume becomes quite large. In addition, all reforming reactions are sensitive to reaction temperature, but existing pellet-type catalysts have the disadvantage that, due to the greatly reduced thermal conductivity, heat is unevenly distributed throughout the reactor. In addition, because the reforming reaction is very fast, in the case of pellet-type supports or extruded catalysts, the efficiency coefficient of the catalyst is below 0.3, so there is a disadvantage of deteriorated catalyst utilization.

[0051] Therefore, the present application aims to alleviate the phenomenon of blocked material flow pipes, a disadvantage of powder-type catalysts, by coating a porous metal support having high heat and mass transfer rates with a catalyst, and to improve the heat and mass transfer rates, a common disadvantage of both powder-type and pellet-type catalysts. Furthermore, the present application aims to provide a catalyst for methane reforming that can support a large amount of catalyst at once and suppresses the side effects caused by the binder.

[0052] A catalyst for methane reforming according to an exemplary embodiment of the present application includes: a porous metal support; a first coating layer disposed on the porous metal support and including a perovskite-based compound represented by Chemical Formula 1; and a second coating layer disposed on the first coating layer and including a perovskite-based compound represented by Chemical Formula 2.

[0053] In an exemplary embodiment of the present application, the perovskite-based compound represented by Chemical Formula 1 is a compound without a catalyst component, the perovskite-based catalyst represented by Chemical Formula 2 is a compound containing a catalyst component (A and / or B of Chemical Formula 2), and these compounds are different from each other.

[0054] In an exemplary embodiment of the present application, Chemical Formula 2 may be represented by Chemical Formula 3 or Chemical Formula 4 below.

[0055] [Chemical Formula 3]

[0056] SrTi α B y O 3-δ

[0057] [Chemical Formula 4]

[0058] Sr 1-x Y x Ti α B y O 3-δ

[0059] In Chemical Formula 3 and Chemical Formula 4,

[0060] B is Ni or Ru,

[0061] x is a real number greater than 0 and less than 1,

[0062] y is a real number greater than 0 and less than 0.3,

[0063] δ is a real number greater than 0 and less than 1,

[0064] α is a real number greater than 0.7 and less than or equal to 1.

[0065] In an exemplary embodiment of the present application, the porous metal support may be composed of a material capable of maintaining thermal stability at a high temperature of 800° C. or higher.

[0066] In an exemplary embodiment of the present application, the porous metal support may be a metal foam including NiFeCrAl, NiCrAl, SiC or α-Al 2 O 3 .

[0067] The porous metal support is a support with a variety of shapes, with a small heat capacity and excellent heat transfer capability, and therefore, can be formed into a desired shape for use. There is no particular restriction on the form, size, etc. of the porous metal support, and the porosity of the porous metal support can be 10% to 99%, 50% to 96%, and 85% to 96%. The average pore size (cell size) of the porous metal support can be 400 μm to 2,000 μm and 450 μm to 1,500 μm. When the average pore size of the porous metal support is less than 400 μm, it will be difficult to coat the porous metal support with a precursor solution, and when the average pore size of the porous metal support is greater than 2,000 μm, the surface area of ​​the catalyst that can be covered will be reduced, and therefore, since this range will be disadvantageous in the process, the average pore size range is not preferred. Those skilled in the art can consider the material, pore size, porosity, etc. of the porous metal support and appropriately prepare the porous metal support using methods known in the art. According to an exemplary embodiment of the present application, as will be described in detail in Examples below, a porous metal support having various materials, pore sizes, etc. may be applied.

[0068] In an exemplary embodiment of the present application, the content of the perovskite-based compound represented by Chemical Formula 1 may be 1% to 20% by weight and 1.5% to 18% by weight, based on the total weight of the porous metal support. When the content of the perovskite-based compound represented by Chemical Formula 1 exceeds 20% by weight, the remaining capacity capable of coating the perovskite-based compound represented by Chemical Formula 2 is reduced, and therefore, the activity of the catalyst is reduced compared to the volume of the porous metal support, and thus the above weight range is not preferred. In addition, when the content of the perovskite-based compound represented by Chemical Formula 1 is less than 1% by weight, it is difficult to obtain the effect caused by the first coating layer due to the low content.

[0069] In an exemplary embodiment of the present application, the weight ratio of the perovskite-based compound represented by Chemical Formula 1: the perovskite-based compound represented by Chemical Formula 2 may be 1:1 to 1:20 and 1:1.1 to 1:15. A weight ratio of the perovskite-based compound represented by Chemical Formula 1: the perovskite-based compound represented by Chemical Formula 2 outside the range is not preferred because the activity of the catalyst may be reduced compared to the volume of the porous metal support.

[0070] In an exemplary embodiment of the present application, (α+y) of Chemical Formula 2 may be 1. In addition, in an exemplary embodiment of the present application, (α+y) of Chemical Formula 2 may be a real number greater than 0.90 and less than 1. In Chemical Formula 2, B such as Ni replaces a portion of Ti, and the theoretical stoichiometric ratio of (α+y) is 1, but when the content of Ti is slightly lower than the theoretical stoichiometric ratio during the preparation of the perovskite-based compound represented by Chemical Formula 2, Ti in Chemical Formula 2 may be more easily replaced by B such as Ni.

[0071] In an exemplary embodiment of the present application, the content of the perovskite-based compound represented by Chemical Formula 2 may be 3% to 40% by weight, 6% to 35% by weight, and 7% to 30% by weight, based on the total weight of the catalyst for methane reforming. When the content of the perovskite-based compound represented by Chemical Formula 2 is less than 3% by weight, the reactivity is reduced due to the relatively small number of active sites on the catalyst surface, and therefore, the content is not preferred. In addition, when the content of the perovskite-based compound represented by Chemical Formula 2 exceeds 40% by weight, a relatively large amount of catalyst components is included compared to the porous metal support, making it difficult to maintain a pore structure and to bond the catalyst components to the porous metal support. Therefore, the actual benefit of the methane reforming reaction is reduced.

[0072] In an exemplary embodiment of the present application, the first coating layer may be provided on the entire surface of the porous metal support.

[0073] In an exemplary embodiment of the present application, at least a portion of the surface of the catalyst for methane reforming may include a protrusion shape, which may be spherical, elliptical, or a combination thereof, but is not limited thereto.

[0074] In an exemplary embodiment of the present application, a first coating layer comprising a perovskite-based compound represented by Chemical Formula 1 may be used to fix a second coating layer comprising a perovskite-based compound represented by Chemical Formula 2 on a porous metal support. Furthermore, the second coating layer comprising the perovskite-based compound represented by Chemical Formula 2 may be present in a protruding form on the first coating layer, thereby improving the performance of the methane reforming reaction by increasing the reaction surface area of ​​the catalyst.

[0075] In addition, according to an exemplary embodiment of the present application, by simultaneously using: a first coating layer comprising a perovskite-based compound represented by Chemical Formula 1; and a second coating layer comprising a perovskite-based compound represented by Chemical Formula 2, the total content of the catalyst supported on the porous metal support can be increased compared to when the catalyst particles are used alone. In addition, according to an exemplary embodiment of the present application, the durability and performance of the catalyst can be improved because the metal (Ni, Cr, etc.) as the main component of the porous metal support can be prevented from being exposed to the surface in the form of metal oxides (NiO, Cr2O3, etc.) under long-term operation conditions at high temperatures (above 750°C), and by using a first coating layer comprising a perovskite-based compound represented by Chemical Formula 1, the component ratio or phase of the catalyst of Chemical Formula 2 can be prevented from changing.

[0076] In an exemplary embodiment of the present application, the catalyst for methane reforming can be applied to a steam reforming process, a carbon dioxide (CO2) reforming process, a catalytic partial oxidation process, an autothermal reforming process, a ternary reforming process or a hybrid reforming process, and there is no particular limitation on the methane reforming process.

[0077] A method for preparing a catalyst for methane reforming according to an exemplary embodiment of the present application includes: preparing a first solution each containing a precursor of a perovskite-based compound represented by Chemical Formula 1 and a second solution containing a precursor of a perovskite-based compound represented by Chemical Formula 2; preparing a catalyst precursor provided with a first coating layer by coating a porous metal support with the first solution, and then performing a first heat treatment process; and preparing a catalyst provided with a second coating layer by coating the catalyst precursor provided with the first coating layer with the second solution, and then performing a second heat treatment process.

[0078] In the method of preparing a catalyst for methane reforming according to an exemplary embodiment of the present application, details of the porous metal support, the perovskite-based compound represented by Chemical Formula 1, the perovskite-based compound represented by Chemical Formula 2, etc. are the same as above.

[0079] In particular, the first solution including the precursor of the perovskite-based compound represented by Chemical Formula 1 and the second solution including the precursor of the perovskite-based compound represented by Chemical Formula 2 may each be applied in the form of a sol or a gel.

[0080] The perovskite-based compound precursor is a precursor of the metal constituting the perovskite-based compound, and the metal molar ratio of the perovskite-based compound can be adjusted by adjusting the content of the metal precursor. Furthermore, there is no particular limitation on the metal precursor, and ammonium salts, nitrates, carbonates, chlorides, lactates, hydroxides, organic acid salts, oxides of the metal element, or mixtures thereof, can be used in combination.

[0081] The method of preparing a catalyst for methane reforming according to an exemplary embodiment of the present application includes preparing first solutions each including a precursor of a perovskite-based compound represented by Chemical Formula 1; and a second solution including a precursor of a perovskite-based compound represented by Chemical Formula 2.

[0082] The first solution and the second solution may each independently further include a solvent, and as the solvent, solvents known in the art may be used, but are not particularly limited thereto.

[0083] A method for preparing a catalyst for methane reforming according to an exemplary embodiment of the present application includes: preparing a catalyst precursor provided with a first coating layer by coating a porous metal support with a first solution, and then performing a first heat treatment process; and preparing a catalyst provided with a second coating layer by coating the catalyst precursor provided with the first coating layer with a second solution, and then performing a second heat treatment process.

[0084] As a coating method of the first solution and the second solution, a method known in the art may be used, and dip coating, wash coating, etc. may be used, but the method is not limited thereto.

[0085] The first heat treatment process and the second heat treatment process may each independently include drying and firing. Drying may be performed at a temperature of 50°C to 150°C for 1 hour to 48 hours, and may be performed at a temperature of 60°C to 100°C for 5 hours to 36 hours, but is not limited thereto. In addition, firing may be performed at a temperature of 350°C to 1,100°C in an air atmosphere for 1 hour to 10 hours, and may be performed at a temperature of 500°C to 1,000°C in an air atmosphere for 1.5 hours to 8 hours, but is not limited thereto. When firing is performed at a temperature below 350°C, a perovskite phase cannot be properly formed, and when firing is performed at a temperature above 1,100°C, the durability of the porous metal support deteriorates, and therefore, this temperature is not preferred.

[0086] In an exemplary embodiment of the present application, the method may further include: measuring the weight of the catalyst supported on the porous metal support after the second heat treatment process. In addition, by measuring the weight of the catalyst supported on the porous metal support, the process of coating the catalyst precursor provided with the first coating layer with the second solution and then performing the second heat treatment process may be repeated 1 to 10 times until the desired amount of catalyst is loaded on the porous metal support.

[0087] The catalyst for methane reforming according to an exemplary embodiment of the present application can not only improve the adhesion between the porous metal support and the second coating layer containing the perovskite-based compound represented by Chemical Formula 2, but also prevent the side reaction of the porous metal support by forming a first coating layer containing the perovskite-based compound without a catalyst component represented by the following Chemical Formula 1.

[0088] In addition, the catalyst for methane reforming according to an exemplary embodiment of the present application is characterized in that since the perovskite-based compound is supported on a porous metal support having high thermal conductivity, it is easy to control reaction heat compared to pellet-type or powder-type catalysts in the related art.

[0089] In addition, the catalyst for methane reforming according to an exemplary embodiment of the present application can increase the active surface area of ​​the catalyst, and therefore, can exhibit high activity even at a high space velocity during the methane reforming reaction.

[0090] Hereinafter, the present application will be described in detail with reference to the embodiments for specifically describing the present application. However, the embodiments according to the present application can be modified in various forms, and it should not be understood that the scope of the present application is limited to the embodiments described in detail below. The embodiments of the present application are provided to more fully illustrate the present application to those of ordinary skill in the art.

[0091] <Example>

[0092] <Example 1>

[0093] 1) A first solution containing a precursor of a perovskite-based compound (SrTiO 3 ) is prepared.

[0094] A solution of the perovskite-based compound components was prepared using the citrate method. Strontium nitrate (Sr(NO₃)₃H₂O) was dissolved in distilled water along with citric acid and ethylene glycol. Isopropyl titanate (Ti(OCH(CH₃)₂)₄) was dissolved in ethanol, and the two solutions were mixed at 70°C. The mixture was then stirred for 3 hours, cooled to room temperature, and stored. The concentration of the solution was 0.1 M.

[0095] 2) Preparing a perovskite-based compound (SrTi 0.97 Ni 0.03 O 3-δ , 0<δ<1).

[0096] The process was performed in the same manner as in 1) above, except that 3 mol % of nickel nitrate (Ni(NO 3 ) 2 ) relative to titanium was added and used, based on the metal.

[0097] 3) Preparation of catalyst for methane reforming

[0098] A porous metal support (NiCrAl, average pore size: 1,200 μm) was dip-coated with the first solution (forming a first coating layer), then dried at 70° C. for 24 hours and heat-treated in an air atmosphere at 300° C. to 900° C. for 3 hours.

[0099] Thereafter, the porous metal support having the first coating layer formed therein was dip-coated with the second solution (forming a second coating layer), and then dried at 70°C for 24 hours and heat-treated in an air atmosphere at 300°C to 900°C for 3 hours. The dipping, drying and heat treatment of the second solution were repeated several times to finally prepare a porous metal support having the first coating layer (SrTiO3) and the second coating layer (SrTiO3). 0.97 Ni 0.03 O 3-δ , 0<δ<1) is provided on a porous metal support. Based on the total weight of the catalyst for methane reforming, the content of the perovskite-based compound (SrTiO3) is 7 wt %, and the perovskite-based compound (SrTiO3) represented by Chemical Formula 2 is 1. 0.97 Ni 0.03 O 3-δ , 0<δ<1) is 20% by weight.

[0100] A set of electron microscope photographs of the surface of the catalyst for methane reforming according to Example 1 of the present application are shown below. Figure 1 middle.

[0101] The content of the perovskite-based compound represented by Chemical Formula 1 or Chemical Formula 2 may be calculated by Formula 1 below.

[0102] [Formula 1]

[0103] Content of the perovskite-based compound represented by Chemical Formula 1 or Chemical Formula 2 (wt%) = (total weight of catalyst - weight of porous metal support) / (total weight of catalyst) × 100

[0104] <Example 2>

[0105] The process was carried out in the same manner as in Example 1, except that during the preparation of the second solution, yttrium nitrate (Y(NO3)2) was added in an amount of 12 mol % relative to strontium on a metal basis, and nickel nitrate (Ni(NO3)2) was added so that the molar ratio of titanium:nickel became 0.80:0.15.

[0106] <Example 3>

[0107] The process was carried out in the same manner as in Example 1, except that during the preparation of the second solution, yttrium nitrate (Y(NO3)2) was added in an amount of 12 mol % relative to strontium on a metal basis, and nickel nitrate (Ni(NO3)2) was added so that the molar ratio of titanium:nickel became 0.80:0.20.

[0108] <Example 4>

[0109] The process was performed in the same manner as in Example 1, except that ruthenium chloride (RuCl 3 ) was added and used in an amount of 5 mol % relative to titanium based on metal instead of nickel nitrate (Ni(NO 3 ) 2 ) during preparation of the second solution.

[0110] <Example 5>

[0111] The process is carried out in the same manner as in Example 1, except that during the preparation of the second solution, yttrium nitrate (Y(NO3)2) is added in an amount of 8 mol % relative to strontium, based on metal, and ruthenium chloride (RuCl3) is added so that the molar ratio of titanium:ruthenium becomes 0.80:0.15.

[0112] <Example 6>

[0113] A process was performed in the same manner as in Example 3, except that the content of the perovskite-based compound (SrTiO 3 ) was adjusted to 1.7 wt % based on the total weight of the catalyst for methane reforming.

[0114] <Example 7>

[0115] A process was performed in the same manner as in Example 3, except that the content of the perovskite-based compound (SrTiO 3 ) was adjusted to 13 wt % based on the total weight of the catalyst for methane reforming.

[0116] <Example 8>

[0117] A process was performed in the same manner as in Example 3, except that the content of the perovskite-based compound (SrTiO 3 ) was adjusted to 17 wt % based on the total weight of the catalyst for methane reforming.

[0118] <Example 9>

[0119] The process was performed in the same manner as in Example 3, except that NiFeCrAl (average pore diameter: 1,200 μm) was used as the porous metal support instead of NiCrAl.

[0120] <Example 10>

[0121] The process was performed in the same manner as in Example 3, except that NiCrAl 800 (average pore diameter: 800 μm) was used instead of NiCrAl as the porous metal support.

[0122] <Example 11>

[0123] The process was performed in the same manner as in Example 3, except that NiCrAl_1500 (average pore diameter: 1,500 μm) was used instead of NiCrAl as the porous metal support.

[0124] <Comparative Example 1>

[0125] As Comparative Example 1, a porous metal support (NiCrAl, average pore diameter: 1,200 μm) was used alone.

[0126] <Comparative Example 2>

[0127] The process was performed in the same manner as in Example 1, except that the porous metal support was coated with only the first solution without coating the catalyst precursor with the second solution.

[0128] <Comparative Example 3>

[0129] The process was performed in the same manner as in Example 1, except that the catalyst precursor was coated with only the second solution without coating the porous metal support with the first solution.

[0130] <Comparative Example 4>

[0131] The process was performed in the same manner as in Example 3, except that the catalyst precursor was coated with only the second solution without coating the porous metal support with the first solution.

[0132] The configurations of the porous metal support, the first coating layer, and the second coating layer in Examples and Comparative Examples are shown in Table 1 below.

[0133] [Table 1]

[0134] Porous metal support First coating Second coating Example 1 NiCrAl <![CDATA[SrTiO3]]> <![CDATA[SrTi 0.97 In 0.03 SHE 3-δ ]]> Example 2 NiCrAl <![CDATA[SrTiO3]]> <![CDATA[Sr 0.88 AND 0.12 You 0.80 Neither 0.15 EITHER 3-δ ]]> Example 3 NiCrAl <![CDATA[SrTiO3]]> <![CDATA[Sr 0.88 AND 0.12 You 0.80 Neither 0.20 EITHER 3-δ ]]> Example 4 NiCrAl <![CDATA[SrTiO3]]> <![CDATA[SrTi 0.95 Ru 0.05 O 3-δ ]]> Example 5 NiCrAl <![CDATA[SrTiO3]]> <![CDATA[SR 0.92 Yes 0.08 Of 0.80 Ru 0.15 SHE 3-δ ]]> Example 6 NiCrAl <![CDATA[SrTiO3]]> <![CDATA[Sr 0.88 AND 0.12 You 0.80 Neither 0.20 EITHER 3-δ ]]> Example 7 NiCrAl <![CDATA[SrTiO3]]> <![CDATA[Sr 0.88 AND 0.12 You 0.80 Neither 0.20 EITHER 3-δ ]]> Example 8 NiCrAl <![CDATA[SrTiO3]]> <![CDATA[Sr 0.88 AND 0.12 You 0.80 Neither 0.20 EITHER 3-δ ]]> Example 9 NiFeCrAl <![CDATA[SrTiO3]]> <![CDATA[Sr 0.88 AND 0.12 You 0.80 Neither 0.20 EITHER 3-δ ]]> Example 10 NiCrAl_800 <![CDATA[SrTiO3]]> <![CDATA[Sr 0.88 AND 0.12 You 0.80 Neither 0.20 EITHER 3-δ ]]> Example 11 NiCrAl_1500 <![CDATA[SrTiO3]]> <![CDATA[Sr 0.88 AND 0.12 You 0.80 Neither 0.20 EITHER 3-δ ]]> Comparative Example 1 NiCrAl - - Comparative Example 2 NiCrAl <![CDATA[SrTiO3]]> - Comparative Example 3 NiCrAl - <![CDATA[SrTi 0.97 In 0.03 SHE 3-δ ]]> Comparative Example 4 NiCrAl - <![CDATA[Sr 0.88 AND 0.12 You 0.80 Neither 0.20 EITHER 3-δ ]]>

[0135] <Test Example 1> Evaluation of dry reforming reaction of methane

[0136] A fixed-bed reactor system was used for dry reforming of methane. A quartz tube reactor (inner diameter = 1 / 2 inch, length = 50 cm) was used and loaded with approximately 2 g of each catalyst from the Examples and Comparative Examples. The catalysts were first reduced under 10% H2 / N2 at 800°C for 1 to 2 hours, followed by a 100-hour catalytic reaction. To more clearly compare the activity differences between the catalysts, the catalyst activity characteristics were evaluated under a strict space velocity.

[0137] Gas composition: CH4∶CO2∶N2 = 1∶1.2∶0.96

[0138] Flow rate: Gas hourly space velocity (GHSV) = 2,500 h-1 -1 (Based on CH4)

[0139] Reaction temperature: 750 °C

[0140] Reaction pressure: 1 bar

[0141] After 100 hours of reaction, the reaction conversion rate was calculated by analyzing the composition of the produced gas using gas chromatography (GC), and the results are shown in Table 2 below.

[0142] Conversion rate (Xi, %) = [(Fi in - Fi out ) / Fi in × 100 (Fi = flow rate of i)

[0143] <GC analysis conditions>

[0144] 1) GC model: Agilent 6890

[0145] 2) Oven temperature: 40 °C / 7 min - 90 °C / 5 min - 180 °C / 6 min

[0146] 3) Detector: TCD, 250 °C

[0147] 4) Sample: 0.25 mL

[0148] 5) Valve box temperature: 150 °C

[0149] [Table 2]

[0150] Catalyst type <![CDATA[GHSV(hr -1 )]]> <![CDATA[CH4 conversion rate (%)]]> <![CDATA[CO2 conversion rate (%)]]> <![CDATA[H2 / CO]]> Example 1 2,500 44 52 0.76 Example 2 2,500 58 65 0.76 Example 3 2,500 60 69 0.76 Example 4 2,500 61 65 0.78 Example 5 2,500 61 64 0.78 Example 6 2,500 57 62 0.75 Example 7 2,500 62 70 0.78 Example 8 2,500 58 64 0.75 Comparative Example 1 2,500 18 20 0.54 Comparative Example 2 2,500 3 4 0.20 Comparative Example 3 2,500 42 50 0.73 Comparative Example 4 2,500 50 58 0.72

[0151] As shown in the results of Table 2, it can be confirmed that when comparing Example 1 and Comparative Example 3 with each other or comparing Example 3 and Comparative Example 4 with each other, the catalyst for methane reforming according to the present invention, which includes a porous metal support, a first coating containing a perovskite-based compound represented by Chemical Formula 1, and a second coating containing a perovskite-based compound represented by Chemical Formula 2, has excellent CH4 conversion rate and CO2 conversion rate compared to Comparative Example 3 and Comparative Example 4 without the first coating.

[0152] <Test Example 2> Evaluation of dry reforming reaction of methane

[0153] A fixed-bed reactor system was introduced for the dry reforming reaction of methane. A quartz tube reactor (inner diameter = 1 / 2 inch, length = 50 cm) was used and loaded with each catalyst (about 2 g) of the examples and comparative examples. First, after the catalyst was reduced under 10% H2 / N2 conditions at 800 °C for 1 to 2 hours, a catalytic reaction was carried out for 100 hours. To more clearly compare the activity differences between the catalysts, the activity characteristics of the catalysts were evaluated at a strict space velocity.

[0154] Gas composition: CH4∶CO2∶N2 = 1∶1.2∶0.96

[0155] Flow rate: Gas hourly space velocity (GHSV) = 1,500 hr -1 (Based on CH4)

[0156] Reaction temperature: 800 °C

[0157] Reaction pressure: 1 bar

[0158] The reaction conversion rate after 100 hours of reaction was calculated by analyzing the composition of the generated gas using gas chromatography (GC) and is shown in Table 3 below.

[0159] Conversion rate (Xi, %) = [(Fi in - Fi out ) / Fi in × 100 (Fi = flow rate of i)

[0160] <GC analysis conditions>

[0161] 1) GC model: Agilent 6890

[0162] 2) Oven temperature: 40 °C / 7 min - 90 °C / 5 min - 180 °C / 6 min

[0163] 3) Detector: TCD, 250 °C

[0164] 4) Sample: 0.25 mL

[0165] 5) Valve box temperature: 150 °C

[0166] [Table 3]

[0167] Catalyst type <![CDATA[GHSV(hr -1 )]]> <![CDATA[CH4 conversion rate (%)]]> <![CDATA[CO2 conversion rate (%)]]> <![CDATA[H2 / CO]]> Example 3 1,500 91 89 0.84 Example 5 1,500 91 90 0.85 Example 9 1,500 90 88 0.84 Example 10 1,500 92 91 0.85 Example 11 1,500 88 87 0.84 Comparative Example 4 1,500 89 88 0.82

[0168] As shown in the results of Table 3, it can be confirmed that when Example 3 and Comparative Example 4 are compared with each other, the catalyst for methane reforming according to the present invention, which includes a porous metal support, a first coating layer including a perovskite-based compound represented by Chemical Formula 1, and a second coating layer including a perovskite-based compound represented by Chemical Formula 2, has excellent CH4 conversion rate and CO2 conversion rate, compared with Comparative Example 4 in which the first coating layer is not coated.

[0169] As shown in the above results, it can be confirmed that the ratio of H2 / CO is increased in the examples of the present application compared to the comparative examples. Therefore, it can be confirmed that the side reactions caused by the porous metal support are reduced in the examples of the present application.

[0170] Therefore, the catalyst for methane reforming according to an exemplary embodiment of the present application can not only improve the adhesion between the porous metal support and the second coating layer containing the perovskite-based compound represented by Chemical Formula 2, but also prevent the side reaction of the porous metal support by forming a first coating layer containing the perovskite-based compound without a catalyst component represented by the following Chemical Formula 1.

[0171] In addition, the catalyst for methane reforming according to an exemplary embodiment of the present application is characterized in that since the perovskite-based compound is supported on a porous metal support having high thermal conductivity, it is easy to control reaction heat compared to pellet-type or powder-type catalysts in the related art.

[0172] In addition, the catalyst for methane reforming according to an exemplary embodiment of the present application can increase the active surface area of ​​the catalyst, and therefore can exhibit high activity even at a high space velocity during the reforming reaction of methane.

Claims

1. A catalyst for methane reforming, comprising: porous metal support; A first coating layer disposed on the porous metal support and comprising a perovskite-based compound represented by the following Chemical Formula 1; and a second coating layer disposed on the first coating layer and comprising a perovskite-based compound represented by the following Chemical Formula 2, in, The catalyst for methane reforming is applied to carbon dioxide (CO2) reforming process: [Chemical Formula 1] SrTiO3 [Chemical Formula 2] Sr 1-x A x Ti α B y The 3-δ Wherein, in Chemical Formula 2, A is selected from Y, Sc, La and lanthanides, B is Ni, Co, Fe, Mn, Cr, Mo, Ru or Rh, x is a real number greater than 0 and less than 1, y is a real number greater than or equal to 0 and less than 0.3, δ is a real number greater than 0 and less than 1, α is a real number greater than 0.7 and less than 1, and Satisfies x+y>0.

2. The catalyst for methane reforming according to claim 1, wherein Chemical formula 2 is represented by the following Chemical formula 3 or Chemical formula 4: [Chemical Formula 3] SrTi α B y The 3-δ [Chemical Formula 4] Mr 1-x AND x You α B y EITHER 3-δ In Chemical Formula 3 and Chemical Formula 4, B is Ni or Ru, x is a real number greater than 0 and less than 1, y is a real number greater than 0 and less than 0.3, δ is a real number greater than 0 and less than 1, α is a real number greater than 0.7 and less than or equal to 1.

3. The catalyst for methane reforming according to claim 1, wherein The porous metal support is a metal foam including NiFeCrAl or NiCrAl.

4. The catalyst for methane reforming according to claim 1, wherein The perovskite-based compound represented by Chemical Formula 2 may be present in an amount of 3 wt % to 40 wt % based on the total weight of the catalyst for methane reforming.

5. A method for preparing a catalyst for methane reforming, the method comprising: Separately preparing a first solution containing a precursor of a perovskite-based compound represented by the following Chemical Formula 1; and a second solution containing a precursor of a perovskite-based compound represented by the following Chemical Formula 2; preparing a catalyst precursor provided with a first coating layer by coating a porous metal support with the first solution, followed by a first heat treatment process; and preparing a catalyst provided with a second coating layer by coating the catalyst precursor provided with the first coating layer with the second solution, and then performing a second heat treatment process, Wherein, the catalyst for methane reforming is applied to carbon dioxide (CO2) reforming process: [Chemical Formula 1] SrTiO3 [Chemical Formula 2] Sr 1-x A x Ti α B y The 3-δ Wherein, in Chemical Formula 2, A is selected from Y, Sc, La and lanthanides, B is Ni, Co, Fe, Mn, Cr, Mo, Ru or Rh, x is a real number greater than 0 and less than 1, y is a real number greater than or equal to 0 and less than 0.3, δ is a real number greater than 0 and less than 1, α is a real number greater than 0.7 and less than 1, and Satisfies x+y>0.

6. The method according to claim 5, wherein: Chemical formula 2 is represented by the following Chemical formula 3 or Chemical formula 4: [Chemical Formula 3] SrTi α B y The 3-δ [Chemical Formula 4] Mr 1-x AND x You α B y EITHER 3-δ In Chemical Formula 3 and Chemical Formula 4, B is Ni or Ru, x is a real number greater than 0 and less than 1, y is a real number greater than 0 and less than 0.3, δ is a real number greater than 0 and less than 1, α is a real number greater than 0.7 and less than or equal to 1.

7. The method according to claim 5, wherein: The porous metal support is a metal foam including NiFeCrAl or NiCrAl.

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