Catalyst for methane reforming and method for producing same

Abstract

The present invention relates to a catalyst for methane reforming and a method for producing the catalyst for methane reforming. The catalyst for methane reforming according to an embodiment can minimize the influence of a metal support component on a catalytic phase by preventing leaching of the porous metal support component.

Description

Catalyst for methane reforming and method for producing the same

[0001] The present application relates to a catalyst for methane reforming and a method for producing the same.

[0002] This application claims the benefit of the filing dates of Korean Patent Application No. 10-2023-0184291, filed with the Korean Intellectual Property Office on December 18, 2023, and Korean Patent Application No. 10-2024-0188464, filed with the Korean Intellectual Property Office on December 17, 2024, the entire contents of which are incorporated herein by reference.

[0003] As part of efforts to reduce greenhouse gas emissions due to global warming, extensive research is underway on carbon dioxide conversion technologies. Carbon dioxide reforming, one such carbon dioxide conversion technology, involves reacting methane and carbon dioxide to produce synthesis gas composed of hydrogen and carbon monoxide. Synthesis gas is a highly valuable material with potential for development as a feedstock for various downstream applications.

[0004] As a method for industrially obtaining such synthesis gas (H2 / CO), the reforming reaction of natural gas can be broadly classified into steam reforming, CO2 reforming, catalytic partial oxidation, autothermal reforming, and tri-reforming, as shown in the following reaction formulas 1 to 5.

[0005] [Reaction Formula 1]

[0006] CH4+ H2O → 3H2+ CO △H = 226 kJ / mol

[0007] [Reaction Formula 2]

[0008] CH4+ CO2→ 2H2+ 2CO △H = 261 kJ / mol

[0009] [Reaction Formula 3]

[0010] CH4+ 0.5O2→ 2H2+ CO △H = -44 kJ / mol

[0011] [Reaction Formula 4]

[0012] autothermal reforming: Reaction 1 + Reaction 3

[0013] [Reaction Formula 5]

[0014] tri-reforming: Reaction 1 + Reaction 2 + Reaction 3

[0015] Meanwhile, various catalysts can be used in the reforming process to enhance reforming activity. Among these, the use of precious metal catalysts in the reforming process offers the advantage of high conversion efficiency from natural gas to hydrogen. However, the high cost of precious metal catalysts reduces economic feasibility.

[0016] Accordingly, nickel catalysts, which boast high hydrogen conversion efficiency and are relatively inexpensive, are primarily used in reforming processes. However, these catalysts face the problem of deactivation due to the carbon that inevitably forms on their surface.

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

[0018] [Prior Art Document] (Patent Document) Republic of Korea Patent Publication No. 10-2019-0076367

[0019] The present application seeks to provide a catalyst for methane reforming and a method for producing the same.

[0020] One embodiment of the present application provides a catalyst for methane reforming, comprising: a porous metal support; a first coating layer provided on the porous metal support and including a perovskite compound represented by the following chemical formula 1; and a second coating layer provided on the first coating layer and including a perovskite compound represented by the following chemical formula 2.

[0021] In addition, another embodiment of the present application provides a method for producing a catalyst for methane reforming, comprising: a first coating step of forming a first coating layer by coating a porous metal support with a first coating solution; and a second coating step of forming a second coating layer by coating a second coating solution on the first coating layer, wherein the first coating layer includes a compound represented by the following chemical formula 1, and the second coating layer includes a compound represented by the following chemical formula 2.

[0022] [Chemical Formula 1]

[0023] Sr 1-a A a TiO3

[0024] [Chemical Formula 2]

[0025] Sr 1-x A x Ti 1-y B y O 3-δ

[0026] In the above chemical formulas 1 and 2,

[0027] A is selected from Y, Sc, La and lanthanide series elements,

[0028] B is Ni, Co, Fe, Mn, Cr, Mo, Ru or Rh,

[0029] a is a real number greater than 0 and less than 1,

[0030] x is a real number greater than or equal to 0 and less than 1,

[0031] y is a real number greater than 0 and less than 1,

[0032] δ is a real number greater than 0 and less than 1.

[0033] A catalyst for methane reforming according to one embodiment of the present application can prevent leaching of a porous metal support component and minimize the influence of the metal support component on the catalyst phase.

[0034] A catalyst for methane reforming according to one embodiment of the present application can prevent carbon deposition. This can increase the life of the catalyst.

[0035] The method for manufacturing a methane reforming catalyst according to one embodiment of the present application can manufacture a methane reforming catalyst having excellent performance. That is, the methane reforming catalyst manufactured using the method for manufacturing a methane reforming catalyst according to one embodiment of the present application can prevent carbon deposition by minimizing the influence of a porous metal support.

[0036] Figures 1 and 2 are graphs showing the results for experimental examples, respectively.

[0037] Hereinafter, the present specification will be described in more detail.

[0038] In this specification, when it is said that a member is located “on” another member, this includes not only cases where the member is in contact with the other member, but also cases where another member exists between the two members.

[0039] In this specification, when a part is said to "include" a certain component, this does not mean that it excludes other components, but rather that it may include other components, unless specifically stated otherwise.

[0040] Catalyst for methane reforming

[0041] A catalyst for methane reforming according to one embodiment of the present application is characterized by including a porous metal support; a first coating layer provided on the porous metal support; and a second coating layer provided on the first coating layer. In addition, the first coating layer and the second coating layer are characterized by including perovskite compounds represented by the chemical formulas 1 and 2, respectively.

[0042] Due to the above characteristics, the methane reforming catalyst according to the present application can prevent side reactions and carbon deposition on the porous metal support. This can increase the efficiency of methane reforming and the stability of the reaction.

[0043] In particular, the first coating layer can prevent the main component of the porous metal support, such as metal (Ni, Cr, etc.), from being exposed to the surface in the form of metal oxide (NiO, Cr2O3, etc.) under long-term operation conditions at high temperatures (750°C or higher), and can prevent the component ratio of the main catalyst represented by chemical formula 2 from changing due to migration of the metal (Ni, Cr, etc.) at high temperatures, thereby improving the durability and performance of the catalyst.

[0044] In addition, the catalyst for methane reforming according to the present application is characterized in that a in the above chemical formula 1 is greater than 0. That is, the catalyst for methane reforming according to the present application is characterized in that it includes a perovskite compound containing a specific element (A) in the first coating layer. By including the above specific element (A), side reactions caused by the porous metal support can be more effectively prevented.

[0045] In one embodiment of the present application, a in the chemical formula 1 may be a real number greater than 0 and less than 1, preferably a real number greater than 0 and less than 0.2, and more preferably a real number greater than 0 and less than 0.1.

[0046] In one embodiment of the present application, y in the chemical formula 2 may be a real number greater than 0 and less than 1, preferably a real number greater than 0 and less than 0.9, more preferably a real number greater than 0 and less than 0.7, even more preferably a real number greater than 0 and less than 0.5, and most preferably a real number greater than 0 and less than 0.3.

[0047] In one embodiment of the present application, the chemical formula 2 may be represented by the following chemical formula 3 or 4.

[0048] [Chemical Formula 3]

[0049] SrTi 1-y B y O 3-δ

[0050] [Chemical Formula 4]

[0051] Sr 1-x Y x Ti 1-y B y O 3-δ

[0052] In the above chemical formulas 3 and 4,

[0053] B is Ni or Ru,

[0054] x is a real number greater than 0 and less than 1,

[0055] y is a real number greater than 0 and less than 0.3,

[0056] δ is a real number greater than 0 and less than 1.

[0057] In one embodiment of the present application, the porous metal support may be a material capable of maintaining thermal stability at a high temperature of 800°C or higher.

[0058] In one embodiment of the present application, the porous metal support may be a metal foam containing NiFeCrAl or NiCrAl.

[0059] The above porous metal support is a support having various shapes, has a small heat capacity, excellent heat transfer capability, and can be formed into a desired shape for use. The shape, size, etc. of the above porous metal support are not particularly limited.

[0060] In one embodiment of the present application, the porosity of the porous metal support may be 10% or more and 99% or less.

[0061] Preferably, the porosity of the porous metal support may be 50% or more, 60% or more, 70% or more, or 80% or more, and 98% or less, 97% or less, or 96% or less. When the porosity is less than 10%, the specific surface area on which the catalyst can be coated becomes small, making it difficult to achieve the activity of the catalyst. When the porosity exceeds 99%, the strength of the porous metal support becomes low, making it difficult to use it as a process catalyst.

[0062] In one embodiment of the present application, the average pore size (cell size) of the porous metal support may be 400 ㎛ or more and 2,000 ㎛ or less.

[0063] Preferably, the average pore size of the porous metal support may be 410 μm or more, 430 μm or more, or 450 μm or more, and 1,900 μm or less, 1,700 μm or less, or 1,500 μm.

[0064] If the average pore size of the porous metal support is less than 400 ㎛, there may be difficulty in coating the precursor solution, and if it exceeds 2,000 ㎛, the surface area that can coat the catalyst is reduced, which may be disadvantageous in the process, and thus is not preferable.

[0065] The above porous metal support can be appropriately manufactured by a person skilled in the art using a method known in the art, taking into consideration the material, pore size, porosity, etc. of the porous metal support described above.

[0066] According to one embodiment of the present application, a porous metal support having various materials, pore sizes, etc. can be applied as in the examples described below.

[0067] In one embodiment of the present application, the content of the perovskite compound represented by the chemical formula 1 may be 1 wt% or more and 10 wt% or less based on the total weight of the porous metal support.

[0068] Preferably, the content of the perovskite compound represented by the chemical formula 1 may be 1.25 wt% or more, or 1.5 wt% or more, and 9 wt% or less, or 8 wt% or less, based on the total weight of the porous metal support.

[0069] When the content of the perovskite compound represented by the above chemical formula 1 exceeds 10 wt%, coating of the perovskite compound represented by the above chemical formula 2 is not easy, and thus the activity of the catalyst may be lowered relative to the volume of the porous metal support, which is not preferable. In addition, when the content of the perovskite compound represented by the above chemical formula 1 is less than 1 wt%, it may be difficult to obtain the effect of the first coating layer.

[0070] In one embodiment of the present application, the content of the perovskite compound represented by the chemical formula 2 may be 3 wt% or more and 40 wt% or less based on the total weight of the methane reforming catalyst.

[0071] Preferably, based on the total weight of the catalyst for methane reforming, the content of the perovskite compound represented by the chemical formula 2 may be 5 wt% or more, 6 wt% or more, or 7 wt% or more, and 38 wt% or less, 35 wt% or less, or 30 wt% or less.

[0072] When the content of the perovskite compound represented by the chemical formula 2 is less than 3 wt% based on the total weight of the methane reforming catalyst, the number of active sites on the catalyst surface is relatively small, which is not preferable because the reactivity is low. In addition, when the content of the perovskite compound represented by the chemical formula 2 exceeds 40 wt%, a relatively large amount of catalyst component is contained compared to the porous metal support, making it difficult to maintain the pore structure, and the bonding of the catalyst component and the porous metal support may not be easy, and thus the practical benefit of the methane reforming reaction may be reduced.

[0073] In one embodiment of the present application, the weight ratio of the perovskite compound (of chemical formula 1) included in the first coating layer and the perovskite compound (of chemical formula 2) included in the second coating layer may be 1:1 to 1:20, and may be 1:1.1 to 1:15. If the weight ratio is out of the above range, the activity of the catalyst relative to the volume of the porous metal support may be lowered, which is not preferable.

[0074] In one embodiment of the present application, the first coating layer may be provided on the entire surface of the porous metal support.

[0075] In one embodiment of the present application, at least a portion of the surface of the methane reforming catalyst may include a protrusion shape. The protrusion shape may be spherical, oval, or a combination thereof, but is not limited thereto.

[0076] In one embodiment of the present application, the first coating layer may serve to secure the second coating layer onto a porous metal support. In addition, the second coating layer may be present in a protruding shape on the first coating layer, thereby increasing the reaction surface area of ​​the catalyst and improving the performance of the methane reforming reaction.

[0077] In one embodiment of the present application, the catalyst for methane reforming can be applied to a steam reforming process, a CO2 reforming process, a catalytic partial oxidation process, an autothermal reforming process, a tri-reforming process, or a mixed reforming process, and the methane reforming process is not particularly limited.

[0078] <Method for producing a catalyst for methane reforming>

[0079] A method for manufacturing a catalyst for methane reforming according to one embodiment of the present application is characterized by including a first coating step of forming a first coating layer and a second coating step of forming a second coating layer. In addition, a method for manufacturing a catalyst for methane reforming according to one embodiment of the present application is also characterized by the fact that the first coating layer and the second coating layer each include a perovskite compound represented by the chemical formula 1 and the chemical formula 2.

[0080] A method for producing a methane reforming catalyst according to one embodiment of the present application can produce a catalyst according to the present application. That is, a methane reforming catalyst having excellent performance can be produced.

[0081] In relation to the production of a catalyst including a perovskite compound, a citric acid method, a Pechini method, a high-temperature calcination method, a polymerization complex method, a freeze-drying method, a co-precipitation method, a sol-gel method, etc. are known, and generally, the citric acid method or the Pechini method can be mainly used.

[0082] Specifically, the known citric acid method is a method of producing an amorphous metal complex in a gel state by adding citric acid, and then drying and calcining the metal complex to obtain a perovskite catalyst (Appl. Catal. B: Environ., 24 (2000) 193-205).

[0083] The method for manufacturing a catalyst for methane reforming according to one embodiment of the present application may further include a step of preparing the first coating solution. The step of preparing the first coating solution may include a solution preparation step of preparing a first metal precursor solution including a strontium (Sr) precursor and a titanium (Ti) precursor; and a pH adjustment step of adjusting the pH of the first metal precursor solution to pH 1 to pH 5, preferably pH 1 to pH 3. If the pH exceeds 5, a precipitate is formed, and the desired form of the catalyst cannot be obtained after calcination.

[0084] Additionally, in one embodiment of the present application, the pH adjustment step may be adding urea to the metal precursor solution.

[0085] The method for manufacturing a catalyst for methane reforming according to one embodiment of the present application may further include a step of preparing the second coating solution. The step of preparing the second coating solution may include a solution preparation step of preparing a second metal precursor solution containing a strontium (Sr) precursor and a nickel (Ni) precursor.

[0086] In one embodiment of the present application, the first metal precursor solution and the second metal precursor solution may each further include a titanium precursor solution.

[0087] The first metal precursor solution and the second metal precursor solution may each be applied in a sol or gel form. In addition, if the first metal precursor solution includes the inorganic oxide, it may be provided in a sol or gel form of a solution including the inorganic oxide precursor.

[0088] In one embodiment of the present application, the metal precursors included in the first metal precursor solution and the second metal precursor solution have no particular limitations, and ammonium salts, nitrates, carbonates, chlorides, sulfates, hydroxides, organic acid salts, oxides, or mixtures thereof of the metal elements can be applied in combination.

[0089] In one embodiment of the present application, the first metal precursor solution and the second metal precursor solution may each independently additionally include a solvent, and the solvent may be a solvent known in the art, and is not particularly limited.

[0090] In the method for manufacturing a catalyst for methane reforming according to one embodiment of the present application, the contents of the porous metal support, the perovskite compound represented by chemical formula 1, the perovskite compound represented by chemical formula 2, etc. are the same as described above.

[0091] A method for manufacturing a catalyst for methane reforming according to one embodiment of the present application comprises the steps of: coating a porous metal support with the first coating solution, and then performing a first heat treatment process to manufacture a catalyst precursor having a first coating layer; and coating the catalyst precursor having the first coating layer with the second coating solution, and then performing a second heat treatment process to manufacture a catalyst having a second coating layer.

[0092] The coating method of the first coating solution and the second coating solution may use a method known in the art, such as dip-coating or wash-coating, but is not limited thereto.

[0093] The first heat treatment process and the second heat treatment process may each independently include drying and firing steps. The drying may be performed at a temperature of 50°C to 150°C for 1 to 48 hours, or at a temperature of 60°C to 100°C for 5 to 36 hours, but is not limited thereto.

[0094] The above calcination may be performed at a temperature of 350°C to 1,200°C for 1 to 10 hours in an air atmosphere, or at a temperature of 500°C to 1,000°C for 1.5 to 8 hours in an air atmosphere, but is not limited thereto. If the calcination step is performed at a temperature lower than 350°C, the perovskite phase may not be properly formed, and if it exceeds 1,200°C, the durability of the porous metal support may be reduced, which is not preferable.

[0095] In one embodiment of the present application, a step of measuring the weight of the catalyst supported on the porous metal support after the second heat treatment process may be additionally included. In addition, by measuring the weight of the catalyst supported on the porous metal support, the step of coating the second coating solution described above and then performing the second heat treatment process may be repeated 1 to 10 times until the desired amount of catalyst is supported on the porous metal support.

[0096] The description of the catalyst for methane reforming according to the present application can be applied to the method for producing the catalyst for methane reforming according to one embodiment of the present application. The opposite is also true.

[0097] Hereinafter, examples will be provided to specifically explain the present application. However, the embodiments according to the present application may be modified in various ways, and the scope of the present application is not construed as being limited to the embodiments described below. The embodiments of the present application are provided to more fully explain the present application to those of average skill in the art.

[0098] Example.

[0099] <Example 1>

[0100] 1) Perovskite compounds (Sr 0.92 Y 0.08 Preparation of a first coating solution containing a precursor of TiO3)

[0101] Perovskite compounds (Sr 0.92 Y 0.08 A solution containing a precursor of TiO3) was prepared using a known citric acid method, and then strontium nitrate (Sr(NO3)3H2O) was dissolved in distilled water together with citric acid and ethylene glycol (distilled water-based solution). In addition, titanium isopropoxide (Ti(OCH(CH3)2)4) was dissolved in ethanol (ethanol-based solution).

[0102] Then, the two solutions were mixed at 70°C, stirred for 3 hours, cooled to room temperature, and stored. At this time, the pH was 0.3.

[0103] Then, urea was added to the mixture to adjust the pH within the range of pH 1 to pH 5, thereby preparing a first coating solution.

[0104] 2) Perovskite compounds (SrTi 0.97 Ni 0.03 O 3-δ Preparation of a second coating solution containing a precursor of (0 < δ < 1)

[0105] Perovskite compound (SrTi 0.97 Ni 0.03 O 3-δ) was prepared by a known citric acid method, and then strontium nitrate (Sr(NO3)3H2O) and nickel nitrate (Ni(NO3)2) were dissolved in distilled water together with citric acid and ethylene glycol (distilled water-based solution). In addition, titanium isopropoxide (Ti(OCH(CH3)2)4) was dissolved in ethanol (ethanol-based solution).

[0106] Then, the two solutions were mixed at 70°C, stirred for 3 hours, cooled to room temperature, and stored. At this time, Ni was contained at 3 mol% relative to Ti.

[0107] 3) Manufacturing of catalyst for methane reforming

[0108] After dip coating (forming a first coating layer) the first coating solution on a porous metal support (NiCrAl, average pore size: 1,200 μm), drying was performed at 70°C for 24 hours, and heat treatment was performed at 300°C to 900°C in an air atmosphere for 3 hours.

[0109] Afterwards, the second coating solution was dip-coated (second coating layer formation) on the porous metal support on which the first coating layer was formed, dried at 70°C for 24 hours, and heat-treated at 300°C to 900°C in an air atmosphere for 3 hours. The dip-coating, drying, and heat-treating of the second coating solution were repeated several times to finally form the first coating layer (Sr) on the porous metal support. 0.92 Y 0.08 TiO3) and the second coating layer (SrTi 0.97 Ni 0.03 O 3-δ , 0 < δ < 1) was prepared. Based on the total weight of the catalyst for methane reforming, the first coating layer (Sr 0.92 Y 0.08 The content of TiO3) was 6 wt%, and the perovskite compound (SrTi) represented by the chemical formula 2 0.97 Ni 0.03 O 3-δ, 0 < δ < 1) was 17 wt% based on the total weight of the catalyst for methane reforming.

[0110] <Examples 2 to 7 and Comparative Examples 1 to 6>

[0111] In the above Example 1, the same method as that for manufacturing the methane reforming catalyst of the above Example 1 was followed, except that the perovskite compound applied to the first coating solution and the second coating solution and each were changed as shown in Table 1 below.

[0112] No. pH of the first coating solution Perovskite compound of the first coating solution Perovskite compound of the second coating solution Example 11Sr 0.92 Y 0.08 TiO3SrTi 0.97 Ni 0.03 O 3-δ Example 23Sr 0.92 Y 0.08 TiO3SrTi 0.97 Ni 0.03 O 3-δ Example 35Sr 0.92 Y 0.08 TiO3SrTi 0.97 Ni 0.03 O 3-δ Example 43Sr 0.92 Y 0.08 TiO3Sr 0.92 Y 0.08 Ti 0.85 Ni 0.15 O 3-δ Example 55Sr 0.92 Y 0.08 TiO3Sr 0.92 Y 0.08 Ti 0.85 Ni 0.15 O 3-δ Example 63Sr 0.99 Y 0.01 TiO3Sr 0.92 Y 0.08 Ti 0.85 Ni 0.15 O 3-δ Example 73Sr 0.9 Y 0.1 TiO3Sr 0.92 Y 0.08 Ti 0.85 Ni0.15 O 3-δ Comparative Example 10.3-SrTi 0.97 Ni 0.03 O 3-δ Comparative example 20.3-Sr 0.92 Y 0.08 Ti 0.85 Ni 0.15 O 3-δ Comparative example 31SrTiO3SrTi 0.97 Ni 0.03 O 3-δ Comparative example 41SrTiO3Sr 0.92 Y 0.08 Ti 0.85 Ni 0.15 O 3-δ Comparative example 53SrTiO3Sr 0.92 Y 0.08 Ti 0.85 Ni 0.15 O 3-δ Comparative example 65SrTiO3Sr 0.92 Y 0.08 Ti 0.85 Ni 0.15 O 3-δ

[0113] There is no device to measure the exact value of the above δ, but it has a real value included in the lattice when Ni is substituted (however, δ is greater than 0 and less than 1).

[0114] Experimental example.

[0115] <Experimental Example 1> Evaluation of dry reforming reaction of methane

[0116] To perform dry reforming of methane using the catalysts of Examples 1 to 7 and Comparative Examples 1 to 6, a fixed-bed reaction system was introduced. A quartz tube reactor (inner diameter = 1 / 2 inch, length = 50 cm) was used and each catalyst (approximately 2 g) of the Examples and Comparative Examples was charged. First, a reduction process was performed at 800°C for 1 to 2 hours under 10% H2 / N2 conditions, and then the catalytic reaction was performed for 28 hours.

[0117] Gas composition: CH4: CO2: N2= 1:1.12:0.1

[0118] Flow rate: GHSV (Gas Hour Space Velocity) = 900 hr-1 (based on CH4)

[0119] Reaction temperature: 850℃

[0120] Reaction pressure: 6 bar

[0121] The composition of the generated gas was analyzed using gas chromatography (GC) and the reaction conversion rate was calculated after 100 hours of reaction, which is shown in Table 2 below.

[0122] Conversion rate (Xi, %) = [(Fiin - Fiout) / Fiin] × 100 (Fi = flow rate of i)

[0123] <GC 분석 조건>

[0124] 1) GC model: Agilent 6890

[0125] 2) Oven temp.: 40℃ / 7min-90℃ / 5min-180℃ / 6min

[0126] 3) Detector: TCD, 250℃

[0127] 4) Sample loop: 0.25 mL

[0128] 5) Valve box Temp.: 150℃

[0129] The coke generation rate was also calculated using Equation 1 below.

[0130] The resulting values ​​are shown in Table 2 below.

[0131] [Formula 1]

[0132] Coke % = (Weight of catalyst after reaction - Weight of initial catalyst) / (Weight of catalyst after reaction)

[0133] No. CH4 Conversion Rate (%) CO2 Conversion Rate (%) H2 / COCoke (%) Example 184870.894.68 Example 284870.893.91 Example 384870.893.62 Example 484870.895.27 Example 584870.895.12 Example 684870.905.5 Example 784870.895.2 Comparative Example 183870.896.48 Comparative Example 283860.897.19 Comparative Example 384870.895.98 Comparative Example 484870.896.8 Comparative Example 584870.896.0 Comparative Example 684870.895.8

[0134] In the above Table 2, H2 / CO refers to the molar ratio of H2 and CO in the synthesis gas. According to the above Table 2, Examples 1 to 7 and Comparative Examples 1 to 6 all had excellent conversion rates. However, it can be confirmed that the coke production rate (%) after the reaction of Examples 1 to 7 was significantly lower than that of Comparative Examples 1 to 6 under the same H2 / CO conditions.

[0135] <Experimental Example 2> Substitution Energy Evaluation

[0136] As a material used in the first coating solution during catalyst manufacturing, Sr without pH change treatment 0.92 Y 0.08 TiO3, Sr 0.99 Y 0.01 TiO3, or Sr 0.9 Y 0.1 The substitution energy was calculated by calculating the density functional theory (DFT) for Ni or Cr substitution in each of TiO3 (see Examples 1 to 7) and SrTiO3 (see Comparative Examples 1 to 6).

[0137] Ni(Cr) substitution energy in the SrTiO3 structure = E[SrTi 1-x Ni x O3] - E[SrTiO3] + 1-x E[Ti] - x E[Ni(Cr)]

[0138] Sr 0.92 Y 0.08Ni(Cr) substitution energy in the TiO3 structure = E[Sr 0.92 Y 0.08 Ti 1-x Ni x O3] - E[Sr 0.92 Y 0.08 TiO3] + 1-x E[Ti] - x E[Ni(Cr)]

[0139] Sr 0.99 Y 0.01 Ni(Cr) substitution energy in the TiO3 structure = E[Sr 0.99 Y 0.1 Ti 1-x Ni x O3] - E[Sr 0.99 Y 0.01 TiO3] + 1-x E[Ti] - x E[Ni(Cr)]

[0140] Sr 0.9 Y 0.1 Ni(Cr) substitution energy in the TiO3 structure = E[Sr 0.9 Y 0.01 Ti 1-x Ni x O3] - E[Sr 0.9 Y 0.1 TiO3] + 1-x E[Ti] - x E[Ni(Cr)]

[0141] According to Figure 1, the SrTiO3 structure (indicated as STO) corresponding to the comparative example is higher than the SrTiO3 structure corresponding to the embodiment. 0.92 Y 0.08 TiO3, Sr 0.99 Y 0.01 TiO3, or Sr 0.9 Y 0.1 It was confirmed that the energy required for Ni or Cr to be substituted at the Ti site in the TiO3 structure (denoted as SYTO) is lower. From this, Sr 0.92 Y 0.08 TiO3, Sr 0.99 Y 0.01 TiO3, or Sr 0.9 Y 0.1In the case of a structure satisfying chemical formula 1, such as TiO3, it is easy to substitute Ni or Cr, and it can be seen that it is more suitable for a buffer layer that can substitute and retain Ni or Cr originating from the porous metal support before it affects the main catalyst layer.

[0142] <Experimental Example 3> Catalytic Reactivity Evaluation

[0143] To evaluate catalytic reactivity, a TPR (Temperature Programmed Reduction) experiment was conducted on the catalysts of Example 2 and Comparative Example 1. The experimental conditions were as follows.

[0144] Equipment Name: Belcat II (Manufacturer: Microtrac)

[0145] Reaction gas: 3% H2 / Ar, 800℃ (5℃ / min)

[0146] For analysis under conditions of the same surface oxidation state, the data analyzed for the first TPR and TPR after O2 oxidation treatment are indicated as (2)TPR in Fig. 2.

[0147] According to Fig. 2, the dotted line corresponding to ref. is a powder sample that was dried and calcined without coating the second coating solution containing the perovskite compound corresponding to the above-described [chemical formula 2].

[0148] For reference, Example 2 and Comparative Example 1 were analyzed by physically removing the coating portion by hammering the catalyst to make the surface condition the same as in ref., and then sampling the catalyst in powder form.

[0149] The results are shown in Fig. 2, and the evaluation results for hydrogen consumption (i.e., ICP-OES analysis results of the desorption catalyst) are shown in Table 3 below.

[0150] No.ICP (normalized to Sr)ICPH2TPR(H2consumption)SrTiNiCrNi+Cr, mmol / g cat mmol / gcat Comparative Example 110.8980.0420.0850.6730.646Example 210.9460.0330.0410.3980.359

[0151] In Fig. 2, the area of ​​each peak represents the amount of hydrogen consumed for the reduction of the oxide. Compared to the ref. powder catalyst that was not coated on the porous metal support, the hydrogen consumption increased in both Example 2 and Comparative Example 1, but the hydrogen consumption in Example 2 was reduced by 44% compared to Comparative Example 1. In particular, the peak around 300-500°C in Fig. 2 is due to the reduction of NiO and Cr6+, indicating that Comparative Example 1 was more affected by Ni or Cr derived from the porous metal support.

[0152] Also, in the ICP-OES results of Table 3 above, starting with Ti / Ni=0.95 / 0.03 of the main catalyst solution, Comparative Example 1 showed a large increase in both Ni and Cr contents compared to the added ones, whereas Example 2 detected relatively little, and Ni was maintained at the 3 mol% level. In particular, if the Ni ratio in the main catalyst increases, it is difficult to implement the desired reactivity, and furthermore, if the Ni content is excessive, it may result in the disadvantage of being vulnerable to coke formation by forming large Ni particles due to sintering at high temperatures. Similarly, as shown in Fig. 1, Cr may be more easily substituted than Ni, so it may hinder the substitution of Ni or substitute instead of Ni to form large Ni particles, which may make it vulnerable to coke formation.

Claims

1. Porous metal support; A first coating layer provided on the porous metal support and including a perovskite compound represented by the following chemical formula 1; and A catalyst for methane reforming comprising a second coating layer provided on the first coating layer and including a perovskite compound represented by the following chemical formula 2: [Chemical Formula 1] Mr. 1-a THE a TiO3 [Chemical formula 2] Sr 1-x A x Ti 1-y B y The 3-δ In the above chemical formulas 1 and 2, A is selected from Y, Sc, La and lanthanide series elements, B is Ni, Co, Fe, Mn, Cr, Mo, Ru or Rh, a is a real number greater than 0 and less than 1, x is a real number greater than or equal to 0 and less than 1, y is a real number greater than 0 and less than 1, δ is a real number greater than 0 and less than 1.

2. In claim 1, A catalyst for methane reforming, wherein the porous metal support is a metal foam containing NiFeCrAl or NiCrAl.

3. In claim 1, The above methane reforming catalyst is a methane reforming catalyst applicable to a steam reforming process, a CO2 reforming process, a catalytic partial oxidation process, an autothermal reforming process, a tri-reforming process, or a mixed reforming process.

4. In claim 1, A catalyst for methane reforming, wherein the porosity of the porous metal support is 10% or more and 99% or less.

5. In claim 1, A catalyst for methane reforming, wherein the average pore size (cell size) of the porous metal support is 400 μm to 2,000 μm.

6. In claim 1, A catalyst for methane reforming, wherein the content of the perovskite compound represented by the chemical formula 1 is 1 wt% or more and 10 wt% or less, based on the total weight of the porous metal support.

7. In claim 1, A methane reforming catalyst, wherein the content of the perovskite compound represented by the chemical formula 2 is 3 wt% or more and 40 wt% or less, based on the total weight of the methane reforming catalyst.

8. A first coating step of forming a first coating layer by coating a porous metal support with a first coating solution; and A second coating step is included, wherein a second coating layer is formed by coating the first coating layer with a second coating solution. The first coating layer comprises a compound represented by the following chemical formula 1, The second coating layer is a method for producing a catalyst for methane reforming comprising a compound represented by the following chemical formula 2: [Chemical Formula 1] Mr. 1-a THE a TiO3 [Chemical formula 2] Sr 1-x A x Ti 1-y B y The 3-δ In the above chemical formulas 1 and 2, A is selected from Y, Sc, La and lanthanide series elements, B is Ni, Co, Fe, Mn, Cr, Mo, Ru or Rh, a is a real number greater than 0 and less than 1, x is a real number greater than or equal to 0 and less than 1, y is a real number greater than 0 and less than 1, δ is a real number greater than 0 and less than 1.

9. In claim 8, Further comprising a step of preparing the first coating solution, The step of preparing the first coating solution is A solution preparation step for preparing a first metal precursor solution including a strontium (Sr) precursor and a titanium (Ti) precursor; and A method for producing a catalyst for methane reforming, comprising a pH adjustment step of adjusting the pH of the first metal precursor solution to pH 1 to pH 5.

10. In claim 9, A method for producing a catalyst for methane reforming, wherein the pH adjustment step comprises adding urea to the first metal precursor solution.

11. In claim 8, A method for producing a catalyst for methane reforming, wherein the porous metal support is a metal foam containing NiFeCrAl or NiCrAl.

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