Monolithic foamed nickel catalyst, preparation method thereof and efficient application of monolithic foamed nickel catalyst in methane dry reforming

Abstract

The invention discloses a monolithic foamed nickel catalyst, a preparation method of the monolithic foamed nickel catalyst and efficient application of the monolithic foamed nickel catalyst in methane dry reforming, and relates to a strategy of in-situ construction of a Ni interface active site monolithic catalyst by taking porous foamed metal as a substrate. The reaction rate of methane dry reforming is improved by utilizing excellent thermal conductivity and abundant three-dimensional channels of a foamed nickel structured metal material, and adverse effects of sintering, carbon deposition and the like on active sites caused by methane cracking and carbon monoxide cracking are balanced; the monolithic catalyst prepared by the invention is applied to a methane dry reforming reaction with a certain concentration, under the conditions that the pressure is 0.1-1 MPa, the mass space velocity is 10000-50000 mL.gcat <-1 >. H <-1 >, CH4: CO2: N2 is 1: 1: 3 and the temperature is 650-700 DEG C, the CO2 conversion rate exceeds 85%, the CH4 conversion rate exceeds 75%, and the monolithic catalyst is expected to be applied to an industrial methane dry reforming process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalyst preparation, in particular to a high-temperature and high-activity monolithic Ni-based catalyst for dry reforming of methane, a preparation method and application thereof. BACKGROUND

[0002] The emission of a large amount of greenhouse gas CO2 in the atmosphere has brought about serious environmental problems, such as global warming and climate change. At the same time, although the concentration of CH4 in the atmosphere is lower than that of CO2, CH4 is also a greenhouse gas, and the greenhouse effect caused by CH4 is 28-36 times that of CO2. It is of great significance to effectively utilize the two main greenhouse gases CH4 and CO2 and convert them into value-added chemicals.

[0003] Dry reforming of methane is considered as a key technology with great application prospect, which can efficiently and synergistically convert CH4 and CO2 into syngas with a theoretical H2 / CO molar ratio of about 1.0, and the obtained syngas can be further used for the production of fuels and chemicals. Transition metals such as Ni are often used as the main active component of dry reforming of methane catalysts due to their comparable performance with noble metals such as Ru, Rh and Pt, but these catalysts are prone to deactivation caused by carbon deposition and sintering of active components under high-temperature reforming conditions. Dry reforming of methane is a strong endothermic reaction, as shown in reaction formula (1), which requires high temperature to obtain high syngas yield, and the H2 / CO of the obtained syngas is 1. The reaction process is also accompanied by side reactions such as reaction formulas (2)-(4), reaction formula (2) is the reverse water gas shift reaction, which leads to H2 / CO<1 of the syngas in the product; reaction formulas (3) and (4) are CH4 cracking and CO disproportionation reactions, respectively, and the CO disproportionation reaction is an exothermic reaction, which is beneficial to the reaction at below 800℃, and the CH4 cracking reaction is an endothermic reaction, which is beneficial to CH4 cracking at a temperature higher than 550℃, in order to ensure the normal progress of the methane reforming reaction, the reaction temperature is usually controlled above 650℃, therefore, in the temperature range of industrial application, carbon deposition on the catalyst is inevitable. The carbon deposition on the catalyst will gather and grow into graphite or filamentous carbon, which will cause the blockage of the pores on the catalyst surface and lead to the deactivation of the catalyst.

[0004] (1)

[0005] (2)

[0006] (3)

[0007] (4)

[0008] In methane dry reforming, noble metal catalysts offer advantages such as high reactivity and resistance to carbon deposition. However, their cost limits their widespread application. Researchers have found that nickel-based catalysts offer comparable performance to noble metal catalysts. However, these catalysts are susceptible to carbon deposition and sintering, limiting their industrial application. Therefore, developing nickel-based catalysts that are less susceptible to carbon deposition is crucial. Summary of the Invention

[0009] In view of the problems existing in the prior art, the present invention proposes a preparation method and application of a monolithic Ni-based catalyst for high-temperature and high-activity methane dry reforming, in which dissociated metallic Ni is uniformly anchored on the surface of a foam metal support, nano-oxides are loaded thereon, and interfacial active sites are constructed, thereby enabling high-temperature and high-activity methane dry reforming.

[0010] The technical solutions of the present invention are as follows:

[0011] A monolithic Ni-based catalyst for high-temperature, high-activity methane dry reforming uses a foam metal as a carrier. Ni, a metal that dissociates methane, and B, a metal that enhances performance, are uniformly anchored on the surface of the foam metal carrier. Nano-metal oxides are further loaded on the foam metal carrier to construct interfacial active sites.

[0012] The foam metal carrier is one of foam nickel, foam cobalt, foam aluminum and foam copper;

[0013] Metal B is at least one of Al, Mg, Cu, and Fe;

[0014] The nano metal oxide is a composite oxide of an active metal M1 and a modified metal M2, the active metal M1 is at least one of Ga and Ce, and the modified metal M2 is at least one of Zr, Al, and Fe.

[0015] Furthermore, the molar ratio of metal Ni to metal B is 0.8-2:1, preferably 1-1.5:1; the molar ratio of active metal M1 to modified metal M2 is 5-15:1, preferably 8-12:1; the loading amount of metal Ni on the foam metal support is 0.5-2 mmol / g, preferably 0.8-1 mmol / g; the loading amount of active metal M1 on the foam metal support is 2-4 mmol / g.

[0016] The method for preparing the monolithic Ni-based catalyst for high-temperature and high-activity methane dry reforming comprises the following steps:

[0017] 1) Pretreatment of metal foam: The metal foam sheet was sanded to remove part of the surface oxide layer, then cleaned, and then ultrasonically treated with hydrochloric acid solution to remove surface oxides and organic impurities. Finally, after washing and drying, the obtained metal foam support was recorded as A-foam;

[0018] 2) BNiO x Preparation of the A-foam: Step 1) The A-foam is added to the aqueous solution of the Ni salt and the B salt, and an etchant is added to the reaction solution, and hydrothermal etching treatment is carried out under heating, and after the reaction is completed, the product is sequentially washed, dried, and calcined to obtain the intermediate product BNiO x / A-foam;

[0019] 3) Preparation of the monolithic Ni-based catalyst: Step 2) The BNiO x / A-foam is added to the aqueous solution of the M1 salt and the M2 salt, and an etchant is added to the reaction solution, and hydrothermal etching treatment is carried out under heating, and after the reaction is completed, the product is sequentially washed, dried, and calcined, and finally subjected to reduction treatment under a H2-N2 mixed atmosphere to obtain the target catalyst, which is named M1M2Ox / BNi / A-foam.

[0020] Further, in Step 2), the Ni salt is at least one of nitrate, chloride, sulfate, acetate, acetylacetone salt of metal Ni, the B salt is nitrate of at least one of Al, Mg, Cu, Fe, the molar ratio of the Ni salt to the B salt is 0.8-2:1, preferably 1-1.5:1, and the feeding ratio of the Ni salt to the foam metal carrier A-foam is 0.5-2 mmol:1 g, preferably 0.8-1 mmol:1 g.

[0021] Further, in Step 2), the reaction temperature of the hydrothermal etching treatment is 120-220°C, preferably 170-180°C, and the reaction time is 5-10 h, and the calcination temperature is 250-350°C, and the calcination time is 0.5-2 h.

[0022] Further, in Step 3), the M1 salt is nitrate, sulfate, and / or chloride of at least one of Ga, Ce, the M2 salt is nitrate, sulfate, and / or chloride of at least one of Zr, Al, Fe, the molar ratio of the M1 salt to the M2 salt is 5-15:1, and the feeding ratio of the M1 salt to the carrier BNiO x / A-foam is 2-4 mmol:1 g.

[0023] Further, in Step 3), the reaction temperature of the hydrothermal etching treatment is 120-220°C, preferably 150-160°C, the reaction time is 5-10 h, the calcination temperature is 350-500°C, and the calcination time is 1-4 h.

[0024] Further, in Step 3), the volume fraction of H2 in the H2-N2 mixed atmosphere is 40-60%, the reduction temperature is 400-450°C, and the reduction time is 1-4 h.

[0025] Furthermore, the etchant in step 2) or step 3) is selected from ammonia, urea, ammonium fluoride, ammonium chloride, ammonium oxalate, and anhydrous oxalic acid, and the quality of the etchant is A-foam or BNiO x / 2-3 times the mass of A-foam.

[0026] The invention also discloses the application of the integral Ni-based catalyst in the catalytic reaction of methane dry reforming.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1) The present invention uses porous metal foam as a substrate to construct an in-situ monolithic catalyst with Ni interface active sites. The excellent thermal conductivity and abundant three-dimensional channels of the nickel foam structured metal material are utilized to improve the reaction rate of methane dry reforming, balancing the adverse effects of methane cracking and carbon monoxide cracking on the active sites, such as sintering and carbon deposition. This is a novel monolithic catalyst.

[0029] 2) The monolithic nickel-based catalyst of the present invention can be applied to methane dry reforming reaction. The specific application method is: place the monolithic catalyst in a fixed bed reactor, introduce the reaction gas of CH4 / CO2 / N2 = 1:1:3, and the volume space velocity is 10000-50000 mL·g cat -1 ·h -1 The reaction pressure range is atmospheric pressure to 5 MPa, and the reaction temperature range is 400-800°C; the catalyst stability test results show that the operation is stable for 300 hours, the carbon dioxide conversion rate is maintained at around 80%, and the methane selectivity is around 75%. The preferred reaction temperature is 700°C and the pressure is atmospheric pressure. It is expected to be used for industrial methane dry reforming. DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to the embodiments, but the scope of protection of the present invention is not limited thereto.

[0031] Example 1

[0032] 1) A 0.5 mm thick, 100 PPI Ni-foam sheet was sanded to remove some surface oxides. A small nickel foam disc approximately 2 to 3 mm long and wide was cut with a hole punch. The disc was placed in a beaker and ultrasonically treated with 50 mL of analytical grade acetone for 5 minutes. The treated nickel foam was rinsed multiple times with anhydrous ethanol. 100 mL of deionized water and 7 mL of 36% concentrated hydrochloric acid were then added and ultrasonically treated for 10 minutes. The treated nickel foam was rinsed multiple times with anhydrous ethanol and ultrasonically treated with 50 mL of anhydrous ethanol for 10 minutes. The treated nickel foam was then dried in an oven.

[0033] 2) Weigh nickel nitrate hexahydrate (0.4 mmol) and aluminum nitrate nonahydrate (0.271 mmol), add 10 ml of ammonia water, dissolve in 30 ml of deionized water, stir until completely dissolved, and add to the 50 mL hydrothermal kettle liner containing 0.4 g of nickel foam pretreated in step 1), then install the liner into the hydrothermal kettle, tighten the hydrothermal kettle, install the hydrothermal kettle into the homogeneous reactor, heat to 180 ° C and hydrothermal for 8 hours. Pour out the blue-green liquid in the hydrothermal kettle liner after hydrothermal treatment, and take out the nickel foam with green flocs in the hydrothermal kettle liner, put it in a 70 ° C oven to dry for 8 hours, and calcine at 250 ° C for 2 hours. The obtained nickel foam is recorded as NiAlO / Ni-foam;

[0034] 3) Gallium nitrate (1.295 mmol) and aluminum nitrate nonahydrate (0.125 mmol) were dissolved in 30 mL of deionized water, followed by the addition of 10 mL of aqueous ammonia. After stirring until completely dissolved, the solution was added to a 50 mL hydrothermal reactor liner containing 0.4 g of NiO / Ni-foam metal foam support. The liner was then placed into the hydrothermal reactor, which was tightened and placed into a homogeneous reactor. The reactor was heated to 150°C and hydrothermal for 7 hours. The liquid in the hydrothermal reactor liner was poured out, and the nickel foam was removed from the hydrothermal reactor liner and dried in a 70°C oven for 12 hours. The dried nickel foam was then placed in a muffle furnace and calcined at 400°C for 3 hours. The catalyst was then removed and reduced in a gas-solid phase reactor with a mixture of 50% H₂ and 50% N₂ at 450°C for 3 hours to yield the catalyst. The catalyst was used in the methane dry reforming reaction. The catalyst was filled in a fixed bed reactor and the reaction gas with a molar ratio of CO2:CH4:N2=1:1:3 was introduced at a space velocity of 30000 ml·g cat -1 ·h -1 , reaction pressure is 0.1MPa, reaction temperature is 700℃.

[0035] Examples 2-4

[0036] The preparation steps of the catalysts of Examples 2-4 are repeated in Example 1, with the only difference being that "the hydrothermal temperatures selected in step 3) are replaced with 130°C, 170°C and 190°C respectively", and the rest are the same as in Example 1.

[0037] The reaction conditions for the application of the catalysts in Examples 2-4 to the methane dry reforming reaction were the same as those in Example 1. The reaction results of the methane dry reforming reactions in Examples 1-4 are summarized in Table 1.

[0038] Examples 5-8

[0039] The preparation steps of the catalysts of Examples 2-4 were repeated in Example 1, with the only difference being that the hydrothermal time selected in step 3) was replaced with 5 h, 9 h, 11 h, and 13 h, respectively. The rest was the same as in Example 1.

[0040] The reaction conditions for the application of the catalysts in Examples 5-8 to the methane dry reforming reaction were the same as those in Example 1. The reaction results of the methane dry reforming reactions in Examples 1 and 5-8 are summarized in Table 2.

[0041] Examples 9-12

[0042] The methane dry reforming reaction steps of Examples 9-12 are the same as those of Example 1, with the only difference being that “the pressures of the catalytic reactions are 0.5 MPa, 1.0 MPa, 1.5 MPa, and 2 MPa, respectively”, and the rest are the same as those of Example 1.

[0043] The reaction results of the methane dry reforming reactions of Examples 1, 9-12 are summarized in Table 3.

[0044] Examples 13-16

[0045] The preparation steps of the catalysts of Examples 13-16 are repeated as in Example 1, with the only difference being that "the supports selected in step 1) are replaced with foamed cobalt, foamed aluminum, foamed copper, and foamed iron, respectively, and the porosity of the supports is 100 PPI", and the rest are the same as in Example 1.

[0046] The reaction results of the methane dry reforming reactions of Examples 1 and 13-16 are summarized in Table 4.

[0047] Example 17

[0048] The preparation steps of the catalyst in Example 17 are repeated as in Example 1, with the only difference being that "aluminum nitrate nonahydrate in step 2) is replaced by an equal molar amount of magnesium nitrate hexahydrate", and the rest are the same as in Example 1.

[0049] Example 18

[0050] The preparation steps of the catalyst in Example 18 are the same as those in Example 1, with the only difference being that "aluminum nitrate nonahydrate in step 2) is replaced by copper nitrate trihydrate in an equal molar amount", and the rest are the same as those in Example 1.

[0051] Example 19

[0052] The preparation steps of the catalyst in Example 19 are repeated in Example 1, with the only difference being that "aluminum nitrate nonahydrate in step 2) is replaced by an equal molar amount of ferric nitrate nonahydrate", and the rest are the same as in Example 1.

[0053] The reaction results of the methane dry reforming reactions of Examples 1 and 17-19 are summarized in Table 5.

[0054] Example 20

[0055] The preparation steps of the catalyst in Example 20 are repeated in Example 1, with the only difference being that "in step 3), gallium nitrate (1.295 mmol) and aluminum nitrate nonahydrate (0.125 mmol) are replaced with zirconium nitrate pentahydrate (0.125 mmol) and cerium nitrate hexahydrate (1.295 mmol)", and the rest are the same as in Example 1.

[0056] Example 21

[0057] The preparation steps of the catalyst in Example 21 were repeated in Example 1, with the only difference being that "in step 3), gallium nitrate (1.295 mmol) and aluminum nitrate nonahydrate (0.125 mmol) were replaced with zirconium nitrate pentahydrate (0.125 mmol) and gallium nitrate (1.295 mmol)", and the rest were the same as in Example 1.

[0058] Example 22

[0059] The preparation steps of the catalyst in Example 22 are repeated in Example 1, with the only difference being that "in step 3), gallium nitrate (1.295 mmol) and aluminum nitrate nonahydrate (0.125 mmol) are replaced with aluminum nitrate nonahydrate (0.125 mmol) and cerium nitrate hexahydrate (1.295 mmol)", and the rest are the same as in Example 1.

[0060] The reaction results of the methane dry reforming reactions of Examples 1 and 20-22 are summarized in Table 6.

[0061] Examples 23-26

[0062] The methane dry reforming reaction steps of Examples 23-26 were repeated in Example 1, except that the selected test space velocities were replaced with 10,000, 20,000, 40,000, and 50,000 ml·g, respectively. cat -1 ·h -1 , the rest are the same as in Example 1.

[0063] The reaction results of the methane dry reforming reactions of Examples 1 and 23-26 are summarized in Table 7.

[0064] Examples 27-30

[0065] The methane dry reforming reaction steps of Examples 27-30 repeat those of Example 1, with the only difference being that the selected reaction atmosphere is replaced with CO2:CH4=1:1, CO2:CH4:N2=1:1:1, CO2:CH4:N2=1:1:2, CO2:CH4:N2=1:1:4, respectively, and the rest are the same as in Example 1.

[0066] The reaction results of the methane dry reforming reactions of Examples 1 and 27-30 are summarized in Table 8.

[0067] Examples 31-34

[0068] In addition to the selected test pressure of 1.5 MPa, the test air velocities were 10,000, 20,000, 40,000, and 50,000 ml·g cat -1 ·h -1 Except for this, the rest are the same as in Example 1.

[0069] The reaction results of the methane dry reforming reactions of Examples 1 and 31-34 are summarized in Table 9.

[0070] Comparative Example 1

[0071] Preparation of traditional powder catalyst by impregnation method

[0072] Nickel nitrate hexahydrate was used as the nickel source of the catalyst and a coprecipitation method was used to prepare a nickel-based catalyst. The method was as follows: 2.0459 g of gallium nitrate, 0.3001 g of aluminum nitrate nonahydrate, and 100 mL of deionized water were added to a beaker and stirred with a magnetic stirrer. A 0.5 mol / L sodium carbonate solution was prepared and added dropwise to the metal salt solution at a rate of 60 ml / h using a syringe pump until the pH of the solution reached 9.0. After stirring for 30 minutes, the liquid in the cup was filtered to obtain a solid precipitate. The solid was dried in an oven at 80°C for 6 hours and then calcined at 400°C for 3 hours to obtain a support. 0.5741 g of nickel nitrate hexahydrate and 0.2955 g of iron nitrate nonahydrate were added to a beaker and dissolved in 2 ml of water. The calcined support was added and the water was evaporated to dryness while stirring in a 60°C water bath. The solid was scraped off and calcined at 400°C for 3 hours to obtain NiGa / AlO x Powder catalyst.

[0073] Comparative Example 2

[0074] Weigh 0.9722g of TEOS, 0.3964g of nickel nitrate, 0.1320g of gallium nitrate, and 0.0556g of aluminum nitrate and dissolve them in 50ml of anhydrous ethanol and 25ml of deionized water. Then, dissolve 0.4g of sodium borohydride in 10ml of deionized water and slowly add it dropwise to the prepared solution. Stir for 10 hours, then filter to obtain a solid, dry it, and calcine it at 400°C to obtain the catalyst.

[0075] Comparative Example 3

[0076] Comparative Example 3 The catalyst preparation steps were repeated in Example 1, with the only difference being that "the amount of aluminum nitrate nonahydrate added in step 2) was 0", and the other conditions remained unchanged.

[0077] Comparative Example 4

[0078] Comparative Example 4 The catalyst preparation steps were repeated in Example 1, with the only difference being that "the amount of aluminum nitrate nonahydrate added in step 3) was 0", and the other conditions remained unchanged.

[0079] Comparative Example 5

[0080] Preparation of Ni@CeO2 catalyst with Ni loading of 10 wt%:

[0081] Prepare cerium nitrate (1.7 mol·L -1 ,25mL) of aqueous solution, and then add appropriate amount of nickel nitrate. In another beaker, prepare citric acid (6.7mol·L -1 , 25 mL) aqueous solution. The two solutions were mixed and stirred at room temperature for 2 hours. The solution was then heated at 70°C under vacuum to remove moisture. The remaining material was dried at 100°C overnight. Calcination was performed in two steps: 300°C for 2 hours and 400°C for 4 hours, with a heating rate of 1°C / min. This catalyst was named Ni@CeO2.

[0082] Comparative Example 6

[0083] Preparation of Ni@CeZrO2 catalyst with Ni loading of 10 wt%:

[0084] Prepare cerium nitrate and zirconium nitrate (the total concentration of the two nitrates is 1.7 mol·L -1 , 25mL, molar ratio Ce:Zr=4:1) aqueous solution, then add appropriate amount of nickel nitrate. In another beaker, prepare citric acid (6.7mol·L -1 , 25 mL) aqueous solution. The two solutions were mixed and stirred at room temperature for 2 hours. The solution was then heated at 70°C under vacuum to remove moisture. The remaining material was dried at 100°C overnight. Calcination was performed in two steps: 300°C for 2 hours and 400°C for 4 hours, with a heating rate of 1°C / min. This catalyst was named Ni@CeZrO2.

[0085] The reaction conditions for the methane dry reforming reaction of the catalysts of Comparative Examples 1-6 were the same as those of Example 1. The reaction results of the methane dry reforming reactions of Comparative Examples 1-6 and Example 1 are summarized in Table 11.

[0086] In Tables 1 to 11, H2 / CO refers to the molar ratio of the two.

[0087] The reaction results in Tables 1-9 and 11 are all experimental results under 10 hours of catalytic reaction.

[0088] Table 1

[0089]

[0090] Table 2

[0091]

[0092] Table 3

[0093]

[0094] Table 4

[0095]

[0096] Table 5

[0097]

[0098] Table 6

[0099]

[0100] Table 7

[0101]

[0102] Table 8

[0103]

[0104] Table 9

[0105]

[0106] Table 10

[0107]

[0108] Table 11

[0109]

[0110] As shown in Table 1, the results of Examples 1 to 4 are shown in Table 1. cat -1 ·h -1 space velocity, 0.1 MPa, step 3) selects CO2 conversion rate, CH4 conversion rate and H2 / CO ratio under different hydrothermal temperature conditions, and the preferred hydrothermal temperature is 150°C.

[0111] As shown in Table 2, the results of Example 1, Example 5 to Example 8 were as follows: cat -1 ·h -1 space velocity, 0.1 MPa, step 3) selects CO2 conversion rate, CH4 conversion rate and H2 / CO ratio under different hydrothermal time conditions, and the preferred hydrothermal time is 7h.

[0112] As shown in Table 3, the results of Example 1, Example 9 to Example 12 were as follows: cat -1 ·h -1 Space velocity, CO2 conversion rate, CH4 conversion rate and H2 / CO ratio under different reaction pressures. Pressure has a greater impact on the reaction conversion rate, and the reaction is more suitable for reaction under normal pressure.

[0113] As shown in Table 4, the results of Example 1, Example 13 to Example 16 were shown in Table 4 at 700°C and 30000 ml·g cat -1 ·h -1 Space velocity, 0.1Mpa, select the CO2 conversion rate, CH4 conversion rate and H2 / CO ratio under different foam metal carriers, the preferred foam metal is foam nickel.

[0114] As shown in Table 5, the results of Example 1, Example 17-Example 19 were shown in Table 5 at 700℃ and 30000ml·g. cat -1 ·h -1 space velocity, 0.1 MPa, CO2 conversion rate, CH4 conversion rate and H2 / CO ratio under different enhanced performance metals are selected, and the preferred metal is aluminum nitrate.

[0115] As shown in Table 6, the results of Example 1, Example 20-Example 22 were shown in Table 6 at 700℃ and 30000ml·g. cat -1 ·h -1 , 0.1Mpa, CO2 conversion rate, CH4 conversion rate and H2 / CO ratio under different metal oxides, the preferred metal oxide is GaAlO x .

[0116] As shown in Table 7, the CO2 conversion rate, CH4 conversion rate and H2 / CO ratio of Example 1, Example 23-Example 26 at 700℃, 0.1Mpa and different space velocities are -1 -50000h -1 Within the space velocity range, the activity of the catalysts does not differ much.

[0117] As shown in Table 8, the results of Example 1, Example 27 to Example 30 are shown in Table 8. cat -1 ·h -1 , CO2 conversion rate, CH4 conversion rate and H2 / CO ratio under different reaction gas concentration conditions of 0.1MPa. The reaction gas concentration has little effect on the catalyst activity. The preferred reaction atmosphere is CO2:CH4:N2=1:1:3.

[0118] As shown in Table 9, the CO2 conversion rate, CH4 conversion rate and H2 / CO ratio of Example 1, Example 31-Example 34 at different space velocities at 700℃ and 1.5MPa pressure are -1 -50000h -1 Within the space velocity range, the activity of the catalysts does not differ much.

[0119] Table 10 shows the catalytic reaction results of the catalyst in Example 1 under continuous operation for 300 hours. As can be seen from Table 10, the catalyst used in Example 1 has good stability within 300 hours.

[0120] As shown in Table 11, Example 1, Comparative Examples 1 to Comparative Examples 6 have the following results: cat -1 ·h -1 , CO2 conversion rate, CH4 conversion rate and H2 / CO ratio under 0.1MPa conditions, it can be seen that compared with different catalysts, the catalyst of Example 1 has a greater advantage in activity.

[0121] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A monolithic Ni-based catalyst for high-temperature and high-activity methane dry reforming, characterized in that Using metal foam as a carrier, the metal Ni that dissociates methane and the metal B that enhances performance are evenly anchored on the surface of the metal foam carrier, and nano-metal oxides are further loaded on it to construct interfacial active sites; The foam metal carrier is one of foam nickel, foam cobalt, foam aluminum and foam copper; Metal B is at least one of Al, Mg, Cu, and Fe; The nano metal oxide is a composite oxide of an active metal M1 and a modified metal M2, the metal M1 is at least one of Ga and Ce, and the modified metal M2 is at least one of Zr, Al, and Fe.

2. The monolithic Ni-based catalyst for high-temperature and high-activity methane dry reforming according to claim 1, characterized in that The molar ratio of the metal Ni to the metal B is 0.8-2:1, the molar ratio of the active metal M1 to the modified metal M2 is 5-15:1; the loading amount of the metal Ni on the foam metal support is 0.5-2 mmol / g, and the loading amount of the metal M1 on the foam metal support is 2-4 mmol / g.

3. The method for preparing a monolithic Ni-based catalyst for high-temperature and high-activity methane dry reforming according to claim 1, characterized in that The following steps are involved: 1) Pretreatment of metal foam: The metal foam sheet was sanded to remove part of the surface oxide layer, then cleaned, and then ultrasonically treated with hydrochloric acid solution to remove surface oxides and organic impurities. Finally, after washing and drying, the obtained metal foam support was recorded as A-foam; 2) BNiO x Preparation of A-foam: Step 1) Add the A-foam to a solution of Ni salt and B salt, add an etchant to the reaction solution, perform hydrothermal etching under heating, and after the reaction is completed, wash, dry, and calcinate in sequence to obtain the intermediate product BNiO x / A-foam; 3) Preparation of monolithic Ni-based catalyst: Step 2) the BNiO x / A-foam is added to the aqueous solution of M1 salt and M2 salt, and an etchant is added to the reaction solution, and hydrothermal etching is performed under heating. After the reaction is completed, it is washed, dried, and calcined in sequence, and finally heated and reduced in a H2-N2 mixed atmosphere to obtain the target catalyst, which is named M1M2Ox / BNi / A-foam.

4. The method for preparing a monolithic Ni-based catalyst for high-temperature and high-activity methane dry reforming according to claim 3, characterized in that In step 2), the Ni salt is at least one of nitrate, chloride, sulfate, acetate, and acetylacetonate of metal Ni, and the B salt is a nitrate of at least one metal of Al, Mg, Cu, and Fe. The molar ratio of the Ni salt to the B salt is 0.8-2:1, and the feed ratio of the Ni salt to the foam metal carrier A-foam is 0.5-2 mmol:1 g.

5. The method for preparing a monolithic Ni-based catalyst for high-temperature and high-activity methane dry reforming according to claim 3, characterized in that In step 2), the reaction temperature of the hydrothermal etching treatment is 120-220° C., preferably 170-180° C., the reaction time is 5-10 h, the calcination temperature is 250-350° C., and the calcination time is 0.5-2 h.

6. The method for preparing a monolithic Ni-based catalyst for high-temperature and high-activity methane dry reforming according to claim 3, characterized in that In step 3), the M1 salt is a nitrate, sulfate and / or chloride of at least one of Ga and Ce, the M2 salt is a nitrate, sulfate and / or chloride of at least one of Zr, Al and Fe, the molar ratio of the M1 salt to the M2 salt is 5-15:1, and the M1 salt is mixed with the carrier BNiO. x The feed ratio of / A-foam is 2-4mmol:1g.

7. The method for preparing a monolithic Ni-based catalyst for high-temperature and high-activity methane dry reforming according to claim 3, characterized in that In step 3), the reaction temperature of the hydrothermal etching treatment is 120-220° C., preferably 150-160° C., the reaction time is 5-10 h, the calcination temperature is 350-500° C., and the calcination time is 1-4 h.

8. The method for preparing a monolithic Ni-based catalyst for high-temperature and high-activity methane dry reforming according to claim 3, characterized in that In step 3), the volume fraction of H2 in the H2-N2 mixed atmosphere is 40-60%, the temperature of heating reduction is 400-450°C, and the time of heating reduction is 1-4h.

9. The method for preparing a monolithic Ni-based catalyst for high-temperature and high-activity methane dry reforming according to claim 3, characterized in that The etchant in step 2) or step 3) is selected from ammonia, urea, ammonium fluoride, ammonium chloride, ammonium oxalate, and anhydrous oxalic acid. The quality of the etchant is A-foam or BNiO x / 2-3 times the mass of A-foam.

10. Use of the monolithic Ni-based catalyst according to claim 1 in a catalytic reaction of methane dry reforming.

Images