Supported catalyst for oxidative dehydrogenation of ethane and preparation method thereof

Abstract

The invention discloses a preparation method of an ethane oxidative dehydrogenation supported catalyst. The catalyst is formed by supporting a transition metal oxide on the surface of an M1 catalyst, the preparation method of the M1 catalyst comprises the following steps: dissolving ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and a dispersing agent in deionized water to form a mixed solution; and adding an aqueous solution of niobium oxalate into the mixed solution within 15-50 minutes to form a suspension, aging, carrying out hydrothermal crystallization, drying, roasting, and removing the M2 phase to obtain the M1 catalyst. The pore structure and the specific surface area of the molybdenum-vanadium-tellurium-niobium catalyst can be improved by adding a dispersing agent in the preparation process of the M1 catalyst and limiting the time for adding an aqueous solution of niobium oxalate into a mixed solution, and through mutual cooperation of all steps and parameters, the pore structure and the specific surface area of the molybdenum-vanadium-tellurium-niobium catalyst can be improved; and then the transition metal oxide is loaded on the surface of the M1 catalyst for phase interface coupling, and the transition metal oxide and the M1 catalyst cooperate with each other, so that the catalytic performance of the loaded catalyst can be remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of ethane oxidative dehydrogenation to ethylene, and in particular to an ethane oxidative dehydrogenation supported catalyst and a preparation method thereof. Background Art

[0002] Ethylene is an important petrochemical raw material, which is mainly produced by traditional steam thermal cracking. In a typical ethane steam cracking plant to produce ethylene, energy consumption costs account for about 70% of the production cost. Compared with high-temperature cracking, the product of ethane oxidative dehydrogenation to ethylene (ODHE) technology is single and easy to separate, and the separation system is simple. It is a low-energy consumption approach with great application prospects and has been one of the research hotspots in recent years.

[0003] MoVNbTeOx composite metal oxides have good catalytic performance in ODHE reactions under mild conditions. The reaction temperature required is generally lower than 450°C. It is a current research hotspot for the oxidative dehydrogenation of low-carbon alkanes.

[0004] For example, Chinese patent document CN104941668B discloses a nanocomposite catalyst for ethane oxidative dehydrogenation reaction and its preparation method. The method first obtains the M1 pure phase compound in the molybdenum, vanadium, niobium and tellurium multi-metal oxide system by hydrothermal synthesis and hydrogen peroxide purification treatment, and then prepares a cerium oxide sol with a CeO2 mass fraction of 5%-30%. Two methods, namely the sol-gel method and the physical mixing method, are used to obtain the finished product of the M1 pure phase compound and the cerium oxide nanocomposite catalyst in the molybdenum, vanadium, niobium and tellurium multi-metal oxide system. The nanocomposite catalyst prepared by this scheme has a large number of CeO2 nanoparticles uniformly distributed on the surface of the rod-shaped crystals of the M1 pure phase compound, and the particle size of the CeO2 nanoparticles is 2-30nm. The introduction of CeO2 improves the catalytic activity and selectivity of the catalyst, and at the same time reduces the synthesis cost of the molybdenum, vanadium, niobium and tellurium multi-metal oxide catalyst system.

[0005] Chinese patent document CN 112138686 A discloses a supported MoVNbTeOx nanocomposite oxide catalyst and its preparation method and application, the method comprising the following steps: impregnating a precursor solution containing metal ions with a pure M1 phase MoVNbTeOx catalyst, then ultrasonically dispersing, aging, drying and calcining to obtain a supported MoVNbTeOx nanocomposite oxide catalyst; the metal ions in the precursor solution containing metal ions are selected from palladium ions, iron ions and potassium ions. In the document, a simple impregnation method is used to regulate the active oxygen species on the catalyst surface, and the content of active oxygen species on the catalyst surface is high, and a high space-time yield (greater than 1kgC2H4 / kgcat / h) can be obtained at a lower temperature (less than 400°C). The preparation process is simple, easy to operate and easy to repeat.

[0006] However, when the catalyst provided in the above scheme is used for ethane oxidative dehydrogenation to produce ethylene, the ethane conversion rate and ethylene selectivity still need to be improved. Summary of the invention

[0007] In view of this, the present invention provides a method for preparing an ethane oxidative dehydrogenation supported catalyst, which includes adding a dispersant during the preparation of a molybdenum vanadium niobium tellurium catalyst (M1 catalyst) and limiting the time for adding a niobium oxalate solution into a mixed solution, and loading a metal oxide on the surface of the M1 catalyst, which cooperate with each other to improve the pore structure and specific surface area of ​​the catalyst, regulate the active oxygen species on the surface of the M1 catalyst, and enhance the redox ability of the catalyst, thereby improving the catalytic reaction performance of the catalyst.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A method for preparing an ethane oxidative dehydrogenation supported catalyst, wherein the ethane oxidative dehydrogenation supported catalyst is formed by loading a transition metal oxide on the surface of an M1 phase catalyst; the M1 phase catalyst is both a carrier and an active component;

[0010] Wherein, the preparation of the M1 phase catalyst comprises the following steps:

[0011] (1) dissolving ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and a dispersant in deionized water to form a mixed solution;

[0012] (2) adding an aqueous solution of niobium oxalate to the mixed solution within 15 to 50 minutes to form a suspension, and subjecting the suspension to aging, hydrothermal crystallization, drying, calcination, and removal of the M2 phase to obtain the M1 phase catalyst.

[0013] Optionally, in the method for preparing the above-mentioned ethane oxidative dehydrogenation supported catalyst provided by the present invention, the aqueous solution of niobium oxalate is added dropwise to the mixed solution.

[0014] Optionally, in the method for preparing the above-mentioned ethane oxidative dehydrogenation supported catalyst provided by the present invention, the added amount of the dispersant is 0.005wt% to 0.1wt% of the mass of the ammonium heptamolybdate tetrahydrate.

[0015] Optionally, in the method for preparing the above-mentioned ethane oxidative dehydrogenation supported catalyst provided by the present invention, the dispersant is selected from any one of propylene glycol, polymethyl cellulose, polyvinyl alcohol, sesbania powder, polyethylene glycol and polyvinyl pyrrolidone.

[0016] Optionally, in the method for preparing the above-mentioned ethane oxidative dehydrogenation supported catalyst provided by the present invention, the transition metal oxide is selected from one or two of MnO2, Fe2O3, Cr2O3, CeO2, NiO, CuO and WO3.

[0017] Optionally, in the method for preparing the above-mentioned ethane oxidative dehydrogenation supported catalyst provided by the present invention, the present invention recommends that the aging temperature is 20 to 90° C. and the time is 20 to 180 min.

[0018] Optionally, in the method for preparing the above-mentioned ethane oxidative dehydrogenation supported catalyst provided by the present invention, the hydrothermal crystallization reaction temperature recommended by the present invention is 150 to 200° C. and the time is 12 to 60 hours;

[0019] The present invention recommends a drying temperature of 70 to 120° C. and a drying time of 6 to 20 hours;

[0020] The calcination recommended by the present invention is selected from two-stage calcination; preferably, the two-stage calcination includes first calcining at 200-400°C in air for 2-6 hours, and then calcining at 550-650°C in an inert atmosphere for 1-4 hours;

[0021] The inert atmosphere is one or more of nitrogen, argon and helium.

[0022] Optionally, in the preparation method of the above-mentioned ethane oxidative dehydrogenation supported catalyst provided by the present invention, in step (1), the ammonium heptamolybdate tetrahydrate, the ammonium metavanadate, the telluric acid and the dispersant are dissolved in deionized water. If necessary, heating can be performed under stirring to promote the dissolution of the ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and the dispersant in the deionized water, for example, stirring can be performed at 70 to 100° C. for 60 to 180 minutes, and the specific time can be adjusted according to actual conditions.

[0023] Optionally, in the method for preparing the above-mentioned ethane oxidative dehydrogenation supported catalyst provided by the present invention, in step (2), the aqueous solution of niobium oxalate is obtained by dissolving niobium oxalate in deionized water. If necessary, heating can be performed under stirring to promote the dissolution of niobium oxalate in deionized water, such as stirring at 60 to 90° C. for 20 to 60 minutes. The specific amount can be adjusted according to actual conditions.

[0024] Optionally, in the preparation method of the above-mentioned ethane oxidative dehydrogenation supported catalyst provided by the present invention, in step (2), hydrogen peroxide is used for purification to remove the M2 phase. The present invention recommends the following operating conditions for purifying and removing the M2 phase with hydrogen peroxide: placing the molybdenum vanadium tellurium niobium catalyst in 5wt% to 15wt% hydrogen peroxide, and purifying it at 50 to 80°C for 60 to 240 minutes to obtain an M1 phase catalyst.

[0025] Optionally, in the method for preparing the above-mentioned ethane oxidative dehydrogenation supported catalyst provided by the present invention, the transition metal oxide is supported on the surface of the M1 phase catalyst by impregnation, gel or ball milling.

[0026] Optionally, in the method for preparing the above-mentioned ethane oxidative dehydrogenation supported catalyst provided by the present invention, the method of impregnating and loading the transition metal oxide comprises the following steps:

[0027] The M1 phase catalyst is immersed in a transition metal precursor salt solution for impregnation (it can be immersed once or multiple times according to the specific situation), and then aged, dried, and calcined to obtain the ethane oxidative dehydrogenation supported catalyst; preferably, the aging temperature is 40-80°C and the time is 0.5-5h; the drying temperature is 60-120°C and the time is 5-16h; the calcination temperature is 300-650°C and the time is 1-8h;

[0028] The method of ball milling to load the transition metal oxide comprises the following steps: ball milling and calcining the transition metal oxide (which can be commercially available or prepared by conventional methods in the industry using a transition metal precursor salt as a raw material) and the M1 phase catalyst to obtain the ethane oxidative dehydrogenation supported catalyst; preferably, the calcination temperature is 300 to 650° C. and the time is 1 to 8 hours;

[0029] The method of loading the transition metal oxide with gel comprises the following steps: mixing the M1 phase catalyst with a colloidal solution of a transition metal salt, drying, and calcining to obtain the ethane oxidative dehydrogenation supported catalyst; preferably, the stirring reaction temperature is 40 to 80°C, and the time is 0.5 to 5 hours; the drying temperature is 60 to 120°C, and the time is 5 to 16 hours; the calcination temperature is 300 to 650°C, and the time is 1 to 8 hours. The colloidal solution of the specific transition metal salt can be prepared by conventional methods in the industry.

[0030] Optionally, in the method for preparing the above-mentioned supported catalyst for ethane oxidative dehydrogenation provided by the present invention, the precursor salt of the transition metal is selected from nitrates, acetates or other salts of the transition metal, as long as they are commercially available and soluble in a solvent. The solvent used in the precursor salt solution of the transition metal is generally one or more of distilled water, deionized water, ethanol, propylene glycol, etc.

[0031] The present invention also provides an ethane oxidative dehydrogenation supported catalyst prepared by the above-mentioned preparation method of the ethane oxidative dehydrogenation supported catalyst, wherein the content of the transition metal oxide is 0.05wt% to 10wt%, based on the mass of the M1 phase catalyst being 100%.

[0032] Optionally, in the above-mentioned ethane oxidative dehydrogenation supported catalyst provided by the present invention, the general formula of the M1 phase catalyst is: Mo a V b Te c Nb d, where a=1, b is 0.25~0.32, c is 0.16~0.23, and d is 0.08~0.15.

[0033] The present invention also provides the use of the above-mentioned ethane oxidative dehydrogenation supported catalyst in preparing ethylene by ethane oxidative dehydrogenation.

[0034] Specifically, the present invention also provides a method for preparing ethylene by oxidative dehydrogenation of ethane, comprising the following steps:

[0035] Ethane is subjected to an oxidative dehydrogenation reaction under the catalytic action of the ethane oxidative dehydrogenation supported catalyst prepared by the above-mentioned preparation method of the ethane oxidative dehydrogenation supported catalyst; preferably, the reaction temperature is 350-400° C., the pressure is normal pressure, and the reaction gas feed space velocity is 200-500 h -1 The molar ratio of the reaction gas ethane: oxygen: nitrogen is 1: 0.4~0.8: 1.2~2.0.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The invention provides a method for preparing a supported catalyst for ethane oxidative dehydrogenation. The method comprises the following steps: adding a dispersant during the preparation process of a molybdenum, vanadium, tellurium, and niobium catalyst and limiting the time for adding an aqueous solution of niobium oxalate into a mixed solution. The various steps and parameters cooperate with each other, thereby improving the pore structure and specific surface area of ​​the molybdenum, vanadium, tellurium, and niobium catalyst. Then, a transition metal oxide is supported on the surface of the molybdenum, vanadium, and tellurium niobium catalyst for phase interface coupling. The supported catalyst prepared by the method is a two-phase catalyst of a transition metal oxide-M1 phase catalyst. The active oxygen species on the surface of the molybdenum, vanadium, and tellurium niobium catalyst are regulated, thereby further improving the oxidation-reduction ability of the catalyst and thus improving the catalytic reaction performance of the catalyst. DETAILED DESCRIPTION

[0038] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention.

[0039] If no specific experimental steps or conditions are specified in the examples and comparative examples, the conventional experimental steps or conditions described in the literature in the art can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be purchased commercially.

[0040] Source of raw materials: All raw materials used in the catalyst preparation process were analytical grade (AR). Raw materials: ammonium heptamolybdate tetrahydrate, polyvinyl alcohol, ferric nitrate, chromium acetate, cerium nitrate, nickel nitrate, copper nitrate, WO3, citric acid, hydrogen peroxide, propylene glycol, polyethylene glycol, polyvinyl pyrrolidone, polymethylcellulose were purchased from Sinopharm Reagent Co., Ltd.; ammonium metavanadate, telluric acid, 50% manganese nitrate solution were purchased from MacLean Reagent Co., Ltd.; niobium oxalate and sesbania powder were purchased from Aladdin Reagent Co., Ltd.;

[0041] Evaluation and analysis method: The catalyst was tableted and crushed, and the 20-40 mesh particles were screened and loaded into a 10 mL fixed bed microreactor with an inner diameter of 5 mm. The reaction temperature was 360 ° C, atmospheric pressure, and the total gas feed space velocity was 300 h -1 The reaction was carried out for 2 hours under the condition that the molar ratio of the reaction gas ethane: oxygen: nitrogen was 1: 0.6: 1.5 to obtain ethylene product. The reaction product was detected by gas chromatography.

[0042] Example 1

[0043] This embodiment provides a supported catalyst for ethane oxidative dehydrogenation, and the specific preparation method thereof is as follows:

[0044] Preparation of MoVTe Catalyst (M1 Catalyst)

[0045] (1) A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and sesbania powder were added to deionized water and stirred at 80° C. for 90 min to form a mixed solution. The amount of sesbania powder added was 0.01 wt % of the mass of ammonium heptamolybdate tetrahydrate.

[0046] (2) adding a certain amount of niobium oxalate into deionized water and stirring at 80° C. for 30 minutes to form a niobium oxalate solution;

[0047] (3) Add the niobium oxalate solution dropwise to the mixed solution (taking 40 minutes) to form a suspension, then age it at 80°C for 180 minutes, crystallize it at 180°C for 30 hours, take it out after cooling, and then dry it at 70°C for 16 hours. Calcinate it at 300°C in an air atmosphere for 4 hours, and then calcine it at 620°C in a nitrogen atmosphere for 2.5 hours to obtain a MoVTeNb catalyst; put the MoVTeNb catalyst into 10wt% hydrogen peroxide, stir it at 60°C for 100 minutes to purify it, remove the M2 phase, and then dry it at 120°C for 8 hours to finally obtain the M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.25 Te 0.18 Nb 0.12 .

[0048] Supported catalyst preparation

[0049] By adopting the equal volume impregnation method, a certain amount of 50% manganese nitrate solution was diluted to obtain an impregnation solution, and the M1 catalyst was added to the impregnation solution. After rotary impregnation at 50°C, it was aged for 1h, dried at 80°C for 8h, and calcined at 500°C in air atmosphere for 3h to obtain a supported catalyst with a MnO2 loading of 2wt%, recorded as ODHE-1;

[0050] Example 2

[0051] This embodiment provides a supported catalyst for ethane oxidative dehydrogenation, and the specific preparation method thereof is as follows:

[0052] Preparation of MoVTe Catalyst (M1 Catalyst)

[0053] (1) A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and polyvinyl pyrrolidone were added to deionized water and stirred at 75° C. for 180 min to form a mixed solution. The amount of polyvinyl pyrrolidone added was 0.05 wt % of the mass of ammonium heptamolybdate tetrahydrate.

[0054] (2) adding a certain amount of niobium oxalate into deionized water and stirring at 60° C. for 40 minutes to form a niobium oxalate solution;

[0055] (3) Add the niobium oxalate solution to the mixed solution (taking 25 minutes) to form a suspension. After aging at 60°C for 90 minutes, crystallize at 200°C for 20 hours, cool and take out, and dry at 90°C for 12 hours. Calcinate at 300°C for 5 hours in an air atmosphere, and then calcine at 550°C for 3 hours in an argon atmosphere to obtain a MoVTeNb catalyst. Put the MoVTeNb catalyst into a 7.5wt% hydrogen peroxide solution, stir at 70°C for 80 minutes to purify, remove the M2 phase, and then dry at 110°C for 6 hours to obtain the M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.32 Te 0.18 Nb 0.13 .

[0056] Supported catalyst preparation

[0057] By adopting the equal volume impregnation method, a certain amount of ferric nitrate was dissolved in deionized water to obtain an impregnation solution, and the M1 catalyst was added to the impregnation solution. After rotary impregnation at 70°C, it was aged for 2h, dried at 70°C for 10h, and calcined in an air atmosphere at 600°C for 5h to obtain a supported catalyst with a Fe2O3 loading of 0.05wt%, recorded as ODHE-2.

[0058] Example 3

[0059] This embodiment provides a supported catalyst for ethane oxidative dehydrogenation, and the specific preparation method thereof is as follows:

[0060] Preparation of MoVTe Catalyst (M1 Catalyst)

[0061] (1) A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and polyvinyl alcohol were added to deionized water and stirred at 100° C. for 30 min to form a mixed solution. The amount of polyvinyl alcohol added was 0.1 wt % of the mass of ammonium heptamolybdate tetrahydrate.

[0062] (2) adding a certain amount of niobium oxalate into deionized water and stirring at 80° C. for 20 minutes to form a niobium oxalate solution;

[0063] (3) Add the niobium oxalate solution to the mixed solution (for 30 minutes) to form a suspension. After aging at 80°C for 60 minutes, perform a crystallization reaction at 170°C for 30 hours, take it out after cooling, and dry it at 70°C for 15 hours. Calcinate at 350°C in an air atmosphere for 3 hours, and then calcine at 580°C in a helium atmosphere for 4 hours to obtain a MoVTeNb catalyst. Put the MoVTeNb catalyst into 8.5wt% hydrogen peroxide, stir at 60°C for 200 minutes to purify, remove the M2 phase, and then dry it at 120°C for 10 hours to finally obtain the M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.28 Te 0.20 Nb 0.15 .

[0064] Supported catalyst preparation

[0065] By adopting the equal volume impregnation method, a certain amount of chromium acetate was dissolved in deionized water to obtain an impregnation solution, and the M1 catalyst was added to the impregnation solution. After rotary impregnation at 80°C, it was aged for 2h, dried at 60°C for 16h, and calcined in an air atmosphere at 650°C for 4h to obtain a supported catalyst with a Cr2O3 loading of 9wt%, recorded as ODHE-3.

[0066] Example 4

[0067] This embodiment provides a supported catalyst for ethane oxidative dehydrogenation, and the specific preparation method thereof is as follows:

[0068] Preparation of MoVTe Catalyst (M1 Catalyst)

[0069] (1) A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and sesbania powder were added to deionized water and stirred at 90° C. for 80 min to form a mixed solution. The amount of sesbania powder added was 0.02 wt % of the mass of ammonium heptamolybdate tetrahydrate.

[0070] (2) adding a certain amount of niobium oxalate into deionized water and stirring at 90° C. for 30 minutes to form a niobium oxalate solution;

[0071] (3) Add the niobium oxalate solution to the mixed solution (taking 35 minutes) to form a suspension. After aging at 90°C for 20 minutes, crystallize at 180°C for 40 hours, cool and take out, and dry at 100°C for 10 hours. Calcinate at 250°C in an air atmosphere for 4 hours, and then calcine at 600°C in a helium atmosphere for 2 hours to obtain a MoVTeNb catalyst. Put the MoVTeNb catalyst into 6wt% hydrogen peroxide, stir at 50°C for 240 minutes to purify, remove the M2 phase, and then dry at 100°C for 8 hours to finally obtain the M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.30 Te 0.18 Nb 0.12 .

[0072] Supported catalyst preparation

[0073] By adopting the equal volume impregnation method, a certain amount of cerium nitrate was dissolved in deionized water to obtain an impregnation solution, and the above-mentioned M1 catalyst was added to the impregnation solution. After rotary impregnation at 60°C, it was aged for 3 hours, dried at 80°C for 12 hours, and calcined at 400°C in an air atmosphere for 3 hours to obtain a supported catalyst with a CeO2 loading of 3wt%, recorded as ODHE-4.

[0074] Example 5

[0075] This embodiment provides a supported catalyst for ethane oxidative dehydrogenation, and the specific preparation method thereof is as follows:

[0076] Preparation of MoVTe Catalyst (M1 Catalyst)

[0077] (1) A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and sesbania powder were added to deionized water and stirred at 90° C. for 80 min to form a mixed solution. The amount of sesbania powder added was 0.02 wt % of the mass of ammonium heptamolybdate tetrahydrate.

[0078] (2) adding a certain amount of niobium oxalate into deionized water and stirring at 90° C. for 30 minutes to form a niobium oxalate solution;

[0079] (3) Add the niobium oxalate solution to the mixed solution (taking 35 minutes) to form a suspension, age it at 90°C for 20 minutes, then crystallize it at 180°C for 40 hours, take it out after cooling, and dry it at 100°C for 6 hours. Calcinate it at 250°C in an air atmosphere for 4 hours, then calcine it at 600°C in a helium atmosphere for 2 hours to obtain a MoVTeNb catalyst, put the MoVTeNb catalyst into 6wt% hydrogen peroxide, stir it at 50°C for 240 minutes to purify it, remove the M2 phase, and then dry it at 100°C for 8 hours to finally obtain the M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.30 Te 0.18Nb 0.12 .

[0080] Supported catalyst preparation

[0081] A certain amount of cerium nitrate was dissolved in deionized water by high-energy ball milling to obtain a solution, which was transferred to a 250 mL polytetrafluoroethylene-lined high-pressure hydrothermal autoclave, reacted at 80°C for 12 hours, cooled to room temperature, filtered, washed, and dried at 80°C for 12 hours to obtain solid cerium oxide. M1 catalyst was added to the obtained solid cerium oxide, mixed and ball milled, and calcined at 450°C in air atmosphere for 2 hours to obtain a supported catalyst with a CeO2 loading of 4wt%, recorded as ODHE-5.

[0082] Example 6

[0083] This embodiment provides a supported catalyst for ethane oxidative dehydrogenation, and the specific preparation method thereof is as follows:

[0084] Preparation of MoVTe Catalyst (M1 Catalyst)

[0085] (1) A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and polyvinyl pyrrolidone were added to deionized water and stirred at 70° C. for 60 min to form a mixed solution. The amount of polyvinyl pyrrolidone added was 0.03 wt % of the mass of ammonium heptamolybdate tetrahydrate.

[0086] (2) adding a certain amount of niobium oxalate into deionized water and stirring at 70° C. for 60 minutes to form a niobium oxalate solution;

[0087] (3) Add the niobium oxalate solution to the mixed solution (for 30 minutes) to form a suspension. After aging at 70°C for 100 minutes, perform a crystallization reaction at 165°C for 55 hours, take it out after cooling, and dry it at 120°C for 10 hours. Calcinate at 300°C in an air atmosphere for 3.5 hours, and then calcine at 650°C in a helium atmosphere for 3.5 hours to obtain a MoVTeNb catalyst. Put the MoVTeNb catalyst into 5wt% hydrogen peroxide, stir and react at 65°C for 180 minutes to purify, remove the M2 phase, and then dry it at 70°C for 8 hours to finally obtain the M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.28 Te 0.16 Nb 0.10 .

[0088] Supported catalyst preparation

[0089] A certain amount of nickel nitrate was dissolved in deionized water by high-energy ball milling to obtain a solution, which was transferred to a 250 mL polytetrafluoroethylene-lined high-pressure hydrothermal autoclave, reacted at 80°C for 12 hours, cooled to room temperature, filtered, washed, and dried at 100°C for 12 hours to obtain nickel oxide. M1 catalyst was added to the obtained nickel oxide solid, mixed and ball milled, and calcined at 500°C in air atmosphere for 1 hour to obtain a supported catalyst with a NiO loading of 10 wt%, recorded as ODHE-6.

[0090] Example 7

[0091] This embodiment provides a supported catalyst for ethane oxidative dehydrogenation, and the specific preparation method thereof is as follows:

[0092] Preparation of MoVTe Catalyst (M1 Catalyst)

[0093] (1) A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and sesbania powder were added to deionized water and stirred at 80° C. for 70 min to form a mixed solution. The amount of sesbania powder added was 0.01 wt % of the mass of ammonium heptamolybdate tetrahydrate.

[0094] (2) adding a certain amount of niobium oxalate into deionized water and stirring at 80° C. for 50 minutes to form a niobium oxalate solution;

[0095] (3) Add the niobium oxalate solution to the mixed solution (taking 50 minutes) to form a suspension. After aging at 80°C for 150 minutes, perform crystallization reaction at 175°C for 60 hours, take out after cooling, and dry at 70°C for 20 hours. Calcinate at 200°C in an air atmosphere for 6 hours and 620°C in an argon atmosphere for 2 hours to obtain a MoVTeNb catalyst. Put the MoVTeNb catalyst into 15wt% hydrogen peroxide, stir at 80°C for 90 minutes to purify, remove the M2 phase, and then dry at 80°C for 16 hours to obtain the M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.31 Te 0.21 Nb 0.08 .

[0096] Supported catalyst preparation

[0097] An equal volume impregnation method was used to dissolve a certain amount of copper nitrate in deionized water to obtain an impregnation solution. The M1 catalyst was added to the impregnation solution, and after rotary impregnation at 60°C, it was aged for 0.5h, dried at 100°C for 8h, and calcined at 550°C in an air atmosphere for 7h to obtain a supported catalyst with a CuO loading of 7wt%, recorded as ODHE-7.

[0098] Example 8

[0099] This embodiment provides a supported catalyst for ethane oxidative dehydrogenation, and the specific preparation method thereof is as follows:

[0100] Preparation of MoVTe Catalyst (M1 Catalyst)

[0101] (1) A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and propylene glycol were added to deionized water and stirred at 85° C. for 120 min to form a mixed solution. The amount of propylene glycol added was 0.06 wt % of the mass of ammonium heptamolybdate tetrahydrate.

[0102] (2) adding a certain amount of niobium oxalate into deionized water and stirring at 85° C. for 40 minutes to form a niobium oxalate solution;

[0103] (3) Add the niobium oxalate solution to the mixed solution (28 minutes) to form a suspension, age it at 40°C for 120 minutes, crystallize it at 150°C for 24 hours, take it out after cooling, and dry it at 80°C for 12 hours; calcine it at 300°C in an air atmosphere for 4.5 hours, and then calcine it at 600°C in a nitrogen atmosphere for 3 hours to obtain a MoVTeNb catalyst, put the MoVTeNb catalyst into 12wt% hydrogen peroxide, stir it at 60°C for 120 minutes to purify it, remove the M2 phase, and then dry it at 80°C for 10 hours to finally obtain the M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.27 Te 0.19 Nb 0.13 .

[0104] Supported catalyst preparation

[0105] The commercially available WO3 and M1 catalysts were mixed and ball-milled by high-energy ball milling, and then calcined at 450°C in air atmosphere for 8 hours to obtain a catalyst with a WO3 loading of 1 wt%, recorded as ODHE-8.

[0106] Example 9

[0107] This embodiment provides a supported catalyst for ethane oxidative dehydrogenation, and the specific preparation method thereof is as follows:

[0108] Preparation of MoVTe Catalyst (M1 Catalyst)

[0109] (1) A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and polymethyl cellulose were added to deionized water and stirred at 80° C. for 100 min to form a mixed solution, wherein the amount of polymethyl cellulose added was 0.005 wt % of the mass of ammonium heptamolybdate tetrahydrate.

[0110] (2) adding a certain amount of niobium oxalate into deionized water and stirring at 80° C. for 30 minutes to form a niobium oxalate solution;

[0111] (3) The niobium oxalate solution was added dropwise to the mixed solution (taking 15 minutes) to form a suspension, aged at 20°C for 100 minutes, and then crystallized at 170°C for 12 hours. After cooling, the suspension was taken out and dried at 80°C for 16 hours, calcined at 250°C in an air atmosphere for 2 hours, and then calcined at 590°C in a nitrogen atmosphere for 2 hours to obtain a MoVTeNb catalyst. The MoVTeNb catalyst was placed in 8wt% hydrogen peroxide, stirred at 70°C for 150 minutes for purification, the M2 phase was removed, and then dried at 130°C for 12 hours to finally obtain an M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.26 Te 0.17 Nb 0.14 .

[0112] Supported catalyst preparation

[0113] An equal volume impregnation method was used to dissolve a certain amount of nickel nitrate in deionized water to obtain an impregnation solution. The M1 catalyst was added to the impregnation solution, and after rotary impregnation at 60°C, it was aged for 2.5 hours, dried at 120°C for 5 hours, and calcined in an air atmosphere at 400°C for 6 hours to obtain a supported catalyst with a NiO loading of 2wt%, recorded as ODHE-9.

[0114] Example 10

[0115] This embodiment provides a supported catalyst for ethane oxidative dehydrogenation, and the specific preparation method thereof is as follows:

[0116] Preparation of MoVTe Catalyst (M1 Catalyst)

[0117] (1) A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and sesbania powder were added to deionized water and stirred at 75° C. for 90 min to form a mixed solution. The amount of sesbania powder added was 0.05 wt % of the mass of ammonium heptamolybdate tetrahydrate.

[0118] (2) adding a certain amount of niobium oxalate into deionized water and stirring at 75° C. for 40 minutes to form a niobium oxalate solution;

[0119] (3) Add the niobium oxalate solution to the mixed solution (taking 40 minutes) to form a suspension, age it at 75°C for 90 minutes, then crystallize it at 175°C for 36 hours, take it out after cooling, and dry it at 100°C for 8 hours. Calcinate it at 350°C in an air atmosphere for 3 hours, then calcine it at 600°C in a helium atmosphere for 2.5 hours to obtain a MoVTeNb catalyst, then put it into a 6wt% hydrogen peroxide solution, stir it at 75°C for 100 minutes to purify it, remove the M2 phase, and then dry it at 100°C for 8 hours to finally obtain the M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.29 Te 0.23 Nb0.10 .

[0120] Supported catalyst preparation

[0121] Copper nitrate, cerium nitrate and citric acid were added to deionized water and heated in a 70°C water bath for 6 hours to form a citrate colloidal solution. The M1 catalyst was placed in the citrate colloidal solution, stirred for 2 hours, and dried at 80°C for 10 hours. The dried sample was calcined at 600°C for 2 hours to obtain a supported catalyst with a CuO-CeO2 loading of 3wt%, recorded as ODHE-10.

[0122] Embodiment 11

[0123] This embodiment provides a supported catalyst for ethane oxidative dehydrogenation, and the specific preparation method thereof is as follows:

[0124] Preparation of MoVTe Catalyst (M1 Catalyst)

[0125] (1) A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and polyvinyl pyrrolidone were added to deionized water and stirred at 90° C. for 150 min to form a mixed solution. The amount of polyvinyl pyrrolidone added was 0.04 wt % of the mass of ammonium heptamolybdate tetrahydrate.

[0126] (2) adding a certain amount of niobium oxalate into deionized water and stirring at 70° C. for 25 minutes to form a niobium oxalate solution;

[0127] (3) Add the niobium oxalate solution to the mixed solution (25 minutes) to form a suspension, age at 60°C for 40 minutes, crystallize at 165°C for 50 hours, cool and take out, dry at 120°C for 10 hours; calcine at 400°C in air atmosphere for 2.5 hours, and then calcine at 630°C in helium atmosphere for 2 hours to obtain the crude product of the MoVTeNb catalyst, then add it into 5wt% hydrogen peroxide, stir and react at 60°C for 150 minutes to purify, remove the M2 phase, and then dry at 70°C for 8 hours to finally obtain the M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.32 Te 0.25 Nb 0.10 .

[0128] Supported catalyst preparation

[0129] Nickel nitrate, cerium nitrate and citric acid were added to deionized water and heated in a 60°C water bath for 2 hours to form a citrate colloidal solution. The M1 catalyst was placed in the citrate colloidal solution, stirred for 2 hours, and dried at 70°C for 15 hours. The dried sample was placed in a muffle furnace and calcined at 500°C at a rate of 5°C / min for 5 hours to obtain a supported catalyst with a NiO-CeO2 loading of 4wt%, recorded as ODHE-11.

[0130] Example 12

[0131] This embodiment provides a supported catalyst for ethane oxidative dehydrogenation, and the specific preparation method thereof is as follows:

[0132] Preparation of MoVTe Catalyst (M1 Catalyst)

[0133] (1) A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and polymethyl cellulose were added to deionized water and stirred at 85° C. for 100 min to form a mixed solution, wherein the amount of polymethyl cellulose added was 0.08 wt % of the mass of ammonium heptamolybdate tetrahydrate.

[0134] (2) adding a certain amount of niobium oxalate into deionized water and stirring at 65° C. for 45 minutes to form a niobium oxalate solution;

[0135] (3) Add the niobium oxalate solution to the mixed solution (for 30 minutes) to form a suspension, and age it at 85°C for 100 minutes; crystallize it at 170°C for 24 hours, take it out after cooling, dry it at 80°C for 14 hours, calcine it at 320°C in an air atmosphere for 4 hours, and then calcine it at 620°C in a nitrogen atmosphere for 1 hour to obtain MoVTeNb catalyst, and then put it into 8wt% hydrogen peroxide, stir it at 80°C for 60 minutes to purify it, remove the M2 phase, and then dry it at 130°C for 12 hours to finally obtain M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.30 Te 0.16 Nb 0.13 .

[0136] Supported catalyst preparation

[0137] 50% manganese nitrate solution, cerium nitrate and citric acid were added to deionized water and heated in a 50°C water bath for 4 hours to form a citrate colloidal solution. The M1 catalyst was placed in the citrate colloidal solution and stirred for 2 hours; then dried at 80°C for 12 hours. The dried sample was placed in a muffle furnace and calcined at 500°C at a rate of 5°C / min for 6 hours to obtain a supported catalyst with a total MnO2-CeO2 loading of 5wt%, recorded as ODHE-12.

[0138] Example 13

[0139] This embodiment provides a supported catalyst for ethane oxidative dehydrogenation, and the specific preparation method thereof is as follows:

[0140] Preparation of MoVTe Catalyst (M1 Catalyst)

[0141] A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and sesbania powder were added into deionized water and stirred at 75°C for 90 minutes to form a mixed solution. The amount of sesbania powder added was 0.5wt% of the mass of ammonium heptamolybdate tetrahydrate.

[0142] A certain amount of niobium oxalate was added into deionized water and stirred at 75°C for 40 minutes to form a niobium oxalate solution;

[0143] The niobium oxalate solution was added to the mixed solution in batches (taking 40 minutes) to form a suspension. After aging at 75°C for 90 minutes, the suspension was crystallized at 175°C for 36 hours, cooled and taken out, and dried at 100°C for 8 hours. The suspension was calcined at 350°C for 3 hours in an air atmosphere, and then calcined at 600°C for 2.5 hours in a helium atmosphere to obtain a MoVTeNb catalyst. The suspension was then placed in a 6wt% hydrogen peroxide solution and stirred at 75°C for 100 minutes for purification to remove the M2 phase. The suspension was then dried at 100°C for 8 hours to obtain the M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.29 Te 0.23 Nb 0.10 .

[0144] Supported catalyst preparation

[0145] Copper nitrate, cerium nitrate and citric acid were added to deionized water and heated in a 70°C water bath for 6 hours to form a citrate colloidal solution. The M1 catalyst was placed in the citrate colloidal solution, stirred for 2 hours, and dried at 80°C for 10 hours. The dried sample was calcined at 600°C for 2 hours to obtain a supported catalyst with a CuO-CeO2 loading of 3wt%, recorded as ODHE-13.

[0146] Comparative Example 1

[0147] This comparative example provides a supported catalyst for ethane oxidative dehydrogenation, and its specific preparation method is as follows:

[0148] A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and sesbania powder were added into deionized water and stirred at 75°C for 90 minutes to form a mixed solution. The amount of sesbania powder added was 0.05wt% of the mass of ammonium heptamolybdate tetrahydrate.

[0149] A certain amount of niobium oxalate was added into deionized water and stirred at 75°C for 40 minutes to form a niobium oxalate solution;

[0150] The niobium oxalate solution was added dropwise to the mixed solution (taking 40 minutes) to form a suspension. After aging at 75°C for 90 minutes, the suspension was crystallized at 175°C for 36 hours, cooled and taken out, and dried at 100°C for 8 hours. The suspension was calcined at 350°C for 3 hours in an air atmosphere, and then calcined at 600°C for 2.5 hours in a helium atmosphere to obtain a MoVTeNb catalyst. The suspension was then placed in a 6wt% hydrogen peroxide solution and stirred at 75°C for 100 minutes for purification to remove the M2 phase. The suspension was then dried at 100°C for 8 hours to obtain an M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.29 Te 0.23 Nb 0.10 , denoted as ODHE-14.

[0151] Comparative Example 2

[0152] This comparative example provides an ethane oxidative dehydrogenation catalyst, and its specific preparation method is as follows:

[0153] A certain amount of cerium nitrate was dissolved in deionized water to obtain a solution, which was transferred to a 250 mL polytetrafluoroethylene-lined high-pressure hydrothermal autoclave. After reacting at 80°C for 12 hours, it was cooled to room temperature, filtered, washed, dried at 80°C for 12 hours, and calcined at 450°C in an air atmosphere for 2 hours to obtain CeO2, which was recorded as ODHE-15.

[0154] Comparative Example 3

[0155] This comparative example provides an ethane oxidative dehydrogenation catalyst, and its specific preparation method is as follows:

[0156] Copper nitrate, cerium nitrate and citric acid were added to deionized water, heated in a water bath at 70°C for 6 hours to form a citrate colloidal solution, and dried at 80°C for 10 hours. The dried sample was calcined at 600°C for 2 hours to obtain CuO-CeO2, which was recorded as ODHE-16.

[0157] Comparative Example 4

[0158] The supported catalyst for ethane oxidative dehydrogenation provided in this comparative example is similar to that in Example 4, except that the time of adding the niobium oxalate solution is different. The specific preparation method of the supported catalyst for ethane oxidative dehydrogenation provided in this comparative example is as follows:

[0159] Preparation of MoVTe Catalyst (M1 Catalyst)

[0160] A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and sesbania powder were added into deionized water and stirred at 90°C for 80 minutes to form a mixed solution. The amount of sesbania powder added was 0.02 wt% of the mass of ammonium heptamolybdate tetrahydrate.

[0161] A certain amount of niobium oxalate was added into deionized water and stirred at 90°C for 30 minutes to form a niobium oxalate solution;

[0162] The niobium oxalate solution was added dropwise to the mixed solution (taking 5 minutes) to form a suspension. After aging at 90°C for 20 minutes, the suspension was crystallized at 180°C for 40 hours. After cooling, the suspension was taken out and dried at 100°C for 10 hours. The suspension was calcined at 250°C for 4 hours in an air atmosphere and then calcined at 600°C for 2 hours in a helium atmosphere to obtain a MoVTeNb catalyst. The MoVTeNb catalyst was placed in a 6wt% hydrogen peroxide solution and stirred at 50°C for 240 minutes for purification to remove the M2 phase. The suspension was then dried at 100°C for 8 hours to obtain the M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.30 Te 0.18 Nb 0.12 .

[0163] Supported catalyst preparation

[0164] By adopting the equal volume impregnation method, a certain amount of cerium nitrate was dissolved in deionized water to obtain an impregnation solution, and the above-mentioned M1 catalyst was added to the impregnation solution. After rotary impregnation at 60°C, it was aged for 3 hours, dried at 80°C for 12 hours, and calcined in an air atmosphere at 400°C for 3 hours to obtain a supported catalyst with a CeO2 loading of 6wt%, recorded as ODHE-17.

[0165] Comparative Example 5

[0166] This comparative example provides an ethane oxidative dehydrogenation composite catalyst, which is similar to the preparation method of Example 10, except that in this comparative example, CuO-CeO2 and M1 catalyst are directly physically mixed. The specific preparation method of this comparative example is as follows:

[0167] Preparation of molybdenum-vanadium-tellurium-niobium catalyst (M1 catalyst): the same as Example 10.

[0168] Preparation of composite catalyst

[0169] Copper nitrate, cerium nitrate and citric acid were added to deionized water, heated in a 70°C water bath for 6 hours to form a citrate colloidal solution, and dried at 80°C for 10 hours. The dried sample was calcined at 600°C for 2 hours to obtain negative CuO-CeO2.

[0170] CuO-CeO2 and the above-mentioned M1 catalyst were physically mixed in a ratio of 3wt%:97wt% to obtain a composite catalyst, which was recorded as ODHE-18.

[0171] Comparative Example 6

[0172] The supported catalyst for ethane oxidative dehydrogenation provided in this comparative example is similar to that in Example 10, except that no dispersant is added in this comparative example. The specific preparation method of the supported catalyst for ethane oxidative dehydrogenation provided in this comparative example is as follows:

[0173] Preparation of MoVTe Catalyst (M1 Catalyst)

[0174] A certain amount of ammonium heptamolybdate tetrahydrate, ammonium metavanadate and telluric acid were added into deionized water and stirred at 75° C. for 90 minutes to form a mixed solution.

[0175] A certain amount of niobium oxalate was added into deionized water and stirred at 75°C for 40 minutes to form a niobium oxalate solution;

[0176] The niobium oxalate solution was added dropwise to the mixed solution (taking 40 minutes) to form a suspension. After aging at 75°C for 90 minutes, the suspension was crystallized at 175°C for 36 hours, cooled and taken out, and dried at 100°C for 8 hours. The suspension was calcined at 350°C for 3 hours in an air atmosphere, and then calcined at 600°C for 2.5 hours in a helium atmosphere to obtain a MoVTeNb catalyst. The suspension was then placed in a 6wt% hydrogen peroxide solution and stirred at 75°C for 100 minutes for purification to remove the M2 phase. The suspension was then dried at 100°C for 8 hours to obtain an M1 catalyst. The molecular formula of the M1 catalyst is Mo1V 0.29 Te 0.23 Nb 0.10 .

[0177] Supported catalyst preparation

[0178] Copper nitrate, cerium nitrate and citric acid were added to deionized water and heated in a water bath at 70°C for 6 hours to form a citrate colloidal solution. The M1 catalyst was placed in the citrate colloidal solution, stirred for 2 hours, and dried at 80°C for 10 hours. The dried sample was calcined at 600°C for 2 hours to obtain a supported catalyst with a CuO-CeO2 loading of 3wt%, recorded as ODHE-19.

[0179] Comparative Example 7

[0180] The supported catalyst for ethane oxidative dehydrogenation provided in this comparative example is similar to that in Example 10, except that the supported metal and the supporting method are different. The specific preparation method of the supported catalyst for ethane oxidative dehydrogenation provided in this comparative example is as follows:

[0181] Preparation of molybdenum-vanadium-tellurium-niobium catalyst (M1 catalyst): the same as Example 10.

[0182] Supported catalyst preparation

[0183] By adopting the equal volume impregnation method, a certain amount of potassium nitrate was dissolved in deionized water to obtain an impregnation solution, and the above-mentioned M1 catalyst was added to the impregnation solution. After rotary impregnation at 60°C, it was aged for 3 hours, dried at 80°C for 12 hours, and calcined at 500°C in an air atmosphere for 3 hours to obtain a supported catalyst with a K2O loading of 3wt%, recorded as ODHE-20.

[0184] Catalyst evaluation results

[0185] The catalysts prepared in the examples and comparative examples were evaluated according to the aforementioned evaluation and analysis methods, and the specific results are shown in the following table.

[0186] Table 1

[0187]

[0188]

[0189] It can be seen from the data in the above table that, compared with the prior art, the supported catalyst prepared by the method for preparing the supported catalyst for ethane oxidative dehydrogenation provided by the present invention has a higher ethane conversion rate and ethylene selectivity when used for ethane oxidative dehydrogenation to prepare ethylene. Specifically,

[0190] (1) As can be seen from Example 10 compared with Comparative Example 1, the introduction of CuO-CeO2 improves the ethane conversion rate while the ethylene selectivity does not decrease. This is because the CuO on the surface of the CuO-CeO2-M1 catalyst x The clusters have abundant oxygen vacancies and excellent oxygen storage and release capacity, which further improves the redox ability and catalytic reaction performance of the M1 catalyst. At the same time, the introduction of CuO adjusts the concentration of oxygen vacancies on the CeO2 surface, which reduces the oxidation ability of CeO2 and inhibits the over-oxidation reaction to a certain extent. Compared with Comparative Example 1, the introduction of CeO2 alone in Example 4 improves the conversion rate of ethane, but at the same time reduces the selectivity of ethylene by about 1.5 points, indicating that the over-oxidation reaction is intensified and a large amount of carbon oxides are generated.

[0191] (2) Compared with Example 5, the catalytic effect of CeO2 alone on the oxidative dehydrogenation of ethane in Comparative Example 2 is very poor. Compared with Example 10, the catalytic effect of CuO-CeO2 alone on the oxidative dehydrogenation of ethane in Comparative Example 3 is also not ideal, but the ethylene selectivity in Comparative Example 3 is slightly higher than that in Comparative Example 2. Overall, the catalytic effect of a single metal oxide on the oxidative dehydrogenation of ethane is general, but after being impregnated / ball milled / gelled to form a two-phase catalyst with the M1 phase catalyst, the reaction performance of the M1 phase catalyst is greatly improved. This is mainly because the introduction of metal oxides can effectively regulate the active oxygen species on the surface of the M1 phase catalyst, and the active components on the surface of the M1 phase catalyst, especially V5+ The content and distribution of

[0192] (3) Compared with Example 4, in Comparative Example 4, the addition time of the niobium oxalate solution was shortened to 5 minutes, and the catalyst reaction performance was significantly reduced. This was mainly because the addition rate of the niobium oxalate solution was too fast, which would have a great negative impact on the formation of the microstructure of the Mo, V, Te, and Nb complexes in the solution. At the same time, the addition rate was too fast, and the resulting crystal nuclei were larger and the crystal phase coating phenomenon was serious. Therefore, it is necessary to strictly control the addition time of the niobium oxalate solution.

[0193] (4) Compared with Example 10, in Comparative Example 5, CuO-CeO2 was physically mixed with the M1 phase catalyst. It can be seen that the catalyst performance was slightly reduced. This is mainly because the metal oxide did not interact with the M1 phase catalyst and did not play a regulatory role in the redox process on the surface of the M1 phase catalyst.

[0194] (5) Compared with Example 10, no dispersant was added in Comparative Example 6, and the ethane conversion rate was slightly lower. Potassium oxide was loaded in Comparative Example 7, and the catalyst reaction performance was significantly deteriorated, mainly because the introduction of K reduced the surface acidity of the M1 phase catalyst and had a certain impact on the redox cycle process of the M1 catalyst surface. In summary, the addition of dispersants and metal oxides greatly improved the physical properties and reaction performance of the catalyst.

[0195] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a supported catalyst for ethane oxidative dehydrogenation, characterized in that: The ethane oxidative dehydrogenation supported catalyst is formed by loading a transition metal oxide on the surface of an M1 phase catalyst; Wherein, the preparation of the M1 phase catalyst comprises the following steps: (1) dissolving ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and a dispersant in deionized water to form a mixed solution; (2) adding an aqueous solution of niobium oxalate to the mixed solution within 15-50 minutes to form a suspension, and subjecting the suspension to aging, hydrothermal crystallization, drying, calcination, and removal of the M2 phase to obtain the M1 phase catalyst.

2. The preparation method according to claim 1, characterized in that The aqueous solution of niobium oxalate is added dropwise into the mixed solution.

3. The preparation method according to claim 1, characterized in that: The added amount of the dispersant is 0.005wt% to 0.1wt% of the mass of the ammonium heptamolybdate tetrahydrate; The dispersant is selected from any one of propylene glycol, polymethylcellulose, polyvinyl alcohol, sesbania powder, polyethylene glycol and polyvinyl pyrrolidone.

4. The preparation method according to claim 1, characterized in that: The transition metal oxide is selected from one or two of MnO2, Fe2O3, Cr2O3, CeO2, NiO, CuO and WO3.

5. The preparation method according to claim 1, characterized in that: The aging temperature is 20-90° C. and the aging time is 20-180 min.

6. The preparation method according to claim 1, characterized in that: The hydrothermal crystallization reaction temperature is 150-200° C. and the time is 12-60 hours; and / or The calcination is selected from two-stage calcination; preferably, the two-stage calcination includes first calcining at 200-400°C in air for 2-6 hours, and then calcining at 550-650°C in an inert atmosphere for 1-4 hours.

7. The preparation method according to claim 1, characterized in that: The transition metal oxide is loaded on the surface of the M1 phase catalyst by means of impregnation, gel or ball milling.

8. The preparation method according to claim 7, characterized in that: The impregnation loading comprises the following steps: The M1 phase catalyst is immersed in a transition metal precursor salt solution for impregnation, and after aging, drying and calcining, the ethane oxidative dehydrogenation supported catalyst is obtained; and / or The ball milling loading comprises the following steps: ball milling and calcining the transition metal oxide and the M1 phase catalyst to obtain the ethane oxidative dehydrogenation supported catalyst; and / or The gel loading comprises the following steps: mixing the M1 phase catalyst with a colloidal solution of a transition metal salt, drying, and calcining to obtain the ethane oxidative dehydrogenation loaded catalyst.

9. An ethane oxidative dehydrogenation supported catalyst prepared by the preparation method of the ethane oxidative dehydrogenation supported catalyst according to any one of claims 1 to 8, wherein the content of the transition metal oxide is 0.05 wt% to 10 wt%, based on the mass of the M1 phase catalyst being 100%.

10. The supported catalyst for ethane oxidative dehydrogenation according to claim 9, characterized in that: The general formula of the molybdenum-vanadium-niobium-tellurium catalyst is: Mo a V b Te c Nb d , where a=1, b is 0.25~0.32, c is 0.16~0.23, and d is 0.08~0.15.

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