Supported non-noble metal catalysts, methods of making and using the same

Abstract

The present application relates to the technical field of hydrogen production by ammonia decomposition, and discloses a supported non-noble metal catalyst and a preparation method and application thereof.A supported non-noble metal catalyst, wherein the catalyst comprises a carrier, an auxiliary agent and a non-noble metal active component, the carrier is alumina, the auxiliary agent is magnesium oxide and / or titanium dioxide, and the non-noble metal active component comprises at least one of iron, cobalt, manganese, copper and zinc and nickel; the loading amount of the non-noble metal active component is 0.5-20% by mass based on the total amount of the carrier in terms of oxides; the ratio of the loading amount of the at least one of iron, cobalt, manganese, copper and zinc to the loading amount of nickel is (0.2-5):1 in terms of oxides; and the particle size distribution of the non-noble metal active component in the catalyst is 20-100 nm.The catalyst can improve the conversion rate of ammonia in hydrogen production by ammonia decomposition, and the use of non-noble metal instead of noble metal can reduce production cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen production by ammonia decomposition, and in particular to a supported non-noble metal catalyst and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of hydrogen energy industry, developing efficient, safe and low-cost hydrogen storage and transportation methods has gradually become a key problem to be solved. Current hydrogen storage technologies mainly include gaseous hydrogen storage, liquid hydrogen storage and solid hydrogen storage. Among them, gaseous hydrogen storage requires high pressure, large energy consumption and limited capacity, and has safety factors such as hydrogen leakage and container explosion during storage and transportation. Liquid hydrogen storage is mainly divided into liquid hydrogen and liquid hydrogen carrier. Hydrogen liquefaction requires low temperature (reduced to about -253℃), and hydrogen volatilization is serious and energy consumption is large during liquefaction. Compared with the above, ammonia as a hydrogen storage medium has obvious advantages, mainly including the following aspects: (1) ammonia can be liquefied at standard atmospheric pressure at -33℃, with low energy consumption; (2) liquid ammonia has high energy density, with a mass hydrogen storage capacity of 17wt%, and a volume hydrogen storage density 1.7 times higher than that of liquid hydrogen, which is also much higher than that of the current mainstream high-pressure long-pipe trailer hydrogen storage and transportation method; (3) compared with organic liquid hydrogen, the hydrogen produced by ammonia decomposition has high purity and no carbon emission during the process; (4) using ammonia as a hydrogen storage medium, the comprehensive cost of long-distance transportation is lower than that of liquid hydrogen and organic liquid hydrogen carrier; (5) there is a mature ammonia synthesis and liquid ammonia transportation network, which is conducive to the rapid development of hydrogen storage and transportation industry.

[0003] The activation energy of ammonia decomposition is high and the kinetics is slow, which limits the practical application. The core technology of "hydrogen-ammonia-hydrogen" conversion lies in the development of efficient ammonia decomposition catalyst. Ammonia decomposition hydrogen production catalysts are mainly supported metal materials. For example, Ru / Al2O3 catalyst, by adding Na as an additive to optimize the electronic environment around Ru, the ammonia conversion rate reaches 73.7% at a reaction temperature of 550℃. However, noble metals are expensive and difficult to be used on a large scale, therefore, exploring non-noble metal catalysts with high activity and low cost is of great significance for ammonia decomposition hydrogen production. SUMMARY

[0004] The purpose of the present application is to overcome the problem of low ammonia conversion rate of ammonia decomposition hydrogen production catalyst in the prior art, and to provide a supported non-noble metal catalyst and a preparation method and application thereof. The catalyst can improve the ammonia conversion rate in ammonia decomposition hydrogen production, and replace noble metals with non-noble metals to reduce production cost.

[0005] To achieve the above object, the present application provides a supported non-noble metal catalyst in a first aspect, wherein the catalyst comprises a carrier, an auxiliary agent and a non-noble metal active component, the carrier is alumina, the auxiliary agent is magnesium oxide and / or titanium dioxide, and the non-noble metal active component comprises at least one of iron, cobalt, manganese, copper and zinc and nickel; the loading amount of the non-noble metal active component is 0.5-20 mass% based on the total amount of the carrier in terms of oxide; the ratio of the loading amount of the at least one of iron, cobalt, manganese, copper and zinc to the loading amount of nickel is (0.2-5):1 in terms of oxide; and the particle size distribution of the catalyst is 20-100 nm.

[0006] The present application provides a preparation method of a supported non-noble metal catalyst in a second aspect, wherein the method comprises: using a co-precipitation method, performing a co-precipitation reaction on a dispersion liquid containing a carrier precursor and an auxiliary agent in the presence of a precipitant, and then performing calcination to obtain the supported non-noble metal catalyst.

[0007] The carrier is alumina, the auxiliary agent is magnesium oxide and / or titanium dioxide, and the non-noble metal active component comprises at least one of iron, cobalt, manganese, copper and zinc and nickel.

[0008] The carrier precursor, the non-noble metal active component precursor and the auxiliary agent are used in an amount such that the loading amount of the non-noble metal active component is 0.5-20 mass% based on the total amount of the carrier in terms of oxide in the prepared catalyst.

[0009] The carrier precursor, the non-noble metal active component precursor and the auxiliary agent are used in an amount such that the loading amount of the non-noble metal active component is 0.5-20 mass% based on the total amount of the carrier in terms of oxide in the prepared catalyst.

[0010] The present application provides a supported non-noble metal catalyst prepared by the preparation method of the second aspect in a third aspect.

[0011] The present application provides an application of the supported non-noble metal catalyst of the first aspect or the third aspect in an ammonia decomposition reaction for hydrogen production in a fourth aspect.

[0012] Compared with the prior art, the present application has the following advantages:

[0013] 1. The catalyst used in the present application does not need to add noble metal, has low cost, and has cheap carrier, simple preparation process, good repeatability and easy scale-up production.

[0014] 2. The synergistic effect between the multi-metal active centers and the addition of additives are used to adjust the electronic and chemical structure, optimize the adsorption and desorption of NH3 molecules and nitrogen-containing reaction intermediates by the active centers, thereby reducing the ammonia decomposition activation energy and accelerating the reaction rate; at the same time, the mutual cooperation of multiple non-noble metals can replace noble metals to reduce production costs;

[0015] 3. The non-noble metal is loaded on the pseudo-boehmite precursor and then subjected to subsequent calcination treatment to form an alumina carrier, which helps to promote the uniform dispersion of the metal center on the carrier and form a strong metal-carrier interaction, thereby improving the ammonia decomposition activity and stability. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 Figure 1 is an X-ray diffraction pattern (XRD) of the supported non-noble metal catalyst of Example 1 of the present application. DETAILED DESCRIPTION

[0017] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The ranges or values should be construed to be roughly around the ranges or values. The endpoints between each range and the individual point values, and the individual point values themselves, can be combined with other endpoints or point values to create new ranges or points. These new ranges or points are to be considered as being included in the present disclosure.

[0018] In the present application, it can be understood that the particle size distribution is used to represent the dispersion degree of the non-noble metal active component on the catalyst carrier, which is measured by high-resolution transmission electron microscopy image statistics and calculation of the average particle size, for example, 30-50 crystal grain sizes can be randomly measured, and the average value is calculated.

[0019] In the present application, the specific surface area of the catalyst is measured by the BET method, and the specific test conditions are as follows: using a full-automatic specific surface area and porosity analyzer, the sample is pretreated at 150°C and under vacuum conditions for 12h before adsorption test.

[0020] In the present application, the resistivity of the catalyst is measured by the electrochemical impedance method, and the specific test conditions are as follows: using an electrochemical workstation for measurement and a three-electrode system (the working electrode is the prepared sample, the counter electrode is a platinum wire, and the reference electrode is a silver / silver chloride), and the electrolyte is a 0.2M Na2SO4 solution. The method for preparing the working electrode is as follows: 10mg of the sample is dispersed in 1.5mL of ethanol, ultrasonic dispersion is performed for 2h, and then spin coating is performed on FTO conductive glass (specification 2cmx2.5cm) using a spin coater, 200 microliters of the dispersion liquid is used each time, and a total of 6 times of spin coating is performed. The test is performed at the open circuit voltage, the disturbance is 10mV, and the test frequency range is 0.01Hz-10 5 Hz.

[0021] In the present application, the loading of each component in the catalyst is calculated by the amount of raw material.

[0022] In the present application, it is to be noted that in the catalyst composition, the oxide of iron is calculated as Fe2O3, the oxide of Ni is calculated as NiO, the oxide of cobalt is calculated as Co3O4, the oxide of copper is calculated as CuO, and the oxide of zinc is calculated as ZnO.

[0023] The first aspect of the present application provides a supported non-noble metal catalyst, wherein the catalyst comprises a carrier, an auxiliary agent, and a non-noble metal active component, the carrier is alumina, the auxiliary agent is magnesium oxide and / or titanium dioxide, and the non-noble metal active component comprises at least one of iron, cobalt, manganese, copper, and zinc, and nickel; the loading of the non-noble metal active component is 0.5-20 mass% based on the total amount of the carrier in terms of oxides; the ratio of the loading of the at least one of iron, cobalt, manganese, copper, and zinc to the loading of nickel is (0.2-5):1 in terms of oxides; and the particle size distribution of the non-noble metal active component in the catalyst is 20-100 nm.

[0024] The preferred embodiment has the advantage of facilitating the adsorption and dissociation of reactants on the active center.

[0025] In the present application, by adjusting the loading of the non-noble metal active component and the auxiliary agent, each non-noble metal active component cooperates to adjust the reaction activity of the catalyst. Preferably, the loading of the non-noble metal active component is 5-15 mass% based on the weight of the carrier in terms of oxides, and the loading of the auxiliary agent is 1-10 mass%.

[0026] In the present application, preferably, the ratio of the loading of the at least one of iron, cobalt, manganese, copper, and zinc to the loading of nickel is (0.5-2):1 in terms of oxides. The preferred embodiment has the advantage of adjusting the active metal composition to control the metal interaction, and optimizing the adsorption and activation of the active center on the reactant molecules.

[0027] In the present application, by preferably selecting the type of non-noble metal active component as the active center of the catalyst, the same synergistic effect between multiple non-noble metal centers improves the reaction activity of the catalyst, and at the same time, the mutual cooperation of multiple non-noble metals can reduce the production cost to replace noble metals. Preferably, the non-noble metal active component comprises iron and / or cobalt and nickel, and further preferably iron and cobalt and nickel.

[0028] In the present application, preferably, the loading of nickel is 1-10 mass%, preferably 2-8 mass%, the loading of iron is 1-6 mass%, preferably 1-2 mass%, and the loading of cobalt is 1-5 mass%, preferably 2-4 mass%, based on the total amount of the carrier, in terms of oxides. The advantage of this preferred embodiment is that by optimizing the metal composition, abundant metal lattice dislocation interfaces are formed, providing abundant active centers to improve the reaction rate.

[0029] In the present application, the dispersion of the catalyst is improved by the coordination between the non-noble metal active component and the carrier. Preferably, the particle size distribution of the non-noble metal active component on the catalyst is 30-50 nm. The advantage of this preferred embodiment is that the active metal size is controlled to increase the number of surface active sites, inhibit the agglomeration and deactivation of the active metal during the reaction due to too small particle size, and avoid the reduction of metal utilization due to too large particles.

[0030] In the present application, preferably, the specific surface area of the catalyst is 300-400 m 2 / g, and further preferably 350-400 m 2 / g. The advantage of this preferred embodiment is to promote the diffusion and migration of reactant and product molecules, and facilitate the contact between the reactant molecules and the active centers.

[0031] In the present application, preferably, the resistivity of the catalyst is 200-800 Ω·m, and further preferably 300-600 Ω·m. The advantage of this preferred embodiment is to facilitate charge migration and improve reaction efficiency.

[0032] The second aspect of the present application provides a preparation method of a supported non-noble metal catalyst, wherein the method comprises: using a co-precipitation method, co-precipitating a dispersion liquid containing a carrier precursor and an additive with a solution containing a non-noble metal active component precursor in the presence of a precipitant, and then calcining to obtain the supported non-noble metal catalyst.

[0033] The carrier is alumina, the additive is magnesium oxide and / or titanium dioxide, and the non-noble metal active component includes at least one of iron, cobalt, manganese, copper and zinc, and nickel;

[0034] The amounts of the carrier precursor, the non-noble metal active component precursor and the additive are such that the loading of the non-noble metal active component is 0.5-20 mass%, based on the total amount of the carrier, in terms of oxides, in the prepared catalyst.

[0035] The amount of the non-noble metal active component precursor is such that the ratio of the loading of at least one of iron, cobalt, manganese, copper and zinc to the loading of nickel in the catalyst prepared is (0.2-5):1, based on oxides.

[0036] The method provided by the present application has simple synthesis steps, and the synthesized catalyst exhibits excellent ammonia decomposition catalytic activity, and has wide application prospects.

[0037] In the present application, preferably, the amounts of the carrier precursor, the non-noble metal active component precursor and the additive are such that the loading of the non-noble metal active component is 5-15 mass% and the loading of the additive is 1-10 mass% based on the total amount of the carrier, based on oxides, in the catalyst prepared.

[0038] In the present application, preferably, the amount of the non-noble metal active component precursor is such that the ratio of the loading of at least one of iron, cobalt, manganese, copper and zinc to the loading of nickel in the catalyst prepared is (0.5-2):1, based on oxides.

[0039] In the present application, the types of the non-noble metal active component have been described in the first aspect, and will not be described here again.

[0040] In the present application, preferably, the amount of the non-noble metal active component precursor is such that the loading of nickel is 1-10 mass% and the loading of iron is 1-6 mass% and the loading of cobalt is 1-5 mass%, based on oxides, based on the total amount of the carrier, in the catalyst prepared.

[0041] In the present application, preferably, the carrier precursor is selected from at least one of pseudo-boehmite, aluminum nitrate, aluminum chloride and aluminum sulfate, and is preferably pseudo-boehmite. The advantage of using this preferred embodiment is that it is beneficial to provide an alkaline carrier environment, promote the reaction bottleneck step rate and improve the reaction activity.

[0042] In the present application, preferably, the dispersion liquid containing the carrier precursor and the additive is prepared by dispersing the carrier precursor and the additive in water.

[0043] In the present application, preferably, the mass ratio of the carrier precursor to the additive to water is 1:0.01-0.1:1-5, based on aluminum oxide.

[0044] In the present application, preferably, the non-noble metal active component precursor is selected from at least one of soluble compounds of the non-noble metal active components, preferably at least one of chloride salts, nitrate salts, sulfate salts and acetylacetone salts. The specific types thereof are not limited in the present application, and can be selected by those skilled in the art according to actual needs.

[0045] In the present application, preferably, the solution containing the non-noble metal active component is prepared by dissolving a non-noble metal active component precursor in water.

[0046] In the present application, preferably, the mass ratio of the non-noble metal active component precursor to water is 5:1-1:5.

[0047] In the present application, the order of adding the carrier precursor, the auxiliary agent and the non-noble metal component is not particularly limited. According to one specific embodiment of the present application, the preparation method of the supported non-noble metal catalyst comprises: dissolving the carrier precursor and the auxiliary agent in water to obtain a dispersion liquid containing the carrier precursor and the auxiliary agent, then dissolving the non-noble metal active component in water to obtain a solution containing the non-noble metal active component, and adding the dispersion liquid containing the carrier precursor and the auxiliary agent into the solution containing the non-noble metal active component, finally adding a precipitant to perform a co-precipitation reaction and then calcining to obtain the supported non-noble metal catalyst.

[0048] In the present application, the type of the precipitant is not particularly limited, which can be a precipitant conventionally defined in the art. Preferably, the precipitant is selected from at least one of potassium hydroxide, sodium hydroxide, ammonia, potassium carbonate, sodium carbonate and ammonium carbonate.

[0049] In the present application, preferably, the concentration of the precipitant is 0.5-10 mol / L, preferably 2-8 mol / L.

[0050] In the present application, preferably, the molar ratio of the precipitant to the non-noble metal active component precursor is 6:1-2:1.

[0051] In the present application, the conditions of the co-precipitation reaction are not particularly limited. Preferably, the conditions of the co-precipitation reaction include: temperature 20-80℃, time 2-24h, preferably, the conditions of the co-precipitation reaction include: temperature 40-60℃, time 8-16h. The advantage of this preferred embodiment is to promote the growth and dispersion of the non-noble metal active center on the carrier and improve the reaction activity.

[0052] In the present application, the conditions of the calcination are not particularly limited. Preferably, the conditions of the calcination include: calcination temperature 300-800℃, time 0.5-12h, heating rate 2-20℃ / min; further preferably, the calcination temperature is 500-700℃, the time is 2-6h, and the heating rate is 2-10℃ / min.

[0053] In the present application, the calcination is performed in a protective atmosphere, which is an inert gas and / or nitrogen. The type of the inert gas is not particularly limited in the present application.

[0054] The third aspect of the present application provides a supported non-noble metal catalyst prepared by the preparation method of the second aspect.

[0055] The fourth aspect of the present application provides an application of the supported non-noble metal catalyst of the first aspect or the third aspect in an ammonia decomposition reaction for hydrogen production, preferably, the supported non-noble metal catalyst of the first aspect or the third aspect is contacted with a raw gas.

[0056] In the present application, preferably, the raw gas comprises 3-15% by volume of ammonia and 85-97% by volume of a protective gas.

[0057] In the present application, preferably, the protective gas is an inert atmosphere, for example, any one of argon, helium and neon, which is not limited in the present application.

[0058] In the present application, preferably, the application condition comprises a temperature of 500-600℃ and a mass space velocity of 10000-20000 mL / (g min).

[0059] The present application will be described in detail by examples below. In the following examples, the raw materials are all commercially available unless otherwise specified.

[0060] In the following examples and comparative examples, the conversion rate of ammonia is calculated by the following formula:

[0061] Conversion rate of ammonia (%) = (inlet ammonia concentration - outlet ammonia concentration) / outlet ammonia concentration * 100%.

[0062] Example 1

[0063] 62.5 g of pseudo-boehmite (solid content 80%) and 2.5 g of magnesium oxide were weighed and uniformly dispersed in 100 mL of water, 10.0 g of nickel nitrate hexahydrate, 5.0 g of iron nitrate nonahydrate and 5.4 g of cobalt nitrate hexahydrate were dissolved in 20 mL of water, and then the dispersion liquid containing pseudo-boehmite and magnesium oxide was added dropwise, 20 mL of 5.0 mol / L NaOH solution was taken and added dropwise into the above mixture, and the mixture was stirred at 50℃ for 12 hours. The obtained solid was recovered and calcined at 600℃ in a muffle furnace for 4 hours, the heating rate was 5℃ / min, and after cooling to room temperature, the supported non-noble metal catalyst was obtained. The catalyst composition is shown in Table 1, and the catalyst properties are shown in Table 2. Figure 1 is the XRD pattern of the supported non-noble metal catalyst, it can be seen that the crystallinity of the sample is high, and there is no other impurity except the alumina carrier and the metal active center.

[0064] Example 2

[0065] Example 1 62.5 g of pseudo-boehmite (solid content 80%) and 1.5 g of magnesium oxide were mixed and uniformly dispersed in 100 mL of water, 4.0 g of nickel nitrate hexahydrate, 2.5 g of iron nitrate nonahydrate and 5.4 g of cobalt nitrate hexahydrate were dissolved in 20 mL of water, and the dispersion containing the pseudo-boehmite and magnesium oxide was added dropwise to the above mixture, 20 mL of a 5.0 mol / L NaOH solution was taken and added dropwise to the above mixture, and the mixture was stirred at 40°C for 8 hours. The obtained solid was recovered and calcined at 500°C for 3 hours in a muffle furnace at a temperature increase rate of 4°C / min, and the supported non-noble metal catalyst was obtained after cooling to room temperature. The catalyst composition is shown in Table 1, and the catalyst properties are shown in Table 2.

[0066] Example 3

[0067] 62.5 g of pseudo-boehmite (solid content 80%) and 3.0 g of magnesium oxide were mixed and uniformly dispersed in 100 mL of water, 15.6 g of nickel nitrate hexahydrate, 5.0 g of iron nitrate nonahydrate and 3.6 g of cobalt nitrate hexahydrate were dissolved in 20 mL of water, and the dispersion containing the pseudo-boehmite and magnesium oxide was added dropwise to the above mixture, 20 mL of a 5.0 mol / L NaOH solution was taken and added dropwise to the above mixture, and the mixture was stirred at 60°C for 26 hours. The obtained solid was recovered and calcined at 700°C for 6 hours in a muffle furnace at a temperature increase rate of 8°C / min, and the supported non-noble metal catalyst was obtained after cooling to room temperature. The catalyst composition is shown in Table 1, and the catalyst properties are shown in Table 2.

[0068] Example 4

[0069] 62.5 g of pseudo-boehmite (solid content 80%) and 2.5 g of magnesium oxide were mixed and uniformly dispersed in 100 mL of water, 2.0 g of nickel nitrate hexahydrate, 5.0 g of iron nitrate nonahydrate and 5.4 g of cobalt nitrate hexahydrate were dissolved in 20 mL of water, and the dispersion containing the pseudo-boehmite and magnesium oxide was added dropwise to the above mixture, 20 mL of a 5.0 mol / L NaOH solution was taken and added dropwise to the above mixture, and the mixture was stirred at 50°C for 12 hours. The obtained solid was recovered and calcined at 600°C for 4 hours in a muffle furnace at a temperature increase rate of 5°C / min, and the supported non-noble metal catalyst was obtained after cooling to room temperature. The catalyst composition is shown in Table 1, and the catalyst properties are shown in Table 2.

[0070] Example 5

[0071] Example 1 62.5 g of pseudo-boehmite (solid content 80%) and 0.5 g of magnesium oxide were weighed and uniformly dispersed in 100 mL of water, 19.5 g of nickel nitrate hexahydrate, 12.6 g of iron nitrate nonahydrate, and 5.4 g of cobalt nitrate hexahydrate were dissolved in 40 mL of water, and the solution was added dropwise to the dispersion containing the pseudo-boehmite and magnesium oxide, 40 mL of a 5.0 mol / L NaOH solution was taken and added dropwise to the above mixture, and the mixture was stirred at 50°C for 12 hours. The obtained solid was recovered and calcined at 600°C for 4 hours in a muffle furnace at a temperature increase rate of 5°C / min, and the supported non-noble metal catalyst was obtained after cooling to room temperature. The catalyst composition is shown in Table 1, and the catalyst properties are shown in Table 2.

[0072] Example 6

[0073] 62.5 g of pseudo-boehmite (solid content 80%) and 1.5 g of titanium dioxide were weighed and uniformly dispersed in 100 mL of water, 10.0 g of nickel nitrate hexahydrate, 5.0 g of iron nitrate nonahydrate, and 5.4 g of cobalt nitrate hexahydrate were dissolved in 20 mL of water, and the solution was added dropwise to the dispersion containing the pseudo-boehmite and titanium dioxide, 20 mL of a 5.0 mol / L KOH solution was taken and added dropwise to the above mixture, and the mixture was stirred at 80°C for 2 hours. The obtained solid was recovered and calcined at 600°C for 4 hours in a muffle furnace at a temperature increase rate of 5°C / min, and the supported non-noble metal catalyst was obtained after cooling to room temperature. The catalyst composition is shown in Table 1, and the catalyst properties are shown in Table 2.

[0074] Example 7

[0075] 62.5 g of pseudo-boehmite (solid content 80%) and 3.0 g of titanium dioxide were weighed and uniformly dispersed in 100 mL of water, 8.0 g of nickel nitrate hexahydrate, 5.0 g of iron nitrate nonahydrate, and 5.4 g of cobalt nitrate hexahydrate were dissolved in 20 mL of water, and the solution was added dropwise to the dispersion containing the pseudo-boehmite and titanium dioxide, 20 mL of a 5.0 mol / L KOH solution was taken and added dropwise to the above mixture, and the mixture was stirred at 50°C for 12 hours. The obtained solid was recovered and calcined at 800°C for 24 hours in a muffle furnace at a temperature increase rate of 10°C / min, and the supported non-noble metal catalyst was obtained after cooling to room temperature. The catalyst composition is shown in Table 1, and the catalyst properties are shown in Table 2.

[0076] Example 8

[0077] Example 1 62.5 g of pseudo-boehmite (solid content 80%) and 2.5 g of magnesium oxide were mixed and uniformly dispersed in 100 mL of water, 10.0 g of nickel nitrate hexahydrate was dissolved in 30 mL of water, and the solution was added dropwise to the dispersion containing the pseudo-boehmite and magnesium oxide, 20 mL of a NaOH solution having a concentration of 5.0 mol / L was taken and added dropwise to the above mixture, and the mixture was stirred at 50°C for 12 hours. The obtained solid was recovered and calcination treatment was performed at 600°C for 4 hours in a muffle furnace at a temperature increase rate of 5°C / min, and the supported non-noble metal catalyst was obtained after cooling to room temperature. The catalyst composition is shown in Table 1, and the catalyst properties are shown in Table 2.

[0078] Example 9

[0079] 62.5 g of pseudo-boehmite (solid content 80%) and 2.5 g of magnesium oxide were mixed and uniformly dispersed in 100 mL of water, 10.0 g of nickel nitrate hexahydrate and 5.0 g of iron nitrate nonahydrate were dissolved in 20 mL of water, and the solution was added dropwise to the dispersion containing the pseudo-boehmite and magnesium oxide, 20 mL of a NaOH solution having a concentration of 5.0 mol / L was taken and added dropwise to the above mixture, and the mixture was stirred at 50°C for 12 hours. The obtained solid was recovered and calcination treatment was performed at 500°C for 4 hours in a muffle furnace at a temperature increase rate of 5°C / min, and the supported non-noble metal catalyst was obtained after cooling to room temperature. The catalyst composition is shown in Table 1, and the catalyst properties are shown in Table 2.

[0080] Comparative Example 1

[0081] 62.5 g of pseudo-boehmite (solid content 80%) was uniformly dispersed in 100 mL of water, 10.0 g of nickel nitrate hexahydrate, 4.0 g of iron nitrate nonahydrate, and 5.4 g of cobalt nitrate hexahydrate were dissolved in 20 mL of water, and the solution was added dropwise to the dispersion containing the pseudo-boehmite, 20 mL of a NaOH solution having a concentration of 5.0 mol / L was taken and added dropwise to the above mixture, and the mixture was stirred at 50°C for 12 hours. The obtained solid was recovered and calcination treatment was performed at 600°C for 4 hours in a muffle furnace at a temperature increase rate of 5°C / min, and the supported non-noble metal catalyst was obtained after cooling to room temperature. The catalyst composition is shown in Table 1, and the catalyst properties are shown in Table 2.

[0082] Comparative Example 2

[0083] Take 62.5 g of pseudo-boehmite (solid content 80%) and 2.5 g of magnesium oxide and mix and uniformly disperse in 100 mL of water, take 19.5 g of nickel nitrate hexahydrate and dissolve in 20 mL of water, and dropwise add the dispersion liquid containing pseudo-boehmite and magnesium oxide, take 20 mL of NaOH solution with a concentration of 5.0 mol / L and dropwise add to the above mixture, and stir at 50°C for 12 hours. Recover the obtained solid and treat by calcination in a muffle furnace at 600°C for 4 hours, with a temperature increase rate of 5°C / min, and after cooling to room temperature, the supported non-noble metal catalyst is obtained. The catalyst composition is shown in Table 1, and the catalyst properties are shown in Table 2.

[0084] Comparative Example 3

[0085] Take 62.5 g of pseudo-boehmite (solid content 80%) and 2.5 g of magnesium oxide and mix and uniformly disperse in 100 mL of water, take 19.5 g of nickel nitrate hexahydrate and dissolve in 20 mL of water, and dropwise add the dispersion liquid containing pseudo-boehmite and magnesium oxide, take 20 mL of NaOH solution with a concentration of 5.0 mol / L and dropwise add to the above mixture, and stir at 50°C for 12 hours. Recover the obtained solid and treat by calcination in a muffle furnace at 600°C for 4 hours, with a temperature increase rate of 5°C / min, and after cooling to room temperature, the supported non-noble metal catalyst is obtained. The catalyst composition is shown in Table 1, and the catalyst properties are shown in Table 2.

[0086] Activity test for hydrogen production by ammonia decomposition

[0087] The above examples and comparative examples were subjected to activity test for hydrogen production by ammonia decomposition using a fixed bed microreactor, the feed gas was 15% NH3 / Ar mixed gas by volume, the mass space velocity was 12000 mL / (g min). The catalyst loading was 1.0 g, and quartz sand was 4.0 g, the reaction temperature was 550°C, and the outlet gas composition was analyzed by infrared detector and chromatography, and the catalyst activity is shown in Table 3.

[0088] Table 1

[0089] Catalyst composition Example 1 5 wt% NiO - 2 wt% Fe203- 3 wt% Co304, 5 wt% MgO Example 2 2 wt% NiO - 1 wt% Fe203- 3 wt% Co304, 3 wt% MgO Example 3 8 wt% NiO - 2 wt% Fe203- 2 wt% Co304, 6 wt% MgO Example 4 1 wt% NiO - 2 wt% Fe203- 3 wt% Co304, 5 wt% MgO Example 5 10 wt% NiO - 5 wt% Fe203- 3 wt% Co304, 1 wt% MgO Example 6 5 wt% NiO - 2 wt% Fe203- 3 wt% Co304, 3 wt% Ti02 Example 7 4wt% NiO - 2wt% Fe203- 3wt% Co304, 6wt% Ti02 Example 8 5 wt% NiO - 2 wt% CuO - 3 wt% ZnO, 5 wt% MgO Example 9 5wt% NiO - 2wt% Fe203, 5wt% MgO Comparative Example 1 5 wt% NiO - 2 wt% Fe203- 3 wt% Co304<!-- 7 --> Comparative Example 2 10 wt% NiO, 5 wt% MgO Comparative Example 3 5 wt% NiO - 2 wt% Fe203- 3 wt% Co304, 5 wt% MgO

[0090] Note: In Table 1, the loading of each component is based on the total amount of the carrier.

[0091] Table 2

[0092]

[0093]

[0094] Table 3

[0095] Reaction temperature (°C) Conversion (%) Example 1 550 99.5 Example 2 550 98.5 Example 3 550 97.5 Example 4 550 88.4 Example 5 550 89.6 Example 6 550 92.4 Example 7 550 89.0 Example 8 550 88.5 Example 9 550 87.2 Comparative Example 1 550 82.5 Comparative Example 2 550 81.3 Comparative Example 3 550 52.5

[0096] As can be seen from the results of Table 3, the preferred embodiments 1-3 of the present application have a significantly better ammonia decomposition effect.

[0097] The above describes the preferred embodiments of the present application in detail, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and belong to the protection scope of the present application.

Claims

1. A supported non-precious metal catalyst, characterized in that, The catalyst comprises a support, an additive, and a non-precious metal active component. The support is alumina, the additive is magnesium oxide and / or titanium dioxide, and the non-precious metal active component comprises iron, cobalt, and nickel. Based on the total amount of the support, the loading of the non-precious metal active component, calculated as oxides, is 0.5-20% by mass; the ratio of the loading of iron and cobalt to the loading of nickel, calculated as oxides, is (0.5-2):1; the particle size distribution of the non-precious metal active component on the catalyst is 20-100 nm. Based on the total amount of the carrier, the loading of nickel (calculated as oxide) is 1-10% by mass, the loading of iron (calculated as oxide) is 1-6% by mass, and the loading of cobalt (calculated as oxide) is 1-5% by mass. The resistivity of the catalyst is 200-800 Ω·m; The catalyst preparation method includes: using a co-precipitation method, in the presence of a precipitant, a dispersion containing a support precursor and an auxiliary agent is co-precipitated with a solution containing a non-precious metal active component precursor, and then calcined to obtain the supported non-precious metal catalyst.

2. The catalyst according to claim 1, wherein, Based on the total amount of the carrier, the loading of the non-precious metal active component, calculated as oxide, is 5-15% by mass, and the loading of the auxiliaries is 1-10% by mass.

3. The catalyst according to claim 1, wherein, Based on the total amount of the carrier, the loading of nickel as oxide is 2-8% by mass, the loading of iron as oxide is 1-2% by mass, and the loading of cobalt as oxide is 2-4% by mass.

4. The catalyst according to any one of claims 1-3, wherein, The particle size distribution of the non-precious metal active component on the catalyst is 30-50 nm.

5. The catalyst according to any one of claims 1-3, wherein, The catalyst has a specific surface area of ​​300-400 m². 2 / g.

6. The catalyst according to claim 5, wherein, The catalyst has a specific surface area of ​​350-400 m². 2 / g.

7. The catalyst according to claim 1, wherein, The resistivity of the catalyst is 300-600 Ω·m.

8. A method for preparing a supported non-noble metal catalyst, wherein, The method includes: using a co-precipitation method, in the presence of a precipitant, a dispersion containing a support precursor and an auxiliary agent is co-precipitated with a solution containing a non-precious metal active component precursor, and then calcined to obtain the supported non-precious metal catalyst. The carrier is alumina, the additive is magnesium oxide and / or titanium dioxide, and the non-precious metal active components are iron, cobalt and nickel; The amounts of the support precursor, the non-precious metal active component precursor, and the promoters are such that, based on the total amount of the support, the loading of the non-precious metal active component, calculated as oxide, in the prepared catalyst is 0.5-20% by mass. The amount of the non-precious metal active component precursor is such that, in the prepared catalyst, the ratio of the loading of iron and cobalt to the loading of nickel, based on oxides, is (0.5-2):

1. The amount of the non-precious metal active component precursor used in the prepared catalyst is such that, based on the total amount of the support, the loading of nickel (calculated as oxide) is 1-10% by mass, the loading of iron (calculated as oxide) is 1-6% by mass, and the loading of cobalt (calculated as oxide) is 1-5% by mass. The resistivity of the catalyst obtained is 200-800 Ω·m.

9. The method according to claim 8, wherein, The amounts of the carrier precursor, the non-precious metal active component precursor, and the additives are such that, based on the total amount of the carrier, the loading of the non-precious metal active component (calculated as oxide) in the prepared catalyst is 5-15% by mass, and the loading of the additives is 1-10% by mass.

10. The method according to claim 8, wherein, The amount of the non-precious metal active component precursor is such that, based on the total amount of the support, the loading of nickel (calculated as oxide) is 2-8% by mass, the loading of iron (calculated as oxide) is 1-2% by mass, and the loading of cobalt (calculated as oxide) is 2-4% by mass.

11. The method according to any one of claims 8-10, wherein, The carrier precursor is selected from at least one of boehmite, aluminum nitrate, aluminum chloride, and aluminum sulfate.

12. The method according to claim 11, wherein, The carrier precursor is pseudoboehmite.

13. The method according to any one of claims 8-10, wherein, The precursors of the non-precious metal active components are selected from soluble compounds of each non-precious metal active component.

14. The method according to claim 13, wherein, The non-precious metal active component precursor is selected from at least one of chloride, nitrate, sulfate and acetylacetonate.

15. The method according to any one of claims 8-10, wherein, The precipitant is selected from at least one of potassium hydroxide, sodium hydroxide, ammonia, potassium carbonate, sodium carbonate, and ammonium carbonate.

16. The method according to any one of claims 8-10, wherein, The concentration of the precipitant is 0.5-10 mol / L.

17. The method according to any one of claims 8-10, wherein, The molar ratio of the precipitant to the non-precious metal active component precursor is 6:1-2:

1.

18. The method according to any one of claims 8-10, wherein, The conditions for the coprecipitation reaction include: a temperature of 20-80℃ and a time of 2-24h.

19. The method according to claim 18, wherein, The conditions for the coprecipitation reaction include: a temperature of 40-60℃ and a time of 8-16h.

20. The method according to any one of claims 8-10, wherein, The calcination conditions include: a calcination temperature of 300-800℃, a calcination time of 0.5-12h, and a heating rate of 2-20℃ / min.

21. The method according to claim 20, wherein, The calcination conditions include: a calcination temperature of 500-700℃, a calcination time of 2-6 hours, and a heating rate of 2-10℃ / min.

22. The supported non-precious metal catalyst prepared by the preparation method according to any one of claims 8-21.

23. The application of the supported non-precious metal catalyst according to any one of claims 1-7 and 22 in the ammonia decomposition to hydrogen production reaction.

24. The application according to claim 23, wherein, The conditions for the application include: a temperature of 500-600℃ and a mass hourly space velocity of 10000-20000 mL / (g·min).

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