A ni-based catalyst for glycerol steam reforming and a method for preparing the same

Abstract

The application belongs to the technical field of catalyst preparation, and particularly relates to a Ni-based glycerol steam reforming catalyst and a preparation method thereof. The method is characterized in that a NiAl2O4 carrier with a multi-level pore structure is prepared by using a template agent assisted co-precipitation, and an alkaline earth metal and a rare earth metal additive are introduced in cooperation, and through accurate control of calcination and reduction conditions, efficient loading of active metals and optimization of interface structure are realized. The prepared catalyst shows excellent hydrogen production performance, high dispersibility and carbon deposition resistance in the glycerol steam reforming reaction for hydrogen production, effectively solves the problems of easy sintering, easy carbon deposition and fast deactivation of traditional Ni-based catalysts, and significantly improves the stability and service life of the catalyst. The method is simple in process and easy in raw material, and provides a new technical approach for efficient conversion of biomass resources and green hydrogen production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of catalyst preparation, and particularly relates to a Ni-based glycerol steam reforming catalyst and a preparation method thereof. BACKGROUND

[0002] Hydrogen energy, as an important part of the future clean energy system, has outstanding advantages such as high energy density and zero carbon emission, and has broad application prospects in the fields of transportation, energy storage, industry and the like. With the increasing demand for sustainable energy worldwide, developing an economic, green and low-carbon hydrogen production method has become the focus of the current energy technology field. Biomass hydrogen production is considered as one of the important ways to achieve the sustainable development of hydrogen energy due to its renewable raw materials, carbon neutrality and environmental friendliness.

[0003] Glycerol is a large by-product of the biodiesel industry, and its production is abundant and its price is low. However, the large-scale accumulation of glycerol brings certain environmental pressure. Therefore, how to efficiently utilize glycerol resources and develop high-value-added products has become an important direction for the extension and upgrading of the biodiesel industry chain. The glycerol steam reforming hydrogen production technology generates hydrogen and carbon dioxide by reacting glycerol with steam at high temperature, which not only realizes the resource utilization of by-products, but also provides a new path for the sustainable production of clean hydrogen.

[0004] In the glycerol steam reforming hydrogen production catalytic system, nickel-based catalysts are widely used in industrial catalytic reforming processes due to their low price, abundant reserves, high activity for carbon-carbon and carbon-hydrogen bond breaking. However, the existing Ni-based catalysts still have many technical bottlenecks in the glycerol steam reforming process. For example, ordinary supported Ni catalysts are prone to sintering and growth of metal nickel particles under high temperature reaction conditions, resulting in reduced activity. At the same time, carbon in the glycerol decomposition products is easy to accumulate on the catalyst surface, causing catalyst poisoning and deactivation. In addition, the interaction between the support material and the active component is limited, making it difficult to effectively improve the dispersion and stability of the metal, thereby affecting the long-term operation and industrial application of the catalyst.

[0005] In order to improve the above problems, some studies attempt to use spinel oxides (such as NiAl2O4) as carriers to enhance the interaction between the metal and the carrier, and to improve the dispersion and sintering resistance of nickel. However, how to realize the uniformity of the carrier structure, the optimization of the pore structure and the efficient loading and stable anchoring of the active metal in the industrial preparation process is still a problem in the industry. In addition, the controllable preparation, reusability and simplicity of the preparation process of the catalyst are also key links that need to be broken through in the current technology.

[0006] Therefore, developing a Ni-based glycerol steam reforming catalyst with high dispersion, high stability and excellent anti-coking performance has become an important technical problem to be solved in the field of high-value utilization of glycerol resources and green hydrogen production. SUMMARY

[0007] The purpose of the present application is to provide a Ni-based glycerol steam reforming catalyst and a preparation method thereof, aiming to solve the problems of metal sintering, severe carbon deposition, insufficient activity and stability of existing Ni-based catalysts in the process of glycerol steam reforming for hydrogen production, to realize high dispersion, high stability and excellent anti-coking performance of the catalyst, and to improve the reaction efficiency of glycerol to hydrogen and the service life of the catalyst.

[0008] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0009] The first aspect of the present application provides a preparation method of a Ni-based glycerol steam reforming catalyst, comprising the following steps:

[0010] (1) Dissolve nickel nitrate and aluminum nitrate in deionized water, add a template agent and a buffer agent to it, stir, then add a precipitating agent, adjust the pH to 7.5-9.0, continue stirring, get a suspension, stand, filter, get a precipitate precursor;

[0011] (2) The precursor is calcined under air atmosphere and nitrogen atmosphere in turn to obtain a NiAl2O4 carrier;

[0012] (3) The NiAl2O4 carrier is added to deionized water together with an alkaline earth metal additive and a rare earth metal additive, stirred, stood, the mixture is dried and calcined under air atmosphere to obtain a double additive modified NiAl2O4 carrier;

[0013] (4) Add nickel nitrate and double additive modified NiAl2O4 carrier to deionized water, stir, stand, dry the mixture, and calcine under air atmosphere to obtain a NiAl2O4 catalyst precursor loaded with Ni active component;

[0014] (5) The catalyst precursor obtained in step (4) is calcined under nitrogen atmosphere and hydrogen / nitrogen mixed atmosphere in turn to obtain a Ni-based glycerol steam reforming catalyst.

[0015] Further, the mass ratio of nickel nitrate and aluminum nitrate in step (1) is 1:2-1:3; the stirring time after adding the template agent and the buffer agent is 0.5-2 hours; the stirring time after adding the precipitating agent is 1-4 hours; the standing time is 8-16 hours.

[0016] Further, the template agent in step (1) is glucose or polyvinylpyrrolidone (PVP), and the addition amount of the template agent is 5% to 20% of the total mass of the nickel nitrate and the aluminum nitrate; the buffer is Na2HPO4, and the addition amount of the buffer is 1% to 10% of the total mass of the nickel nitrate and the aluminum nitrate; and the precipitant is ammonia water, NaOH or Na2CO3.

[0017] Further, the temperature for calcination in step (2) under the air atmosphere is 300 to 400 ℃, and the calcination time is 1 to 3 hours; the temperature for calcination under the nitrogen atmosphere is 700 to 900 ℃, and the calcination time is 4 to 10 hours.

[0018] Further, the alkaline earth metal additive in step (3) is magnesium nitrate or calcium nitrate, and the addition amount is 0.1% to 1.0% of the mass of the NiAl2O4 carrier; the rare earth metal additive is cerium nitrate or lanthanum nitrate, and the addition amount is 0.05% to 0.5% of the mass of the NiAl2O4 carrier.

[0019] Further, the temperature for drying in step (3) is 100 to 120 ℃, and the drying time is 8 to 16 hours; the temperature for calcination is 400 to 600 ℃, and the calcination time is 1 to 4 hours.

[0020] Further, the mass ratio of the nickel nitrate to the double additive modified NiAl2O4 carrier in step (4) is 0.04:1 to 0.25:1; the temperature for drying is 100 to 120 ℃, and the drying time is 8 to 16 hours; and the temperature for calcination is 400 to 600 ℃, and the calcination time is 3 to 6 hours.

[0021] Further, the temperature for calcination under the nitrogen atmosphere in step (5) is 350 to 450 ℃, and the time is 0.5 to 2 hours; the temperature for calcination under the hydrogen / nitrogen mixed atmosphere is 600 to 750 ℃, and the time is 1 to 4 hours; at the half time point after the start of the calcination under the hydrogen / nitrogen mixed atmosphere, the atmosphere is switched to a nitrogen / carbon monoxide mixed gas, and the switching is continued for 5 to 15 minutes, and then the original hydrogen / nitrogen mixed gas is switched back until the reduction calcination is completed.

[0022] Further, the volume ratio of hydrogen to nitrogen in the hydrogen / nitrogen mixed atmosphere in step (5) is 1:9 to 1:4; and the volume ratio of nitrogen to carbon monoxide in the nitrogen / carbon monoxide mixed gas is 4:1 to 1:1.

[0023] The present application adopts a template-assisted co-precipitation method to prepare a NiAl2O4 carrier. The introduction of the template can release gas during calcination, thereby generating a hierarchical pore structure inside the carrier. This porous structure greatly improves the specific surface area and activity site dispersion, is conducive to the uniform loading of subsequent active components, and provides a good channel for the efficient mass transfer of reactants and products. The addition of a buffer stabilizes the pH of the reaction system and the precipitation rate of metal ions, thereby achieving uniform co-precipitation of Ni and Al ions and effectively avoiding composition segregation and particle agglomeration. Subsequently, a two-step calcination method is used. First, the template and residual organic matter are removed by calcination at medium temperature in an air atmosphere. Then, the precursor is further calcined at high temperature in a nitrogen atmosphere, so that the precursor is fully converted into a NiAl2O4 spinel carrier with excellent thermal stability and structural integrity, providing a physical and chemical basis for high-temperature applications of the catalyst.

[0024] On the basis of carrier structure optimization, the present application realizes the stable anchoring and surface electronic structure regulation of Ni particles by synergistically loading alkaline earth metal and rare earth metal two types of additives. The alkaline earth metal additive can neutralize the acidic sites on the surface of the carrier, reduce the risk of Ni migration and sintering at high temperature, and is also conducive to improving the redox cycle stability. The rare earth metal additive can promote the low-temperature reduction and activation of Ni, enhance the electronic interaction at the metal-carrier interface, and further improve the dispersion and reactivity of Ni in the catalytic reaction process. The synergistic effect of the double additives can effectively improve the utilization rate of active metal, enhance the anti-sintering ability, and inhibit the generation of carbon deposition, thereby significantly prolonging the service life of the catalyst and maintaining high-efficiency catalytic performance.

[0025] The Ni active component is mixed with the dual-promoter modified support by impregnation method, and the loading amount is accurately controlled by mass ratio to ensure the rationality and repeatability of the proportion of each component of the catalyst. Drying and air calcination not only makes the Ni component uniformly distributed and preliminarily oxidized, but also further eliminates impurities and weakly bound precursors, which helps to form more stable and highly dispersed Ni species. First, calcination is carried out in a nitrogen atmosphere to remove impurities and weakly bound phases, avoiding the formation of large Ni agglomerates in the early stage of reduction; then, reduction calcination is carried out in a hydrogen / nitrogen mixed atmosphere, so that Ni ions are gradually reduced to highly dispersed metal Ni nanoparticles; at the half-time point of reduction calcination, switch to a nitrogen / carbon monoxide mixed atmosphere, CO can react with the surface of Ni and the interface with the support, on the one hand, CO adsorbs on the metal surface and reduces the residual oxide, promoting the formation of more low-coordination, active Ni sites; on the other hand, CO can also react with the surface oxygen of the support to generate oxygen vacancies and interface defects, improving the electronic structure between the metal and the support. This interface reconstruction helps to improve the adsorption and activation ability of the catalyst to the reaction intermediates, thereby enhancing the overall catalytic performance and carbon deposition resistance. Finally, switch back to a hydrogen / nitrogen mixed atmosphere to ensure that Ni is fully reduced and maintains excellent dispersion and surface activity.

[0026] The second aspect of the present application provides a Ni-based glycerol steam reforming catalyst prepared by the above method.

[0027] Compared with the prior art, the advantages and beneficial effects of the present application are:

[0028] Compared with the prior art, the Ni-based glycerol steam reforming catalyst of the present application has significant overall performance advantages. By introducing a template to optimize the pore structure of the support, the dispersion and specific surface area of Ni are significantly improved, which is beneficial to the mass transfer of reactants and the rapid release of products. The synergistic regulation of alkaline earth metal and rare earth metal promoters not only enhances the interaction between the active component and the support, improves the anchoring stability of Ni, but also effectively inhibits metal sintering and agglomeration at high temperatures. The unique step-by-step calcination and dynamic reduction atmosphere regulation technology further optimizes the surface and interface structure of the catalyst, exposes more active sites, and promotes the adjustment of oxygen vacancies and electronic structure, greatly improving the carbon deposition resistance and catalytic life. The performance test results show that the hydrogen yield, Ni particle size after reaction, and 400-hour activity retention rate of the catalyst of the present application are much better than those of the comparative sample. Overall, the present application not only improves the efficient conversion of glycerol to hydrogen, but also significantly prolongs the service life of the catalyst, and has good industrial application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 TEM images and particle size distribution histograms of the catalysts prepared for Example 1 (a) and Comparative Example 3 (b).

[0030] Figure 2 Glycerol conversion and product selectivity of the catalyst prepared in Example 1 in the glycerol steam reforming reaction as a function of time. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0032] The raw materials used in the embodiments are all commercially available unless otherwise specified.

[0033] Example 1: The present embodiment provides a preparation method of a Ni-based glycerol steam reforming catalyst, comprising the following steps:

[0034] (1) 12.0 g of nickel nitrate (Ni(NO3)2·6H2O) and 30.0 g of aluminum nitrate (Al(NO3)3·9H2O) were weighed with a mass ratio of 1:2.5 and dissolved in 200 mL of deionized water. 2.94 g of glucose and 0.84 g of Na2HPO4 were added, and stirring was performed at 55°C water bath for 1 hour. Then, 25% ammonia water was slowly added dropwise to adjust the pH to 8.5, and stirring was continued for 2 hours to obtain a suspension. After standing for 12 hours, the suspension was filtered by a Buchner funnel, and the precipitate was repeatedly washed with deionized water until the pH of the filtrate was close to neutral. The obtained precursor was collected and dried in a vacuum drying oven at 105°C for 12 hours.

[0035] (2) The dried precursor was placed in a muffle furnace and heated to 350°C at a heating rate of 5°C / min under air atmosphere, and calcined at this temperature for 2 hours to remove organic matter and impurities. After cooling to room temperature, the sample was transferred to a tube furnace and heated to 800°C at a heating rate of 5°C / min under nitrogen atmosphere (N2 flow rate 100 mL / min), and calcined at this temperature for 6 hours to obtain a porous NiAl2O4 carrier.

[0036] (3) 10.0 g of the above NiAl2O4 carrier was weighed and added to 50 mL of deionized water, then 0.08 g of magnesium nitrate and 0.035 g of cerium nitrate were added thereto. After magnetic stirring for 30 minutes, the slurry was left to stand at room temperature for 6 hours, and then transferred to a porcelain evaporating dish and dried in an oven at 110°C for 10 hours. The dried sample was placed in a muffle furnace and heated to 500°C at a heating rate of 5°C / min under air atmosphere, and calcined at this temperature for 2 hours to obtain a dual-additive modified NiAl2O4 carrier.

[0037] (4) Take 2.0 g of nickel nitrate (Ni(NO3)2·6H2O) and add it to 10.0 g of the above-mentioned dual-additive modified NiAl2O4 carrier in 50 mL of deionized water, magnetically stir for 1 hour, and ultrasonically disperse in an ultrasonic cleaner for 30 minutes, then place the slurry in a 70°C water bath and stand for 8 hours. After standing, transfer the mixture to a porcelain evaporating dish, dry at 110°C for 12 hours, and place the dried material in a muffle furnace, heat to 500°C at a rate of 5°C / min under an air atmosphere, and calcine at this temperature for 4 hours to obtain a NiAl2O4 catalyst precursor loaded with a Ni active component.

[0038] (5) Place the precursor sample obtained in step (4) in a quartz boat and place it in the center of a tube furnace. First, pass high-purity nitrogen gas (N2flow rate 120 mL / min) and heat to 400°C at a rate of 6°C / min, and hold for 1 hour. Then switch to a hydrogen / nitrogen mixed gas (H2flow rate 30 mL / min, N2flow rate 120 mL / min) and continue to heat to 700°C at a rate of 6°C / min for reduction calcination. Hold at this temperature for 2 hours. At 1 hour after the start of reduction calcination, switch to a nitrogen / carbon monoxide mixed gas (N2flow rate 120 mL / min, CO flow rate 30 mL / min) and pass it in for 10 minutes. After 10 minutes, switch back to the original hydrogen / nitrogen mixed gas and continue to hold for 1 hour. After the holding period is over, cool the furnace to obtain the final Ni-based glycerol steam reforming catalyst.

[0039] Example 2: This example provides a method for preparing a Ni-based glycerol steam reforming catalyst, which differs from Example 1 in that 2.94 g of glucose in step (1) is replaced by 8 g of polyvinylpyrrolidone.

[0040] Example 3: This example provides a method for preparing a Ni-based glycerol steam reforming catalyst, which differs from Example 1 in that 2.94 g of glucose in step (1) is replaced by 5.5 g of glucose.

[0041] Example 4: This example provides a method for preparing a Ni-based glycerol steam reforming catalyst, which differs from Example 1 in that 0.08 g of magnesium nitrate in step (3) is replaced by 0.01 g of calcium nitrate.

[0042] Example 5: This example provides a method for preparing a Ni-based glycerol steam reforming catalyst, which differs from Example 1 in that 0.08 g of magnesium nitrate in step (3) is replaced by 0.04 g of magnesium nitrate.

[0043] Example 6: This example provides a method for preparing a Ni-based glycerol steam reforming catalyst, which differs from Example 1 in that 0.035 g of cerium nitrate in step (3) is replaced by 0.005 g of lanthanum nitrate.

[0044] Example 7: This example provides a method for preparing a Ni-based glycerol steam reforming catalyst, which differs from Example 1 in that 0.035 g of cerium nitrate in step (3) is replaced by 0.05 g of lanthanum nitrate.

[0045] Comparative Example 1: This comparative example provides a method for preparing a Ni-based glycerol steam reforming catalyst, which differs from Example 1 in that step (1) is: 12.0 g of nickel nitrate and 30.0 g of aluminum nitrate are weighed out to have a mass ratio of 1:2.5, dissolved in 200 mL of deionized water. 2.94 g of sucrose and 0.84 g of Na2HP04 are added, and stirring is carried out at 55°C in a water bath for 1 hour. Then 25% by mass ammonia water is slowly added dropwise, the pH is adjusted to 8.5, and stirring is continued for 2 hours to obtain a suspension. After standing for 12 hours, the suspension is suction filtered, the precipitate is repeatedly washed with deionized water until the pH of the filtrate approaches neutrality, and the obtained precursor is collected and dried in a vacuum drying oven at 105°C for 12 hours.

[0046] Comparative Example 2: This comparative example provides a method for preparing a Ni-based glycerol steam reforming catalyst, which differs from Example 1 in that step (2) is: the dried precursor is calcined at 400°C for 4 hours under an air atmosphere, and then calcined at 700°C for 3 hours under a nitrogen atmosphere at a temperature increase rate of 5°C / min.

[0047] Comparative Example 3: This comparative example provides a method for preparing a Ni-based glycerol steam reforming catalyst, which differs from Example 1 in that step (3) is: 10.0 g of the above NiAl204support is weighed out and added to 50 mL of deionized water, 0.10 g of calcium carbonate and 0.05 g of silver nitrate are added, magnetic stirring is carried out for 30 minutes, and the slurry is left to stand at room temperature for 6 hours. Then the slurry is transferred to a porcelain evaporating dish and placed in a 110°C oven to dry for 10 hours. The dried sample is placed in a muffle furnace and calcined at 500°C under an air atmosphere at a temperature increase rate of 5°C / min, and calcined at this temperature for 2 hours to obtain a double-additive modified NiAl204support.

[0048] Comparative Example 4: This comparative example provides a method for preparing a Ni-based glycerol steam reforming catalyst, which differs from Example 1 in that step (4) is: 0.2 g of nickel nitrate (Ni(NO3)2·6H2O) is weighed out and added to 10.0 g of the dual-promoted NiAl2O4 support in 50 mL of deionized water, magnetically stirred for 1 hour, ultrasonically treated for 30 minutes, and left to stand at 70°C for 8 hours. After standing, the mixture is transferred to a porcelain evaporating dish, dried at 110°C for 12 hours, and the dried material is placed in a muffle furnace and heated to 500°C at a heating rate of 5°C / min under an air atmosphere, and calcined at this temperature for 4 hours to obtain a NiAl2O4 catalyst precursor loaded with a Ni active component.

[0049] Comparative Example 5: This comparative example provides a method for preparing a Ni-based glycerol steam reforming catalyst, which differs from Example 1 in that in step (5), the reduction and calcination process is carried out using only a hydrogen / nitrogen mixed gas, and the temperature is held at 700°C for 2 hours without switching the atmosphere, and the final catalyst is obtained after cooling.

[0050] Comparative Example 6: This comparative example provides a method for preparing a Ni-based glycerol steam reforming catalyst, which differs from Example 1 in that step (2) is: the dried precursor is placed in a tube furnace and heated to 800°C at a heating rate of 5°C / min under a nitrogen atmosphere (N2 flow rate 100 mL / min), and calcined at this temperature for 8 hours to obtain a porous NiAl2O4 support.

[0051] Performance testing: The catalysts prepared in Examples 1-4 and Comparative Examples 1-6 are subjected to performance testing, and the testing method is as follows:

[0052] (1) Hydrogen yield

[0053] Testing method: The catalyst is loaded into a fixed-bed quartz reaction tube and subjected to continuous reaction with a water vapor and glycerol mixed gas (mass ratio 9:1, gas velocity 30 mL / min) at 400°C. The gas produced by the reaction is measured using a gas flow meter, and the hydrogen content is quantified by gas chromatography. After 2 hours of stable operation, 3 gas samples are taken, and their average value is calculated as the number of moles of hydrogen generated per hour per unit mass of catalyst (μmol / g·min).

[0054] (2) Carbon deposition resistance

[0055] Testing method: The catalyst is removed after the glycerol steam reforming reaction and placed in a muffle furnace, which is heated to 800°C at a rate of 10°C / min under an air atmosphere, and held at this temperature for 30 minutes. The mass change of the catalyst before and after the reaction and after calcination is recorded, and the carbon deposition is expressed as the weight loss of the catalyst (mg / g).

[0056] (3) High-temperature stability / sintering resistance

[0057] Test method: After reaction, catalyst sample was taken and the morphology and size of Ni particles were observed by transmission electron microscope (TEM). 100 particles were randomly measured to calculate the average particle size and standard deviation. The sintering degree was determined according to the Ni particle size. The increase of Ni particle size directly reflects the sintering phenomenon of metal particle migration and aggregation at high temperature. The larger the particle size, the worse the sintering resistance. The TEM image of the catalyst of Example 1 is shown in Figure 1 , the TEM image of the catalyst of Comparative Example 3 is shown in Figure 1 .

[0058] (4) Catalyst life (stability test)

[0059] Test method: The reaction method in (1) was used. The catalyst was continuously reacted for 400 hours under glycerol steam reforming conditions. The hydrogen production rate was recorded every 10 hours. The activity retention rate was defined as the yield after 400 hours / the initial yield x 100%.

[0060] The test results are shown in Table 1.

[0061] .

[0062] In addition, in order to further evaluate the stability and selectivity of the catalyst during long-term reaction, the change of glycerol conversion rate and selectivity of main products (CO, CO2, CH4) during the reaction of the catalyst of Example 1 was monitored, and the results are shown in Figure 2 . During the 400-hour operation of the catalyst in Example 1, the glycerol conversion rate was always maintained above 95%, and CO2 was the main product, and the selectivity of CO and CH4 was low and stable, indicating that the side reaction was suppressed, and metal sintering and carbon deposition did not occur significantly, further verifying the excellent life and stability of the catalyst.

[0063] The above results show that the Ni-based catalyst prepared by the present application exhibits excellent hydrogen production capacity, and maintains good metal dispersion, structural stability and excellent anti-coking performance under high temperature reaction conditions. In contrast, the performance of each comparative catalyst is significantly decreased, and the reasons are as follows: in Comparative Example 1, sucrose is used as a template instead of glucose, and due to the difference in carbon source structure, the gas release during pyrolysis of the precursor is uneven, the pore structure distribution is disordered, thereby affecting the dispersion of the active component and reducing the catalytic performance; in Comparative Example 2, the calcination conditions under nitrogen atmosphere are insufficient, and the spinel structure of NiAl2O4 is not fully formed, resulting in weakened anchoring ability of the carrier to Ni, and easy migration and agglomeration of metal particles; in Comparative Example 3, calcium carbonate and silver nitrate are used as substitutes for the additives, silver is easy to migrate and block the pores in a high temperature reduction environment, and its redox cycling ability is insufficient, which makes it difficult to effectively promote the reduction and stability of Ni, resulting in structure collapse and Ni particle overflow; in Comparative Example 4, the amount of Ni precursor is greatly reduced, resulting in a significant lack of effective active sites, and the conversion rate and stability are limited; in Comparative Example 5, the key CO-induced restructuring atmosphere is omitted, and this step plays an important role in optimizing the interface electronic structure and defect regulation, and after omission, the metal-support interface synergistic effect is weakened, and the overall performance is greatly reduced. In Comparative Example 6, one-step calcination is used, resulting in insufficient order and porosity of the carrier structure, poor Ni dispersion, easy agglomeration of metal particles, and deterioration of the overall performance.

[0064] The above is a preferred embodiment of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, several improvements and refinements can be made, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A method for preparing a Ni-based glycerol steam reforming catalyst, comprising the following steps: (1) dissolving nickel nitrate and aluminum nitrate in deionized water, adding a template and a buffer, stirring, then adding a precipitant, adjusting the pH to 7.5-9.0, continuing to stir to obtain a suspension, allowing it to stand, and filtering to obtain a precipitated precursor; (2) calcining the precursor in an air atmosphere and a nitrogen atmosphere in sequence to obtain a NiAl2O4 carrier; the calcination temperature in the air atmosphere is 300-400°C, and the calcination time is 1-3 hours; the calcination temperature in the nitrogen atmosphere is 700-900°C, and the calcination time is 4-10 hours; (3) adding a NiAl2O4 support, an alkaline earth metal additive, and a rare earth metal additive into deionized water, stirring, standing, drying the mixture, and calcining in an air atmosphere to obtain a dual-additive-modified NiAl2O4 support; (4) adding nickel nitrate and a double-adjuvant modified NiAl2O4 carrier into deionized water, stirring, standing, drying the mixture, and calcining in an air atmosphere to obtain a NiAl2O4 catalyst precursor loaded with Ni active components; (5) calcining the catalyst precursor obtained in step (4) in a nitrogen atmosphere and a hydrogen / nitrogen mixed atmosphere in sequence to obtain a Ni-based glycerol steam reforming catalyst; the calcination temperature in the nitrogen atmosphere is 350-450° C. and the time is 0.5-2 hours; the calcination temperature in the hydrogen / nitrogen mixed atmosphere is 600-750° C. and the time is 1-4 hours; at half the time point after the start of calcination in the hydrogen / nitrogen mixed atmosphere, switching the atmosphere to a nitrogen / carbon monoxide mixed gas and continuously passing it for 5-15 minutes, and then switching back to the original hydrogen / nitrogen mixed gas until the reduction calcination is completed; The volume ratio of hydrogen to nitrogen in the hydrogen / nitrogen mixed atmosphere is 1:9 to 1:4; the volume ratio of nitrogen to carbon monoxide in the nitrogen / carbon monoxide mixed gas is 4:1 to 1:

1.

2. The preparation method according to claim 1, wherein: In step (1), the mass ratio of nickel nitrate to aluminum nitrate is 1:2 to 1:3; the stirring time after adding the template and the buffer is 0.5 to 2 hours; the stirring time after adding the precipitant is 1 to 4 hours; and the standing time is 8 to 16 hours.

3. The preparation method according to claim 1, wherein: In step (1), the template agent is glucose or polyvinyl pyrrolidone, and the amount of the template agent added is 5% to 20% of the total mass of nickel nitrate and aluminum nitrate; the buffer agent is Na2HPO4, and the amount of the buffer agent added is 1% to 10% of the total mass of nickel nitrate and aluminum nitrate; and the precipitant is ammonia water, NaOH or Na2CO3.

4. The preparation method according to claim 1, wherein: The alkaline earth metal additive in step (3) is magnesium nitrate or calcium nitrate, and the addition amount is 0.1% to 1.0% of the mass of the NiAl2O4 carrier; the rare earth metal additive is cerium nitrate or lanthanum nitrate, and the addition amount is 0.05% to 0.5% of the mass of the NiAl2O4 carrier.

5. The preparation method according to claim 1, wherein: In step (3), the drying temperature is 100-120° C., and the drying time is 8-16 hours; the calcining temperature is 400-600° C., and the calcining time is 1-4 hours.

6. The preparation method according to claim 1, wherein: In step (4), the mass ratio of the nickel nitrate to the double-adjuvant modified NiAl2O4 carrier is 0.04:1 to 0.25:1; the drying temperature is 100 to 120°C, and the drying time is 8 to 16 hours; the calcination temperature is 400 to 600°C, and the calcination time is 3 to 6 hours.

7. A Ni-based glycerol steam reforming catalyst, prepared by the preparation method according to any one of claims 1 to 6.

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