Alkali-stable metalloporphyrin-hydroxyapatite covalent hybrid catalyst

Abstract

The invention relates to the technical field of chemical catalysts, in particular to an alkali-stable metalloporphyrin-hydroxyapatite covalent hybrid catalyst which comprises a hydroxyapatite carrier subjected to surface activation and metalloporphyrin covalently connected with the carrier through an amido bond. The HAP-A is prepared by etching hydroxyapatite with a salpeter solution with the mass fraction of 1%-10% at the temperature of 50-80 DEG C for 2-4 hours; the metalloporphyrin is a tetraphenyl porphyrin derivative with central coordination of Fe < 2 + >, Co < 2 + > or Ni < 2 + >, and the molecular formula of the metalloporphyrin is C44H28MN4. An amido bond (-CONN-) is formed through covalent hybridization, so that the electron transfer efficiency of metalloporphyrin and hydroxyapatite is enhanced, the hydrogen evolution overpotential and Tafel slope are remarkably reduced, and the reaction kinetics is accelerated; the HAP carrier is pretreated by nitric acid to form a stable skeleton, metalloporphyrin is wrapped by a covalent bond, dissolution or agglomeration of metalloporphyrin in an alkaline environment is avoided, and the current retention rate reaches 85% or above after continuous operation for 100 h at 10mA / cm < 2 >, which is far superior to that of a physical mixed system and a single component.

Description

Technical Field

[0001] This invention relates to the field of chemical catalyst technology, specifically to an alkali-stabilized metal porphyrin-hydroxyapatite covalent hybrid catalyst and its application in alkaline water electrolysis for hydrogen evolution. Background Technology

[0002] Among existing hydrogen evolution catalysts for water electrolysis, traditional iron-based catalysts suffer from insufficient activity at low temperatures, while ruthenium-based and other precious metal catalysts are too expensive for large-scale application. Non-precious metal catalysts, although lower in cost, are susceptible to corrosion under alkaline conditions, exhibit poor stability, and are often physically mixed with the support, resulting in low electron transfer efficiency, high hydrogen evolution overpotential, and slow reaction kinetics. Furthermore, without optimized support treatment, the limited number of surface active sites hinders the effective dispersion of active components, further restricting catalytic performance. Therefore, developing a low-cost, highly active, and highly stable alkali-stabilized hydrogen evolution catalyst has become an urgent technical challenge. Summary of the Invention

[0003] The primary objective of this invention is to provide an alkali-stabilized metal porphyrin-hydroxyapatite covalent hybrid catalyst and its application in alkaline water electrolysis for hydrogen evolution.

[0004] A further objective of this invention is to provide a base-stabilized metalporphyrin-hydroxyapatite covalent hybrid catalyst and its application in alkaline water electrolysis for hydrogen evolution, including the following:

[0005] A base-stabilized metalloporphyrin-hydroxyapatite covalent hybrid catalyst comprises a surface-activated hydroxyapatite support and a metalloporphyrin covalently linked to the support via an amide bond; the HAP-A is prepared by etching hydroxyapatite with a 1%-10% (w / w) nitric acid solution at 50-80°C for 2-4 hours; the metalloporphyrin is centrally coordinated with Fe. 2+ Co 2+ or Ni 2+ Tetraphenylporphyrin derivatives with the molecular formula C 44 H 28 MN4.

[0006] Preferably, the mass ratio of the metalloporphyrin to HAP-A is (0.2-5):5; the amide bond is formed by activation of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and the mass ratio of EDC to metalloporphyrin is (0.1-1):1.

[0007] A method for preparing the catalyst according to claim 1, comprising the following steps:

[0008] (1) HAP pretreatment: Add hydroxyapatite powder to a nitric acid solution with a mass fraction of 1%-10%, stir at 50-80℃ for 2-4 hours, wash and dry to obtain HAP-A;

[0009] (2) Preparation of metal porphyrin: Tetraphenylporphyrin (TPP) and chloride were added to N,N-dimethylformamide (DMF) at a mass ratio of (1-2):1. The mixture was refluxed at 100-160°C for 2-8 hours under nitrogen protection. The metal porphyrin was then obtained after post-treatment.

[0010] (3) Covalent hybridization: HAP-A is dispersed in DMF, ultrasonically treated for 20-50 min, metal porphyrin and EDC are added, and the reaction is stirred at 60-100℃ for 8-16 h under nitrogen protection. After washing and drying, the target catalyst is obtained.

[0011] Preferably, in step (1), the mass fraction of the nitric acid solution is 3%-8%, the stirring temperature is 60-70℃, and the stirring time is 2-3h.

[0012] Preferably, the reflux reaction temperature in step (2) is 120-140℃ and the reaction time is 4-6h; the molar ratio of the chloride to TPP is (1-1.5):1.

[0013] Preferably, in step (3), the ultrasonic treatment time is 30-40 min, the reaction temperature is 70-90℃, and the reaction time is 10-14 h.

[0014] An application of the catalyst in alkaline water electrolysis for hydrogen evolution involves using the catalyst as a cathode catalyst in alkaline solutions with a concentration of 1 mol / L or higher, at a speed of 0-200 mA / cm². 2 The hydrogen evolution reaction is achieved at a current density of ≤160mV@10mA / cm. 2 Tafel slope ≤ 100mV / dec, 10mA / cm 2 The current retention rate is ≥85% after 100 hours of continuous operation.

[0015] Preferably, the alkaline solution is KOH, NaOH, or LiOH solution; the electrolysis reaction is carried out in a fixed-bed reactor or a fluidized-bed reactor, equipped with heat recovery and hydrogen separation devices.

[0016] Compared with the prior art, the present invention has the following significant advantages:

[0017] 1. Covalent hybridization to form amide bonds (-CON-) enhances the electron transfer efficiency between metalloporphyrin and hydroxyapatite, significantly reducing the hydrogen evolution overpotential and Tafel slope, and accelerating reaction kinetics. The HAP support, after nitric acid pretreatment, forms a stable framework that covalently encapsulates the metalloporphyrin, preventing its dissolution or aggregation in alkaline environments. (10 mA / cm) 2 After 100 hours of continuous operation, the current retention rate reaches over 85%, which is far superior to physical mixture systems and single-component systems.

[0018] 2. It adopts non-precious metal porphyrin and inexpensive HAP support, resulting in low raw material costs; the preparation process is controllable and suitable for fixed-bed or fluidized-bed reactors, which can be applied to hydrogen production on a large scale, reducing cell pressure by 0.2-0.3V, and the performance degradation is less than 10% after 1000 hours of continuous operation; by optimizing the HAP pretreatment concentration, metal porphyrin coordination conditions and covalent hybridization parameters, the density of active sites and electron transfer efficiency can be precisely controlled, making it suitable for different alkaline electrolysis scenarios. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: Preparation of FeP-HAP-1, a covalently hybridized catalyst of iron porphyrin-hydroxyapatite.

[0021] (1) Pretreatment of hydroxyapatite: Weigh 10g of HAP powder. HAP has a hexagonal crystal system and is composed of Ca... 2+ PO4 3- and OH - The resulting layered structure was treated with 200 mL of 5% (w / w) dilute nitric acid (HNO3) and stirred at 60°C for 2 h. The dilute nitric acid etched the HAP surface, increasing the hydroxyl group density. The HAP was washed with deionized water until neutral and then vacuum dried at 80°C for 12 h to obtain surface-activated HAP, i.e., HAP-A.

[0022] (2) Preparation of iron porphyrin: 0.5 g of tetraphenylporphyrin and 0.3 g of ferrous chloride FeCl2·4H2O were added to 100 mL of N,N-dimethylformamide. The mixture was refluxed at 120 °C for 4 h under nitrogen protection. The reaction proceeded as follows: TPP reacted with Fe... 2+ Coordination forms an iron porphyrin. After cooling the reaction solution, 500 mL of deionized water is added, resulting in a purple precipitate. The precipitate is filtered, washed three times, and dried under vacuum at 60°C for 8 hours to obtain FeP. Tetraphenylporphyrin, or TPP, has the structural formula of a central porphyrin macrocycle with four phenyl groups substituting the β-position of the pyrrole ring, and the molecular formula is C1. 44 H 30 N4,LN,N-dimethylformamide, or DMF, has the molecular formula C3H7NO and the structure (CH3)2N-CHO. Iron porphyrin, or FeP, has the structural formula of Fe coordinated at the center of the porphyrin ring. 2+ The molecular formula is C 44 H 28 The structural formula of FeN4-tetraphenylporphyrin TPP is shown in Formula 1 below:

[0023]

[0024] Add 0.3g of ferrous chloride to 100mL of N,N-dimethylformamide (DMF) as shown in Formula 2:

[0025]

[0026] Under nitrogen protection, the reaction was carried out under reflux at 120°C for 4 hours, and TPP and Fe were reacted. 2+ Coordination forms iron porphyrin as shown in Equation 3:

[0027]

[0028] (3) Covalent hybridization reaction: 5g HAP-A was added to 100mL LDM and ultrasonically dispersed for 30min. 2g FeP and 0.5g 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC, molecular formula: C8H) were added. 17 N3·HCl (structure: (CH3)2N(CH2)3-N=C=N-CH2CH3·HCl) was used to react the HAP surface under nitrogen protection at 80℃ with stirring for 12 h. EDC activated the hydroxyl groups on the HAP surface to form amide bonds (-CON-) covalently with the carboxyl or amino groups of FeP. After centrifugation, the HAP was washed three times each with DMF and deionized water, and then dried under vacuum at 80℃ for 12 h to obtain FeP-HAP-1.

[0029] Add 0.5g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride EDC as follows:

[0030] Formula 4:

[0031]

[0032] Example 2: Preparation of Cobalt Porphyrin-Hydroxyapatite Covalent Hybrid Catalyst CoP-HAP-1

[0033] (1) Pretreatment of hydroxyapatite: Same as step 1 in Example 1, to obtain HAP-A.

[0034] (2) Preparation of cobalt porphyrin: 0.5 g TPP and 0.3 g cobalt chloride CoCl2·6H2O were added to 100 mL of LDMF and refluxed at 130 °C for 5 h under nitrogen protection to generate cobalt porphyrin, namely CoP, with the structural formula: Co coordinated at the center of the porphyrin ring. 2+ Molecular formula: C 44 H 28 CoN4. Subsequent processing is the same as step 2 in Example 1, yielding CoP.

[0035] (3) Covalent hybridization reaction: 5g HAP-A was added to 100ml LDM and ultrasonically dispersed for 30min. 1.5g CoP and 0.4g EDC were added, and the mixture was stirred at 70℃ for 10h under nitrogen protection. Subsequent treatment was the same as step 3 in Example 1 to obtain CoP-HAP-1.

[0036] Example 3: Preparation of NiP-HAP-1, a nickel porphyrin-hydroxyapatite covalent hybrid catalyst

[0037] (1) Pretreatment of hydroxyapatite: 10g HAP powder was added to 200mL of 8% HNO3 and stirred at 70℃ for 3h to enhance the surface etching effect. After washing and drying, HAP-A was obtained.

[0038] (2) Preparation of nickel porphyrin: 0.5g TPP and 0.3g nickel chloride NiCl2·6H2O were added to 100mL LDM and refluxed at 140℃ for 6h under nitrogen protection to generate nickel porphyrin, which is NiP. The structural formula is: Ni coordinated at the center of the porphyrin ring. 2+ Molecular formula: C 44 H 28 NiN4. Subsequent processing is the same as step 2 in Example 1, yielding NiP.

[0039] (3) Covalent hybridization reaction: 5g HAP-A was added to 100mL LDM and ultrasonically dispersed for 40min. 2.5g NiP and 0.6g EDC were added, and the mixture was stirred at 90℃ for 14h under nitrogen protection. Subsequent processing was the same as step 3 in Example 1 to obtain NiP-HAP-1.

[0040] The structural diagram of nickel porphyrin is shown in Equation 5 below:

[0041]

[0042] Example 4: Preparation of FeP-HAP-2 covalently hybridized catalyst with iron porphyrin-hydroxyapatite

[0043] (1) Pretreatment of hydroxyapatite: Same as step (1) in Example 1, to obtain HAP-A.

[0044] (2) Preparation of iron porphyrin: Same as step (2) in Example 1, to obtain FeP.

[0045] (3) Covalent hybridization reaction: 5g HAP-A was added to 100ml LDM and ultrasonically dispersed for 30min. 1g FeP and 0.5g EDC were added, and the mixture was stirred at 80℃ for 12h under nitrogen protection. Subsequent treatment was the same as step 3 in Example 1 to obtain FeP-HAP-2.

[0046] Example 5: Preparation of iron porphyrin-hydroxyapatite covalent hybrid catalyst (FeP-HAP-3)

[0047] (1) Pretreatment of hydroxyapatite: Same as step (1) in Example 1, to obtain HAP-A.

[0048] (2) Preparation of iron porphyrin: Same as step (2) in Example 1, to obtain FeP.

[0049] (3) Covalent hybridization reaction: 5g HAP-A was added to 100ml LDM and ultrasonically dispersed for 30min. (4) 2g FeP and 0.5g EDC were added and stirred at 60℃ for 12h under nitrogen protection. Subsequent treatment was the same as step (3) in Example 1 to obtain FeP-HAP-3.

[0050] (4) HAP pretreatment optimization: Dilute nitric acid etching can regulate the hydroxyl density on the HAP surface. 8% HNO3 treatment, as in Example 3, significantly increases active sites compared to 5%, but excessive etching may damage the structure, so the concentration and time need to be balanced.

[0051] (5) Optimization of metalloporphyrin synthesis: based on metal ions such as Fe 2+ Co 2+ Ni 2+ To improve coordination activity, the reaction temperature was adjusted to 120-140℃ and the reaction time was 4-6 hours to ensure complete coordination between the metal ions and TPP, thereby increasing the purity of porphyrin.

[0052] (6) Covalent hybridization optimization:

[0053] The amount of EDC used should be matched with the ratio of metalloporphyrin. For example, in Example 1, the EDC:FeP ratio is 0.25:1 to avoid excess and side reactions.

[0054] Ultrasonic dispersion (30-40 min) ensures uniform dispersion of HAP-A and improves the efficiency of covalent bond formation.

[0055] The reaction temperature (60-90℃) affects the reaction rate, and 80℃ is the optimal reaction temperature for FeP and HAP (Example 1 compared with Example 5).

[0056] Comparative Example 1: Simple iron porphyrin catalyst FeP

[0057] The FeP prepared in step 2 of Example 1 was used directly, without the HAP carrier.

[0058] Comparative Example 2: Pure hydroxyapatite catalyst (HAP)

[0059] Raw HAP powder that has not been treated with nitric acid.

[0060] Comparative Example 3: FeP / HAP physical mixed catalyst of iron porphyrin and hydroxyapatite

[0061] FeP from Example 1 was physically ground and mixed with the original HAP at a mass ratio of 2:5, without any covalent bond interaction.

[0062] Performance testing

[0063] The results of the test using a three-electrode system in a 1 mol / L KOH solution are as follows:

[0064]

[0065]

[0066] Analysis: The catalyst of this invention enhances electron transfer efficiency and reduces overpotential and Tafel slope due to covalent bonding; the HAP support protects the metal porphyrin from alkali corrosion, and its stability is significantly better than that of physically mixed and single-component catalysts.

[0067] When the catalyst of this invention is used as a cathode catalyst in an alkaline electrolyzer, the cell voltage can be reduced by 0.2-0.3V. Compared with traditional non-precious metal catalysts, the performance decay is less than 10% after 1000 hours of continuous operation, which significantly reduces the cost of hydrogen production and is suitable for large-scale hydrogen energy production.

[0068] The working principle of this base-stabilized metalporphyrin-hydroxyapatite covalent hybrid catalyst can be explained from the aspects of structural design, activity mechanism, and performance enhancement mechanism:

[0069] (1) The catalyst uses hydroxyapatite as a support and is covalently bonded to metal porphyrin. After pretreatment with dilute nitric acid, the surface hydroxyl density of HAP increases. Under the activation of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, it forms amide bonds (-CON-) with the carboxyl or amino groups of metal porphyrin, achieving a stable covalent connection between the two and avoiding the problem of poor interfacial contact during physical mixing.

[0070] (2) HAP is a hexagonal layered structure. After etching, the surface defects increase. It serves as a stable framework to disperse metal porphyrin and participates in electron transfer through hydroxyl sites. The porphyrin macrocycle of metal porphyrin has a conjugated structure, and the central metal ion is the catalytic active center. It activates water molecules through coordination and promotes the hydrogen evolution reaction.

[0071] (3) Under alkaline conditions, the central metal ion of the metalloporphyrin acts as an active site, adsorbing and activating water molecules, which then accept electrons to generate hydrogen atoms, which in turn combine to form H2. Covalent bonding enhances the electron transfer efficiency between HAP and metalloporphyrin, lowering the reaction energy barrier, resulting in a low hydrogen evolution overpotential (e.g., FeP-HAP-1 at 10 mA / cm). 2 The small Tafel slope (85 mV / dec) and the low 120 mV (lower) accelerate the reaction kinetics.

[0072] (4) The coordination activity and electronic structure of different metal ions lead to performance differences: Fe 2+ Fe has moderate coordination ability and the best electronic matching with porphyrin macrocycles, so Fe-based catalysts have better activity than Co-based and Ni-based catalysts.

[0073] (5) The HAP support exhibits excellent alkali stability, covalently encapsulating the metalloporphyrin to prevent its dissolution or aggregation in strong alkalis; simultaneously, the covalent bond interaction is stronger than physical adsorption, preventing the active component from detaching, thus ensuring the catalyst operates at 10 mA / cm². 2 After 100 hours of continuous operation, the current retention rate still reaches 85%-92%, which is much higher than that of physical mixture systems and single components.

[0074] (6) Dilute nitric acid etching regulates the hydroxyl density on the HAP surface, balancing the number of active sites and the stability of the carrier structure.

[0075] (7) Ultrasonic dispersion and reaction temperature optimization to ensure uniform HAP dispersion and efficient covalent bond formation;

[0076] (8) Match the amount of EDC with the ratio of metal porphyrin to avoid side reactions and ensure bonding efficiency.

[0077] In summary, this catalyst achieves high activity and high stability in alkaline water electrolysis for hydrogen production through a synergistic mechanism of "covalent hybridization enhancing electron transfer - support stabilizing active centers - structural optimization improving reaction kinetics", significantly reducing hydrogen production energy consumption.

[0078] Compared with the comparative example, the embodiments of the present invention have significant advantages in catalytic performance, structural stability, and application value, as detailed below:

[0079] The hydrogen evolution overpotentials of the catalysts in the examples were all much lower than those in the comparative examples:

[0080] (1) The overpotential of the optimal embodiment FeP-HAP-1 is 120mV, which is only 43% of that of pure iron porphyrin, 34% of that of pure hydroxyapatite, and 55% of that of a physically mixed catalyst. The lower the overpotential, the smaller the additional voltage required for the catalytic reaction, and the easier it is to start the hydrogen evolution reaction with low energy consumption.

[0081] (2) The Tafel slope (85-98 mV / dec) of the example was significantly lower than that of the comparative example:

[0082] The Tafel slope of FeP-HAP-1 was 85 mV / dec, which was only 53% of that of Comparative Example 1, 43% of that of Comparative Example 2, and 65% of that of Comparative Example 3. The smaller the Tafel slope, the faster the hydrogen evolution reaction kinetics, the higher the catalytic efficiency, and the more hydrogen can be generated in the same amount of time.

[0083] (3) The catalysts in the examples showed far greater stability than the comparative examples in an alkaline environment: NiP-HAP-1, which had the worst stability in the examples, still reached 85%, while Comparative Example 1 was only 45%, Comparative Example 2 was only 30%, and Comparative Example 3 was only 60%.

[0084] The reason is that: in the examples, the metal porphyrin is tightly linked to the pretreated HAP through covalent bonds, and the HAP carrier forms a stable framework to encapsulate the metal porphyrin, preventing it from dissolving or agglomerating in strong alkali; while in Comparative Example 1, there is no carrier protection and it is easily corroded; in Comparative Example 2, the untreated HAP has few active sites and a loose structure; and in Comparative Example 3, there is no chemical bond interaction due to physical mixing, and the active components are easily detached.

[0085] (4) The covalent hybrid structure of the embodiment solves the interface contact defects of the comparative example:

[0086] In Comparative Example 3, the metalloporphyrin and HAP interface were not tightly connected due to mechanical grinding alone, resulting in high resistance to electron transfer. In contrast, the example formed amide bonds through EDC activation, achieving a molecular-level covalent connection of "metalloporphyrin-HAP", which made the electron transfer path smoother and significantly reduced charge transfer resistance.

[0087] (5) After nitric acid pretreatment, the surface hydroxyl density of HAP increases, which provides more binding sites for covalent bonds and allows HAP to participate in electron transfer. In contrast, the original HAP in Comparative Example 2 has fewer surface defects and cannot effectively assist electron transfer.

[0088] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only to the claims and their full scope and equivalents.

Claims

1. A base-stabilized metalporphyrin-hydroxyapatite covalent hybrid catalyst, characterized in that, The HAP-A comprises a surface-activated hydroxyapatite support and a metalloporphyrin covalently linked to the support via amide bonds; the HAP-A is prepared by etching hydroxyapatite with a 1%-10% nitric acid solution at 50-80°C for 2-4 hours; the metalloporphyrin is centrally coordinated with Fe. 2+ Co 2+ or Ni 2+ Tetraphenylporphyrin derivatives with the molecular formula C 44 H 28 MN4.

2. The catalyst according to claim 1, characterized in that, The mass ratio of the metalloporphyrin to HAP-A is (0.2-5):5; the amide bond is formed by activation of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and the mass ratio of EDC to metalloporphyrin is (0.1-1):

1.

3. A method for preparing the catalyst according to claim 1, characterized in that, Includes the following steps: (1) HAP pretreatment: Add hydroxyapatite powder to a nitric acid solution with a mass fraction of 1%-10%, stir at 50-80℃ for 2-4 hours, wash and dry to obtain HAP-A; (2) Preparation of metal porphyrin: Tetraphenylporphyrin (TPP) and chloride were added to N,N-dimethylformamide (DMF) at a mass ratio of (1-2):

1. The mixture was refluxed at 100-160°C for 2-8 hours under nitrogen protection. The metal porphyrin was then obtained after post-treatment. (3) Covalent hybridization: HAP-A is dispersed in DMF, ultrasonically treated for 20-50 min, metal porphyrin and EDC are added, and the reaction is stirred at 60-100℃ for 8-16 h under nitrogen protection. After washing and drying, the target catalyst is obtained.

4. The method according to claim 3, characterized in that, In step (1), the mass fraction of the nitric acid solution is 3%-8%, the stirring temperature is 60-70℃, and the stirring time is 2-3h.

5. The method according to claim 3, characterized in that, In step (2), the reflux reaction temperature is 120-140℃ and the reaction time is 4-6h; the molar ratio of the chloride to TPP is (1-1.5):

1.

6. The method according to claim 3, characterized in that, In step (3), the ultrasonic treatment time is 30-40 min, the reaction temperature is 70-90℃, and the reaction time is 10-14 h.

7. The application of the catalyst according to claim 1 in alkaline water electrolysis for hydrogen evolution, characterized in that, The catalyst was used as a cathode catalyst in alkaline solutions with concentrations of 1 mol / L and above, at a speed of 0-200 mA / cm². 2 The hydrogen evolution reaction is achieved at a current density of ≤160mV@10mA / cm. 2 Tafel slope ≤ 100mV / dec, 10mA / cm 2 The current retention rate is ≥85% after 100 hours of continuous operation.

8. The application according to claim 7, characterized in that, The alkaline solution is KOH, NaOH, or LiOH solution; the electrolysis reaction is carried out in a fixed-bed reactor or a fluidized-bed reactor, equipped with heat recovery and hydrogen separation devices.

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