Thermally induced self-assembly mineral-based chemical hydrogen production materials, methods of making and applications thereof

Abstract

The application provides a heat-induced self-assembly mineral-based chemical hydrogen production material and a preparation method and application thereof, and belongs to the technical field of chemical hydrogen production, and comprises the following steps: mixing fayalite particles and an aqueous solution of reducible metal salt to construct a reaction system; and applying a mild heating condition to the reaction system, so that metal ions in the reducible metal salt are in-situ reduced and self-assembled to grow on the surface of the mineral particles, and a core-shell structure composite particle composed of a mineral particle core and a metal element shell is formed; wherein under the heating condition, the divalent iron ions in the core of the composite particle are oxidized and release electrons, the electrons are conducted to the shell through solid phase, and hydrogen gas is produced by catalyzing water molecules on the surface of the shell; the whole process does not need external power supply. In the application, the hydrogen production rate of the in-situ formed core-shell structure is improved by orders of magnitude compared with a traditional reaction, and the reaction temperature is greatly reduced, so that a new way of chemical hydrogen production with high efficiency and without external power input is provided.

Description

Technical Field

[0001] This invention belongs to the field of inorganic chemical hydrogen production technology, specifically relating to a core-shell structured chemical hydrogen production material that forms a metal shell on the surface of iron olivine particles through thermally induced self-assembly, its preparation method, and its application in hydrogen production. Background Technology

[0002] Current hydrogen production technologies are mainly divided into two categories: thermochemical hydrogen production and electro / photochemical hydrogen production. Thermochemical hydrogen production (represented by natural gas reforming and water-rock reaction) is usually carried out under high temperature (>700℃) or high temperature and high pressure (>300℃, >10 MPa) conditions, which consumes a lot of energy, has a low reaction rate, and requires demanding equipment. Electrochemical hydrogen production (represented by water electrolysis) relies on an external power source to drive hydrogen evolution at the cathode, requiring complex electrolyzers, membranes, and electrode systems, and often uses precious metal catalysts, resulting in high cost and limited stability. Photocatalytic hydrogen production relies on light energy input and photocatalytic materials, and its efficiency is limited by light conditions.

[0003] Traditional water-rock reaction hydrogen production utilizes the reaction of natural minerals with water to produce hydrogen, but it requires extremely high temperatures and pressures, making it difficult to implement practically. To improve reaction efficiency, some studies have attempted to add metal salts or metal particles to the system, but simple physical mixing cannot form stable electron transfer channels, resulting in limited catalytic effects, and still requires relatively high temperatures or external energy.

[0004] Currently, there are no publicly available reports on a method for in-situ growth of a metallic elemental shell on the surface of fir olivine particles via thermally induced self-assembly, utilizing Fe... 2+ This technology utilizes electrons released from chemical oxidation, which are conducted through a solid phase to a metal shell to catalyze the reduction of water to produce hydrogen. It differs fundamentally from water electrolysis, which relies on external electrical energy. This technology requires no external power source, no diaphragm, and no anode or cathode; it only requires gentle heating to achieve high-performance hydrogen production. Summary of the Invention

[0005] To address the shortcomings of the prior art, the technical problem to be solved by the embodiments of the present invention is to provide thermally induced self-assembled mineral-based chemical hydrogen production materials, their preparation methods and applications.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A method for preparing a thermally induced self-assembled mineral-based chemical hydrogen-generating material includes the following steps:

[0008] A reaction system is constructed by mixing fir olivine particles with an aqueous solution of a reducible metal salt. The reaction system is then heated, causing the metal ions in the reducible metal salt to be reduced in situ on the surface of the fir olivine particles and to self-assemble and grow, forming a core-shell composite particle consisting of a fir olivine particle core and a metal elemental shell. Under heating conditions, the ferrous ions in the core of the composite particle are oxidized and release electrons. These electrons are conducted to the shell through the solid phase, catalyzing the reduction of water molecules on the shell surface to produce hydrogen gas. The entire process requires no external power supply.

[0009] As a further embodiment of the present invention, the reducible metal salt is at least one of nickel salt, cobalt salt, iron salt, copper salt or zinc salt.

[0010] As a further embodiment of the present invention, the heating temperature is 120-300℃.

[0011] As a further embodiment of the present invention, the heating temperature is 180°C.

[0012] As a further embodiment of the present invention, the particle size of the iron olivine particles is 50-400 mesh.

[0013] As a further embodiment of the present invention, the particle size of the iron olivine particles is 200-300 mesh.

[0014] This invention also provides a thermally induced self-assembled mineral-based chemical hydrogen production material, with fir olivine particles as the core and a metallic element as the shell. The metallic element shell is coated on the surface of the fir olivine particles. Under heating conditions, a single composite particle can spontaneously catalyze the reduction of water to produce hydrogen. The metallic element shell is a continuous or diffuse coating layer and is an integrated structure with the fir olivine core that is self-assembled in situ.

[0015] This invention also provides the application of thermally induced self-assembled mineral-based chemical hydrogen-producing materials in hydrogen evolution reactions.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] Eliminating external power input: This invention does not rely on the complex electrochemical system such as external power supply, diaphragm, and anode / cathode required for hydrogen production by water electrolysis. It only requires gentle heating to trigger the Fe in iron olivine. 2+ The chemical oxidation and electron release of the electrons are conducted through the solid phase to the metal shell, directly catalyzing the reduction of water to produce hydrogen.

[0018] Mild reaction conditions: The core reaction temperature is mild, far lower than that of traditional water-rock reaction and natural gas reforming (>700℃), making it energy-efficient and safe.

[0019] Significantly improved hydrogen production efficiency: Compared with pure water-rock reaction or systems with simple addition of metal salts under the same temperature and pressure, the metal shell formed by in-situ self-assembly forms a tight solid-phase contact with the iron olivine core, resulting in a shorter electron transport path and a built-in electric field that promotes the directional migration of electrons (from the olivine core directly to the metal shell), thus increasing the hydrogen production rate by orders of magnitude.

[0020] The material is reusable: the metal shell remains intact after the reaction, and hydrogen can be produced again simply by adding water. Attached Figure Description

[0021] Figure 1 This is a TEM image of pure iron olivine (unreacted).

[0022] Figure 2 Elemental analysis diagram of pure iron olivine (unreacted).

[0023] Figure 3 This is a comparison chart of hydrogen production in Example 1.

[0024] Figure 4 The image shows the solid composition XRD patterns before and after the reaction in Example 1.

[0025] Figure 5 The following are XPS images of the solid composition before and after the reaction in Example 1: (a) is the Ni 2p characterization of pure nickel nitrate before the reaction; (b) is the Ni 2p characterization of the solid sample after the reaction; (c) is the Fe 2p characterization of pure fir olivine before the reaction; and (d) is the Fe 2p characterization of the solid sample after the reaction.

[0026] Figure 6 Figures (a) to (e) are TEM images of the solid components after the reaction in Example 1; Figure (f) is an elemental distribution diagram of the solid components after the reaction in Example 1; and Figure (g) is a chromatographic peak diagram of the gas components collected after the reaction in Example 1.

[0027] Figure 7 This is a schematic diagram of a core-shell structure.

[0028] Figure 8 This is a comparison chart of hydrogen production in Example 2.

[0029] Figure 9 This is a comparison chart of hydrogen production in Example 3.

[0030] Figure 10 This is a comparison chart of hydrogen production in Example 4.

[0031] Figure 11 This is a comparison chart of hydrogen production in Example 5.

[0032] Figure 12 This is a comparison chart of hydrogen production in Example 6.

[0033] Figure 13 This is a comparison chart of hydrogen production in Example 7.

[0034] Figure 14 This is a comparison chart of hydrogen production in Example 8.

[0035] Figure 15 This is a comparison chart of hydrogen production in Example 9. Detailed Implementation

[0036] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0037] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0038] In Example 1, 5g of fir olivine pulverized to 100-200 mesh was added to a 1L autoclave along with 50mL of a 0.3mol / L NiCl2 solution, with a liquid-to-solid ratio of 10:1. The reaction was carried out at 180℃ and 2MPa for 12h, allowing the metal ions in the reducible metal salt to be reduced in situ on the surface of the fir olivine particles and self-assembled to form a metal elemental shell, resulting in core-shell composite particles with fir olivine particles as the core and metal elemental shells as the outer shell. After the reaction, the gas outlet of the high-temperature, high-pressure reactor was in situ connected to a chromatograph for gas composition and content analysis; solid samples were also collected for component characterization.

[0039] The composite particles, acting as independent chemical hydrogen-producing active units, exhibit Fe cores within their cores under mild heating conditions. 2+ Ni undergoes an oxidation reaction that releases electrons. 2+ The material accepts electrons and undergoes a reduction reaction to become a shell of metallic nickel, which adheres to the fritillary olivine and catalyzes the reduction of water molecules to produce hydrogen. The entire process requires no external power source, no diaphragm, and no anode or cathode; it is driven solely by the chemical energy of the material itself. Furthermore, the material is reusable; after replenishing with deionized water, hydrogen production can be restarted at 20-1000°C.

[0040] Before the reaction, such as Figure 1 As shown, TEM characterization revealed that the unreacted pure iron olivine lattice striations exhibited (112) crystal planes of (Fe,Mg)₂SiO₄, (040) crystal planes of SiO₂, and (311) crystal planes of Si; Figure 2As shown, EDS characterization of unreacted pure fir olivine revealed the presence of Fe, Mg, Si, and O elements, further confirming that the unreacted solid sample was indeed pure fir olivine. Figure 3 As shown, after adding 0.3 mol / L NiCl2 solution and reacting for 12 hours, 170 × 10⁻⁶ ppm of NiCl₂ solution is generated. -6 The average hydrogen production rate of this batch of H2 was 25 times that of the pure water-rock reaction without nickel salt under the same conditions, and also 5 times that of the system of directly mixing equal amounts of pre-prepared nickel powder and fir olivine (simple physical mixtures of fir olivine and metal salt solutions are named "fir olivine + metal salt", and samples with a core-shell structure formed by fir olivine and metal salt solutions are named "fir olivine@metal salt" or "olivine@metal salt", and this naming method will be used in the following text). The solid products after the reaction were analyzed by XRD ( Figure 4 XPS Figure 5 TEM Figure 6 Characterization revealed that the ferrous iron was oxidized to ferric iron, and zero-valent nickel was present, confirming the formation of a metallic nickel coating on the surface of the fir olivine (e.g., Figure 7 As shown in the figure, the efficient hydrogen production effect of the "in-situ self-assembled core-shell structure" was verified.

[0041] Example 2, with other conditions fixed as in Example 1, 5g of fir olivine was crushed and sieved to obtain five different mesh sizes of fir olivine particles: 50-80 mesh, 80-100 mesh, 100-200 mesh, 200-300 mesh, and 300-400 mesh. Figure 8As shown, 50-80 mesh fir olivine particles have a large particle size and the smallest specific surface area. Metallic nickel ions can only be reduced to form a shell on the outer surface of the particles. Although the shell layer is thick, the coverage area is small, and there are no active sites inside the particles, resulting in low utilization of the core-shell structure. The average hydrogen production rate is 10 times that of the pure water-rock reaction under the same conditions. Due to its small specific surface area and few active sites, the hydrogen production efficiency is the lowest. 80-100 mesh, 100-200 mesh, and 200-300 mesh fir olivine particles have moderate particle sizes, with the specific surface area increasing sequentially. The particle surface is rich in pores, allowing metallic nickel ions to fully contact and uniformly reduce and self-assemble, forming a continuous, dense, and fully covered metallic nickel shell layer. The core-shell structure formation effect is excellent. Among them, 200-300 mesh particles have the best matching degree between specific surface area and surface porosity, and the best shell uniformity. The average hydrogen production rate of 80-100 mesh fir olivine is 22 times that of the pure water-rock reaction under the same conditions. Increased surface area leads to more active sites, significantly improving hydrogen production performance. The average hydrogen production rate of 100-200 mesh fir olivine is 25 times that of pure water-rock reaction under the same conditions. It achieves optimal matching of specific surface area, surface porosity, and shell formation effect, resulting in the highest electron transfer efficiency and utilization rate of hydrogen evolution catalytic sites, making it the optimal mesh size. The average hydrogen production rate of 200-300 mesh fir olivine is 23 times that of pure water-rock reaction under the same conditions, with near-optimal hydrogen production performance. Only slight agglomeration due to the slightly finer particle size results in a small number of unutilized active sites. For 300-400 mesh fir olivine particles, the particle size is too small, resulting in an excessively large specific surface area and a tendency for agglomeration. The average hydrogen production rate is 16 times that of pure water-rock reaction under the same conditions, indicating a significant decrease in hydrogen production performance. In this invention, the suitable mesh size range for fir olivine is 80-300 mesh. Within this range, the fir olivine particles have a moderate specific surface area and good dispersibility, which can achieve complete and uniform coating of the metallic nickel shell and fully utilize the hydrogen production efficiency. The optimal mesh size is 100-200 mesh. At this mesh size, the matching degree between the particle specific surface area, porosity and shell formation effect is optimal, and the hydrogen production rate and active site utilization rate both reach their peak values. If the mesh size is too small, the specific surface area will be insufficient, and if the mesh size is too large, it will easily agglomerate. Both of these will significantly affect the core-shell structure formation and hydrogen production performance.

[0042] Example 3: Other conditions were kept the same as in Example 1, except that the amount of iron olivine added was varied to adjust the liquid-solid ratio of iron olivine to the total aqueous solution. Liquid-solid mass ratios were set as follows: 5 (50 mL aqueous solution): 1 (10 g iron olivine), 8 (50 mL aqueous solution): 1 (6.25 g iron olivine), 10 (50 mL aqueous solution): 1 (5 g iron olivine), 12 (50 mL aqueous solution): 1 (4.2 g iron olivine), and 15 (50 mL aqueous solution): 1 (3.3 g iron olivine). The active ingredient (Fe) of iron olivine was calculated. 2+ The dissolution and conversion efficiency of olivine were investigated to verify the effect of the liquid-solid ratio of fir olivine to the total aqueous solution on hydrogen production performance. Figure 9As shown, when the liquid-to-solid ratio is 5:1, the total amount of aqueous solution is small, the fir olivine particles slightly agglomerate, and Fe... 2+ The dissolution rate is slow, with an average hydrogen production of 85% of the baseline group. (Fe) 2+ Conversion efficiency 82%; at a liquid-to-solid ratio of 8:1, average hydrogen production is 96% of the baseline group, Fe 2+ The conversion efficiency was 95%, the particles were well dispersed, and the electron transfer and shell formation efficiencies were close to optimal; at a liquid-to-solid ratio of 10:1, the hydrogen production was 170 × 10⁻⁶. -6 g (reference peak value), Fe 2+ Conversion efficiency 98%, Fe 2+ The efficiencies of dissolution, electron transfer, and nickel-shell catalytic hydrogen evolution were all optimally matched; at a liquid-to-solid ratio of 12:1, the average hydrogen production was 97% of the baseline group, and Fe... 2+ A conversion efficiency of 96% indicates that dilution with a small amount of pure water has no significant negative impact, and particle dispersibility is further improved; a liquid-to-solid ratio of 15:1 indicates a relatively high total aqueous solution volume, and Fe... 2+ After dissolution, excessive dilution slows down electron transfer, reduces the rate of nickel ion reduction to a shell, and results in an average hydrogen production of 90% of the baseline group. 2+ The conversion efficiency is 90%. In summary, when the liquid-to-solid ratio is 8:1, 10:1, or 12:1, the total aqueous solution volume is moderate, the fir olivine particles are completely dispersed, and the Fe... 2+ Uniform dissolution provides a stable electron source for nickel ion reduction, leading to uniform nucleation and directional growth of nickel ions on the fir olivine surface, forming a continuous and dense metallic nickel shell. The integrity of the core-shell structure and the interfacial bonding force are both optimal. This embodiment verifies the effect of the fir olivine liquid-to-solid ratio on the hydrogen production system, confirming that 5:1 to 15:1 is the suitable range for the liquid-to-solid ratio of the fir olivine pure aqueous solution. Within this range, it is not necessary to change the metal salt concentration; the liquid-to-solid ratio can be flexibly adjusted simply by changing the mass of the fir olivine, and the complete formation of the core-shell structure and efficient hydrogen production can be achieved in all cases.

[0043] Example 4, with other conditions fixed the same as in Example 1, experiments were conducted at 120℃, 150℃, 180℃, 240℃, and 300℃ respectively. Figure 10 As shown, the hydrogen production rate initially increases and then decreases with increasing temperature, reaching its optimum at 180℃. Crucially, even at a lower temperature of 120℃, the hydrogen production rate is significantly measurable, while conventional water-rock reactions almost stagnate at this temperature. This demonstrates that this chemical hydrogen production system effectively improves reaction performance.

[0044] Example 5: With other conditions fixed as in Example 1, hydrogen production was collected after 1, 5, 12, 24, and 36 hours of reaction. Figure 11As shown, the hydrogen production rate initially increases and then decreases with reaction time, reaching its optimum at 12 h. Crucially, even in the initial 1 h of reaction, the hydrogen production rate is significantly measurable. At 1 h, only a small number of nickel nuclei form on the fir olivine surface, without a complete shell, and the hydrogen production is 31 × 10⁻⁶. -6 g; After 5 hours of reaction, the shell initially formed, and the hydrogen production was 121 × 10 g. -6 g; after 12 hours of reaction, the shell was fully formed, and the hydrogen production reached 170 × 10 g. -6 g; When the reaction time is 24-36h, the shell thickness increases slightly and the increase in hydrogen production tends to level off; This confirms that the optimal reaction time of this invention is 5-12h, during which the core-shell structure can be fully formed and achieve efficient hydrogen production.

[0045] Example 6: With other conditions fixed the same as in Example 1, the concentration of the NiCl2 solution was modified to 0.1, 0.2, 0.3, 0.5, and 1 mol / L, and the corresponding hydrogen production was collected. Figure 12 As shown, the hydrogen production rate initially increases and then decreases with increasing NiCl2 solution concentration, reaching its optimum at a NiCl2 solution concentration of 0.3 mol / L. Crucially, even at a lower concentration of 0.1 mol / L, the hydrogen production rate is significantly measurable, verifying the feasibility of hydrogen production using low-concentration nickel salt systems.

[0046] Example 7: With other conditions fixed as in Example 1, 5g of fir olivine was mixed with 50mL of 0.3mol / L aqueous solutions of nickel chloride (NiCl2), nickel sulfate (NiSO4), and nickel nitrate (Ni(NO3)2), respectively. All mixtures were added to a 1L autoclave, and parallel experiments were conducted under the same reaction conditions (180℃, 2MPa, 12h). All other operations remained consistent. Figure 13As shown, SEM characterization of the three nickel salt systems confirmed the formation of a metallic nickel coating layer on the surface of the fir olivine, successfully constructing a core-shell type chemical hydrogen production material of "fir olivine@metallic nickel". This indicates that the in-situ self-assembly mechanism of the present invention is applicable to common nickel salts. However, due to differences in ionic properties, the compactness of the core-shell structure and the hydrogen production performance vary among different nickel salts. Among them, the nickel shell layer formed by the NiCl2 system is continuous and uniform, with the strongest interfacial bonding force. The average hydrogen production rate is 25 times that of the pure water-rock reaction under the same conditions and 5 times that of the system of directly mixing equal amounts of pre-prepared nickel powder and fir olivine, showing the best performance. The nickel shell layer formed by the NiSO4 system is dispersed, with a hydrogen production rate 22 times that of the pure water-rock reaction under the same conditions and 4.2 times that of the system of directly mixing equal amounts of pre-prepared nickel powder and fir olivine. The nickel shell layer formed by the Ni(NO3)2 system has a small amount of porosity, with a hydrogen production rate 20 times that of the pure water-rock reaction under the same conditions and 4 times that of the system of directly mixing equal amounts of pre-prepared nickel powder and fir olivine. This experiment demonstrates that nickel salts have a greater advantage in in-situ shell formation and hydrogen production performance in this invention. It also clarifies the compatibility of this invention with various nickel salts, providing experimental basis for the selection of nickel salts under different costs and process requirements.

[0047] Example 8: With other conditions fixed as in Example 1, only the metal salts were changed to soluble nickel, cobalt, iron, copper, and zinc salts to verify the applicability of different metal salts. For example... Figure 14 As shown, all five soluble metal salt systems can spontaneously produce hydrogen through the formation of core-shell chemical hydrogen-producing materials, and their hydrogen production rates are all significantly higher than those of pure water-rock reactions under the same conditions. Specifically, the improvement in hydrogen production performance is as follows: the nickel salt system has an average hydrogen production rate 25 times that of the pure water-rock reaction, exhibiting the best hydrogen production performance; the cobalt salt system has an average hydrogen production rate 23 times that of the pure water-rock reaction, second only to the nickel salt system; the iron salt system has an average hydrogen production rate 18 times that of the pure water-rock reaction, demonstrating good hydrogen production performance; the copper salt system has an average hydrogen production rate 15 times that of the pure water-rock reaction, achieving effective hydrogen production; and the zinc salt system has an average hydrogen production rate 12 times that of the pure water-rock reaction, with a stable and measurable hydrogen production rate. This embodiment illustrates that the preparation method of the present invention is applicable to soluble nickel, cobalt, iron, copper, and zinc salts. Among them, nickel and cobalt salts are preferred metal salts with better hydrogen production performance. Iron, copper, and zinc salts can be flexibly selected according to actual process costs and hydrogen production requirements. This experiment provides direct experimental evidence for the broad selection of metal salts and also verifies the technical feasibility of extending the scope of protection of the present invention to the all-metal salt system.

[0048] Example 9: With other conditions fixed as in Example 1, the solid material with a nickel coating after the reaction in Example 1 was recovered. No new nickel salt was added; only fresh water was replenished, and the material was heated again under the same mild conditions (180°C). Figure 15As shown, the system can generate hydrogen again at a high initial rate. This indicates that the core-shell structure formed in the first reaction is a stable and reusable "prefabricated electrode," and subsequent reactions only consume the Fe from the fir olivine core. 2+ This further highlights the advanced nature of this method in material design.

[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0050] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a thermally induced self-assembled mineral-based chemical hydrogen-generating material, characterized in that, Includes the following steps: A reaction system was constructed by mixing fir olivine particles with an aqueous solution of a reducible metal salt. The reaction system is heated so that the metal ions in the reducible metal salt are reduced in situ on the surface of the iron olivine particles and self-assembled and grown to form core-shell composite particles composed of the core of the iron olivine particles and the outer shell of the metal element. Under heating conditions, the ferrous ions in the core of the composite particles are oxidized and release electrons. The electrons are conducted to the outer shell through the solid phase and catalyze the reduction of water molecules on the surface of the outer shell to produce hydrogen gas. The entire process does not require an external power source.

2. The method for preparing a thermally induced self-assembled mineral-based chemical hydrogen-generating material according to claim 1, characterized in that, The reducible metal salt is at least one of nickel, cobalt, iron, copper, or zinc salts.

3. The method for preparing a thermally induced self-assembled mineral-based chemical hydrogen-generating material according to claim 1, characterized in that, The heating temperature is 120-300℃.

4. The method for preparing a thermally induced self-assembled mineral-based chemical hydrogen-generating material according to claim 3, characterized in that, The heating temperature is 180°C.

5. The method for preparing a thermally induced self-assembled mineral-based chemical hydrogen-generating material according to claim 1, characterized in that, The particle size of the iron olivine particles corresponds to 50-400 mesh.

6. The method for preparing a thermally induced self-assembled mineral-based chemical hydrogen-generating material according to claim 5, characterized in that, The corresponding particle size of the iron olivine particles is 200-300 mesh.

7. A thermally induced self-assembled mineral-based chemical hydrogen production material, characterized in that, The composite material is prepared by any one of claims 1-6, with fir olivine particles as the core and a metallic element as the shell. The metallic element shell coats the surface of the fir olivine particles. Under heating conditions, a single composite particle can spontaneously catalyze the reduction of water to produce hydrogen. The metallic element shell is a continuous or diffuse coating layer and is an integrated structure that is self-assembled in situ with the fir olivine core.

8. The application of the thermally induced self-assembled mineral-based chemical hydrogen production material as described in claim 7 in hydrogen production or catalytic hydrogen evolution reactions.

Images