A lunar soil-like hydrogen storage material and its preparation method

Abstract

The present invention discloses a lunar soil-like hydrogen storage material, which is FeTiO3 doped with Ca and Si elements. The outer surface of the lunar soil-like hydrogen storage material is an amorphous phase, and the thickness of the amorphous phase is not less than 10 nm. The lunar soil-like hydrogen storage material has a high hydrogen storage capacity. The present invention also discloses a method for preparing the lunar soil-like hydrogen storage material, comprising obtaining FeTiO3 doped with Mg, Ca, and Si elements, and irradiating the FeTiO3 doped with Mg, Ca, and Si elements with hydrogen ions under vacuum conditions to obtain the lunar soil-like hydrogen storage material. The process parameters of the hydrogen ion irradiation are: a voltage of 5-120 keV, a hydrogen ion flux of 1×10 17 ‑1×10 18 ions / cm 2 .

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen storage materials, and specifically relates to a lunar soil-like hydrogen storage material and a preparation method thereof. Background Art

[0002] Over millions of years, lunar crustal geological activity has blanketed the lunar surface with a thick layer of dust, forming lunar regolith. Unlike most "soils" on Earth, which are rich in microorganisms and water, lunar regolith is dry and powdery.

[0003] The lunar soil on the surface of the moon has undergone significant changes in its material composition and properties due to space weathering such as solar wind, cosmic rays and meteorite impacts.

[0004] Lunar regolith minerals are primarily composed of glass, ilmenite, pyroxene, plagioclase, and olivine. Studies have discovered numerous helium bubbles within the amorphous layer on the surface of ilmenite, demonstrating its robust storage capacity for hydrogen and helium ions injected by the solar wind. The hydrogen stored in ilmenite could become a crucial source of water on the moon, facilitating future lunar landings and the establishment of a lunar base.

[0005] Chinese patent number CN202210245989.7 discloses a method for producing oxygen from lunar regolith using hydrogen reduction and electrolysis. The lunar regolith is heated to the reduction temperature under vacuum conditions. Hydrogen is introduced into the regolith and maintained at this temperature for a period of time to produce metallic iron and anorthite-rich lunar regolith, which is then condensed to produce water. The anorthite-rich lunar regolith, separated from the metallic iron, is placed in a sealed electrolytic cell and heated to the electrolysis temperature, melting the regolith into liquid slag. The anorthite-rich lunar regolith slag is electrolyzed to produce an aluminum-silicon alloy at the cathode and oxygen at the anode. This patent directly utilizes lunar regolith for hydrogen reduction by heating, using a condensation method to condense and collect water. The water production process involves placing lunar regolith into a sealed reactor, heating it to 1100°C under vacuum conditions, introducing hydrogen at a rate of 210 ml / min, and maintaining this temperature for 4.5 hours. This produces metallic iron and anorthite-rich lunar regolith, which is then condensed to produce water.

[0006] Chinese patent number CN202310061124.X discloses a lunar soil hydrogen reduction water production device and method. The lunar soil hydrogen reduction water production device includes a screening device, a magnetic separation device, a heating device, a pressure device, a condensing device, a vibrating device, and a hydrogen storage tank. The screening device is connected to the magnetic separation device and transfers the screened lunar soil to the magnetic separation device. The magnetic separation device is connected to the heating device and feeds magnetic materials into the heating chamber of the heating device. The magnetic separation device is mounted on the vibrating end of the vibrating device. The hydrogen storage tank is connected to the top of the heating device via a hydrogen transmission pipeline. The bottom of the heating device is connected to the condensing device via a gas channel. The top of the condensing device is connected to the hydrogen storage tank via a hydrogen recovery pipeline. The pressure device is connected to the hydrogen transmission pipeline via a first pressure pipeline, and the pressure device is also connected to the gas channel via a second pressure pipeline. The hydrogen transmission pipelines on both sides of the first pressure pipeline are respectively equipped with a first valve and a second valve, and the gas channels on both sides of the second pressure pipeline are respectively equipped with a third valve and a fourth valve. The device uses the magnetic separation device to filter magnetic materials from the lunar soil and transfers them to the heating device. After hydrogen is introduced into the heating device, it reacts with the magnetic material through heating to produce water vapor, which is then collected by the condensing device. At the same time, the hydrogen in the heating device can be recycled.

[0007] The two aforementioned patents primarily focus on extracting water from lunar soil, but do not address the reproduction of lunar minerals capable of storing hydrogen. Therefore, there is an urgent need to develop hydrogen storage materials similar to lunar soil hydrogen storage minerals and to clarify the high-capacity hydrogen storage performance of such materials. Summary of the Invention

[0008] The present invention provides a lunar soil-like hydrogen storage material with high hydrogen storage capacity.

[0009] A specific embodiment of the present invention provides a lunar soil-like hydrogen storage material, which is FeTiO3 doped with Ca and Si elements. The outer surface of the lunar soil-like hydrogen storage material is an amorphous phase, and the thickness of the amorphous phase is not less than 10 nm.

[0010] The present invention utilizes the unique lattice structure of FeTiO3 to allow hydrogen to easily enter the ilmenite through ion irradiation simulated by the solar wind. Furthermore, because Ca, Si, Ti, and O elements readily form an amorphous phase on the particle surface during the simulated solar radiation process, the amorphous phase, due to its isotropic nature, lacks a channeling effect and effectively inhibits hydrogen diffusion, making it difficult for hydrogen that has entered the ilmenite to escape, thereby achieving the purpose of hydrogen storage. Furthermore, hydrogen can be retained not only in the amorphous phase of the lunar soil-like hydrogen storage material provided by the present invention, but also in the crystalline phase within it, thereby achieving the purpose of large-capacity hydrogen storage.

[0011] Furthermore, the atomic fractions of Ca and Si in the lunar regolith hydrogen storage material are 0-5 at% and 0-5 at%, respectively. Trace amounts of Ca and Si doping are beneficial for the lunar regolith hydrogen storage material to form an amorphous layer under ion irradiation conditions.

[0012] Furthermore, the element doped into FeTiO3 further includes Mg. The addition of Mg increases the thickness of the amorphous phase, so that the thickness of the amorphous phase is 15-25 nm.

[0013] Furthermore, the combined atomic fractions of Mg, Ca, and Si must not exceed 15 at% of the total atomic ratios of Mg, Ca, Si, Fe, and Ti. Exceeding 15 at% would cause the lunar regolith hydrogen storage material to transform from the typical FeTiO3 lattice to other lattice structures, hindering hydrogen storage. The amorphous layer is primarily composed of SiO2, and the addition of Mg and Ca promotes the formation of the SiO2 into amorphous structures, facilitating its formation.

[0014] Furthermore, the thickness of the amorphous phase is 10-25 nm. If the thickness is too thin, hydrogen ions can easily escape.

[0015] The present invention also discloses a method for preparing a lunar soil-like hydrogen storage material, comprising:

[0016] FeTiO3 doped with Mg, Ca and Si elements was obtained, and the FeTiO3 doped with Mg, Ca and Si elements was irradiated with hydrogen ions under vacuum conditions to obtain a lunar soil-like hydrogen storage material. The process parameters of the hydrogen ion irradiation were: voltage of 5-120 keV, hydrogen ion flux of 1×10 17 -1×10 18 ions / cm 2 .

[0017] The present invention proposes for the first time to carry out hydrogenation treatment by hydrogen ion irradiation under vacuum conditions. Compared with traditional pressurized hydrogenation, irradiation can form an amorphous phase of sufficient thickness on the surface of the perovskite provided by the present invention, making it difficult for the infiltrated hydrogen ions to escape. In addition, due to the combination of appropriate flux of hydrogen ions and FeTiO3, a large number of hydrogen ions can enter the interior of the lunar soil hydrogen storage material and are not easily aggregated in the amorphous phase, thereby ensuring that a large amount of hydrogen ions are stored in the lunar soil hydrogen storage material.

[0018] Furthermore, the voltage is 5-60 keV. If the voltage is too low, the thickness of the surface amorphous layer will be reduced, or even the amorphous layer cannot be formed, and only an amorphous-polycrystalline layer or a polycrystalline layer will be formed.

[0019] Furthermore, the flux of hydrogen ions is 1×10 17 -5×10 17 ions / cm2 If the flux is too low, the hydrogen content stored in the material will be too little, and the purpose of hydrogen storage cannot be achieved; if the flux is too high, the hydrogen storage capacity of the material will be saturated, resulting in ineffective irradiation.

[0020] Furthermore, the preparation method of FeTiO3 doped with Mg, Ca and Si elements comprises:

[0021] (1) Grinding and mixing Fe2O3 powder and TiO2 powder in an atomic ratio of 2:1-1:4 to obtain a mixed powder;

[0022] (2) adding CaO, MgO and SiO2 powders to the mixed powder obtained in step (1), wherein the sum of the atomic ratios of Mg, Ca and Si elements accounts for no more than 15 at% of the sum of the atomic ratios of Mg, Ca, Si, Fe and Ti elements, and ablating at 800-1300° C. for 8-12 h;

[0023] (3) The ablated powder obtained in step (2) is reduced in a mixed atmosphere of CO and CO2 to obtain FeTiO3 doped with Mg, Ca and Si elements.

[0024] This method can produce FeTiO3 doped with Mg, Ca, and Si, where the Mg, Ca, and Si content can be controlled below 15 at%. Compared to Earth's native ilmenite, which contains multiple impurity elements and easily forms associated crystal structures with other minerals, the Mg-, Ca-, and Si-doped FeTiO3 produced by this method has a single composition and is free of other elements that could affect hydrogen storage performance under ion irradiation. Furthermore, the doping with Mg, Ca, and Si does not affect the FeTiO3's lattice structure.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention provides an oxygen-containing lunar regolith mineral so that the oxygen in the mineral reacts with hydrogen to form OH / H2O, allowing a large amount of hydrogen ions to enter the lunar regolith mineral provided by the present invention. Moreover, through the amorphous phase with an appropriate thickness on the surface, the hydrogen ions that enter the lunar regolith mineral are difficult to escape, thereby achieving the purpose of storing a large amount of hydrogen.

[0027] The present invention destroys the lattice structure of the outer layer of ilmenite through hydrogen ion irradiation under vacuum, so that the outer layer forms an amorphous phase, so that the formed imitation lunar soil mineral has a higher hydrogen storage capacity and can be preserved for a long time in harsh environments without hydrogen ions easily leaking, that is, it has better stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The SEM micromorphology of the lunar soil-like hydrogen storage material, Earth's native ilmenite, and lunar soil ilmenite prepared in Example 1 of the present invention;

[0029] Figure 2 The ilmenite of the lunar soil-like hydrogen storage material prepared in Example 1 of the present invention is + TEM micromorphology before and after irradiation, TEM micromorphology of Earth's native ilmenite, and TEM micromorphology of lunar soil ilmenite;

[0030] Figure 3 The lunar soil-like hydrogen storage material prepared in Example 1 of the present invention is subjected to H + The morphology of the amorphous layer produced after irradiation, the original ilmenite of the earth after H + The morphology of the polycrystalline layer produced after irradiation and the morphology of the amorphous layer formed by lunar soil ilmenite after long-term solar wind irradiation;

[0031] Figure 4 The lunar soil-like hydrogen storage material prepared in Example 1 of the present invention is subjected to H + Different locations after irradiation, the original ilmenite of the earth after H + EELS absorption peak spectra at different positions after irradiation and at different positions of lunar soil ilmenite;

[0032] Figure 5 The lunar soil-like hydrogen storage material prepared in Example 2 of the present invention;

[0033] Figure 6 The ilmenite of the lunar soil-like hydrogen storage material prepared in Example 2 of the present invention is + TEM micromorphology after irradiation;

[0034] Figure 7 The lunar soil-like hydrogen storage material prepared in Example 2 of the present invention is subjected to H + Topography of the amorphous layer produced after irradiation;

[0035] Figure 8 The lunar soil-like hydrogen storage material prepared in Example 2 of the present invention is subjected to H + EELS absorption peak spectra at different positions after irradiation. DETAILED DESCRIPTION

[0036] In order to make the purpose, content, and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below with reference to the accompanying drawings and examples.

[0037] Example 1

[0038] This embodiment provides a method for preparing a lunar regolith-like hydrogen storage material, comprising:

[0039] (1) Grind ferric oxide (Fe2O3) and titanium dioxide (TiO2) powders at an atomic ratio of 1:2 for 10 h and then mix;

[0040] (2) adding calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2) powders to the ground mixed powder according to the atomic ratio of Fe:Ti:Ca:Mg:Si=20:20:1:1:1, and sintering at 1200°C for 10h;

[0041] (3) The sintered powder is reduced in a mixed atmosphere of CO and CO2 to obtain a FeTiO3 product doped with appropriate amounts of Mg and Ca elements.

[0042] (4) The FeTiO3 doped with Mg, Ca and Si elements was irradiated with hydrogen ions under vacuum conditions to obtain a lunar soil-like hydrogen storage material. The process parameters of the hydrogen ion irradiation were: voltage of 5 keV, hydrogen ion flux of 1×10 17 ions / cm 2 Ion irradiation produces an amorphous layer of about 15 nm thick on the surface of the material.

[0043] like Figure 1 As shown in a and c, the lunar soil-like hydrogen storage material obtained in this embodiment is similar to lunar soil ilmenite in morphology, and both are angular particles. Figure 1 The b in the figure is the morphology of the Earth's native ilmenite. The Earth's native ilmenite has other associated minerals and an irregular shape, which is significantly different from the lunar soil-like hydrogen storage material and lunar soil ilmenite.

[0044] like Figure 2 As shown in a, the lattice spacing of the Earth's native ilmenite on the

[001] crystal plane is 0.256nm; Figure 2 The lattice spacing of the lunar soil ilmenite in b on the

[001] crystal plane is 0.264nm. The lunar soil ilmenite has obvious lattice expansion, which is caused by the solar wind irradiation injecting a large amount of hydrogen into the lattice of the lunar soil ilmenite. The lunar soil-like hydrogen storage material obtained in this example is H + The lattice spacing of the

[001] plane before and after irradiation is as follows Figure 2 As shown in Figures c and d, before irradiation, the lattice spacing of the

[001] crystal plane is 0.254nm, which is similar to the native ilmenite on Earth; after irradiation, the lattice spacing of the

[001] crystal plane expands to 0.269nm, which is similar to the lunar soil ilmenite. This shows that the lunar soil hydrogen storage material has been exposed to H + After irradiation, there is a significant lattice expansion, indicating that H + Irradiation enables the lunar soil-like hydrogen storage material to effectively store hydrogen.

[0045] like Figure 3 a in the figure is the lunar soil-like hydrogen storage material after H + Amorphous layer produced after irradiation. Figure 3 b in the figure is the original ilmenite of the earth after H + Polycrystalline layer produced after irradiation. Figure 3 The c in the figure is the amorphous layer produced by lunar soil ilmenite after long-term solar wind irradiation. + After irradiation, an amorphous layer of about 15 nm can be formed on the surface, which is similar to the amorphous layer produced by lunar soil ilmenite after long-term solar wind irradiation. + The amorphous layer produced after irradiation can effectively inhibit the diffusion and escape of injected hydrogen, making the lunar soil-like hydrogen storage material have a higher hydrogen storage performance. + After irradiation, no amorphous layer is formed, and only a polycrystalline layer is formed on the surface. The channeling effect in the polycrystalline layer will promote the diffusion and release of the injected hydrogen, making it impossible to realize the hydrogen storage function.

[0046] When using electron energy loss spectroscopy (EELS) to characterize different locations in the sample, the hydrogen storage performance of different locations in different samples can be characterized by whether the absorption peak belonging to H (12eV) can be observed. Figure 4 As shown in a and b, the lunar soil material is subjected to H + EELS absorption peak spectra at different locations after irradiation. There is no H absorption peak in the Pt protective layer deposited on the sample surface, but distinct H absorption peaks are observed at different locations in the material. The resulting amorphous layer can effectively prevent hydrogen diffusion and escape, ensuring the hydrogen storage performance of the material. Figure 4 c and d are the earth's ilmenite after H + The EELS absorption peak spectra at different positions after irradiation do not show obvious H absorption peaks. e and f are EELS absorption peak spectra at different positions of lunar soil ilmenite. Different positions of lunar soil ilmenite also show obvious H absorption peaks. This shows that the lunar soil hydrogen storage material has been exposed to H + After irradiation, a large amount of H can be effectively stored, achieving an effect equivalent to that of lunar soil ilmenite after solar wind irradiation.

[0047] The commercial earth ilmenite provided in this embodiment is obtained by mining ilmenite ore on the earth.

[0048] This embodiment provides lunar soil ilmenite, which is derived from the Chang'e 5 lunar soil sample. The lunar soil sample was brought back from the moon by the Chang'e 5 mission and issued by the China Manned Space Administration upon application, with the number CE5C0400.

[0049] Example 2

[0050] Compared with Example 1, the difference is that calcium oxide (CaO) and silicon dioxide (SiO2) powders are added to the ground mixed powder according to the atomic ratio of Fe:Ti:Ca:Si=20:20:1:1. The process parameters of the hydrogen ion irradiation are: voltage of 60keV, hydrogen ion flux of 5×1017 ions / cm 2 Ion irradiation produces an amorphous layer of about 12 nm thick on the surface of the material.

[0051] like Figure 5 As shown, the lunar soil-like hydrogen storage material obtained in this embodiment is similar in morphology to lunar soil ilmenite, and is also angular particles.

[0052] like Figure 6 As shown, the lunar soil hydrogen storage material obtained in this embodiment is The interplanar spacings on the crystal planes are 0.289 nm and 0.437 nm, respectively.

[0053] like Figure 7 As shown, the lunar soil-like hydrogen storage material obtained in this embodiment can form an amorphous layer of about 12 nm on the surface after H+ irradiation, which is similar to the amorphous layer produced by lunar soil ilmenite after long-term solar wind irradiation.

[0054] like Figure 8 As shown in Figures a and b, electron energy loss spectroscopy (EELS) was used to characterize different locations within the sample. While the Pt protective layer deposited on the sample surface lacks any H absorption peaks, distinct H absorption peaks are observed at various locations within the material. The resulting amorphous layer effectively prevents hydrogen diffusion and escape, ensuring the material's hydrogen storage performance.

Claims

1. A lunar soil-like hydrogen storage material, characterized in that: The lunar soil-like hydrogen storage material is FeTiO3 doped with Ca and Si elements. The outer surface of the lunar soil-like hydrogen storage material is an amorphous phase, and the thickness of the amorphous phase is not less than 10 nm.

2. The lunar soil-like hydrogen storage material according to claim 1, characterized in that: The elements doped in FeTiO3 also include Mg.

3. The lunar soil-like hydrogen storage material according to claim 2, characterized in that: The sum of the atomic fractions of Mg, Ca and Si in the sum of the atomic fractions of Mg, Ca, Si, Fe and Ti elements does not exceed 15 at%.

4. The lunar soil-like hydrogen storage material according to claim 1, characterized in that: The thickness of the amorphous phase is 10-25 nm.

5. A method for preparing the lunar regolith hydrogen storage material according to any one of claims 1 to 4, characterized in that: include: FeTiO3 doped with Mg, Ca and Si elements was obtained, and the FeTiO3 doped with Mg, Ca and Si elements was irradiated with hydrogen ions under vacuum conditions to obtain a lunar soil-like hydrogen storage material. The process parameters of the hydrogen ion irradiation were: voltage of 5-120 keV, hydrogen ion flux of 1×10 17 -1×10 18 ions / cm 2 .

6. The method for preparing the lunar regolith hydrogen storage material according to claim 5, characterized in that: The voltage is 5-60keV.

7. The method for preparing the lunar regolith hydrogen storage material according to claim 5, characterized in that: The flux of hydrogen ions is 1×10 17 -5×10 17 ions / cm 2 .

8. The method for preparing the lunar regolith hydrogen storage material according to claim 5, characterized in that: The preparation method of FeTiO3 doped with Mg, Ca and Si elements comprises: (1) Grinding and mixing Fe2O3 powder and TiO2 powder in an atomic ratio of 2:1-1:4 to obtain a mixed powder; (2) Adding CaO, MgO and SiO2 powders to the mixed powder obtained in step (1), wherein the sum of the atomic fractions of Mg, Ca and Si in the sum of the atomic fractions of Mg, Ca, Si, Fe and Ti does not exceed 15 at%, and the content is between 800 and 1300. o Ablation at C for 8-12 h; (3) The ablated powder obtained in step (2) is heated in CO and CO2 FeTiO3 doped with Mg, Ca and Si elements is obtained by reduction in a mixed atmosphere.

Images