Aluminum complexes for hydrogen production and methods of making the same

Abstract

A method of generating hydrogen comprising contacting an aqueous solution with an active aluminum complex comprising aluminum, AIN, gamma-Al2O3, and optionally a carbonaceous material. The active aluminum complex can be safely stored and can be used for safe on-demand generation of hydrogen in water.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 293,668, filed December 24, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to aluminum complexes for generating hydrogen and methods of using them. Background Technology

[0004] Hydrogen is increasingly replacing fossil fuels in the transportation industry because its combustion produces only water, not polluting gases. Traditional large-scale hydrogen production methods include steam reforming of natural gas, coal gasification, and electrolysis. Hydrogen delivery technologies and pipelines are still in the early stages of development. Therefore, manufacturers typically transport H2 in steel containers at pressures below 150 bar. At this pressure, a 65 kg cylinder can only carry approximately 0.5 kg of H2, or about 0.8% by weight in terms of gravimetric H2 density. New technologies have introduced lighter carbon fiber reinforced polymer (CFRP) cylinders that can hold approximately five times more H2 at higher pressures, up to 700 bar. However, these polymer composite containers are expensive and unstable at high temperatures. A noteworthy approach is to store H2 in solid materials, such as metal hydrides (MH). n Aluminum hydride (MAl(H4)) n Amide M(NH2) n Boronhydride M(BH4) n Although complexed compounds can have a maximum H2 density of 17% by weight, these metal hydrides require chemical reactants to regenerate the H2. Other options are reversible room-temperature alloys (e.g., FeTiH) in the form of commercially available steel cans. 1.7 Or LaNi5H6), used for filling and discharging at pressures of 15 to 30 bar. These alloys have a relatively low weight H2 density, approximately 2% by weight, which further decreases to 1% by weight when contained in steel tanks. Nevertheless, this option is economically viable for capacities exceeding 10,000 fill / discharge cycles.

[0005] Hydrogen can be produced through the accelerated corrosion (oxidation) of fine metal particles in water. Aluminum is an abundant and lightweight element with a density of approximately 11% by weight (H₂). With the addition of water and an accelerator, it oxidizes under atmospheric pressure to produce hydrogen.

[0006] Al+3H2O→Al(OH)3+1.5H2(g),ΔH RT ≈-4.3kWh / kg Al (1)

[0008] The reaction generates a large amount of heat (4.3 kWh / kg). Al This process produces aluminum hydroxide clay, which is widely used as a flame retardant, in medical applications, and has other uses. This technology holds promise for hydrogen backup systems in remote towns, villages, and offshore vessels. However, Al particles cannot be oxidized in pure water because the passivation mechanism of the natural alumina surface can be easily repaired by forming an am-Al₂O₃ layer. Therefore, the continuous destruction of the alumina surface requires fine aluminum particles, high temperatures (>100°C), acidic (low pH) or alkaline (high pH) solutions, electric current, and combinations thereof. The most effective promoters of aluminum oxidation are hydroxides NaOH, KOH, and Ca(OH)₂, but the molar concentration of NaOH solutions is, for example, 1M to 5M (4 wt% to 20 wt% NaOH). This makes systems packed with aluminum particles cumbersome to store and operate. Therefore, most methods for generating H₂ from fine aluminum particles optimize for or even eliminate alkaline additives in the water.

[0009] Hydrogen generation in pure water without alkaline promoters has been shown to be efficient using aluminum nanoparticles within a protective oleic acid layer. In such systems, aluminum nanoparticles (20 nm to 65 nm) in the organic layer can account for approximately 35% by weight of the product. These aluminum nanoparticles are produced by the decomposition of aluminum trihydride precursors AlH3 or (AlH3) in the presence of catalysts such as titanium isopropoxide (IV) and organic passivators such as oleic acid. n It can also be prepared from aluminum trihydride complexes such as dimethylethyl aluminum trihydride. Due to the very high H2 production rate in pure water, each gram of this composition contains 0.01 g of H2. -1 Therefore, these aluminum nanoparticles are unsafe for large-scale storage and transportation. Other disadvantages include a relatively low hydrogen yield (approximately 65%), high production costs, and difficulty in handling aluminum nanoparticles.

[0010] Methods involving aluminum microparticles have been developed, but they have drawbacks such as fast reaction rates, high risk of combustion during storage, relatively low reaction yields, and high production costs.

[0011] Therefore, there is a need for compositions and methods for hydrogen production that overcome at least some of the aforementioned disadvantages. Summary of the Invention

[0012] This disclosure provides an active aluminum composite comprising aluminum and AlN, γ-Al₂O₃, and optionally a carbonaceous material, which can be used for on-demand hydrogen production. The active aluminum composite described herein can be prepared by thermal shock heating of aluminum in the presence of a carbonaceous material precursor. The heat treatment can be performed by rapid heating once or multiple times to initiate the growth of AlN with a defective microstructure. In some embodiments, the carbonaceous material and γ-Al₂O₃ are primarily formed in the cracks of the AlN surface and can form galvanic pairs with aluminum. The carbonaceous material may include a mixture of compounds containing one or more of aluminum, carbon, oxygen, and nitrogen.

[0013] In a first aspect, this document provides a method for generating hydrogen (H2) comprising contacting an aqueous solution with an active aluminum complex comprising aluminum, γ-Al2O3, AlN, and optionally a carbonaceous material, thereby forming H2.

[0014] In some embodiments, the active aluminum composite comprises a diameter D 50 The thickness D is 1μm to 50μm. 50 Aluminum composite sheets ranging from 10nm to 100nm.

[0015] In some embodiments, a layer comprising γ-Al2O3, AlN, and optionally carbonaceous materials is arranged on the surface of aluminum.

[0016] In some embodiments, the carbonaceous material comprises carbon and one or more elements selected from the group consisting of nitrogen and oxygen.

[0017] In some embodiments, the carbonaceous material is prepared by carbonization of a carbonaceous material precursor, which is selected from the group consisting of carboxylic acids, polyvinyl alcohol, epoxy resins and their salts.

[0018] In some embodiments, the carbonaceous material precursor is C6-C. 25 Saturated carboxylic acids, C6-C 25 Unsaturated carboxylic acids or their salts.

[0019] In some embodiments, the carbonaceous material precursor is lauric acid, palmitic acid, stearic acid, or a salt thereof.

[0020] In some embodiments, the active aluminum composite contains at least 85% by weight aluminum.

[0021] In some embodiments, the active aluminum composite comprises a diameter D 50 The thickness is 10μm to 30μm and the thickness D 50The aluminum composite sheet is 10 nm to 100 nm in size; the carbonaceous material is prepared by carbonization of a carbonaceous material precursor, which is selected from the group consisting of carboxylic acids, polyvinyl alcohol and their salts; and the active aluminum composite contains at least 87% by weight of aluminum.

[0022] In some embodiments, the active aluminum composite is prepared from aluminum parts, aluminum cans, or aluminum scrap; and the aluminum composite comprises particles with a length ranging from 1 μm to 10,000 μm and a thickness of less than 500 μm.

[0023] In some embodiments, carbonaceous materials are prepared by carbonization of stearic acid or its salts.

[0024] In some embodiments, the method further includes providing an aluminum mixture comprising aluminum and optionally a carbonaceous material precursor; subjecting the aluminum mixture to one or more thermal shock heating cycles, wherein the one or more thermal shock heating cycles independently include a heating time of 40°C / min. -1 up to 400℃min -1 The aluminum mixture is heated at a rate of 450°C to 650°C to form a thermally shock-prone aluminum mixture; and the thermally shock-prone aluminum mixture is annealed at 450°C to 650°C to form an active aluminum composite.

[0025] In some embodiments, the aluminum mixture is subjected to 1 to 4 thermal shock heating cycles.

[0026] In some embodiments, the thermal shock aluminum mixture is annealed at a temperature between 500°C and 650°C.

[0027] In some embodiments, the aqueous solution has a pH of 7 or greater.

[0028] In some embodiments, the aqueous solution has a pH of 12.4 to 13.4 or 13 to 13.4.

[0029] In some embodiments, the aqueous solution contains NaCl, KCl, or CaCl2.

[0030] In some implementations, the aqueous solution contains distilled water or seawater.

[0031] In some embodiments, H2 is used at a concentration of less than 500 ml / min per gram of active aluminum complex. -1 The rate of H2 production was measured at a temperature of 22°C and atmospheric pressure.

[0032] In some embodiments, the active aluminum composite comprises a diameter D 50 The thickness is 10μm to 30μm and the thickness D 50The aluminum composite sheet or spherical aluminum particles are 10 nm to 100 nm in size; the carbonaceous material is prepared by carbonizing stearic acid; the active aluminum composite contains at least 85% by weight aluminum; the aqueous solution has a pH of 13 to 13.4; and the H2 content is less than 500 ml / min per gram of active aluminum composite. -1 The rate at which H2 is generated is measured at atmospheric pressure and temperature.

[0033] In some embodiments, the method further includes providing an aluminum mixture comprising aluminum and stearic acid; subjecting the aluminum mixture to one or more thermal shock heating cycles, wherein the one or more thermal shock heating cycles independently include a heating time of 40°C / min. -1 up to 400℃min -1 The aluminum mixture is heated to 450°C to 650°C or cooled from 450°C to 650°C to 100°C to 200°C at a rate to form a thermally shocked aluminum mixture; and the thermally shocked aluminum mixture is annealed at a temperature between 450°C and 650°C to form an active aluminum composite.

[0034] The active aluminum composite described herein can be prepared by rapidly converting aluminum in a partially sealed metal container under an air or nitrogen atmosphere.

[0035] The activated aluminum composite can be densified / compacted into cassettes with varying levels of open porosity. The porous cassettes are easy to handle and safe for long-term storage, in humid air, and under fire conditions. This invention also provides a method for generating hydrogen using slightly alkaline water, seawater, groundwater, tap water, distilled water, deionized water, and heavy water. In the last example, the system generates deuterium gas instead of hydrogen. It is not desirable to be bound by theory; it is assumed that the composite structure can bind water, and that this bound water can be released upon heating and react with Al to generate hydrogen. This disclosure also provides a system for implementing the methods disclosed herein. Packaging containers for the activated aluminum composite and / or cassettes containing the activated aluminum composite can be made of high-density polyethylene, low-density polyethylene, polypropylene, glass, ceramics, and metal alloys. In some embodiments, a group of packaging containers can be connected in series using pipes, flow regulators, fittings, sensors, purification devices, and other accessories. In other embodiments, the cassettes can be refilled with hydrogen and generate a gas mixture upon heating to a specific temperature. Attached Figure Description

[0036] The above and other objects and features of this disclosure will become apparent from the following description of this disclosure when described in conjunction with the accompanying drawings.

[0037] Figure 1 A schematic diagram of an exemplary method for producing an active aluminum sheet box according to certain embodiments described herein is shown.

[0038] Figure 2 A scanning electron microscope (SEM) image of initial aluminum particles according to certain embodiments described herein is shown.

[0039] Figure 3 A steel container with a semi-permeable cap is described for optimizing gas exchange between the atmosphere and the initial Al particles.

[0040] Figure 4 SEM images of initial aluminum particles (A) and active aluminum composites (B), (C) according to certain embodiments described herein are shown.

[0041] Figure 5 Energy dispersive X-ray (EDS) spectra of active aluminum composites according to certain embodiments described herein are shown.

[0042] Figure 6 The X-ray diffraction (XRD) spectra of active aluminum composite particles according to certain embodiments described herein are shown.

[0043] Figure 7 An exemplary system for generating and incorporating hydrogen using an active aluminum compound and / or a cartridge according to certain embodiments described herein is schematically depicted.

[0044] Figure 8 Example 1 illustrates a comparison of hydrogen production rates (ml·min) in 0.05 M and 0.5 M NaOH solutions between spherical aluminum powder (reference) and an active aluminum composite according to certain embodiments described herein. -1 ·g Al -1 ).

[0045] Figure 9 The effect of temperature (40°C to 80°C) on the hydrogen production rate (ml·min) of the active aluminum complex in distilled water according to certain embodiments described herein is shown. -1 g Al -1 The impact of ).

[0046] Figure 10 Example 2 is shown, in which densification of the active aluminum composite according to certain embodiments described herein affects the hydrogen production rate (ml·min) in distilled water at 60°C. -1 ·g Al -1 The impact of ).

[0047] Figure 11 The hydrogen production rates (ml·min) in distilled water using activated (Example 3) and unactivated (reference) 1-μm aluminum particles, according to certain embodiments described herein, are shown.-1 ·g Al -1 ).

[0048] Figure 12 The following figures illustrate the effect of aqueous solution molar concentration (0.0625 M to 0.5 M NaOH) on the hydrogen production rate (ml·min) of active aluminum composites made from aluminum can waste, according to certain embodiments described herein. -1 ·g Al -1 The effect of (Example 4). Detailed Implementation

[0049] definition

[0050] Throughout this application, when a composition is described as having, including, or comprising a specific component, or when a method is described as having, including, or comprising a specific method step, it is contemplated that the composition of this teaching may also consist substantially of or comprise the said component, and the method of this teaching may also consist substantially of or comprise the said method step.

[0051] In this application, when an element or component is referred to as being included in and / or selected from the list of elements or components, it should be understood that the element or component can be any one of the elements or components, or the element or component can be selected from a group consisting of two or more of the elements or components. Furthermore, it should be understood that the elements and / or features of the compositions or methods described herein can be combined in various ways, whether express or implied herein, without departing from the spirit and scope of the teachings herein.

[0052] It should be understood that the order of steps or the sequence of actions used to perform certain movements is not important, as long as the teachings of this article remain operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0053] Unless otherwise expressly stated, the use of the singular form in this document includes the plural form (and vice versa). Furthermore, if the term "about" is used before a quantity value, the teachings of this document also include that particular quantity value itself, unless otherwise expressly stated. As used herein, the term "about" is a deviation of ±10%, ±7%, ±5%, ±3%, ±1%, or ±0% of an index value, unless otherwise stated or inferred.

[0054] This disclosure provides an active aluminum composite comprising aluminum, γ-Al₂O₃, aluminum nitride (AlN), and optionally a carbonaceous material. In some embodiments, the active aluminum composite comprises a layer comprising γ-Al₂O₃ and AlN disposed on an aluminum surface, wherein the γ-Al₂O₃ and AlN include surface defects such as cracks, fractures, fissures, pits, etc., and a carbonaceous material is disposed on the surface of the γ-Al₂O₃ and / or AlN.

[0055] Not wanting to be bound by theory, aluminum nitride is theoretically considered to provide an unstable protective layer in water, through which carbon and γ-Al₂O₃ embedded in the protective layer can permeate. Since the nitride layer can exist within aluminum, its destruction simultaneously exposes pure aluminum to oxidation and hydrogen production.

[0056] The activated aluminum complex may contain Al2O3 with γ-Al2O3 as the main crystalline phase. However, it is not required that all Al2O3 present in the activated aluminum complex is a homogeneous γ-Al2O3 phase. The activated aluminum complex may include aluminum hydroxide Al(OH)3 and / or aluminum hydroxide hydrate Al(OH)3×xH2O, where x can be 1, 2, or 3.

[0057] The carbonaceous material may be derived from one or more carbonaceous material precursors carbonized during the thermal shock heating cycle and / or annealing step used to prepare the active aluminum composite. The carbonaceous material precursor may be a carboxylic acid, polyvinyl alcohol, epoxy resin, or a salt thereof. In some embodiments, only trace amounts, such as 0.1% by mass or less, of the carbonaceous material are used.

[0058] There are no particular restrictions on the structure of carboxylic acids. This disclosure envisions saturated, unsaturated, linear, branched, and cyclic carboxylic acids. Non-polymeric carboxylic acids may contain one, two, three, or four carboxylic acid moieties.

[0059] In some embodiments, the carboxylic acid is C6-C. 25 Saturated carboxylic acids, C8-C 25 Saturated carboxylic acids, C 10 -C 25 Saturated carboxylic acids, C 10 -C 22 Saturated carboxylic acids, C 10 -C 20 Saturated carboxylic acids, C 12 -C 20 Saturated carboxylic acids, C 14 -C 20 Saturated carboxylic acids, C 16 -C 20 Saturated carboxylic acids, C 16 -C 10 Saturated carboxylic acids, C6-C 25 Unsaturated carboxylic acids, C8-C 25Unsaturated carboxylic acids, C 10 -C 25 Unsaturated carboxylic acids, C 10 -C 22 Unsaturated carboxylic acids, C 10 -C 20 Unsaturated carboxylic acids, C 12 -C 20 Unsaturated carboxylic acids, C 14 -C 20 Unsaturated carboxylic acids, C 16 -C 20 Unsaturated carboxylic acids, C 16 -C 10 Unsaturated carboxylic acids or their salts.

[0060] Exemplary carboxylic acids include, but are not limited to, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanic acid, stearic acid, nonadecanic acid, arachidic acid, or their salts.

[0061] Salts can contain alkali metal cations, alkaline earth metal cations, and NH4+. + or N + (C 1-4 Alkyl)4. Exemplary cations include, but are not limited to, Li. + Na + K + 、Rb + Cs + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and NH 4+ .

[0062] In some embodiments, the carbonaceous material precursor is stearic acid or a salt thereof.

[0063] The active aluminum complex may contain 85% to 98% by weight aluminum (i.e., Al). 0 In some embodiments, the active aluminum composite comprises 85 wt% to 90 wt%, 91 wt% to 98 wt%, 92 wt% to 98 wt%, 93 wt% to 98 wt%, 94 wt% to 98 wt%, 95 wt% to 98 wt%, 96 wt% to 98 wt%, 92 wt% to 97 wt%, 92 wt% to 96 wt%, 92 wt% to 95 wt%, 93 wt% to 95 wt%, or about 87 wt% of aluminum.

[0064] The activated aluminum composite may contain 0.01 wt% to 15 wt% of carbonaceous material. In some embodiments, the carbonaceous material is present in the activated aluminum composite in amounts of 0.01 wt% to 14 wt%, 0.01 wt% to 13 wt%, 0.01 wt% to 12 wt%, 0.1 wt% to 11 wt%, 0.01 wt% to 10 wt%, 0.01 wt% to 9 wt%, 0.01 wt% to 8 wt%, 0.01 wt% to 7 wt%, 0.01 wt% to 6 wt%, 0.01 wt% to 5 wt%, 0.01 wt% to 4 wt%, 0.01 wt% to 3 wt%, 0.01 wt% to 2.3 wt%, 0.1 wt% to 2.3 wt%, 0.5 wt% to 2.3 wt%, 1 wt% to 2.3 wt%, 1.5 wt% to 2.3 wt%, or 2 wt% to 2.3 wt%. In some embodiments, the carbonaceous material is present in the active aluminum composite in 10% by weight or less, 9% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2.5% by weight or less, 2.3% by weight or less, 2% by weight or less, 1.5% by weight or less, 1% by weight or less, 0.5% by weight or less, or 0.1% by weight or less.

[0065] The activated aluminum complex may contain 0.1 wt% to 5 wt% γ-Al₂O₃. In some embodiments, γ-Al₂O₃ is present in the activated aluminum complex in amounts of 0.1 wt% to 4 wt%, 0.1 wt% to 3 wt%, 0.1 wt% to 2 wt%, 0.1 wt% to 1.5 wt%, 0.1 wt% to 1 wt%, 0.1 wt% to 0.75 wt%, 0.1 wt% to 0.5 wt%, and 0.1 wt% to 0.25 wt%.

[0066] The activated aluminum complex may contain 0.1 wt% to 10 wt% AlN. In some embodiments, AlN is present in the activated aluminum complex in amounts of 0.1 wt% to 8 wt%, 0.1 wt% to 6 wt%, 0.1 wt% to 4 wt%, 0.1 wt% to 2 wt%, 0.1 wt% to 1 wt%, 0.1 wt% to 0.5 wt%, and 0.1 wt% to 0.25 wt%.

[0067] In some embodiments, the active aluminum complex further comprises Al(OH)3×3H2O. The active aluminum complex may comprise 0.1 wt% to 20 wt% of Al(OH)3×3H2O. In some embodiments, the active aluminum complex comprises 0.1 wt% to 15 wt%, 0.1 wt% to 10 wt%, 0.1 wt% to 9 wt%, 0.1 wt% to 8 wt%, 0.1 wt% to 7 wt%, 0.1 wt% to 6 wt%, 0.1 wt% to 5 wt%, 1 wt% to 5 wt%, 1 wt% to 4 wt%, or 1 wt% to 3 wt% of Al(OH)3×3H2O.

[0068] The activated aluminum composite may comprise multiple particles. The particles can be of any shape or combination of shapes, including but not limited to angular, flake, spherical, cylindrical, and elliptical shapes. In some embodiments, the particles are flake-shaped. The flake-shaped particles may have at least one dimension at the micrometer scale and one dimension at the nanometer scale.

[0069] In some embodiments, the active aluminum composite comprises spherical and / or sheet-like particles having a diameter D 50 The thickness D is 1μm to 50μm, 5μm to 50μm, 10μm to 50μm, 15μm to 50μm, 20μm to 50μm, 20μm to 45μm, 20μm to 40μm, 20μm to 35μm, 25μm to 35μm, or 10μm to 30μm, and has a thickness D 50 For 10nm to 100nm, 10nm to 90nm, 10nm to 80nm, 10nm to 70nm, 10nm to 60nm, 10nm to 50nm, 10nm to 40nm, 10nm to 30nm, 20nm to 100nm, 30nm to 100nm, 40nm to 100nm, 50nm to 100nm, 20nm to 90nm, 30nm to 80nm, 40nm to 70nm, or 50nm to 60nm.

[0070] In some embodiments, crushed or ground aluminum scrap (e.g., flat pieces) is used to produce active aluminum composites with dimensions no greater than 10 mm in lateral direction and less than 0.5 mm in thickness.

[0071] In some embodiments, the activated aluminum compound can be molded (e.g., using compression) into a box. The box can take any shape, including but not limited to cubes, cuboids, cylinders, triangular prisms, hexagonal prisms, triangular-base pyramids, square-based pyramids, hexagonal pyramids, planar structures, or rods. The box can also be irregularly shaped. In some embodiments, the box is in the shape of a cube or cuboid.

[0072] The porosity of the box can be varied by appropriately selecting the compressive force used to mold the active aluminum composite particles. In some embodiments, the box has a porosity of 10% to 70%. In some embodiments, the box has a porosity of 20% to 70%, 30% to 70%, 40% to 70%, 40% to 60%, or 45% to 60%.

[0073] The activated aluminum composite described herein can be readily prepared from commercially available raw materials. In some embodiments, the activated aluminum composite is prepared by the following steps: heat treatment of additive-free pigment aluminum particles or Al paste or aluminum particles; subjecting an aluminum mixture to one or more thermal shock heating cycles to form a thermal shock aluminum mixture; and annealing the thermal shock aluminum mixture in a nitrogen-containing atmosphere (air or nitrogen) to form the activated aluminum composite. In some embodiments, the initial particles used for activation are prepared by cutting and grinding Al waste and Al alloy compositions of any quality. This may include, but is not limited to, Al cans for beverage and oily products, scraps, or Al component processing products.

[0074] Carbonaceous precursors, such as carboxylic acids, polyvinyl alcohol, epoxy resins, or their salts, can be added to modulate the activity of aluminum composites.

[0075] There are no particular limitations on the structure of carboxylic acids. This invention conceives of saturated, unsaturated, linear, branched, and cyclic carboxylic acids. Non-polymeric carboxylic acids may contain one, two, three, or four carboxylic acid moieties.

[0076] In some embodiments, the carboxylic acid is C6-C. 25 Saturated carboxylic acids, C8-C 25 Saturated carboxylic acids, C 10 -C 25 Saturated carboxylic acids, C 10 -C 22 Saturated carboxylic acids, C 10 -C 20 Saturated carboxylic acids, C 12 -C 20 Saturated carboxylic acids, C 14 -C 20 Saturated carboxylic acids, C 16 -C 20 Saturated carboxylic acids, C 16 -C 10 Saturated carboxylic acids, C6-C 25 Unsaturated carboxylic acids, C8-C 25 Unsaturated carboxylic acids, C 10 -C 25 Unsaturated carboxylic acids, C 10 -C 22 Unsaturated carboxylic acids, C 10 -C 20 Unsaturated carboxylic acids, C12 -C 20 Unsaturated carboxylic acids, C 14 -C 20 Unsaturated carboxylic acids, C 16 -C 20 Unsaturated carboxylic acids, C 16 -C 10 Unsaturated carboxylic acids or their salts.

[0077] Exemplary carboxylic acids include, but are not limited to, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanic acid, stearic acid, nonadecanic acid, arachidic acid, or their salts.

[0078] Salts can contain alkali metal cations, alkaline earth metal cations, and NH4+. + or N + (C 1-4 Alkyl)4. Exemplary cations include, but are not limited to, Li. + Na + K + 、Rb + Cs + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and NH 4+ .

[0079] In some embodiments, the carbonaceous material precursor is stearic acid or a salt thereof.

[0080] The aluminum used to prepare the active aluminum composite can be aluminum particles. The aluminum particles can be of any shape or combination of shapes, including but not limited to sheet-like, spherical, and elliptical shapes. In some embodiments, the particles are sheet-like. The aluminum sheet may have at least one dimension at the micrometer scale and one dimension at the nanometer scale.

[0081] When the aluminum particles are only in the form of flakes, the diameter D that the flakes can have is... 50 The thickness D is 1μm to 50μm, 5μm to 50μm, 10μm to 50μm, 15μm to 50μm, 20μm to 50μm, 20μm to 45μm, 20μm to 40μm, 20μm to 35μm, 25μm to 35μm, or 10μm to 30μm, and has a thickness D 50The diameters are 10nm to 100nm, 10nm to 90nm, 10nm to 80nm, 10nm to 70nm, 10nm to 60nm, 10nm to 50nm, 10nm to 40nm, 10nm to 30nm, 20nm to 100nm, 30nm to 100nm, 40nm to 100nm, 50nm to 100nm, 20nm to 90nm, 30nm to 80nm, 40nm to 70nm, or 50nm to 60nm. In other cases, the aluminum particles can be spherical or irregular in shape, with a particle size D50 of 1μm to 30μm, 4.6μm to 30μm, 10μm to 30μm, 4.6μm to 10μm, or 20μm to 30μm.

[0082] Aluminum particles can have a BET surface area of ​​2 cm². 2 g -1 Up to 20cm 2 g -1 7cm 2 g -1 Up to 20cm 2 g -1 or 7cm 2 g -1 Up to 15.5cm 2 g -1 When applicable, the WCA of aluminum particles can be up to 10,000 cm⁻¹. 2 g -1 Up to 50,000cm 2 g -1 16,000cm 2 g -1 Up to 48,000cm 2 g -1 26,000cm 2 g -1 Up to 48,000cm 2 g -1 16,000cm 2 g -1 Up to 26,000cm 2 g -1 20,000cm 2 g -1 Up to 50,000cm 2 g -1 30,000cm 2 g -1 Up to 50,000cm 2 g -1 40,000cm 2 g -1 Up to 50,000cm 2 g-1 Or 30,000cm 2 g -1 Up to 40,000cm 2 g -1 Within the range.

[0083] The concentration of the carbonaceous material precursor in the aluminum mixture relative to the weight of other components can be 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight or less, 10% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 1.5% by weight or less, or 1% by weight or less. In some embodiments, the concentration of the carbonaceous material precursor in the aluminum mixture relative to the weight of other components is 1% to 30% by weight, 1% to 25% by weight, 1% to 20% by weight, 1% to 18.3% by weight, 1.5% to 18.3% by weight, 3% to 18.3% by weight, 1% to 15% by weight, 1% to 10% by weight, 1% to 5% by weight, or 1.5% to 3% by weight.

[0084] The concentration of aluminum in the aluminum mixture relative to the weight of other components can be at least 99% by weight, at least 98.5% by weight, at least 98% by weight, at least 97% by weight, at least 96% by weight, at least 95% by weight, at least 90% by weight, or at least 85% by weight. In some embodiments, the concentration of aluminum in the aluminum mixture relative to the weight of other components is 85% to 99% by weight, 90% to 99% by weight, 95% to 99% by weight, 96% to 99% by weight, 97% to 99% by weight, or 97% to 98.5% by weight.

[0085] The aluminum mixture can be subjected to one or more thermal shock heating cycles in a container with a screw cap. The atmosphere can be air or nitrogen. The screw cap can be a bolt-like component, and its rotation allows for precise adjustment of the opening and the physicochemical processes within the aluminum powder mixture. The rotation of the cap is crucial for the optimal release and oxidation of unwanted hydrocarbon gases, as well as the intake of nitrogen.

[0086] Thermal shock heating cycles can be independently comprised of cycles at 40°C / min. -1 up to 400℃min -1The aluminum mixture is heated to 450°C to 650°C at a rate of [missing information] to form a thermal shock aluminum mixture. In some embodiments, the thermal shock aluminum mixture is subsequently annealed between 450°C to 600°C, 400°C to 500°C, 450°C to 550°C, 450°C to 500°C, 550°C to 600°C, or 500°C to 600°C, 500°C to 650°C. The aluminum mixture can be annealed at 40°C / min. -1 up to 400℃min -1 40℃min -1 up to 350℃min -1 40℃min -1 up to 300℃min -1 40℃min -1 up to 250℃min -1 40℃min -1 up to 200℃min -1 40℃min -1 up to 150℃min -1 40℃min -1 up to 100℃min -1 100℃min -1 up to 400℃min -1 150℃min -1 up to 400℃min -1 200℃min -1 up to 400℃min -1 250℃min -1 up to 400℃min -1 300℃min -1 up to 400℃min -1 Or 350℃min -1 up to 400℃min -1 Heating rate.

[0087] The aluminum mixture may be subjected to one or two thermal shocks prior to annealing. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more thermal shock heating cycles. In some embodiments, the aluminum mixture may be subjected to 1 to 5, 1 to 4, 1 to 3, 1 to 2, 2 to 5, 2 to 4, 2 to 4 or 2-3 thermal shock heating cycles.

[0088] Thermal shock aluminum mixtures can be annealed at temperatures between 450°C and 650°C.

[0089] The thermal shock aluminum mixture can be annealed for a period of 6 minutes to 600 minutes. In some embodiments, the thermal shock aluminum mixture can be annealed for a period of 6 minutes to 540 minutes, 6 minutes to 480 minutes, 6 minutes to 420 minutes, 6 minutes to 360 minutes, 6 minutes to 300 minutes, 30 minutes to 300 minutes, 30 minutes to 240 minutes, 30 minutes to 180 minutes, 30 minutes to 120 minutes, or 30 minutes to 60 minutes.

[0090] Thermal shock aluminum mixtures can be annealed in air or nitrogen or in an atmosphere containing O2, N2, CO2, H2O or in any combination of O2, N2, CO2 and H2O.

[0091] The present invention also provides a method for generating hydrogen (H2), the method comprising: contacting an aqueous solution with an active aluminum complex comprising aluminum, AlN, γ-Al2O3 and carbonaceous material to form H2.

[0092] In some embodiments, the aqueous solution includes tap water, distilled water, seawater, reclaimed water, river water, lake water, wastewater, rainwater, or combinations thereof. In some embodiments, water is not added but incorporated, for example, as Al(OH)3×xH2O present in the structure of an active aluminum complex.

[0093] The aqueous solution can be neutral (pH 7) or have a pH greater than 7. In some embodiments, the pH of the aqueous solution is greater than 7.5, greater than 8.0, greater than 8.5, greater than 9.0, greater than 9.5, greater than 10.0, greater than 10.5, greater than 11.0, greater than 11.5, greater than 12.0, greater than 12.5, greater than 13.0, greater than 13.5, or greater. Advantageously, the methods described herein can be carried out in pure water without the use of acid or alkali.

[0094] In some embodiments, the pH of the aqueous solution is between 7.0 and 7.5, 8 and 14.0, 8.5 and 14.0, 9.0 and 14.0, 9.5 and 14.0, 10.0 and 14.0, 10.5 and 14.0, 11.0 and 14.0, 11.5 and 14.0, 12.0 and 14.0, 12.4 and 13.4, 12.5 and 14.0, 13.0 and 14.0, 13.0 and 13.4, or 13.5 and 14.0.

[0095] The pH of the aqueous solution can be adjusted using any base that is at least partially soluble in the aqueous solution. In some embodiments, the base is a metal hydroxide. Exemplary metal hydroxides include, but are not limited to, LiOH, NaOH, KOH, RbOH, CsOH, Mg(OH)2, Ca(OH)2, Sr(OH)2, and Ba(OH)2. In some embodiments, the aqueous solution contains a metal hydroxide with a concentration between 0.01M and 10M, 0.01M and 5M, 0.01M and 4M, 0.01M and 3M, 0.01M and 2M, 0.01M and 1M, 0.01M and 0.9M, 0.01M and 0.8M, 0.01M and 0.7M, 0.01M and 0.5M, 0.01M and 0.4M, 0.01M and 0.3M, 0.01M and 0.25M, 0.05M and 0.25M, 0.05M and 0.20M, 0.1M and 0.2M, 0.025M and 0.25M, 0.0625M and 0.25M, 0.125M and 0.25M, or 0.0625M and 0.125M.

[0096] Advantageously, hydrogen production can occur in aqueous solutions with a lower pH if a salt is added. The choice of salt is not particularly limited. In some embodiments, the salt contains one or more components selected from Li. + Na + K + Mg 2+ Ca 2+ and NH 4+ The group consists of cations and one or more selected from Br - Cl - F - I - NO3 - CO3 2- SO4 2- and PO4 3- The group of anions. Exemplary salts include, but are not limited to, NaCl, KCl, and CaCl2. Salts may be present in aqueous solutions at concentrations of 4% by weight or less, 3.5% by weight or less, 3% by weight or less, 2.5% by weight or less, 2% by weight or less, 1.5% by weight or less, 1% by weight or less, or 0.5% by weight or less.

[0097] Hydrogen generation can occur at any temperature ranging from 20°C to 100°C in the presence of water, or at temperatures up to 400°C when water is released primarily from the microstructure of the complex (e.g., Al(OH)3×xH2O). Generally, the hydrogen generation rate increases at higher temperatures. In some embodiments, the active aluminum complex and the aqueous solution are contacted at temperatures between 20°C and 40°C, 20°C and 30°C, 40°C and 60°C, 60°C and 80°C, or 80°C and 100°C.

[0098] The hydrogen production rate can be adjusted by changing hydrogen production conditions such as the concentration of the alkali. In some embodiments, each gram of active aluminum complex produces 125 ml / min. -1 Up to 500ml min -1 The volume of hydrogen is measured at standard temperature and pressure.

[0099] Figure 1 The production of an active aluminum composite according to certain embodiments described herein is illustrated schematically. Step (10) includes providing aluminum particles having a specific geometry. These particles may contain a small amount of fatty acids or salts thereof (e.g., metal stearates) on their surface. In some embodiments, the fatty acid mass percentage on the initial aluminum sheet is 0% to 5% by weight. In some embodiments, the aluminum particles comprise spheres with a size between 1 μm and 30 μm, a transverse sheet width between 1 μm and 30 μm, and a thickness between 10 nm and 100 nm. Exemplary microscopic images of the initial aluminum particles are shown below. Figure 2 As shown. The initial aluminum particle specific surface area can be relatively high, for example, 16,000 cm² for both water-covered and Brunauer-Emmett-Teller (BET) surfaces. 2 g -1 Up to 60000cm 2 g -1 Or 4cm 2 g -1 up to 21m 2 g -1 .

[0100] Step (20) involves loading the initial aluminum sheet and additional amounts of fatty acids or their salts into a metal container. The addition of these fatty acids or their salts can range from 0% by weight to 40% by weight. The container has a permeable screw cap, see [link to relevant documentation]. Figure 3 In some embodiments, the container wall thickness is not less than 0.3 mm and not more than 3 mm to provide optimal heat transfer from the furnace heating zone to the aluminum sheet. In some embodiments, the container material is nickel steel, stainless steel, or copper. In some embodiments, partially sintered Ni particle blocks are added to the container to catalyze the synthesis of aluminum composite particles.

[0101] In step (30), the container is subjected to thermal shock (40°C min). -1 up to 400℃min -1 The temperature is raised to between 450°C and 650°C. This thermal shock heating causes the am-Al2O3 surface layer of the alumina to gradually crack and irregularly crystallize into γ-Al2O3. Simultaneously, carbonaceous precursors or their salts can decompose and partially inhibit the uniform formation of the alumina surface layer, triggering Al nitriding. The heat treatment can result in the formation of a composite material containing carbon, aluminum, nitrogen, and oxygen. The aluminum sheet can be subjected to one or more thermal shocks to achieve the desired activation level. In some embodiments, the aluminum sheet is further annealed at a temperature of 450°C to 650°C for 6 minutes to 600 minutes. The annealing step can be carried out in an air atmosphere or in an atmosphere containing any combination of gases selected from N2, H2O, and CO2.

[0102] In step (40), the container is heated to 40°C for 40 minutes. -1 up to 400℃min -1 The activated aluminum composite particles are cooled at a rate that allows them to be removed and optionally ground. Figure 4 Microscopic images of the activated aluminum composite particles are shown. Although the dominant element is aluminum, exceeding 85% by weight, EDS identified carbon concentrations of up to approximately 13% by weight in certain sites of the activated aluminum composite (see [link to EDS]). Figure 5 In some embodiments, the carbon concentration in certain sites of the active aluminum composite can range from 10% to 30% by weight. In some embodiments, carbon can be present in the form of a complex chemically bonded to aluminum, oxygen, and nitrogen. In some embodiments, AlN(2,2-dimethylamine) in the composition can be observed using X-ray diffraction. Figure 6 ).

[0103] Step (50) involves compacting the active sheet into a porous box to increase the volumetric hydrogen density. The box is a convenient form of handling active aluminum composite particles, providing safe long-term storage and resistance to moisture and fire. Partial generation of H2 from the box leads to the formation of Al(OH)3 and its hydrates, and water is not required in some applications. In this case, temperatures up to 400°C are needed to release bound water from its structure. The compaction of the active composite particles can be performed using one or more machines for densification, such as presses, extruders, and other machines. In some embodiments, the sheet densification is partial, such that the box includes open channels.

[0104] This article also provides a system for storage and hydrogen generation in step (60). Figure 7An exemplary schematic diagram illustrating step (60) is shown. Containers (110, 130) for the cartridges containing the activated aluminum compound (120) and water (140) can be made of carbon steel, glass, titanium, high-density polyethylene, low-density polyethylene, polypropylene, and other rigid and heat-resistant polymers. After opening the screw cap (160), the container (130) can be refilled with water (140) and hydroxide additive (150). In some embodiments, the containers (110, 130) can be cylindrical. In some embodiments, the containers can be connected via parallel conduits. Each container has a body (110, 130) and a screw cap (160) for easy opening, loading of the aluminum cartridge / activated aluminum compound, and discharge of the reaction products. The ease of discharging aluminum hydroxide is part of some embodiments because it is a valuable product. Therefore, the containers can be reused for multiple loading / discharging cycles. The screw cap (160) may have a conduit inlet and an outlet (170) with a water flow regulator (180). Other conduits are used for the distribution and filtration of the generated gas. In some embodiments, the box or activated aluminum composite (120) can be packaged in a container using a water-degradable package containing an alkaline activator (150) (e.g., NaOH). This allows for the supply of pure water (140) to the loaded container. In some embodiments, the container (130) can be filled with an effective alkaline solution. Hydrogen or a hydrogen-containing mixture is released through an outlet (170). In some embodiments, the water container (130) can be filled with tap water, seawater, groundwater, or heavy water. In some embodiments, the box (120) can be immersed and cured in water, steam, or humid air, and subjected to thermal exposure. Depending on the mass, porosity, composition, and heat intensity, this treatment can last from several hours to several days. It results in the partial generation of hydrogen and the in-situ formation of Al(OH)3 to provide a dry composition with bound water. The refillable box (121) of this example can be dried and loaded into a container (110). When the refillable box (121) is heated to a maximum of 400°C, the bound hydrogen is released through the reaction of Al and Al(OH)3. In some embodiments, the cartridge (121) can generate hydrogen by applying thermal solar radiation without adding water. On the other hand, the cartridge (120) may require a higher temperature or an alkaline aqueous solution to completely release hydrogen. For example, the cartridge (120) can be completely released into water using 0.1% to 1% by weight (0.025M to 0.25M NaOH), more preferably 0.3% to 0.6% by weight (0.1M to 0.2M NaOH). In some embodiments, the hydroxide concentration can be reduced by adding no more than 4% by weight, more preferably no more than 3% by weight of a salt (e.g., NaCl, KCl, CaCl2). In some preferred embodiments, hydrogen is efficiently generated in seawater.

[0105] All these embodiments are intended to be within the scope of the invention disclosed herein. It should be understood that... Figure 7 The components 110-180 shown schematically are considered to be further integrated, separated, or replaced for a specific application.

[0106] The effectiveness of the active aluminum composite and the cartridge is further described in the examples. Hydrogen yield and rate were measured by water displacement at 22°C. The average size (D) of the active composite particles is also described. 50 The value (μm) was obtained by measuring with a MICROTRAC particle size analyzer. When applicable, water cover area (WCA; cm²) is used. 2 g -1 ) is the value obtained by measuring according to the method described in [7].

[0107] Example

[0108] Example 1

[0109] The active aluminum composite consists of an average particle size D 50 It is 4.6 μm and the WCA is approximately 48,000 cm. 2 g -1 It is made from leafing aluminum flake powder. These aluminum particles contain stearic acid, with a content of approximately 3% by weight. The flake powder is placed in a stainless steel container and transferred to a furnace at 600°C. The screw cap is set to three full turns to allow for the release of excess gas buildup, and atmospheric nitrogen is injected into the container. The container is subjected to a single thermal shock by heating to 600°C at a rate of 200°C / min and annealing at 600°C for 30 minutes.

[0110] Figure 8 Hydrogen production was compared between the active aluminum composite particles and spherical aluminum microparticles (35 μm) from Example 1 in 0.05 M NaOH and 0.5 M NaOH. Each sample weighed 1 gram and theoretically, complete oxidation at 22°C would produce 1,345 ml of hydrogen. Figure 8 As shown, the active aluminum complex in 0.5M NaOH initially reacted at a rate of 500 ml / min. -1 g Al -1 Hydrogen is produced at a rate that decreases over time. The amounts of hydrogen produced are 1,120 ml and 1,160 ml at 10 min and 25 min, respectively. This maximum amount corresponds to a reaction yield of 87% when compared to the amount of hydrogen produced from the spherical aluminum particles. That is, the proportion of Al in the complex is 87%. It should be noted that the initial Al flake particles are coated with stearic acid and do not produce hydrogen even in alkaline aqueous solutions. Reference particles exhibit comparable activity in 0.5 M NaOH, demonstrating the kinetics used to define the theoretical H2 limit.

[0111] Figure 8The effect of NaOH concentration on the reaction kinetics of the active aluminum complex from Example 1 was also shown. Although the reaction rate was slightly slower in 0.05 M NaOH, the reaction proceeded to completion. However, the reference particles in 0.05 M NaOH produced only about 100 ml of H2 over 8 hours.

[0112] Figure 9 The results show that the active Al complex particles can completely generate hydrogen in water without NaOH but at a temperature below 100°C. The optimal temperature range is 40°C to 60°C. Reference Al particles do not generate hydrogen in distilled water.

[0113] Example 2

[0114] This example demonstrates the effect of densification on hydrogen production in distilled water at 60°C. Figure 10 Here, the active Al composite particles were densified using cold isostatic compression at 25 MPa (Example 2-1), 37 MPa (Example 2-2), 50 MPa (Example 2-3), and 75 MPa (Example 2-4). Although the reaction rate decreased with increasing compaction density, partial hydrogen generation occurred near the Al in the microstructure, producing Al(OH)3 and its hydrate. Such a composition does not require liquid water to generate hydrogen, and the reaction Al + Al(OH)3 = 1.5H2 + Al2O3 was carried out in a temperature range of 100°C to 300°C. Sample Example 2-1 produced approximately 577 ml of H2 in distilled water at 60°C. After drying at 120°C for 20 hours, the loaded sample was placed in a 20 ml vial connected to a water displacement system. The vial was rapidly heated on a hot plate (3 to 4 minutes) to a temperature of approximately 350°C. During heating, the sample released approximately 480 ml of hydrogen.

[0115] It should be noted that the emission temperature can be much higher, up to 400°C, which can be achieved by using solar concentrators, furnaces or other facilities.

[0116] Provides average particle size D 50 It is 30μm and the BET surface area is 7m². 2 g -1 Leaf-shaped aluminum powder. These aluminum particles contain 1.5% stearic acid by weight. The water coverage of these particles is approximately 16,000 cm³. 2 g -1The powder was placed into a stainless steel container with an outlet approximately 1 mm in diameter. The container was then placed in a furnace heating zone at 580°C. The medium surrounding the container was a flowing atmosphere of nitrogen (99.99%). The container was subjected to three thermal shocks: from 450°C to 150°C and from 150°C to 450°C, followed by annealing at 450°C for 40 minutes. After annealing and cooling to a cooling temperature of approximately 150°C, the atmosphere was changed to air, and the container was further annealed for 120 minutes. The activated aluminum composite was compacted into a box with a porosity of approximately 60% using cold isostatic pressing at 20 MPa. In this embodiment, the oxidation of the activated aluminum composite was carried out using an infrared lamp (275 kW) in tap water heated to a maximum of 60°C. Figure 7 The relationship between hydrogen production rate and temperature is described in the paper. The experiment shows that the hydrogen production rate is moderate, at 3 ml / min. -1 Up to 11 ml / min -1 Furthermore, it is possible to generate H2 using solar radiation.

[0117] Example 3

[0118] It provides a diameter of approximately 1 μm and a BET surface area of ​​3 m². 2 g -1 Spherical Al particles were obtained. A container containing these Al particles was sealed with a screw cap (2 turns) and placed in a furnace preheated to 600°C. A triple thermal shock was generated by heating to 600°C, cooling to 100°C, and then heating back to 600°C. After the shock heat treatment, the particles were annealed at 600°C for 20 minutes. After rapid cooling to room temperature (100°C / min), the active Al particles were removed from the container.

[0119] Figure 11 The kinetics of hydrogen production in distilled water at 50°C and 80°C in Example 3 are shown. The reaction rate is lower than that in Example 1, but this does not necessarily limit the solution to certain applications. It should be noted that the initial Al particles (1 μm) will not produce hydrogen under similar conditions.

[0120] Example 4

[0121] The fine aluminum particles used for heat treatment are produced by cutting an epoxy-coated Al can (Coca-Cola). This embodiment demonstrates the applicability to relatively large aluminum particles and waste that is difficult to sort and recycle. The cut pieces can be 8 mm in diameter laterally. The epoxy coating serves as a source of carbon incorporation, while the use of water (1% by weight of the waste) added to the container enhances the nitriding effect. The screw cap on the container is set to one turn. The container is placed in a furnace at 650°C to generate thermal shock and initiate a chemical reaction. The container is further annealed for 60 minutes and cooled to 22°C at 200°C / min. During annealing, the epoxy layer cracks as nitrogen and carbon are introduced into the aluminum microstructure.

[0122] The kinetics of hydrogen production from active complex particles in NaOH solutions of different concentrations are as follows: Figure 12 As shown in the figure. The results show that in 0.5M NaOH, H2 production can almost reach the theoretical value of 1,345 ml. Other examples show that the reaction rate decreases with decreasing NaOH concentration. This does not necessarily limit the application of these active aluminum complexes, as the kinetics can be enhanced at higher temperatures.

[0123] Provides average particle size D 50 It has a thickness of 10 μm and a BET surface area of ​​8.4 m². 2 g -1 Leaf-shaped aluminum powder. These particles have a water coverage of approximately 26,000 cm³. 2 g -1 The stearic acid content is approximately 2% by weight. Approximately 25g of this powder is mixed with 5g of stearic acid and placed in a stainless steel container with a screw cap. The container is then placed in a furnace at 500°C in air. The container is subjected to a thermal shock and annealed at 500°C for 60 minutes. At a cooling temperature of 110°C, the screw cap is removed, and the opened container is annealed for another 30 minutes. Approximately 2g of activated aluminum powder is compacted at 46MPa into a box with a porosity of 45%. The box is placed in distilled water for 24 hours. After drying at 30°C for 12 hours, the loaded box weighs 3.2g. A portion of the stored hydrogen is released by heating the loaded box (Example 3) using an infrared lamp (275kW). When the temperature rises to approximately 110°C, the sample releases approximately 184ml of hydrogen. The loading-discharging cycle can be repeated by immersing the discharged sample in water for 12 to 24 hours. It should be noted that the emission temperature can be much higher, up to 400°C, which can be achieved by using solar concentrators, furnaces or other facilities.

Claims

1. A method for producing hydrogen (H2), the method comprising providing an aluminum mixture comprising aluminum and optionally a carbonaceous material precursor; subjecting the aluminum mixture to one or more thermal shock heating cycles, wherein the one or more thermal shock heating cycles independently comprise a temperature of 40°C for 1 minute. -1 up to 400℃ min -1 The aluminum mixture is heated to 450°C to 650°C at a rate of [missing information] to form a thermally shock-prone aluminum mixture; and the thermally shock-prone aluminum mixture is annealed at 450°C to 650°C to form an active aluminum composite comprising aluminum, γ-Al₂O₃, AlN, and optionally a carbonaceous material; and [missing information] The aqueous solution is brought into contact with the active aluminum complex to form H2.

2. The method according to claim 1, wherein the active aluminum composite comprises a diameter D 50 The thickness is 1 μm to 50 μm and the thickness D 50 Aluminum composite sheets ranging from 10 nm to 100 nm.

3. The method of claim 1, wherein a layer comprising γ-Al₂O₃, AlN, and optionally a carbonaceous material is disposed on the surface of aluminum.

4. The method of claim 1, wherein the carbonaceous material comprises carbon and one or more elements selected from the group consisting of nitrogen and oxygen.

5. The method according to claim 1, wherein the carbonaceous material is prepared by carbonization of a carbonaceous material precursor, said carbonaceous material precursor being selected from the group consisting of carboxylic acids, polyvinyl alcohol, epoxy resins and their salts.

6. The method according to claim 5, wherein the carbonaceous material precursor is C6-C. 25 Saturated carboxylic acids, C6-C 25 Unsaturated carboxylic acids or their salts.

7. The method according to claim 5, wherein the carbonaceous material precursor is lauric acid, palmitic acid, stearic acid or a salt thereof.

8. The method of claim 1, wherein the active aluminum composite comprises at least 85% by weight aluminum.

9. The method according to claim 1, wherein the active aluminum composite comprises a diameter D 50 The thickness is 10 μm to 30 μm and the thickness D 50 The aluminum composite sheet is 10 nm to 100 nm in size; the carbonaceous material is prepared by carbonization of a carbonaceous material precursor selected from the group consisting of carboxylic acids, polyvinyl alcohol and their salts; and the active aluminum composite contains at least 87% by weight of aluminum.

10. The method of claim 1, wherein the active aluminum composite is processed from aluminum parts or prepared from aluminum scrap; and the aluminum composite comprises particles ranging in length from 1 µm to 10,000 µm and having a thickness of less than 500 µm.

11. The method of claim 10, wherein the active aluminum composite is prepared from an aluminum can.

12. The method of claim 9, wherein the carbonaceous material is prepared by carbonization of stearic acid or a salt thereof.

13. The method of claim 1, wherein the aluminum mixture is subjected to 1 to 4 thermal shock heating cycles.

14. The method of claim 1, wherein the thermal shock aluminum mixture is annealed at a temperature of 500°C to 650°C.

15. The method of claim 1, wherein the aqueous solution has a pH equal to or greater than 7.

16. The method of claim 1, wherein the aqueous solution has a pH of 12.4 to 13.

4.

17. The method of claim 16, wherein the aqueous solution has a pH of 13 to 13.

4.

18. The method according to claim 1, wherein the aqueous solution comprises NaCl, KCl or CaCl2.

19. The method of claim 1, wherein the aqueous solution comprises distilled water or seawater.

20. The method according to claim 1, wherein H2 is present at a concentration of less than 500 ml / min per gram of active aluminum complex. -1 The rate of H2 production is measured at a temperature of 22°C and standard atmospheric pressure.

21. The method according to claim 1, wherein the active aluminum composite comprises a diameter D 50 The thickness is 10 μm to 30 μm and the thickness D 50 The aluminum composite material is in the form of 10 nm to 100 nm aluminum flakes or spherical aluminum particles; the carbonaceous material is prepared by carbonization of stearic acid; the active aluminum composite contains at least 85% by weight aluminum; the aqueous solution has a pH of 13 to 13.4; and the H2 concentration is less than 500 ml / min per gram of active aluminum composite. -1 The rate of H2 production is measured at standard atmospheric pressure and a temperature of 22°C.

22. The method of claim 21, further comprising providing an aluminum mixture comprising aluminum and stearic acid; subjecting the aluminum mixture to one or more thermal shock heating cycles, wherein the one or more thermal shock heating cycles independently comprise a temperature of 40°C for 1 minute. -1 up to 400℃ min -1 The aluminum mixture is heated to 450°C to 650°C or cooled from 450°C to 650°C to 100°C to 200°C at a rate to form a thermally shocked aluminum mixture; and the thermally shocked aluminum mixture is annealed at a temperature between 450°C and 650°C to form the active aluminum composite.

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