Method for generating hydrogen and oxygen gases

Abstract

The present disclosure relates to methods and reactors for generating gases, and in particular, to methods and reactors for generating oxygen and hydrogen gases.

Description

[Technical field]

[0001] The present disclosure relates to methods and reactors for generating hydrogen and oxygen gases. [Background technology]

[0002] References that are considered relevant as background to the subject matter disclosed herein are listed below.

[0003] Acknowledgement of the above references in this specification should not be inferred as meaning that they are in any way relevant to the patentability of the subject matter disclosed herein.

[0004] background Efforts to use alternative energy sources are underway due to environmental concerns and regulations to eliminate CO2 emissions in transportation and petrochemical industries. Common alternative energy sources that exist today are based on wind or solar energy, which are inconsistent and therefore depend on storage that is less economically efficient. Another alternative energy source uses nuclear reactors for electricity production, however, nuclear energy is also limited due to negative perceptions. Thus, existing alternative energy sources have shortcomings that continue the search for available and economical alternative energy sources.

[0005] Existing alternative energy sources such as solar, wind, and nuclear energy each have drawbacks such as lack of consistency, low economic efficiency, and negative public perception. Fuel cells using hydrogen as fuel are an option for clean power generation. However, existing methods for producing hydrogen are expensive. Furthermore, existing methods for producing hydrogen require electricity. For example, electrolyzers produce hydrogen by splitting water using electricity. For green hydrogen production, electricity is generated by renewable green energy such as solar, wind, or nuclear sources. Such technologies are not cost-effective when looking at electricity-to-hydrogen conversion due to the reliance on energy storage in the case of wind and solar energy, or the negative perception in the case of nuclear energy. Summary of the Invention

[0006] The present invention is based on the development of a method and reactor for the generation of oxygen gas and / or hydrogen gas in temporally and / or spatially separated steps.

[0007] The methods and reactors described herein allow for control over the type of gas produced (generated), i.e., hydrogen gas or oxygen gas, as well as the ability to produce gas in a sequential or continuous manner.

[0008] As shown in the Examples below, it has been found that irradiation of a metal oxide (MO) with radiation, including, inter alia, alpha, beta, or gamma radiation, reduces the mass of the metal oxide. It has been suggested that upon irradiation of the metal oxide, oxygen atoms are released (removed) from the metal oxide, and possibly from the metal oxide surface, generating vacant oxygen sites in the metal oxide, as well as oxygen gas.

[0009] In the following text, metal oxides characterized by having vacant oxygen sites will be referred to as oxygen vacancy metal oxides (OVMOs). Note that the term OVMO encompasses metal oxide molecules in which one or more of the oxygen atoms have been removed (released).

[0010] Notably, the observed reduction in metal oxide mass and oxygen gas evolution occurred at temperatures below, and sometimes even at temperatures half, third, or fifth of, that required to overcome the binding energy of the MOs. In other words, the methods described herein do not involve heating to temperatures typically required to overcome the binding energy of the MOs to release oxygen atoms, yet still form OVMOs and generate oxygen gas.

[0011] As will be shown further herein below, in the presence of oxygen, in the ambient air as well as in the presence of water, oxygen atoms can recombine with OVMOs such that the OVMOs can undergo regeneration to form MOs. Thus, considering the reversibility of MO-OVMOs, it has been suggested that, for example, under conditions of continuous exposure to irradiation, oxygen gas can be continuously generated. In such an example, the formed OVMOs recombine with oxygen atoms to regenerate MOs, which can be further used to generate oxygen gas.

[0012] As further demonstrated in the Examples below, exposure of OVMO to water vapor evolves hydrogen gas.

[0013] It has been suggested that in the presence of OVMOs, the recombination (reabsorption) of oxygen atoms (from water vapor) into the OVMOs causes the water to decompose (split), regenerate the MOs, and produce hydrogen gas.

[0014] It has therefore been further suggested that the OVMO may be suitable for generating hydrogen gas after exposure to water vapor. This method for generating hydrogen may be performed in situ, i.e., at the site where the OVMO is generated, or remotely, i.e., by transporting or shipping the OVMO to a facility. In either case, the OVMO is exposed to water vapor to generate hydrogen.

[0015] Additionally or alternatively, the method allows for the sequential generation of oxygen gas and hydrogen gas (in a mutually related manner). Specifically, irradiation of the metal oxide results in the generation of oxygen gas and the formation of an OVMO, and upon exposure of the OVMO to water vapor, hydrogen gas is generated and the metal oxide is regenerated for further cycles. Thus, controlling the timing of exposure to one or more of the radiation or water vapor provides a tool to control the type of gas generated.

[0016] According to some embodiments, the present disclosure provides a method that includes irradiating a metal oxide to obtain a metal oxide having oxygen vacancies (OVMO) and oxygen gas, the irradiation being at a temperature below the temperature required to overcome the metal oxide binding energy.

[0017] According to some other aspects, the present disclosure provides a method that includes irradiating a metal oxide to obtain a metal oxide having oxygen vacancies (OVMO) and oxygen gas, wherein the metal oxide is maintained at a temperature below the temperature required to overcome the metal oxide binding energy.

[0018] In the following text, when a process is mentioned, it should be understood as also referring to the reactor, or the system, or the generator disclosed herein. Thus, whenever a feature is provided with respect to a process, it should be understood as defining the same feature with respect to the reactor, or the system, or the generator, mutatis mutandis.

[0019] It should be noted that references to temperatures below the temperature required to overcome the metal oxide binding energy should be understood as temperatures below the temperature typically required to release at least one oxygen atom from the metal oxide.

[0020] As will be understood, the bond energy of a metal oxide is the energy required to break the bond between the metal and at least one oxygen atom. Note that sometimes there are two bond energies, one for each oxygen atom in the metal oxide molecule.

[0021] For example, for metal oxides whose temperature for releasing oxygen atoms is about 1500° C., in the method developed herein, oxygen atoms were released at a four or even five times lower temperature, which was suggested to be due to the absorption of energy by the metal oxide as a result of irradiation.

[0022] As will be appreciated, the metal oxide can be irradiated with a variety of radiations, provided that the radiation is capable of releasing at least one oxygen atom from the metal oxide compound at a temperature lower than that required to overcome the binding energy of the MO. In other words, radiation according to the present disclosure is radiation that does not require heating the metal oxide to a temperature typically required to overcome the binding energy of the MO. In some examples, methods are employed such that the metal oxide is maintained (kept) at a temperature lower than that required to overcome the binding energy of the MO.

[0023] In some instances, during irradiation, the metal oxide is at a temperature of up to about 1500°C, sometimes up to about 1000°C, sometimes up to about 500°C, sometimes up to about 100°C, sometimes up to about 80°C, and sometimes up to 50°C.

[0024] In some examples, during irradiation, the metal oxide is at a temperature of about 1° C. to about 500° C., sometimes about 2° C. to about 400° C., sometimes about 3° C. to about 300° C., sometimes about 4° C. to about 200° C., and sometimes about 5° C. to about 150° C.

[0025] In some examples, during irradiation, the metal oxide is at a temperature of about 20°C to about 500°C, sometimes about 20°C to about 400°C, sometimes about 20°C to about 300°C, sometimes about 20°C to about 200°C, sometimes about 20°C to about 150°C, sometimes about 20°C to about 100°C, and sometimes about 20°C to about 80°C.

[0026] In some examples, during irradiation, the metal oxide is at a temperature of about 30°C to about 500°C, sometimes about 50°C to about 500°C, sometimes about 70°C to about 500°C, sometimes about 100°C to about 500°C, and sometimes about 150°C to about 500°C.

[0027] In some examples, the methods are applicable to generating OVMO and oxygen gas, and the metal oxide is at a temperature of about 5° C., sometimes about 10° C., sometimes about 15° C., sometimes about 17° C., sometimes about 20° C., sometimes about 22° C., sometimes about 25° C., sometimes about 28° C., sometimes about 30° C., and sometimes about 35° C.

[0028] In some examples, the methods are applicable to generate OVMO and oxygen gas, and the metal oxide is at a temperature of about 50° C., sometimes about 60° C., sometimes about 70° C., sometimes about 80° C., sometimes about 90° C., sometimes about 100° C., sometimes about 110° C., sometimes about 120° C., sometimes about 130° C., and sometimes about 140° C.

[0029] In some examples, the methods are applicable to generate OVMO and oxygen gas, and the metal oxide is at a temperature of about 200° C., sometimes about 220° C., sometimes about 240° C., sometimes about 260° C., sometimes about 300° C., sometimes about 350° C., sometimes about 400° C., sometimes about 450° C., and sometimes about 500° C.

[0030] In some embodiments, the temperature may be about one-third, about one-quarter, about one-fifth, about one-sixth, about one-seventh, about one-eighth, about one-ninth, about one-tenth, about one-twelfth, about one-fifteenth, about one-seventeenth, about one-twentieth, about one-twenty-second, about one-twenty-fifth, about one-twenty-seventh, about one-thirtieth, about one-thirty-second, about one-thirty-fifth, about one-thirty-seventh, about one-fortieth, about one-forty-second, about one-forty-fifth, about one-forty-seventh, or about one-fiftieth of the temperature required to overcome the binding energy of the MO.

[0031] As will be appreciated, the temperature at which the bond between the metal atom and the oxygen atom breaks can be calculated by measuring the energy required to break the bond by any method known in the art.

[0032] As will be understood, the term radiation refers to the emission or transmission of energy in the form of electromagnetic waves or particles. As used herein, radiation encompasses natural and artificial radiation. Additionally, radiation as used herein refers to thermal and non-thermal radiation.

[0033] In some embodiments, the radiation is thermal radiation.

[0034] In some embodiments, the radiation is non-thermal radiation.

[0035] As used herein, the term non-thermal radiation refers to radiation that is not dependent on the temperature of the radiation source.

[0036] In some examples, the irradiation is at atmospheric pressure. In some embodiments, the radiation carries at least 10 eV per emitted particle or photon.

[0037] In some examples, the radiation is electromagnetic radiation. In some examples, the electromagnetic radiation includes high-energy photons.

[0038] In some examples, the electromagnetic radiation is or includes at least one of ultraviolet radiation, x-rays, and gamma radiation (γ).

[0039] In some examples, the electromagnetic radiation is or includes X-rays, which are a form of electromagnetic radiation that typically has wavelengths in the range of 0.01 to 10 nanometers.

[0040] In some examples, the radiation is or includes particle radiation, hi some examples, the particle radiation is alpha radiation (α) or beta radiation (β).

[0041] In some embodiments, the radiation source is a radioactive material.

[0042] There are a variety of radioactive materials that can be used in the present disclosure, including naturally occurring and artificially radioactive materials. In some examples, the radioactive material is at least one or more of Co-60, Sr-90, Cs-137, Cs-135, and Mo-99.

[0043] As will be appreciated, radioactive materials emit radiation, beta radiation, or gamma radiation, or a combination thereof. Such radiation emitted from radioactive materials can include one or more of alpha radiation, beta radiation, or gamma radiation. Alpha, beta, and gamma radiation each have different masses, charges, energies, and therefore different penetration depths through media, and current commercial uses.

[0044] In some examples, the radiation is selected from the group consisting of alpha radiation, beta radiation, and gamma radiation.

[0045] In some instances, the radiation is alpha radiation (particles). Alpha particles are the heaviest type of radioactive particle, consisting of two protons and two neutrons (e.g., A helium nucleus) and carrying a positive charge. Many of the naturally occurring radioactive materials on Earth, such as uranium and thorium, emit alpha particles due to spontaneous fission reactions. Alpha radiation cannot penetrate the skin and travels very short distances in the air. Note that this is not a nuclear chain reaction, but a natural decay.

[0046] In some instances, the radiation is beta radiation (particles). A beta particle is an electron or positron that is not bound to an atom. It has a small mass and has either a negative or positive charge. Beta radiation can travel several meters through the air and penetrate human skin to the innermost layer of the epidermis, where new skin cells are produced. If beta-emitting contaminants remain on the skin for an extended period of time, they can cause skin damage. Clothing and turnout gear provide some protection against most beta radiation. Personal protective equipment should be worn to protect clothing and other uncovered skin from any type of contamination.

[0047] In some instances, the radiation is gamma radiation. Gamma radiation is electromagnetic radiation, a known example is X-rays. Gamma rays are specific to radioactive decay from radioactive nuclei. These rays are like sunlight but with much more energy per photon, about a million times greater. Quantum mechanics considers electromagnetic waves as a stream of discrete particles called photons, which carry no charge and have very low mass. Gamma radiation is the most penetrating, with the ability to travel several meters through air and several centimeters into human tissue.

[0048] In some examples, the radiation is UV radiation. UV radiation or ultraviolet radiation is in the wavelength range of about 10 to 400 nanometers and is divided into three categories, UV-A, UV-B, and UV-C, based on their wavelength and energy. As described herein, the UV radiation can be applied using a UV source. In some examples, the UV source is a UV lamp.

[0049] As described herein, irradiating at least one metal oxide results in a metal oxide having an empty oxygen site (designated as OVMO) due to the release of an oxygen atom. Therefore, as described herein, the emitted particle / photon energy according to the present disclosure should exceed the metal oxide binding energy.

[0050] When referring to metal oxide bond energy, it includes oxygen-oxygen and / or metal-oxygen. Typically, the first oxygen atom that bonds to the metal has a lower bond energy than the second oxygen atom.

[0051] As used herein, a metal oxide refers to a crystalline solid containing a metal cation and an oxide anion. Note that the term metal oxide generally refers to a metal cation with one or more oxide anions.

[0052] In the context of this disclosure, a metal oxide can include a single metal atom or a combination of the same or different metal atoms.

[0053] The present disclosure is not limited to a particular metal oxide, but may be applied to the various metal oxides described herein.

[0054] According to the present disclosure, the metal oxide is characterized by a reducing property that allows for the formation of oxygen vacancies in the metal oxide.

[0055] In some instances, the metal oxide is a reducible oxide.

[0056] As used herein, a reducible oxide refers to a solid state material characterized by its ability to exchange oxygen.

[0057] As described herein, it has been remarkably discovered that metal oxides can be reduced, i.e., oxygen vacancies can be formed, without heating the metal oxide to a temperature required to overcome the binding energy. Generally, as is known in the art, the formation of oxygen vacancies in metal oxides requires conditions involving temperatures that exceed the temperature required to overcome the binding energy of the metal oxide.

[0058] Thus, the metal oxides of the present disclosure tend to lose or donate oxygen to species, resulting in a change in surface composition, thereby generating metal oxides with oxygen vacancies; e.g., the change may be due to MO m From MO m-x It could be.

[0059] The metal in each metal oxide may be selected from among the metallic elements of the periodic table, including the alkali metals, alkaline earths, transition metals, lanthanides, and actinides.

[0060] In some examples, the metal in the metal oxide is a transition metal, a lanthanide, an actinide, or any combination thereof.

[0061] In some embodiments, the metal in the metal oxide is at least one alkali metal. An alkali metal is a metal located in the first row, or group, of the periodic table of the elements. In some embodiments, the alkali metal is at least one of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).

[0062] In some embodiments, the metal in the metal oxide is at least one alkaline earth metal. An alkaline earth metal is a metal located in Group 2 of the periodic table of elements. In some embodiments, the alkaline earth metal is at least one of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). In some embodiments, the metal in the metal oxide is a transition metal.

[0063] As used herein, transition metals include any element in the d-block elements (groups 3-12 of the periodic table) as well as the f-block elements (including the lanthanides and actinides). Thus, the transition metals that form part of the metal oxides of the present disclosure also include inner transition metals.

[0064] As noted herein, a metal may be a single metal forming a metal oxide, or a combination of different metal atoms forming a combination of metal oxides. Thus, reference to a metal should be understood as referring to a combination of metals, and therefore to a combination of metal oxides (same or different).

[0065] In some examples, the metal or combination of metals is a metal from the d-block of elements of the periodic table.

[0066] In some examples, the metal or combination of metals is a metal from the f-block elements of the periodic table.

[0067] In some examples, the metal or combination of metals is a metal from the d block of elements of the periodic table of elements and / or an f block element of the periodic table of elements.

[0068] In some instances, the metal is a lanthanide.

[0069] In some instances, the metal is an actinide.

[0070] In some examples, the metal in the metal oxide is at least one metal selected from the group consisting of scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn). The fifth-period transition metals are yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), lanthanum (La), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), and gold (Au), as well as mercury (Hg), actinium (Ac), rutherfordium (Rf), dubnium (Db), seaborgium (Sg), bohrium (Bh), hassium (Hs), meitnerium (Mt), darmstadtium (Ds), roentgenium (Rg), ununbium (Uub), and mercury (Hg). ), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), thorium (Th), protactinium (Pa), uranium (U), neptunium (Np), plutonium (Pu), americium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), fermium (Fm), mendelevium (Md), nobelium (No), and lawrencium (Lr).

[0071] In some examples, the metal in the metal oxide is at least one metal selected from the group consisting of scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn). The fifth-period transition metals are yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and cadmium (Cd).

[0072] In some examples, the metal in the metal oxide is at least one metal selected from the group consisting of lanthanum (La), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), and mercury (Hg), actinium (Ac), (Rf), dubnium (Db), seaborgium (Sg), bohrium (Bh), hassium (Hs), meitnerium (Mt), darmstadtium (Ds), roentgenium (Rg), and ununbium (Uub).

[0073] In some examples, the metal in the metal oxide that is a lanthanide is at least one metal selected from the group consisting of cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0074] In some examples, the metal in the metal oxide is an actinide. In some examples, the metal in the metal oxide is at least one metal selected from the group consisting of thorium (Th), protactinium (Pa), uranium (U), neptunium (Np), plutonium (Pu), americium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), fermium (Fm), mendelevium (Md), nobelium (No), and lawrencium (Lr).

[0075] In some embodiments, the metal is Zr, Ce, Fe, Ni, or Ti.

[0076] In some embodiments, the metal is Ce.

[0077] In some embodiments, the metal oxide is selected from ZrO2 (zirconia), CeO2 (ceria), FeO (ferrous oxide), NiO (nickel(II) oxide), TiO (titanium(II) oxide), or any combination thereof.

[0078] In some embodiments, the metal oxide is CeO2.

[0079] Metal oxides according to the present disclosure may be in the form of a solid state, the term solid state referring to a physical state in which atoms or molecules are closely packed together in fixed locations to form a solid material having a definite shape and volume.

[0080] In some instances, the metal oxide is in powder form. From the powdered solid state to particulate or powdered form of material, the particles are typically less than a millimeter in size and can be of either crystalline or amorphous material.

[0081] In some other instances, the metal oxide is in a slurry form.

[0082] In some other instances, the metal oxide may be used in the form of a coating. In some instances, the metal oxide may be used to coat the anode.

[0083] In some instances, the metal oxide is in the form of a film.

[0084] As described herein, the metal oxide is configured to release at least one oxygen atom upon exposure to radiation (i.e., being irradiated). In other words, the metal oxide is configured to release at least one oxygen atom upon exposure to radiation (i.e., being irradiated). x From MO x-y The metal oxide formed after the release of the oxygen atoms is characterized as having an oxygen vacancy. As used herein, an oxygen vacancy refers to an oxygen atom that is missing from the metal oxide (e.g., from a crystalline form).

[0085] Also, as described herein, metal oxides having oxygen vacancies are referred to herein as OVMOs.

[0086] The method comprising exposing a metal oxide to radiation may be represented by the following formula (I):

[0087]

number

[0088] In the formula, MO represents a metal oxide, x represents the number of oxygen atoms on each metal atom in MO, Ep represents the radiant energy per particle / photon, and y represents the amount of oxygen molecules (O2) released from MO (e.g., surface, ranging from 1 to x) to form y / 2 molecules of oxygen (O2). x-y represents a metal oxide having oxygen vacancies (OVMOs), as described herein, characterized by the ability to recombine oxygen atoms after exposure to, for example, water vapor or air.

[0089] In some instances, the OVMO is characterized by a vacancy.

[0090] OVMO as used herein refers to a functional form of a metal oxide.

[0091] In some instances, the OVMO is surface exposed.

[0092] It is noted that in some instances, the OVMOs are stable for up to 48 hours, and in some cases up to 24 hours. When referring to stability, it is noted that the OVMOs maintain at least 50% oxygen vacancies for up to 48 hours when fully exposed to an oxygen source (e.g., air or water vapor environment). In the case of vacuum-sealed metal oxides with oxygen vacancies, the stability can last much longer.

[0093] The stability of OVMOs can be determined by methods known in the art, among which scanning tunneling microscopy (STM), mass spectroscopy (MS), thermogravimetric analysis (TGA) or X-ray photoelectron spectroscopy (XPS) can be used to characterize these vacancies.

[0094] In some embodiments, the method includes collecting oxygen gas.

[0095] In some embodiments, the method includes collecting the OVMO.

[0096] According to some examples, the method includes exposing CeO2 to radioactive radiation. According to some examples, the method includes exposing CeO2 to radioactive radiation and generating oxygen gas. According to some examples, the method includes exposing CeO2 to radioactive radiation and generating oxygen gas and CeO. According to some examples, the method includes exposing CeO2 to radioactive radiation and generating oxygen gas and Ce.

[0097] As described herein, the method includes generating hydrogen gas.

[0098] As described herein, OVMOs are characterized by being stable and therefore can be transported or shipped to remote locations requiring hydrogen generation. Such hydrogen gas can be used in fuel cells. As will be appreciated, fuel cells using hydrogen gas as fuel are an option for clean power generation. They can also affect the catalytic activity and reactivity of the material, which can be useful in applications such as fuel cells, catalysts, and gas sensors.

[0099] Additionally or alternatively, the method may include the additional step of the OVMO forming hydrogen gas.

[0100] In some embodiments, the method includes exposing the OVMO (containing the oxygen vacancy) to water vapor.

[0101] As will be appreciated, water vapor can be used at a variety of pressures, for example, atmospheric pressure.

[0102] The method including exposure of the OVMO to water (water vapor) may be represented by the following formula (II): MO x-y +yH2O→MO x +yH2(II) In the formula, MO x-yrepresents a metal oxide with oxygen vacancies (OVMOs) that, in the presence of water vapor, releases hydrogen (H2) gas and reforms back to its original form (by recombining with oxygen atoms).

[0103] In some embodiments, the method includes collecting hydrogen gas produced upon exposure of the OVMO to water vapor.

[0104] As described herein, the methods of the present disclosure generate both oxygen gas and hydrogen gas. Thus, according to some other aspects, the present disclosure provides a method that includes (i) irradiating a metal oxide to obtain OVMOs and oxygen gas, and (ii) exposing the OVMOs to water vapor to generate hydrogen gas and recombine the OVMOs with oxygen.

[0105] Note that recombination of the OVMO with an oxygen atom essentially reforms the metal oxide molecule.

[0106] According to some examples, the method includes: 2+ According to some examples, the method includes exposing Ce to water vapor. 4+ to water vapor.

[0107] The method, which includes exposing a metal oxide to radiation (i.e., irradiating the metal oxide) and exposing the OVMO to water (water vapor), may be represented by formula (III) below:

[0108]

number

[0109] where MO represents metal oxide, x represents the number of oxygen atoms on each metal atom in the MO molecule, Ep represents the radiant energy per particle / photon, y represents the amount of oxygen atoms released from the MO (e.g., surface, ranging from 1 to x) to form y / 2 oxygen molecules (O2), and MO x-yrepresents an OVMO that, in the presence of water vapor, releases hydrogen (H2) gas and undergoes regeneration (by recombining with oxygen atoms).

[0110] In some embodiments, the method may be adapted or used to generate oxygen gas and hydrogen gas.

[0111] In some embodiments, the method may be adapted or used to generate oxygen gas.

[0112] In some embodiments, the method may be adapted or used to generate hydrogen gas.

[0113] As disclosed herein, hydrogen gas may be produced following the evolution of oxygen gas, where the metal oxide has oxygen vacancies (OVMOs) capable of decomposing water in the form of steam.

[0114] According to some embodiments, the method includes exposing the metal oxide to radiation at a first time and exposing the OVMO to water vapor at a different time.

[0115] In some examples, the different time point is later than the first time point. In some examples where the different time point is later than the first time point, the method includes generating oxygen gas, followed by generating hydrogen gas.

[0116] In some examples, the method includes sequential generation of oxygen gas and hydrogen gas. In such examples, the method includes repeating the generation of oxygen gas followed by the generation of hydrogen gas. In other words, the method includes repeating steps (i) and (ii) sequentially to allow for the sequential generation of oxygen gas and hydrogen gas.

[0117] In some embodiments, the method includes evacuating the oxygen gas prior to exposing the OVMO to water vapor.

[0118] In some embodiments, the method includes evacuating the hydrogen gas before exposing the metal oxide to radiation.

[0119] As will be appreciated, either the oxygen gas or the hydrogen gas may be vented to be collected for further purposes.

[0120] In some embodiments where the method involves sequential generation of oxygen gas and hydrogen gas, the method involves sequential transfer of a metal oxide and an OVMO, as described herein, a metal oxide is required for oxygen gas generation, while an OVMO is required for hydrogen gas generation.

[0121] Thus, according to some aspects, the present disclosure provides a method for continuous sequential generation of oxygen gas and hydrogen gas, the method comprising: - irradiating a metal oxide to obtain an oxygen vacancy containing metal oxide (OVMO) and oxygen gas; - venting at least a portion of the oxygen gas; exposing the OVMO to water vapor to regenerate the metal oxide and generate hydrogen gas; venting at least a portion of the hydrogen gas.

[0122] The above process when used for the continuous sequential generation of oxygen gas and hydrogen gas is referred to herein as a "sequential operating cycle."

[0123] As will be appreciated, the method involves sequential operating cycles that can be repeated several times as required.

[0124] In some embodiments, the method includes at least two sequential operating cycles, each sequential operating cycle including the generation of hydrogen gas and oxygen gas.

[0125] In some embodiments, the method includes generating oxygen gas in parallel with generating hydrogen gas, in which the different time point is the same as the first time point.

[0126] In some examples, the method includes generating oxygen gas and hydrogen gas. In such examples, the method includes repeating the steps of generating oxygen gas and generating hydrogen gas. In other words, the method includes repeating step (i) to allow for the generation of oxygen gas and repeating step (ii) to allow for the generation of hydrogen gas.

[0127] In some embodiments, the method includes venting the oxygen gas.

[0128] In some embodiments, the method includes venting the hydrogen gas.

[0129] As will be appreciated, either the oxygen gas or the hydrogen gas may be vented to be collected for further purposes.

[0130] Thus, according to some aspects, the present disclosure provides a method for continuous generation of oxygen gas and hydrogen gas, the method comprising: - exposing metal oxide particles to radiation to obtain OVMOs (containing oxygen vacancies) and oxygen gas; - exposing the OVMOy to water vapor to regenerate the metal oxide particles and generate hydrogen gas.

[0131] The above process when used for the continuous generation of oxygen and hydrogen gases is referred to herein as a "continuous operating cycle."

[0132] As will be appreciated, the method involves successive operating cycles that may be repeated several times as required.

[0133] In some aspects, the present disclosure provides a method for oxygen gas generation, the method comprising exposing a metal oxide to radioactive radiation.

[0134] In some embodiments, the present disclosure provides a method for oxygen gas generation, the method comprising exposing CeO2 to radioactive radiation.

[0135] In some embodiments, the present disclosure provides a method for oxygen gas generation, the method comprising exposing a metal oxide to radioactive radiation, the metal oxide being at a temperature up to 1000°C.

[0136] In some embodiments, the present disclosure provides a method for oxygen gas generation, the method comprising exposing CeO2 to radioactive radiation, where the CeO2 is at a temperature up to 1000°C.

[0137] In some embodiments, the present disclosure provides a method for generating hydrogen gas, the method comprising exposing OVCeO2 to water vapor.

[0138] In some embodiments, the present disclosure provides a method for gas generation, the method comprising exposing a metal oxide to radioactive radiation to form an OVMO, and exposing the OVMO to water vapor.

[0139] In some embodiments, the present disclosure provides a method for gas generation, the method including exposing CeO2 to radioactive radiation to form OVCeO2, and exposing the OVCeO2 to water vapor.

[0140] In some examples where the method is applicable to CeO2, exposing CeO2 to radiation (i.e., irradiating CeO2) and 2-y The method, which includes exposure to water (water vapor), can be represented by the following formula (IV):

[0141]

number

[0142] The present disclosure also provides, according to some embodiments, a reactor. As used herein, a reactor can be considered an oxygen generator and / or a hydrogen generator.

[0143] The reactor comprises a gas outlet, and a reactor chamber including a radiation source, the reactor chamber configured to hold a metal oxide such that upon irradiation by the radiation source, the metal oxide is exposed to radiation, and upon exposure to radiation, gas is evolved by the metal oxide particles and released from the chamber through the gas outlet, the irradiation not involving heating the metal oxide to a temperature above that required to overcome the binding energy of the MO.

[0144] In some embodiments, the gas outlet is configured to exhaust oxygen gas from the chamber.

[0145] In some embodiments, the radiation source is configured to irradiate the metal oxide with radioactive radiation.

[0146] The reactor may include additional components.

[0147] In some embodiments, the chamber comprises a means for collecting the OVMOs from the chamber.

[0148] In some embodiments, the chamber comprises a water vapor reservoir.

[0149] In some embodiments, the gas outlet is configured to exhaust hydrogen gas from the reactor.

[0150] In some embodiments, a reactor for generating oxygen gas and hydrogen gas is provided, the reactor comprising at least one chamber, at least one irradiation source, and a water reservoir, the at least one chamber configured to hold at least one metal oxide and / or OVMOs, such that upon irradiation by the radiation source, the metal oxide is exposed to radiation, and upon exposure of the MOs to radiation, oxygen gas and OVMOs are generated by the metal oxide, and upon exposure of the OVMOs to water vapor, hydrogen gas is generated and MOs are formed.

[0151] The reactor, according to some examples, includes at least one gas outlet, sometimes an oxygen gas outlet and a hydrogen gas outlet.

[0152] In some examples, the metal oxide in the at least one chamber is at a temperature below the temperature required to overcome the binding energy of the MO.

[0153] In some examples, the reactor comprises a conveyor belt.

[0154] In some embodiments, the OVMO and the reactor for generating oxygen gas are shown in Figure 13A. In some embodiments, the OVMO and the reactor for generating oxygen gas are shown in Figure 13B.

[0155] In some embodiments, the reactor for generating OVMOs and oxygen gas is shown in Figure 15. In some embodiments, the reactor for generating OVMOs and oxygen gas is shown in Figure 16.

[0156] In some embodiments, a reactor for generating hydrogen gas is shown in Figure 17A. In some embodiments, a reactor for generating hydrogen gas is shown in Figure 17B.

[0157] As used herein, the term "about" refers to values ​​that may deviate up to 1%, more specifically 5%, more specifically 10%, more specifically 15%, and in some cases up to 20% higher or lower than the stated value, the deviation range including integer values, where applicable, non-integer values ​​also constitute a continuous range. As used herein, the term "about" refers to ±10%.

[0158] It should be noted that various embodiments of the present invention may be presented in a range format. The description of a range should be considered to have all possible subranges specifically disclosed as well as individual numerical values ​​within that range. For example, the description of a range such as 1 to 6 or 1-6 should be considered to specifically disclose subranges such as 1 to 3, 1 to 4, 1 to 5, 2 to 4, 2 to 6, 3 to 6, etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6.

[0159] As used herein, the forms "a," "an," and "the" include the singular and plural unless the context clearly dictates otherwise.

[0160] It is understood that certain features of the invention that are described for clarity in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features of the invention that are described for brevity in the context of a single embodiment may also be provided separately or in any suitable subcombination, or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperable without those elements.

[0161] It should be noted that various embodiments and examples detailed herein in relation to various aspects of the invention may be applicable to one or more aspects disclosed herein. It should be further noted that any embodiment described herein, e.g., method-related embodiments, may be applied separately or in various combinations. Various embodiments and aspects of the invention described herein above and claimed in the claims section below are experimentally supported in the following examples. As used herein, the phrase "in another embodiment" or any reference made to an embodiment does not necessarily refer to a different embodiment, although it may. Thus, various embodiments of the invention may be combined (from the same aspect or from different aspects) without departing from the scope of the invention.

[0162] Various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below are supported experimentally in the following examples.

[0163] Although disclosed and described, it is to be understood that the invention is not limited to the specific examples, process steps, and reactors disclosed herein, and that such process steps and reactors may vary somewhat. It is also to be understood that the terminology used herein is used only for the purpose of describing particular embodiments, and is not intended to be limiting, since the scope of the invention is limited only by the appended claims and equivalents thereof.

[0164] The following examples are representative of techniques employed by the inventors in carrying out aspects of the present invention. It should be understood that while these techniques are illustrative of preferred embodiments for carrying out the invention, those skilled in the art will recognize that many modifications may be made upon consideration of this disclosure without departing from the spirit and intended scope of the invention.

[0165] Embodiment Several embodiments of the present disclosure are now described in the following numbered paragraphs. The following description is intended to supplement the general description above and is not intended to limit it in any way.

[0166] 1. A method comprising exposing a metal oxide to radiation to generate oxygen vacant metal oxides (OVMOs) and oxygen gas.

[0167] 2. The method of embodiment number 1, comprising exposing the metal oxide to irradiation, wherein the metal oxide is at a temperature below the temperature required to overcome the metal oxide binding energy.

[0168] 3. The method of embodiment no. 2, wherein the temperature is up to about 1500° C.

[0169] 4. The method of embodiment number 3, wherein the temperature is up to about 500° C.

[0170] 5. The method according to embodiment number 4, wherein the temperature is at most about 80° C.

[0171] 6. The method according to embodiment 2, wherein the temperature is from about 20° C. to about 500° C.

[0172] 7. The method of embodiment 1, wherein the radiation is non-thermal radiation.

[0173] 8. The method of embodiment 1, wherein the radiation is selected from the group consisting of electron beam radiation, alpha radiation, beta radiation, gamma radiation, and UV radiation.

[0174] 9. The method according to any one of the preceding embodiments, wherein the metal in the metal oxide is at least one of (i) at least one alkali metal, (ii) at least one alkaline earth metal, (iii) at least one transition metal, (iv) at least one lanthanide metal, (v) at least one actinide metal, or (vi) a combination thereof.

[0175] 10. The method of any one of the preceding embodiments, wherein the metal in the metal oxide is at least one of: (i) at least one transition metal; (ii) at least one lanthanide metal; (iii) at least one actinide metal; or (iv) a combination thereof.

[0176] 11. The method according to any one of the preceding embodiments, wherein the metal in the metal oxide is at least one of zirconium (Zr), cerium (Ce), iron (Fe), titanium (Ti), nickel (Ni), or any combination thereof.

[0177] 12. The method according to any one of the preceding embodiments, wherein the metal oxide is selected from the group consisting of ZrO2, CeO2, FeO, TiO and NiO.

[0178] 13. The method of embodiment 12, wherein the metal oxide is CeO2.

[0179] 14. The method according to any one of the preceding embodiments, wherein the metal oxide is in a solid state.

[0180] 15. The method of any one of the preceding embodiments, wherein the metal oxide is in powder form or is a surface coating.

[0181] 16. The method according to any one of the preceding embodiments, further comprising collecting oxygen gas.

[0182] 17. The method according to any one of embodiments 1 to 16, comprising collecting OVMOs containing oxygen vacancies.

[0183] 18. The method of any one of embodiments 1 to 17, comprising exposing the OVMO to water vapor.

[0184] 19. The method of embodiment 18, comprising collecting hydrogen gas produced upon exposure of the OVMO to water vapor.

[0185] 20. A method comprising: (i) exposing a metal oxide to radiation to obtain OVMOs and oxygen gas; (ii) exposing the OVMO to water vapor to regenerate the metal oxide particles and generate hydrogen gas.

[0186] 21. The method of embodiment 20, comprising exposing the metal oxide to radiation, wherein the metal oxide is at a temperature below the temperature required to overcome the metal oxide binding energy.

[0187] 22. The method of embodiment 21, wherein the temperature is up to about 1500°C.

[0188] 23. The method of embodiment 22, wherein the temperature is at most about 500°C.

[0189] 24. The method of embodiment 23, wherein the temperature is at most about 80°C.

[0190] 25. The method of embodiment 21, wherein the temperature is from about 20°C to about 500°C.

[0191] 26. The method of embodiment 20, comprising repeating steps (i) and (ii) to allow for the generation of oxygen gas and hydrogen gas.

[0192] 27. The method of embodiment 20, comprising repeating steps (i) and (ii) to allow for the sequential generation of oxygen gas and hydrogen gas.

[0193] 28. The method of embodiment 20, comprising repeating steps (i) and (ii) to allow for continuous generation of oxygen gas and hydrogen gas.

[0194] 29. The method of any one of embodiments 20 to 28, comprising collecting oxygen gas.

[0195] 30. The method of embodiment 29, comprising collecting oxygen gas prior to step (ii).

[0196] 31. The method of any one of embodiments 20 to 30, comprising collecting OVMO.

[0197] 32. The method according to embodiment 31, comprising collecting OVMO prior to step (ii).

[0198] 33. The method of any one of embodiments 20 to 32, comprising collecting hydrogen gas.

[0199] 34. The method of embodiment 33, comprising collecting hydrogen gas after step (ii).

[0200] 35. A method comprising exposing CeO2 to radiation to generate oxygen vacancies CeO2 (OVMOs) and oxygen gas.

[0201] 36. A method comprising: (i) exposing CeO2 to radiation to obtain oxygen vacancies, CeO2, and oxygen gas; (ii) exposing the oxygen vacancies CeO2 to water vapor to regenerate CeO2 and generate hydrogen gas.

[0202] 37. The method of any one of embodiments 35 to 36, comprising exposing CeO2 to irradiation, wherein the CeO2 is at a temperature below 1500°C.

[0203] 38. The method of embodiment 37, wherein the CeO2 is at a temperature below 300°C.

[0204] 39. The method of embodiment 37 or 38, wherein the CeO2 is at a temperature of about 20°C to about 100°C.

[0205] 40. The method of any one of embodiments 35 to 39, wherein the radiation is selected from the group consisting of electron beam radiation, alpha radiation, beta radiation, gamma radiation, and UV radiation.

[0206] 41. The method according to embodiment 40, wherein the radiation is radioactive radiation.

[0207] 42. The method of any one of embodiments 35-41, comprising collecting oxygen gas.

[0208] 43. The method of any one of embodiments 35 to 42, comprising collecting oxygen vacancies CeO2, which contain oxygen vacancies.

[0209] 44. The method of embodiment 35, comprising exposing oxygen vacancy CeO2 to water vapor.

[0210] 45. The method of embodiment 44, comprising collecting hydrogen gas produced upon exposure of oxygen vacancy CeO2 to water vapor.

[0211] 46. ​​A reactor comprising a reactor chamber and a radiation source, the reactor chamber configured to hold a metal oxide such that upon irradiation by the radiation source, the metal oxide particles are exposed to radiation and a gas is generated by the metal oxide upon exposure to radiation.

[0212] 47. A reactor comprising a reactor chamber including a gas outlet and a radiation source, the reactor chamber configured for holding metal oxide particles such that upon irradiation by the radiation source, the metal oxide particles are exposed to the radiation, and upon exposure to the radiation, a gas is generated by the metal oxide and released from the chamber through the gas outlet.

[0213] 48. The reactor of embodiment number 46 or 47, wherein the radiation source is a radioactive source.

[0214] 49. The reactor of any one of embodiments 46 or 37, wherein the metal oxide is configured to release oxygen atoms upon exposure to radiation to generate oxygen gas and OVMOs.

[0215] 50. The reactor of any one of embodiments 46 to 47, wherein the gas outlet is configured to exhaust oxygen gas from the chamber.

[0216] 51. The reactor of any one of embodiments 46 to 47, further comprising a means for collecting OVMO from the chamber.

[0217] 52. The reactor of any one of embodiments 46 to 51, further comprising a water vapor reservoir.

[0218] 53. The reactor of embodiment number 52, wherein the OVMO is configured to generate hydrogen gas upon exposure to water vapor from the water vapor reservoir and undergo regeneration to obtain metal oxide.

[0219] 54. The reactor of any one of embodiments 52 and 53, wherein the gas outlet is or comprises a hydrogen gas outlet.

[0220] 55. A reactor comprising a reactor chamber and a radiation source, the reactor chamber configured to hold a metal oxide such that upon irradiation by the radiation source, the metal oxide particles are exposed to radiation and a gas is generated by the metal oxide upon exposure to radiation, and the radiation source is a radioactive source. [Brief description of the drawings]

[0221] In order to better understand the subject matter disclosed herein, and to illustrate how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: [Figure 1A] FIG. 1 is a block diagram of an example of a system including a hydrogen generator. [Figure 1B] 1 is a flow diagram 150 of an example method for generating hydrogen gas. [Diagram 2] FIG. 1 is a diagram of a hydrogen generator having a photoionization mechanism for generating hydrogen. [Diagram 3] FIG. 1 is a flow diagram of an example method for hydrogen generation via photoionization. [Figure 4A] Illustrates examples of components for a hydrogen generator having a photoionization mechanism for generating hydrogen. [Figure 4B] Illustrates examples of components for a hydrogen generator having a photoionization mechanism for generating hydrogen. [Figure 4C] Illustrates examples of components for a hydrogen generator having a photoionization mechanism for generating hydrogen. [Diagram 5] FIG. 1 is a diagram of a hydrogen generator having a chemical loop mechanism for generating hydrogen. [Figure 6] FIG. 1 is a flow diagram of an example method for generating hydrogen gas via chemical looping with metal oxide. [Figure 7] 1 illustrates a three-dimensional view of an example of a hydrogen generator housing. [Figure 8] FIG. 2 is a three-dimensional view of a hydrogen generator within a spent nuclear fuel (SNF) storage cask. [Figure 9A] 1 illustrates a three-dimensional view of a spent nuclear fuel (SNF) storage cask in different positions during operation. [Figure 9B] 1 illustrates a three-dimensional view of a spent nuclear fuel (SNF) storage cask in different positions during operation. [Figure 9C] 1 illustrates a three-dimensional view of a spent nuclear fuel (SNF) storage cask in different positions during operation. [Figure 9D] 1 illustrates a three-dimensional view of a spent nuclear fuel (SNF) storage cask in different positions during operation. [Figure 10A] 1 is an example image of CeO2 and oxygen vacancies CeO2, with arrows indicating color changes, according to some embodiments. [Figure 10B] 1 is an example image of CeO2 and oxygen vacancies CeO2, with arrows indicating color changes, according to some embodiments. [Figure 10C] 1 is an example image of CeO2 and oxygen vacancies CeO2, with arrows indicating color changes, according to some embodiments. [Figure 10D] 1 is an example image of CeO2 and oxygen vacancies CeO2, with arrows indicating color changes, according to some embodiments. [Figure 11A] 1 is an exemplary image of CeO2 and oxygen vacancies CeO2, according to some embodiments. [Figure 11B] 1 is an exemplary image of CeO2 and oxygen vacancies CeO2, according to some embodiments. [Figure 11C] 1 is an exemplary image of CeO2 and oxygen vacancies CeO2, according to some embodiments. [Figure 11D] 1 is an exemplary image of CeO2 and oxygen vacancies CeO2, according to some embodiments. [Figure 12A] 1 is an exemplary image of CeO2 and oxygen vacancies CeO2, according to some embodiments. [Figure 12B]1 is an exemplary image of CeO2 and oxygen vacancies CeO2, according to some embodiments. [Figure 12C] 1 is an exemplary image of CeO2 and oxygen vacancies CeO2, according to some embodiments. [Figure 13A] 1 is an exemplary setup for the generation of oxygen gas. [Figure 13B] 1 is an exemplary setup for the generation of oxygen gas. [Figure 14] 1 is a graph showing the change in metal oxide mass. [Figure 15] FIG. 1 is an exemplary schematic diagram of an experimental setup for oxygen generation. [Figure 16] FIG. 1 is an exemplary schematic diagram of an experimental setup for oxygen generation. [Figure 17A] 1 is an exemplary schematic diagram of an exemplary system for hydrogen release. [Figure 17B] 1 is an exemplary schematic diagram of an exemplary system for hydrogen release. [Figure 18A] 1 is a graph showing hydrogen levels in a control experiment. [Figure 18B] 1 is a graph showing hydrogen levels in a control experiment. [Figure 19A] 1 is an exemplary image of CeO2 and oxygen vacancies CeO2, according to some embodiments. [Figure 19B] 1 is an exemplary image of CeO2 and oxygen vacancies CeO2, according to some embodiments. [Figure 19C] 1 is an exemplary image of CeO2 and oxygen vacancies CeO2, according to some embodiments. [Figure 20] 1 is a graph showing hydrogen generation. [Figure 21] 1 is a graph showing hydrogen generation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0222] The following refers to exemplary processes and reactors.

[0223] FIG. 1A is a block diagram of an example of a system including a hydrogen generator (which may be part of a reactor described herein). The system 100 includes a hydrogen generator 102 for generating or producing hydrogen and a storage tank 106 for storing input and output materials of the system 100. The hydrogen generator includes a metal oxide 114. As noted herein, the present disclosure is not limited to a particular metal oxide. Non-limiting examples of metal oxides include ZrO2 (zirconia), CeO2 (ceria), FeO (ferrous oxide), NiO (nickel(II) oxide), and TiO (titanium(II) oxide). In one example, the metal oxide 114 is in the form of a metal oxide powder. In another example, the metal oxide 114 is in the form of a coating (e.g., a coating on a substrate). The metal oxide 114 may be in other forms, such as pellets, a "slurry" in an aqueous environment, or another form.

[0224] The system 100 also includes a radiation source or electron beam generator. The energy source may include, for example, a radioactive material, an electron gun, or a UV source 116. In examples where the energy source is a radioactive material, the radioactive material may be any radioactive material that generates radiation (alpha radiation, beta radiation, and / or gamma radiation) having sufficient energy to remove electrons or oxygen from the surface of the metal oxide 114. Examples of radioactive materials include spent nuclear fuel, Co-60, Sr-90, Cs-137, Cs-135, Mo-99, or any other radioactive material.

[0225] As noted above, radiation such as that emitted from a radioactive material may include one or more of alpha radiation, beta radiation, or gamma radiation. Alpha, beta, and gamma radiation each have different masses, charges, energies, and consequently different penetration depths through media, and current commercial uses.

[0226] The radioactive material may be internal or external to the system 100. For example, the radioactive material may be external but coupled to the hydrogen generator 102 via a window 117 to allow radiation from the radioactive material to enter the chamber containing the metal oxide 114. In another example, the radioactive material is contained within the hydrogen generator (e.g., in the same chamber as the metal oxide).

[0227] Regardless of whether the radioactive material is internal or external to the hydrogen generator 102, in one example, the radioactive material is surrounded by a shield 118. In examples where the radioactive material is within the hydrogen generator 102, the hydrogen generator may include an additional shield surrounding the hydrogen generator 102. In one such example, the shield around the hydrogen generator is not as thick (i.e., thinner) as the shield surrounding the radioactive material.

[0228] Similarly, in examples where the energy source is an electron gun or a UV source (e.g., a UV lamp or other UV source), the electron gun or UV source may be located inside or outside the hydrogen generator 102. In examples where the UV source or electron gun is located outside the hydrogen generator, a device that produces UV radiation or an electron beam may be coupled to the hydrogen generator through window 117. An optional heating element 119 may be included to accelerate the reaction and increase the rate of hydrogen production.

[0229] The hydrogen generator 102 also includes input and output ports 120 for introducing water or water vapor into the hydrogen generator and removing oxygen and hydrogen from the hydrogen generator 102. In one example, the input / output ports 120 include valves to allow the ports 120 to be opened or closed. In one example, the hydrogen generator 102 includes separate ports for water or water vapor (input), oxygen (output), and hydrogen (output). In another example, the hydrogen generator 102 includes one input port for water or water vapor and one output port for gas (either hydrogen or oxygen depending on the time the port is used to extract gas from the chamber of the hydrogen generator 102).

[0230] In one example, the input / output port 120 is coupled to a storage tank or receiver 106. For example, the H2O port is coupled to a H2O storage tank 112, which stores H2O (e.g., water). In one example, the gas port (or individual hydrogen and oxygen ports) is coupled to an H2 storage 108 and an O2 storage 110. The H2 storage 108 stores hydrogen exhausted from the hydrogen generator, and the O2 storage 110 stores oxygen exhausted from the hydrogen generator 102. The system 100 may also include a fuel cell 104 for generating electricity using hydrogen generated by the hydrogen generator 102, which may be stored in a battery 105 or exhausted to a power grid.

[0231] FIG. 1B is a flow diagram 150 of an example method for generating hydrogen gas. Method 150 may be performed in a hydrogen generator, such as hydrogen generator 102 of FIG. 1A. Method 150 involves exposing a metal oxide to radiation from a radioactive material or UV source, or an electron beam from an electron gun, at block 152. For example, with reference to FIG. 1A, the method involves exposing metal oxide 114 to radiation or an electron beam from a radioactive material, electron gun, or UV source 116. Exposing the metal oxide to the radiation or electron beam activates the surface of the metal oxide. For example, the radiation or electron beam causes the metal oxide to release or lose electrons or oxygen molecules.

[0232] 1B, the method 150 involves exposing the activated surface of the metal oxide to HO (water or water vapor) at block 154. For example, referring to FIG. 1A, the metal oxide 114 is exposed to HO input from the HO storage receiver 112 through the input port 120 to the hydrogen generator 102. In one example, the activated metal oxide acts as a catalyst and reacts with the HO introduced to the hydrogen generator, decomposing the HO and releasing hydrogen.

[0233] 1B, the released hydrogen is then stored in the storage receptacle at block 156. For example, referring to FIGURE 1A, hydrogen gas is extracted from the hydrogen generator 102 via the exhaust port 120 and stored in the hydrogen storage receptacle 108. The hydrogen gas can then be transported or used on-site to generate electricity.

[0234] FIG. 2 is a diagram of a hydrogen generator with a photoionization mechanism for generating hydrogen. The hydrogen generator 200 includes a chamber 201. The chamber 201 is separated by a membrane 208 and a barrier support structure 216. In one example, the membrane 208 is a proton membrane. The anode 204 and the cathode 206 generate an electric field to attract electrons released (upon irradiation) from the metal oxide and protons released from the water molecules following interaction of the metal oxide ions with the water molecules. The membrane 208 and the barrier 216, in combination with the electric field generated at the electrodes 204 and 206, allow separation of hydrogen and oxygen after splitting the water to prevent recombination.

[0235] The hydrogen generator 200 includes a metal oxide 210 in a chamber 201. In one example, the metal oxide 210 is a metal oxide powder. The chamber 201 has an input port 220 for inputting water into the chamber 201 and output ports 218 and 222 for outputting oxygen gas and hydrogen gas, respectively. In one example, the hydrogen generator is operated with the metal oxide in water, as indicated by water line 214. Hydrogen and oxygen gas released during operation of the hydrogen generator rise above the water line 214 and can be extracted from the chamber 201 via ports 218 and 222.

[0236] 2, the radiation or electron beam source 211 is external to the chamber 201. The radiation or electron beam 202 from the source 211 is directed to the metal oxide in the chamber 201 through a window 212. In one example, the window 212 is glass, quartz, magnesium fluoride (MgF), or another material that allows transmission of the radiation or electron beam into the chamber 201. In one example where a radioactive material is used, a shield 224 surrounds the hydrogen generator 200. An additional shield may surround the radioactive material.

[0237] 3 is a flow diagram of an example method of hydrogen generation via photoionization. Method 300 may be implemented in a hydrogen generator, such as hydrogen generator 200 of FIG.

[0238] The method 300 begins at block 302 with exposing a metal oxide in a chamber to radiation from a radioactive material, UV radiation, or an electron beam. For example, with reference to FIG. 2, a metal oxide 210 is irradiated with radiation or an electron beam from a radiation or electron beam source 211 (e.g., a radiation source or UV source or an electron gun). In one example, the metal oxide 210 is a metal oxide powder in water, forming a slurry. In one example, when the metal oxide is irradiated, the metal oxide releases electrons, resulting in a metal oxide having an ionized surface.

[0239] Referring again to FIG. 3, in block 306, the ionized surface of the metal oxide is exposed to water, which breaks down the H2O molecules and releases protons from the H2O molecules. The method also involves generating an external electric field in block 308 to attract the released electrons to a first electrode and the released protons through the membrane to a second electrode. For example, referring to FIG. 2, radiation or an electron beam ionizes the metal oxide 210, releasing electrons and forming cations. The electrons are attracted to the anode 204, while the cations attack water, releasing protons, which migrate through the proton membrane 208 to the cathode 206 on the other side of the cell. This process can be represented by equation (III) above.

[0240] 3, at block 310, the released hydrogen and oxygen can then be extracted from the chamber. For example, referring to FIG. 2, oxygen that has accumulated above the water line 214 on one side of the barrier 216 can be removed via port 218. Similarly, hydrogen gas that has accumulated on the other side of the barrier 216 can be removed via port 222. Although gases can be pumped out of the chamber 201, gases can be removed from the chamber 201 without pumping due to positive pressure built up in the chamber 201 by opening valves / ports 218 and 222.

[0241] Referring again to FIG. 3, at block 312, the hydrogen gas may then be stored in the storage receptacle.

[0242] It should be noted that the modifications to the metal oxide are reversed during the process, such that the same metal oxide can be used over and over again to perform the hydrogen generation process 300.

[0243] 4A-4C illustrate examples of components for a hydrogen generator having a photoionization mechanism to generate hydrogen. FIGS. 4A and 4B illustrate a three-dimensional view of an example of a hydrogen generator housing 400. Housing 400 is an example of a housing for a hydrogen generator, such as generator 200 of FIG. 2. Housing 400 includes a main box 406 having a hollow area to form a sealed chamber 402 when closed with a lid 404. In the example illustrated in FIGS. 4A and 4B, main box 406 includes a slot 414 for a proton membrane and a window 412 to expose the membrane to allow separation of released protons, and electrons are transferred from anode 204 to cathode 206 (FIG. 2) through a metal conductive wire 215 connecting both electrodes.

[0244] The main box 406 also includes a water port 410 for introducing water into the chamber 402 and a window 408 for transmitting radiation or an electron beam from an external source. The lid 404 includes two openings or ports 418 and 416 to allow extraction of oxygen and hydrogen gas released during operation of the hydrogen generator. Figure 4C illustrates separate gas tanks 420 and 422 for storing the released hydrogen and oxygen.

[0245] Figure 5 is a diagram of a hydrogen generator with a chemical loop mechanism for generating hydrogen. Similar to the hydrogen generator 200 of Figure 2, the hydrogen generator 500 of Figure 5 includes a chamber 501. However, unlike the chamber 201 of Figure 2, the chamber 501 is not separated by a membrane or barrier. In the chemical loop mechanism used by the hydrogen generator 500 of Figure 5, oxygen and hydrogen are released at different times, eliminating the need for a barrier inside the chamber to separate the two gases.

[0246] The hydrogen generator 500 includes a metal oxide 510 in a chamber 501. The metal oxide 510 can be the same as or similar to the metal oxides described above with respect to FIG. 2. For example, the metal oxide 510 can be a metal oxide powder. The chamber 501 has an input port 520 for inputting water vapor into the chamber 501 and exhaust ports 518 and 522 for exhausting oxygen gas and hydrogen gas, respectively. However, in another example, a single exhaust port may be used to exhaust both hydrogen gas and oxygen gas.

[0247] 5, a radiation or electron beam source 511 is external to the chamber 501. Radiation or electron beam 502 from source 511 is directed to the metal oxide within the chamber 501 through a window 512. In one example, window 512 can have the same or similar characteristics as window 212 of FIG. 2, discussed above.

[0248] In one example where a radioactive material is used, a shield 524 surrounds the hydrogen generator 500. An additional shield may surround the radioactive material.

[0249] 6 is a flow diagram of an example method for generating hydrogen gas via a chemical loop with a metal oxide. Method 600 may be performed by a hydrogen generator, such as hydrogen generator 500 of FIG.

[0250] The method 600 begins in block 602 by exposing a metal oxide in a drying chamber to radiation from a radioactive material or UV source, or to an electron beam from an electron gun, to release oxygen from the surface of the metal oxide. The released oxygen is then extracted from the chamber in block 604. For example, referring to FIG. 5, a metal oxide 510 is irradiated with radiation or an electron beam 502 to release O2. The oxygen can then be removed via an exhaust port or valve 518. In one example, the oxygen is pumped out of the chamber 501 to completely evacuate the chamber 501. In another example, the oxygen gas is removed using the pressure increase from the release of oxygen gas by opening the valve 518.

[0251] Referring again to Figure 6, the activated metal oxide is then exposed to water vapor in block 606. For example, referring to Figure 5, water vapor is introduced into chamber 501 via port 520. Exposure of the activated metal oxide 510 to water vapor causes the water vapor to release hydrogen gas. Oxygen from the water vapor recombines with the surface of the metal oxide, breaking down the water molecules and releasing hydrogen. The general process can be represented by equation (III) shown above.

[0252] 6, after releasing the hydrogen gas, the released hydrogen is extracted from the chamber at block 608. For example, referring to FIG. 5, the hydrogen gas can be extracted through port 522 by pumping or opening a valve and utilizing the increased pressure from the released gas. At block 610, the hydrogen gas is then stored in a storage receptacle.

[0253] It should be noted that the changes to the metal oxide are reversed during the process so that the same metal oxide can be used over and over again to perform the hydrogen generation process 600. For example, irradiating the metal oxide causes it to release oxygen, which creates oxygen pores or gaps in the metal oxide (creating an activated catalyst). After adding water vapor, the oxygen pores or gaps take the oxygen from the water vapor, returning the metal oxide to its original form and releasing hydrogen.

[0254] Figure 7 illustrates a three-dimensional view of an example of a hydrogen generator housing 700. Housing 700 is an example of a housing for a hydrogen generator, such as generator 500 of Figure 5. Housing 700 includes a main box 702 having a hollow interior to form a sealed chamber when closed with a lid 704.

[0255] The main box 702 also includes a window 710 for transmitting radiation or an electron beam from an external source. The lid 704 includes an opening or HO port 708 for introducing water vapor into the chamber, and an opening or gas port 706 to allow extraction of oxygen and hydrogen gas released during operation of the hydrogen generator. The hydrogen generator housing 700 can be coupled with separate gas tanks for storing the released hydrogen and oxygen, as shown in FIG. 4C.

[0256] FIG. 8 is a three-dimensional view of a hydrogen generator in a spent nuclear fuel (SNF) storage cask 800. Currently, there are no known uses for spent nuclear fuel, and spent nuclear fuel casks are used only for the safe storage of spent nuclear fuel. In contrast, a spent nuclear fuel container with a hydrogen generator can not only safely store spent nuclear fuel, but can also use the spent nuclear fuel as a free energy source to provide high power (as a function of material mass) that lasts for several years with very low maintenance.

[0257] SNF storage cask 800 includes a spent nuclear fuel canister 802 within a chamber 801 surrounded by a shield 804. A movable support arm 806 is coupled to a metal oxide coated substrate 810 within the chamber 801. The movable support arm alternately moves the metal oxide coated substrate 810 in close proximity to the nuclear fuel canister 802 (to expose the metal oxide to radiation from the canister 802) and away from the nuclear fuel canister 802 (to contact the activated metal oxide with water vapor that is input to the system via port 808). Released oxygen and hydrogen can be removed from the cask through one or more gas ports, such as gas port 812.

[0258] 9A-9D illustrate three-dimensional views of a spent nuclear fuel (SNF) storage cask 800 in different positions during operation. In the example of FIGS. 9A-9D, the metal oxide used for hydrogen generation is a metal oxide coating or film on two cylindrically shaped substrates 810A and 810B around a spent nuclear fuel canister 802. In the example of FIGS. 9A-9D, the system includes an inner metal oxide coated substrate 810A and an outer metal oxide coated substrate 810B. The inner substrate 810A has a smaller diameter and can pass the outer substrate 810B as the substrate is moved by support arms 806A and 806B to positions proximate and away from the canister 802.

[0259] 9A shows a metal oxide coated substrate 810B located near or in close proximity to the canister 802 and another metal oxide coated substrate 810A located away or at a distance from the canister 802. The metal oxide coated substrate 810B adjacent to the canister 802 is shown with a lighter color (yellow) indicating that the metal oxide is not activated (e.g., not releasing oxygen due to irradiation from the spent nuclear fuel canister 802). The metal oxide coated substrate 810A not adjacent to the canister 802 is shown with a darker color (black) indicating that the metal oxide is activated and thus moving away from the canister 802 towards the water vapor introduced into the system to release hydrogen from the activated surface of the metal oxide coated substrate 810A.

[0260] Figure 9B shows metal oxide coated substrates 810A and 810B in the same position as Figure 9A, but at a later time. The metal oxide coated substrate 810B adjacent to the canister 802 is shown in Figure 9B as having a darker color (black), indicating that the metal oxide has been activated (e.g., released oxygen due to irradiation from the spent nuclear fuel canister 802). The metal oxide coated substrate 810A not adjacent to the canister 802 is shown as having a lighter color (yellow), indicating that oxygen from the water vapor has recombined with the activated metal oxide, returning the metal oxide to its original state. The released oxygen and hydrogen gases can then be removed from the system.

[0261] 9C shows metal oxide coated substrates 810A and 810B moved to opposite positions after releasing hydrogen and oxygen, respectively. The movable support arms have moved metal oxide 810B upward, away from canister 802, and metal oxide 810A downward, towards canister 802.

[0262] FIG. 9D shows the metal oxide coated substrates 810A and 810B in the same position as FIG. 9C, but at a later time. Thus, the metal oxide coated substrate 810A adjacent to the canister 802 is shown in FIG. 9D as having a darker color (black), indicating that the metal oxide has been activated. The metal oxide coated substrate 810B not adjacent to the canister 802 is shown in FIG. 9D as having a lighter color (yellow), indicating that oxygen from the water vapor has recombined with the activated metal oxide and the metal oxide has returned to its original state. The released oxygen and hydrogen gas can again be removed from the system. Thus, the change to the metal oxides 810A and 810B is reversible and the process can continue with minimal intervention. Additionally, in one example, the movable arm can alternately move the metal oxide towards and away from the canister 802, as the metal oxide becomes lighter as it releases oxygen, automatically lifting the metal oxide. However, in other examples, an external power source can be provided.

[0263] 9A-9D, the system may include a barrier or separation between the upper and lower levels (e.g., between an area near the canister 802 and an area away from the canister where water vapor is introduced) to prevent recombination of the released hydrogen and oxygen. In other examples, a single metal oxide coated substrate, or three or more metal oxide coated substrates may be used.

[0264] The flow diagrams as illustrated herein provide examples of sequences of various process operations. The flow diagrams may depict operations performed by software or firmware routines as well as physical operations. Although shown in a particular sequence or order, unless otherwise specified, the order of operations may be modified. Thus, the illustrated diagrams should be understood as examples only, and processes may be performed in different orders and some operations may be performed in parallel. Additionally, one or more operations may be omitted, and therefore not all implementations may perform all operations.

[0265] Non-limiting examples Example 1: Testing the reversibility of metal oxides material Thin ceria pellets were used; up to 100 nm for nano powder and 4-5 μm for micro powder.

[0266] method Oxygen generation was tested with CeO2 (a metal oxide) and an electron gun (to simulate beta radiation) as the power source, as well as in vacuum.

[0267] Because cerium metal has a natural black-blue color, the color change from the white color of CeO2 suggested that the color change was associated with the release of all (both) oxygen atoms from each one of the metal oxide molecules.

[0268] Example 1A: CeO2 Pellets A 3 mm thick pellet of CeO2 was prepared with a uniform flat anode behind it. The CeO2 was irradiated with an electron beam from an electron gun at about 300 kW for several minutes, resulting in a color change shown as blackening of the CeO2, as can be seen in Figures 10A and 10B, which show CeO2 before and after irradiation, respectively (the arrows in Figure 10B point to the color change and blackening of the CeO2).

[0269] The pellets formed after irradiation (Figure 10C) were kept in ambient air, and the original color was observed after 2 days (Figure 10D), suggesting that oxygen had been reabsorbed by natural oxygen (air) diffusion at room temperature.

[0270] Example 1B: Thin CeO2 Film on Mesh Anode Thin coatings of CeO2 were prepared on a tight mesh anode and tested in vacuum and ambient air. Direct arc discharge produced a black-blue color on the coating, as can be seen from Figures 11A and 11B, which show CeO2 before and after irradiation, respectively.

[0271] After about 2–3 h, the CeO2 coating began to revert to a yellow color, and upon irradiation with additional CeO2, the black-blue color reappeared (Figure 11C), disappearing after a few days and the original color was observed (Figure 11D).

[0272] Example 1C: Thin CeO2 Film on Mesh Aluminum Foil A few millimeters coating of CeO2 was prepared on a thin aluminum foil, patterned, and tested in a vacuum environment (FIG. 12A, red circles indicate a visual change in color in all images). Both direct arcing and electron scattering were generated for 35 minutes, after which the CeO2 film changed color to a more black-blue color (FIG. 12B).

[0273] Warm water was then added to the vacuum chamber in two small cups and the air was pumped out to create a humid environment within the chamber. After about 30 minutes, the film began to return to its whitish-yellow color, as can be seen in FIG. 12C, suggesting that oxygen atoms were reabsorbed onto the CeO2 film.

[0274] Upon impact (electron beam passing through CeO2 to the anode), the color of the beam was purple-blue and a change in the CeO2 was observed.

[0275] When water vapor was forced through the ceria, a color change was observed within minutes, suggesting that recombination of oxygen occurs from the water molecules and releases hydrogen. Recombination with oxygen from the air takes two days, so this is not the reason for the color change.

[0276] Therefore, based on these visual findings, a chemical loop involving a two-step mechanism was suggested: the first step involves an electron beam being used to remove oxygen from CeO2, and in the second step, "oxygen vacancies" in the CeO2 recombine with oxygen from water, essentially splitting the water and releasing hydrogen.

[0277] Example 2: Examination of changes in metal oxide mass Materials and Methods A 15 mL sample bottle containing approximately 22 grams of CeO2 Micro Powder (5 μm) was exposed to a known Co-60 source (1.7 Mrad / s) for various durations (various fluences) as detailed below. Experiments were performed at the University of Maryland Co-60 Source.

[0278] A rack was fabricated to ensure that each of the sample bottles was axially centered on the cobalt pencil at the same radius. The rack was designed to fit against the outside radius of the stainless steel "top hat" and not interfere with the mechanism used to raise and lower the source to and from the top hat. The rack includes adjustable feet to allow for leveling of the rack and to place the centerline of the bottles at the axial center of the cobalt pencil when raised to the top position inside the "top hat". The rack positions the bottles at a radius of 5.88 inches from the center of the "top hat". Below is a photograph of the rack that was fabricated. An exemplary experimental setup is shown in Figures 13A and 13B.

[0279] The experiment included the following steps: bottles (30) were sterilized and the weight of each bottle was recorded. Fifteen bottles were then filled with approximately 22 grams of ceria oxide (CeO2) powder and the weight of each bottle with CeO2 was recorded. From these measurements, the weight of CeO2 in each bottle was calculated. The samples were placed in a rack and positioned around the Co-60 source. An empty bottle was placed adjacent to each bottle with CeO2, as can be seen in FIG. 13B.

[0280] The samples were irradiated for a given period of time. After irradiation, the bottles were removed and the irradiation time was recorded. Each bottle (without cap) was then weighed and the post-irradiation weight was recorded.

[0281] The difference between the pre- and post-irradiation weights was calculated to determine the weight loss due to irradiation.

[0282] Table 1 shows the exposure time and location in the rack for each sample combination (empty bottle and bottle with approximately 22 grams of ceria).

[0283] [Table 1]

[0284] The weight loss for each sample was then measured to calculate the weight loss due to oxygen vacancies created in the ceria.

[0285] result The CeO2 was weighed before and after irradiation, and a reduction in CeO2 mass of 0.0005 mg (5 micrograms) was observed after irradiation. This suggests that upon irradiation, oxygen atoms are released from CeO2, resulting in a reduction in mass. Figure 14 shows the mass reduction as a function of irradiation time.

[0286] Example 3: Generation of oxygen and hydrogen gas Equipment Two power systems were used: (i) a high power electron beam (simulating beta radiation) - measured dose of 2 Gy per pulse, 100 pulses per second (University of Maryland, USA) (ii) a Co emitting gamma radiation with a measured dose of 1.7 Mrad / s. 60 Source (University of Maryland, USA).

[0287] irradiation As mentioned above, the two power supplies were each set up separately, as outlined below: In both cases, the metal oxide (MO) was irradiated at ambient conditions (atmospheric pressure and room temperature).

[0288] E-Beam Direct electron beam irradiation of the sample was used to simulate beta radiation in terms of interaction (beta radioisotopes emit electrons isotropically, unlike a beam). A schematic of the experimental setup is shown in FIG.

[0289] Gamma radiation source - Co 60 2 kg of ceria powder was placed in the jar relative to the outer diameter of the source cylinder: Source diameter = 254 mm → I@r = 127 mm = 0.7 MRad / hr. A schematic of the experimental setup is shown in Figure 16.

[0290] Hydrogen release measurement 17A and 17B show schematic diagrams of an exemplary system for hydrogen release, where P represents pressure, T - temperature, V - volume, Q - volumetric flow rate, M - mass, LEL - lower explosion limit of hydrogen.

[0291] In each test, the hydrogen LEL% in Tank 2 as well as pressure and temperature were measured directly in both tanks.

[0292] Since the pressure and temperature were not constant over time, the actual amount of hydrogen from LEL%, P2 and T2 at any given time was calculated.

[0293] The calculation for the amount of hydrogen (in moles) was (assuming both tanks are ideal gases):

[0294]

number

[0295] To measure the actual formation of hydrogen in a given sensor, first a test in the absence of MO (ceria) was performed and the maximum %LEL was determined as "%LEL ref" in the stability region (marked with a red dashed line in the chart below). Later, a value was reduced from the measured %LEL and the resulting value was defined as %LEL-real.

[0296] Figures 18A and 18B show hydrogen control measurements with %LEL ref of 12% and 21%, respectively.

[0297] Results and Discussion The setup consisted of CeO2 (ceria) as the metal oxide and two types of power sources: a high-power electron beam (simulating beta radiation) and a Co 60 Evaluate based on:

[0298] Example 3A: Nanoceria with Electron Beam Irradiation (E-Beam) for 150 minutes The method of this example included two steps: the first step of irradiation and oxygen release, and the second step of hydrogen release.

[0299] Irradiation and oxygen release As detailed above, 251.3 g of ceria (CeO2) was placed in the jar, 43 cm from the barrel to the center of the jar, and the beam exposure was 100 pulses / sec, 2 Gy / pulse.

[0300] The samples were irradiated at 100 pulses / sec (2 Gy / pulse) for 30 min × 5 / 6 cycles (total 150 / 180 min).

[0301] Every 30 minutes the temperature was measured and the samples were manually stirred.

[0302] As can be seen in Figures 19A, 19B, and 19C, taken before irradiation and after 0.5 and 1 hour, respectively, there was no visible discoloration or any change in the CeO2.

[0303] No discoloration of the ceria was observed, suggesting that only one oxygen atom was released per ceria molecule (CeO2), and therefore, no discoloration is evident since no cerium is formed.

[0304] Hydrogen Release Nanoceria after 150 min of irradiation The irradiated ceria was placed in the inner bucket of Tank 2 (shown in FIG. 17B). Hydrogen release data is shown in FIG.

[0305] By considering a %LEL ref of 12%, performing an extrapolation and integrating over the H2 production rate for the relevant time interval, the total amount of hydrogen in this test was 0.35 mol → 0.7 g per 21 min → 0.03 g / min = 1.8 g / hr average production rate.

[0306] Figure 21 shows the integral of H2 production in moles versus time to assess the total H2 production. A maximum production rate of 0.00093 mol / sec = 0.11 g / min = 6.7 g / hr was measured - this depends on the amount of water vapor and ceria in the chamber. The results suggest that oxygen vacancies were formed that can recombine with oxygen atoms from the water vapor and generate hydrogen.

[0307] Example 2: Nanoceria after 180 minutes of electron beam irradiation Ceria with oxygen vacancies was placed in a bucket inside Tank 2. The %LEL ref was 12% and the total amount of hydrogen in this test was 0.22 mol → 0.44 g / 11 min → average production rate 0.04 g / min = 2.4 g / hr.

[0308] A maximum production rate of 0.00047 mol / sec = 0.056 g / min = 3.38 g / hr was measured.

[0309] Example 3C: Gamma irradiation (Co 60 ) Nanoceria Irradiation and oxygen release 2 kg of ceria was placed in a jar placed flush with the outer diameter of the source cylinder. Source diameter = 254 mm → I@r = 127 mm = 0.7 MRad / hr.

[0310] The CeO2 sample was continuously irradiated for 44 hours. There was no discoloration of the CeO2 following irradiation.

[0311] Hydrogen release test Ceria was placed in a bucket inside Tank 2 - total mass 120g. %LEL ref is 21%. In this experiment the maximum production rate obtained was 0.0014mol / sec=0.17g / min=10.08g / hr.

[0312] According to the measured hydrogen production rate of 0.0014 mol / s, it can be concluded that the minimum rate of released oxygen is 0.0007 mol / s (per the stoichiometry of the above reaction), which may indicate a higher absorption probability or that each impact releases more than one oxygen atom.

Claims

1. A method comprising exposing a metal oxide to radiation to obtain an oxygen-vacant metal oxide (OVMO) in said metal oxide and oxygen gas.

2. The method of claim 1 , wherein during said exposing, said metal oxide is at a temperature below the temperature required to overcome a metal oxide bond energy.

3. The method of claim 1 , wherein the radiation is non-thermal radiation.

4. 10. The method of claim 1, wherein the radiation is selected from the group consisting of electron beam radiation, alpha radiation, beta radiation, gamma radiation, and UV radiation.

5. 5. The method of any one of claims 1 to 4, wherein the metal in the metal oxide is at least one of: (i) at least one alkali metal, (ii) at least one alkaline earth metal, (iii) at least one transition metal, (iv) at least one lanthanide metal, (v) at least one actinide metal, or (vi) combinations thereof.

6. 6. The method of any one of claims 1 to 5, wherein the metal in the metal oxide is at least one of: (i) at least one transition metal, (ii) at least one lanthanide metal, (iii) at least one actinide metal, or (iv) combinations thereof.

7. 7. The method of any one of claims 1 to 6, wherein the metal in the metal oxide is at least one of zirconium (Zr), cerium (Ce), iron (Fe), titanium (Ti), nickel (Ni), or any combination thereof.

8. The metal oxide is ZrO ２ , CeO ２ 8. The method according to claim 1, wherein the oxide is selected from the group consisting of FeO, TiO, and NiO.

9. The method according to any one of claims 1 to 8, wherein the metal oxide is in a solid state.

10. The method according to any one of claims 1 to 9, wherein the metal oxide is in powder form or is a surface coating.

11. The method of any one of claims 1 to 9, comprising collecting the oxygen gas.

12. The method of any one of claims 1 to 11, comprising collecting the OVMOs containing oxygen vacancies.

13. The method of any one of claims 1 to 11, comprising exposing the OVMO to water vapor.

14. The method of claim 13 comprising collecting hydrogen gas produced upon exposure of the OVMO to the water vapor.

15. 1. A method comprising: (i) exposing a metal oxide to radiation to obtain OVMO and oxygen gas; (ii) exposing the OVMO to water vapor to regenerate metal oxide particles and generate hydrogen gas.

16. 15. The method of claim 14, comprising repeating steps (i) and (ii) to allow for the sequential generation of oxygen gas and hydrogen gas.

17. 17. The method of claim 15 or 16, further comprising collecting the oxygen gas.

18. 20. The method of claim 17, comprising collecting the oxygen gas prior to step (ii).

19. 17. The method of claim 15 or 16, comprising collecting the OVMO.

20. 20. The method of claim 19, comprising collecting the OVMO prior to step (ii).

21. The method of any one of claims 15 to 20, comprising collecting the hydrogen gas.

22. 22. The method of claim 21 , comprising collecting the hydrogen gas after step (ii).

23. 1. A reactor comprising a reactor chamber including a gas outlet and a radiation source, the reactor chamber configured to hold metal oxide particles such that upon irradiation by the radiation source, the metal oxide particles are exposed to the radiation, and upon exposure to the radiation, a gas is generated by the metal oxide and released from the reactor through the gas outlet.

24. 24. The reactor of claim 23, wherein the radiation is free of thermal radiation.

25. 24. The reactor of claim 23, wherein the radiation source is a radioactive source.

26. 24. The reactor of claim 23, wherein the metal oxide is configured to release oxygen atoms upon exposure to the radiation to generate oxygen gas and OVMOs.

27. 24. The reactor of claim 23, wherein the gas outlet is configured to exhaust oxygen gas from the chamber.

28. 30. The reactor of claim 27 comprising a means for collecting the OVMOs from the chamber.

29. A reactor according to any one of claims 23 to 28, comprising a water vapor reservoir.

30. 30. The reactor of claim 29, wherein the OVMO is configured to generate hydrogen gas upon exposure to water vapor from the water vapor reservoir and undergo regeneration to obtain the metal oxide.

31. 31. The reactor of claim 29 or 30, wherein the gas outlet is or comprises a hydrogen gas outlet.

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