Hydrogen storage in perfluorocarbon emulsions

Abstract

A hydrogen storage and / or delivery system comprises a hydrogen storing emulsion formed from a perfluorocarbon (PFC) and a surfactant present in an aqueous medium. The hydrogen storing emulsion releasably retains hydrogen gas and may be in a hydrogen containing emulsion state or a hydrogen absorbable emulsion state. The emulsion may be supplied in a vessel configured to receive and provide hydrogen gas, thereby comprising a device for storing and providing hydrogen gas. The hydrogen containing emulsion may be configured to release the hydrogen gas upon sonication.

Description

MATERIAL FOR HYDROGEN STORAGECROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of and priority to U.S. Provisional patent application No. 63 / 712,666, filed October 28th, 2024. The content of the above-noted patent application is hereby expressly incorporated by reference into the detailed description hereof.FIELD

[0002] The specification relates to a system, an emulsion and device for gas storage, along with process for preparation of the emulsion. In particular, the specification discloses an emulsion for hydrogen storage, a process for preparation of the emulsion, a device containing the emulsion and a system for storage of hydrogen.BACKGROUND

[0003] Hydrogen, is an abundant element in the universe and a potential source of clean fuel; and can play a significant role in the transition to low-carbon energy systems in the future. However, its efficient and sustainable storage and transportation remain a significant challenge, due to hydrogen’s low density and high reactivity ((a) H. Li, X. Cao, Y. Liu, Y. Shao, Z. Nan, L. Teng, W. Peng, and J. Bian, “Safety of hydrogen storage and transportation: An overview on mechanisms, techniques, and challenges,” Energy Reports, vol. 8, pp. 6258-6269, 2022; and (b) M. Yang, R. Hunger, S. Berrettoni, B. Sprecher, and B. Wang, “A review of hydrogen storage and transport technologies,” Clean Energy, vol. 7, no. 1 , pp. 190-216, 2023), both incorporated herein by reference). In addition, in response to the global demand for sustainable energy solutions, hydrogen has emerged as a key element in the energy transition movement due to its abundance and high energy density. The widespread hydrogen production faces limitations in our capability for safe and efficient hydrogen storage, transportation and delivery. The existing hydrogen storage infrastructures, both above-ground facilities and geographically limitedunderground storage facilities, face challenges in capacity, cost, and operational complexity.

[0004] Current hydrogen storage methods, such as high-pressure tanks and cryogenic liquids, are fraught with problems. High-pressure tanks require substantial energy to compress hydrogen, while cryogenic storage demands complex thermal management and poses risks of spontaneous combustion and boil-off (H. Li, X. Cao, Y. Liu, Y. Shao, Z. Nan, L. Teng, W. Peng, and J. Bian, “Safety of hydrogen storage and transportation: An overview on mechanisms, techniques, and challenges,” Energy Reports, vol. 8, pp. 6258-6269, 2022, incorporated herein by reference). These methods necessitate specialized, costly infrastructure resistant to hydrogen’s material-damaging properties ((a) B. Ghorbani, S. Zendehboudi, N. M. C. Saady, and M. B. Dusseault, “Hydrogen storage in North America: Status, prospects, and challenges,” Journal of Environmental Chemical Engineering, vol. 11 , no. 3, p. 109957, 2023; (b) E. Rivard, M. Trudeau, and K. Zaghib, “Hydrogen storage for mobility: A review,” Materials, vol. 12, no. 12, p. 1973, 2019; and (c) A. I. Osman, N. Mehta, A. M. Elgarahy, M. Hefny, A. Al-Hinai, A. H. Al-Muhtaseb, and D. W. Rooney, “Hydrogen production, storage, utilisation and environmental impacts: a review,” Environmental Chemistry Letters, pp. 1-36, 2022; all incorporated herein by reference).

[0005] The transportation of hydrogen, whether via pipelines or vehicles, carries the risks of leakage, leading to economic loss, safety hazards, and unintended environmental impact due to the potential contribution of escaped hydrogen to greenhouse gas emissions (M. Yang, R. Hunger, S. Berrettoni, B. Sprecher, and B. Wang, “A review of hydrogen storage and transport technologies,” Clean Energy, vol. 7, no. 1 , pp. 190-216, 2023, incorporated herein by reference). Furthermore, current technologies are not ideally suited for widespread commercial and personal use, often involving high costs, complex infrastructure, and safety issues. Alternatives like liquid-state hydrogen carriers (e.g., ammonia, methanol) present more viable solutions, but they too have limitations and safety concerns. The current actions addressing these storage issues include various activities, with a focus on performance and safety ((a) N. R. Council, D. on Engineering, P. Sciences, B. on Energy, E. Systems, C. on Alternatives, and S. for Future Hydrogen Production, The hydrogen economy: opportunities, costs, barriers, and R&D needs.National Academies Press, 2004; and (b) T. H. Ulucan, S. A. Akhade, A. Ambalakatte, T. Autrey, A. Cairns, P. Chen, Y. W. Cho, F. Gallucci, W. Gao, J. B. Grinderslev, et al., “Hydrogen storage in liquid hydrogen carriers: recent activities and new trends,” Progress in Energy, vol. 5, no. 1 , p. 012004, 2023, both incorporated herein by reference).

[0006] Perfluorocarbons (PFCs) exhibit high gas solubility, and are compounds where fluorine atoms replace most of or entirely all the hydrogen atoms bonded to carbon. These molecules create a heavy fluorous phase that can make them immiscible with both aqueous and organic solvents due to their dense molecular structure. The inherent stability of PFCs arises from the stiffness of the molecules and the minimal force of attraction between them.

[0007] There is a need in the art for a hydrogen storage and delivery system. In addition, there is a need in the art for a hydrogen storing emulsion. Further, there is a need in the art for a process for storing and providing hydrogen gas. Moreover, there is a need in the art for a device for storing and providing hydrogen gas.Furthermore, there is a need in the art for a process for preparation of a hydrogen storing emulsion.

[0008] The background herein is included solely to explain the context of the disclosure. This is not to be taken as an admission that any of the material referred to was published, known, or part of the common general knowledge as of the priority date.SUMMARY

[0009] In one aspect, the specification relates to a hydrogen storage and delivery system, comprising:

[0010] a vessel configured to receive and provide hydrogen gas, the vessel containing a hydrogen storing emulsion,

[0011] the hydrogen storing emulsion configured to releasably retain the hydrogen gas, the hydrogen storing emulsion being in a hydrogen containing emulsion state or a hydrogen absorbable emulsion state;

[0012] the hydrogen storing emulsion comprising a perfluorocarbon (PFC) and a surfactant present in an aqueous medium.

[0013] In a second aspect, the specification relates to a hydrogen storing emulsion comprising:

[0014] a perfluorocarbon (PFC) and a surfactant present in an aqueous medium; and

[0015] wherein the hydrogen storing emulsion releasably retains hydrogen gas.

[0016] In a third aspect, the specification relates to a process for storing and providing hydrogen gas, comprising:

[0017] providing the hydrogen gas to a hydrogen storing emulsion in a hydrogen absorbable emulsion state to form the hydrogen storing emulsion in a hydrogen containing emulsion state; the hydrogen storing emulsion comprising a perfluorocarbon (PFC) and a surfactant present in an aqueous medium.

[0018] In a fourth aspect, the specification relates to a device for storing and providing hydrogen gas, the device comprising:

[0019] a vessel configured to receive and provide hydrogen gas, the vessel containing a hydrogen storing emulsion,

[0020] the hydrogen storing emulsion configured to releasably retain the hydrogen gas, the hydrogen storing emulsion being in a hydrogen containing emulsion state or a hydrogen absorbable emulsion state;

[0021] the hydrogen storing emulsion comprising a perfluorocarbon (PFC) and a surfactant present in an aqueous medium.

[0022] In a fifth aspect, the specification relates to a process for preparation of a hydrogen storing emulsion, the process comprising:

[0023] contacting a surfactant with a perfluorocarbon (PFC) and an aqueous medium to form the hydrogen storing emulsion,

[0024] wherein the surfactant is present in an amount equal to or above the critical micelle concentration.BRIEF DESCRIPTION OF DRAWINGS

[0025] Reference will now be made, by way of example, to the accompanying drawings which show example embodiments of the present application, and by which the present application can be further understood from the following description with reference to the Figures. The present application includes drawings, wherein:

[0026] Figure 1 shows a schematic of the experimental procedure of an embodiment disclosed in the specification for the preparation and use of the hydrogen storing emulsion;

[0027] Figure 2 shows a graph of viscosity of pure perfluorodecalin (PFD) before hydrogenation, after hydrogenation and after sonication;

[0028] Figure 3 shows microscopic analysis of PFD emulsions prehydrogenation, post-hydrogenation and post-sonication at three different: 4x, 10x and 40x;

[0029] Figure 4 shows a droplet size distribution of emulsions prepared with 80% PFC before hydrogenation and after four consecutive hydrogenation cycles; and

[0030] Figure 5 shows hydrogen release profiles from samples saturated with hydrogen, where the samples are PFD-emulsion, PFD, decan-emulsion, decane, and Dl-water.DESCRIPTION OF EXAMPLE EMBODIMENTS

[0031] Unless otherwise explained, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice for testing of the present invention, the typical materials and methods are described herein. In describing and claiming the present invention, the common terminology generally used is described herein below. It is also to be understood that the terminology usedherein is for the purpose of describing particular aspects only, and is not intended to be limiting.

[0032] Many patent applications, patents, and publications are referred to herein to assist in understanding the aspects described. Each of these references are incorporated herein by reference in their entirety.

[0033] When introducing elements disclosed herein, the articles “a”, “an”, “the”, and “said” are intended to mean that there may be one or more of the elements.

[0034] The term "comprising" and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, integers, and / or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers and / or steps. The foregoing also applies to words having similar meanings such as the terms, "including", "having" and their derivatives. It will be understood that any embodiments described as “comprising” certain components may also “consist of” or “consist essentially of,” these components, wherein “consisting of” has a closed- ended or restrictive meaning and “consisting essentially of” means including the components specified but excluding other components except for materials present as impurities, unavoidable materials present as a result of processes used to provide the components, and components added for a purpose other than achieving the technical effects described herein. For example, a composition defined using the phrase “consisting essentially of” encompasses any known acceptable additive, excipient, diluent, carrier, and the like, suitable for the composition described herein. Typically, a composition consisting essentially of a set of components will comprise less than 5% by weight, typically less than 3% by weight, more typically less than 1 % by weight of non-specified components.

[0035] It will be understood that any component defined herein as being included may be explicitly excluded from the claimed invention by way of proviso or negative limitation, such as any specific compounds or method steps, whether implicitly or explicitly defined herein.

[0036] In addition, all ranges given herein include the end of the ranges and also any intermediate range points, whether explicitly stated or not.

[0037] Finally, terms of degree such as "substantially", "about" and "approximately" as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree should be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.

[0038] The abbreviation, “e.g.” is derived from the Latin exempli gratia, and is used herein to indicate a non-limiting example. Thus, the abbreviation “e.g.” is synonymous with the term “for example.” The word “or” is intended to include “and” unless the context clearly indicates otherwise.

[0039] The phrase “at least one of” is understood to be one or more. The phrase “at least one of... and...” is understood to mean at least one of the elements listed or a combination thereof, if not explicitly listed. For example, “at least one of A, B, and C” is understood to mean A alone or B alone or C alone or a combination of A and B or a combination of A and C or a combination of B and C or a combination of A, B, and C.

[0040] In one aspect, the specification relates to a hydrogen storage and delivery system, comprising:

[0041] a vessel configured to receive and provide hydrogen gas, the vessel containing a hydrogen storing emulsion,

[0042] the hydrogen storing emulsion configured to releasably retain the hydrogen gas, the hydrogen storing emulsion being in a hydrogen containing emulsion state or a hydrogen absorbable emulsion state;

[0043] the hydrogen storing emulsion comprising a perfluorocarbon (PFC) and a surfactant present in an aqueous medium.

[0044] In a second aspect, the specification relates to a hydrogen storing emulsion comprising:

[0045] a perfluorocarbon (PFC) and a surfactant present in an aqueous medium; and

[0046] wherein the hydrogen storing emulsion releasably retains hydrogen gas.

[0047] The phrase, hydrogen storage and delivery system, as used herein is not particularly limited and should be understood by a person of skill in the art. The system relates to and can be designed for storage only, delivery only, or both storage and delivery of hydrogen gas. The system can include structural components, specification of materials, process steps, and / or process controls for the performance of storage, delivery, or both storage and delivery of hydrogen gas. Such features can include, for example and without limitation, design of the vessel, tubing or piping for receiving and providing hydrogen gas, specification of the hydrogen storing emulsion, controls for flow of the hydrogen gas, and others. In addition, the system can have safety features designed or required for proper operation of the system. Further, the delivery of hydrogen gas is not particularly limited, and can include providing hydrogen gas from the system at a point of location at the system, or at a distant point using means, such as, piping for flow of the hydrogen gas.

[0048] The term, hydrogen gas or hydrogen, as used herein is not particularly limited and should be known to a person of skill in the art. Hydrogen is a diatomic molecule having the chemical formula H2, and being colourless, odourless, non-toxic and highly combustible. Hydrogen is believed to be the most abundant chemical element in the universe. At room temperature and atmospheric pressure, hydrogen is present as a gas, and further, for the purposes of this application, reference to hydrogen relates to hydrogen gas. In addition, the purity of the hydrogen gas used, stored or provided by the system is not particularly limited and can vary based on design and application requirements.

[0049] The term, vessel, as used herein is not particularly limited and should be understood by a person of skill in the art. The vessel can include any body, chamber, container cylinder, drum, housing, well or the like that can be used for holding or receiving the hydrogen storing emulsion (described herein). The vessel can be hollow and have an opening for flow of the hydrogen storing emulsion. In addition, the vessel can allow for hydrogen gas to enter and exit from the vessel and the hydrogen storing emulsion. The vessel can be designed to be a closed container or the like, having one or more ports, to allow hydrogen gas to be received by and / or provided by the hydrogen storing emulsion.

[0050] The phrase, hydrogen storing emulsion, is not particularly limited. An emulsion is a mixture of two or more fluids that are normally immiscible owing to liquid-liquid phase separation. In an emulsion, one fluid (the dispersed phase) is dispersed in the other (the continuous phase). In one embodiment, for example and without limitation, in the hydrogen storing emulsion disclosed herein, the perfluorocarbon forms the dispersed phase, while the aqueous medium forms the continuous phase. The hydrogen storing emulsion provides the medium for storage of hydrogen gas. In addition, if needed, hydrogen can be released from the hydrogen storing emulsion for providing or delivery of the hydrogen gas.

[0051] The hydrogen storing emulsion disclosed herein is broadly described as being in a hydrogen containing emulsion state or a hydrogen absorbable emulsion state. As should be appreciated by a person of skill in the art, there is no clear line, point or concentration separating the hydrogen containing emulsion state from the hydrogen absorbable emulsion state. Rather, the two states can be broadly considered as having a gradation between the two, and the state being described as a hydrogen containing emulsion state or a hydrogen absorbable emulsion state depend on the function performed by the hydrogen storing emulsion. When hydrogen is present or absorbed (partly or completely) in the hydrogen storing emulsion, the hydrogen storing emulsion can be considered as being in the hydrogen containing emulsion state, as the hydrogen storing emulsion contains hydrogen gas. While, after hydrogen gas is removed (partly or completely) from or provided by the hydrogen storing emulsion, the hydrogen storing emulsion has capacity to receive and store hydrogen, and as such, can be considered to be in a hydrogen absorbable emulsion state, as it can absorb hydrogen.

[0052] The hydrogen storing emulsion can have a maximum hydrogen absorption limit (i.e. , referring to the maximum amount of hydrogen that can be stored or absorbed in a given amount of emulsion under defined conditions) for storing hydrogen gas, and upon reaching the maximum hydrogen absorption limit, the hydrogen storing emulsion would be in the hydrogen containing emulsion state, and no further hydrogen gas can be stored in the hydrogen storing emulsion under the given conditions. In such a state, the hydrogen storing emulsion can be considered as having its hydrogen absorption limit filled to 100%. On the other end of the spectrum, when hydrogen is completely removed from the hydrogen storingemulsion, the hydrogen storing emulsion is considered to be in the hydrogen absorbable emulsion state, where no further hydrogen gas can be provided by the hydrogen storing emulsion. In this state, the hydrogen storing emulsion can be considered as having its hydrogen absorption limit filled to 0% (or being empty), and it can absorb hydrogen. In practice however, the hydrogen storing emulsion can have its hydrogen absorption limit filled, for example and without limitation, to 80%, 60%, 40%, 20% or any and all values between 0% to 100%. When the hydrogen storing emulsion has its hydrogen absorption limit filled between 0% to 100%, such as, for example and without limitation, at 60%, the hydrogen storing emulsion can receive (store) or provide (deliver and / or discharge) hydrogen gas. Hence, as should be appreciated by a person of skill in the art, the state being used to describe the hydrogen storing emulsion should be considered based on the function, i.e. store or deliver, of the hydrogen storing emulsion. In addition, it should be appreciated that when the hydrogen capacity of the hydrogen storing emulsion is at 0%, the hydrogen storing emulsion can only be considered to be in the hydrogen absorbable emulsion state. Similarly, when the hydrogen capacity of the hydrogen storing emulsion is at 100%, the hydrogen storing emulsion can only be considered to be in the hydrogen containing emulsion state. In addition, for purposes of convenience, in one embodiment, for example and without limitation, the hydrogen storing emulsion can be considered to be in a hydrogen containing emulsion state when the hydrogen absorption limit of the hydrogen storing emulsion is filled more than 50%, while the hydrogen storing emulsion can be considered in a hydrogen absorbable emulsion state when the hydrogen absorption limit of the hydrogen storing emulsion is filled less than 50%.

[0053] The hydrogen storing emulsion contains perfluorocarbon (PFC), a surfactant and an aqueous medium, as disclosed herein, for forming the emulsion. In one embodiment, for example and without limitation, the hydrogen storing emulsion as disclosed herein is a high internal phase emulsion (HIPE). A high internal phase emulsion (HIPE) have internal phase volume fractions exceeding the close-packing limit (around 74%). In other words, a high internal phase emulsion (HIPE) is a concentrated system possessing a large volume of internal, or dispersed phase (PFC). Hence, when the hydrogen storing emulsion forms a HIPE, the amount (or volume fraction) of PFC present in the hydrogen storing emulsion ismuch higher. In one embodiment, for example and without limitation, the volume fraction is above 0.74. In a second embodiment, for example and without limitation, the hydrogen storing emulsion disclosed herein has a volume fraction of about 0.80, 0.85 or higher.

[0054] The term, perfluorocarbon (PFC), as used herein is not particularly limited and should be known or understood by a person of skill in the art. Fluorocarbons are broadly described as chemical compounds with carbon-fluorine (C-F) bonds. Compounds that contain many C-F bonds have distinctive properties, such as, for example and without limitation, enhanced stability, volatility and hydrophobicity. PFC’s as disclosed herein can be considered as compounds where fluorine atoms replace most of or entirely all the hydrogen atoms bonded to carbon. As such, the PFC’s disclosed herein can have one or some hydrogen atoms bonded to the carbon atom(s), with the majority of atoms bonded to carbon being fluorine. In one embodiment, for example and without limitation, the PFC disclosed herein can have one, two, three, four or five hydrogen atoms bonded to the carbon atoms in the PFC. In a second embodiment, for example and without limitation, the PFC disclosed herein has more than 85%, 90% or 95% of the atoms bonded to carbon atoms in the PFC being fluorine. In a third embodiment, for example and without limitation, the PFC can have one or more other heteroatoms (atoms other than H or F) bonded to the carbon atoms of the PFC. In a fourth embodiment, for example and without limitation, the PFC is a perfluoroalkane, perfluoroalkene, perfluoroalkyne, or perfluoroaromatic compound, optionally having one or more heteroatoms (atoms other than H or F).

[0055] The length of PFC or the number of carbon atoms in the PFC as used herein are not particularly limited and can be varied based on design and application requirements, so long as they can form the hydrogen storing emulsion. In one embodiment, for example and without limitation, the PFC has from Ce - Cis atoms, or from Ce - C14 atoms. Non-limiting examples of PFC include perfluorooctane (CsFis), perfluorohexane (CeF ), perfluorodecane (C10F22), perfluorotriethylamine (N(C2FS)3), perfluorobutylamine (C4F9NH2), perfluoroethylcyclohexane (CsFie), perfluorodibutylamine (CsF N), perfluoropolyether (various structures, e.g., C2F5O(CF2)2OCF3), perfluorodecalin (C10F18 or PFD), perfluoromethylcyclohexane (C7F14), perfluorobutylcyclohexane (CioFis), perfluorodimethylcyclohexane (CsFie),perfluoroperhydrophenanthrene (C14F24), perfluorooctyl bromide (CsBrFiz), or bis(perfluorobutyl)ethene (C10H2F18).

[0056] The amount of PFC used in preparation of the emulsion is not particularly limited and will vary depending on design and application requirements. In one embodiment, for example and without limitation, the PFC present in the emulsion is from 20 - 80 vol.%. In a second embodiment, for example and without limitation, the PFC present in the emulsion is from 50 - 80% vol. %. In a third embodiment, for example and without limitation, the PFC present in the emulsion is 80 vol.%

[0057] The term, surfactant, as used herein is not particularly limited and should be known or understood by a person of skill in the art. Surfactants are chemical compounds that decrease the surface tension or interfacial tension between two fluids. The word “surfactant” is a blend of surface-active agent, and have a water-repellent and a water-attracting part, and can enable an aqueous phase and a hydrophobic phase, such as, oil, to mix. Surfactants can be used as emulsifiers, i.e. an agent that helps form emulsions.

[0058] Most surfactants are organic compounds having a hydrophilic head (water-attracting part) and a hydrophobic tail (water-repellent part). The head of a surfactant are polar and may or may not carry an electrical charge. The tails of most surfactants are fairly similar, consisting of a hydrocarbon chain, which can be branched, linear, or aromatic. In addition, most surfactants are classified according to their polar head group. A non-ionic surfactant has no charged groups in its head. The head of an ionic surfactant carries a net positive, or negative, charge. If the charge is negative, the surfactant is categorized as an anionic surfactant. If the charge is positive, the surfactant is categorized as a cationic surfactant. If a surfactant contains a head with two oppositely charged groups, it is termed a zwitterionic, or amphoteric surfactant. In a first embodiment, for example and without limitation, the surfactant disclosed herein is a non-ionic surfactant. In a second embodiment, for example and without limitation, the surfactant disclosed herein is an ionic surfactant. Non-limiting examples of surfactants can include ammonium lauryl sulfate, sodium lauryl sulfate (sodium dodecyl sulfate, SLS, or SDS), sodium lauryl ether sulfate (SLES), sodium myreth sulfate, dioctyl sodium sulfosuccinate, sodium stearate, sodium lauroyl sarcosinate, cetrimonium bromide(CTAB), cetylpyridinium chloride (CPC), benzalkonium chloride (BAC), benzethonium chloride (BZT), dimethyldioctadecylammonium chloride, dioctadecyldimethylammonium bromide (DODAB), narrow-range ethoxylate, octaethylene glycol monododecyl ether, pentaethylene glycol monododecyl ether, nonoxynols, Triton X-100, polyethoxylated tallow amine, cocamide monoethanolamine, cocamide diethanolamine, poloxamers, glycerol monostearate, glycerol monolaurate, Span™, Tween™, decyl glucoside, lauryl glucoside, or octyl glucoside.

[0059] The amount of surfactant used in preparation of the emulsion is not particularly limited and will vary depending on design and application requirements. In one embodiment, for example and without limitation, the surfactant used in preparation of the emulsion is from 0.001 - 10 wt.%. In a second embodiment, for example and without limitation, the surfactant used in preparation of the emulsion is from 1 - 5 wt.%. In a third embodiment, for example and without limitation, the surfactant used in preparation of the emulsion is 1 wt.%.

[0060] The term, aqueous medium, as used herein is not particularly limited and should be known or understood by a person of skill in the art. Aqueous medium as used herein refers to a water phase that may contain one or more compounds that does not affect the water like nature of the aqueous medium, and does not inhibit the formation of emulsions. In a first embodiment, for example and without limitation, the aqueous medium is water. In a second embodiment, for example and without limitation, the aqueous medium is water having hydrogen dissolved in it.

[0061] In a third aspect, the specification relates to a process for storing and providing hydrogen gas, comprising:

[0062] providing the hydrogen gas to a hydrogen storing emulsion in a hydrogen absorbable emulsion state to form the hydrogen storing emulsion in a hydrogen containing emulsion state; the hydrogen storing emulsion comprising a perfluorocarbon (PFC) and a surfactant present in an aqueous medium.

[0063] In a fourth aspect, the specification relates to a device for storing and providing hydrogen gas, the device comprising:

[0064] a vessel configured to receive and provide hydrogen gas, the vessel containing a hydrogen storing emulsion,

[0065] the hydrogen storing emulsion configured to releasably retain the hydrogen gas, the hydrogen storing emulsion being in a hydrogen containing emulsion state or a hydrogen absorbable emulsion state;

[0066] the hydrogen storing emulsion comprising a perfluorocarbon (PFC) and a surfactant present in an aqueous medium.

[0067] The step of providing hydrogen gas to a hydrogen storing emulsion in a hydrogen absorbable emulsion state to form the hydrogen storing emulsion in a hydrogen containing emulsion state, in the system or process disclosed herein is not particularly limited. In addition, the method of providing hydrogen gas to the hydrogen storing emulsion is also not particularly limited. In one embodiment, for example and without limitation, the step of providing hydrogen gas can involve injecting, pumping, flowing or bubbling hydrogen gas into the hydrogen storing emulsion. In another embodiment, for example and without limitation, the step of providing hydrogen gas can involve providing hydrogen gas in a vessel containing the hydrogen storing emulsion. In such an embodiment, for example and without limitation, the hydrogen gas can be provided or enters directly into the emulsion or in any space in the vessel, where the hydrogen gas can contact the hydrogen storing emulsion, and allow the hydrogen gas to be absorbed by the hydrogen storing emulsion.

[0068] The method of providing hydrogen, source of hydrogen, and rate of providing hydrogen gas to the hydrogen storing emulsion are not particularly limited, and can be varied depending on design and application requirements. In one embodiment, for example and without limitation, hydrogen gas is provided directly into the hydrogen storing emulsion. In an embodiment, for example and without limitation, hydrogen gas is provided using a hydrogen generator. In another embodiment, for example and without limitation, hydrogen gas is provided at a flow rate from about 10-100 cc / min, and all values and ranges in between. In a further embodiment, for example and without limitation, hydrogen gas is provided at a pressure of from about 15-50 pounds per square inch (psi), and all values and ranges in between.

[0069] The step of sonicating the hydrogen storing emulsion to release hydrogen gas therefrom, in the system or process disclosed herein is not particularlylimited. Sonication is the act of applying sound energy to agitate particles in a sample, for various purposes. Ultrasonic frequencies (> 20 kHz) are usually used, leading to the process also being known as ultrasonication or ultra-sonication. Without being bound to a particular theory, it is believed that sonication leads to agitation of the emulsion leading to release of hydrogen gas from the hydrogen storing emulsion, when it is in the hydrogen containing emulsion state.

[0070] The system and process disclosed herein can undergo the addition or removal (for storage or discharge) of hydrogen gas from the hydrogen containing emulsion multiple times. Hence, the system and process can cycle between the storage state, where hydrogen is stored in the hydrogen storing emulsion, and the delivery (or discharge) state, where hydrogen gas is released from the hydrogen storing emulsion. The hydrogen storing emulsion disclosed herein can be utilized multiple times, cycling or recycling (and form a closed-cycle) between the hydrogen storage state and the hydrogen discharge state, without significant deterioration in the hydrogen absorption capacity of the hydrogen storing emulsion. In one embodiment, for example and without limitation, the process, system or hydrogen storing emulsion cycles 100, 200, 300, 400, 500 times or more, going back and forth, from the hydrogen storage state and the hydrogen discharge state.

[0071] In addition, the hydrogen storing emulsion disclosed herein show significant stability and avoid separation of the different reagents, thereby maintaining the emulsion form, and its use in the system, device and process, disclosed herein. In one embodiment, for example and without limitation, the hydrogen storing is stable for about two months at room temperature and atmospheric pressure.

[0072] Given the stability, in one embodiment, for example and without limitation, the hydrogen storing emulsion can be used for storing of hydrogen only. While in another embodiment, the hydrogen storing emulsion can be used for providing hydrogen only. In other words, process for storing and providing hydrogen gas can entail only storing, providing or both storing and providing hydrogen.

[0073] The device as used herein, for storing and providing hydrogen gas is not particularly limited. The device can include any vessel, as described herein, that can be used for containing the hydrogen storing emulsion.

[0074] In a fifth aspect, the specification relates to a process for preparation of a hydrogen storing emulsion, the process comprising:

[0075] contacting a surfactant, a perfluorocarbon (PFC) and an aqueous medium to form the hydrogen storing emulsion,

[0076] wherein the surfactant is present in an amount equal to or above the critical micelle concentration.

[0077] The step of contacting as used herein is not particularly limited. Contacting can include bringing together the different agents. In addition, contacting can involve mixing, agitation, forcing, driving or propelling the different agents, such that the different agents can come into contact with one another to form hydrogen storing emulsion.

[0078] The phrase, critical micelle concentration (CMC), as used herein is not particularly limited and should be known or understood by a person of skill in the art. CMC is the concentration of surfactants above which micelles form, or with the reference to the subject disclosure, emulsion forms. Any further addition of surfactants added to the system will form micelles or emulsions.

[0079] For preparing the hydrogen storing emulsion, different methods and sequence of addition of the reagents can be carried out. For instance, the method for mixing the reagents can involve, for example and without limitation, agitation of the reagents, sonication of the reagents to promote mixing and emulsion formation, high pressure homogenization by creating turbulent flow to promote mixing and emulsion formation.

[0080] As noted above, the sequence of addition of the reagents is also not particularly limited, and can be varied depending on design and application requirements. In one embodiment, for example and without limitation, PFC and surfactant is first brought into contact with one another, and can be optionally, mixed with one another, before addition of the PFC and surfactant to the aqueous medium. In a second embodiment, for example and without limitation, PFC is first added to the aqueous medium, before addition of the surfactant. The reagents can be mixed to promote emulsion formation. In a third embodiment, for example and without limitation, the surfactant is added to the aqueous medium before addition of the PFC. This can be followed by mixing to form the hydrogen storing emulsion. In a fourthembodiment, for example and without limitation, hydrogen gas be added to any of the reagents (PFC, surfactant or aqueous medium) or their combination, before all the reagents are brought into contact with one another. For example, and without limitation, hydrogen can be added to the PFC before addition of the surfactant and / or the aqueous medium. Alternatively, hydrogen can be added to the aqueous medium before addition of the surfactant and / or the PFC.

[0081] The hydrogen storing emulsion formed and used in the system and process disclosed herein can vary, and is not particularly limited, in the size of the dispersed average droplet size in the emulsion. In one embodiment, for example and without limitation, the hydrogen storing emulsion is a nano-emulsion having a dispersed average droplet size of less than or equal to about 200 nm, 150 nm, 100 nm, 50 nm or 10 nm. In a second embodiment, for example and without limitation, the hydrogen storing emulsion is a micro-emulsion having a dispersed average droplet size of less than or equal to about 1 pm, or having a dispersed average droplet size of from about 300 nm to about 1 pm.

[0082] Figure 1 shows an embodiment of a process for preparation and use of the hydrogen storing emulsion, and its use for storage and delivery of hydrogen.Initially, as shown in the top left corner of the figure, the aqueous phase and PFC are placed in a vessel. Mixing of the reagents can be initiated by, for example and without limitation, sonication for emulsion formation. Sonication can also help to remove any dissolved residual gases, including hydrogen from the emulsions, to provide a hydrogen storing emulsion in a hydrogen absorbable emulsion state. Hydrogen can be provided to the vessel containing the hydrogen storing emulsion to form the hydrogen containing emulsion state (labelled in the figure as hydrogenated- PFC emulsion), by having the hydrogen absorb in the emulsion. This allows for storage of the hydrogen in the emulsion for prolonged periods. For delivery of hydrogen, the hydrogen storing emulsion in the hydrogen containing emulsion state can be, for example and without limitation, sonicated to release hydrogen gas from the hydrogen storing emulsion. The process can be repeated multiple times for storage and delivery of hydrogen. The number of cycles for storage and delivery can vary based on design and application requirements, and can be two to a hundred or more, and all values in between.

[0083] In an embodiment of Figure 1 , the aqueous phase and m-PFC are first mixed by stirring or sonication to form a stable emulsion. The sample is then exposed to hydrogen to produce a hydrogenated m-PFC emulsion. Application of ultrasonication facilitates the release of hydrogen from the emulsion, allowing repeated hydrogenation, dehydrogenation cycles. The inset image shows the droplet morphology of the emulsion in grayscale.

[0084] Figure 1 illustrates a representative process for preparing and cycling a modified perfluorocarbon (m-PFC) emulsion system designed for hydrogen storage and controlled release. In an embodiment of this approach, an aqueous phase containing a surfactant and an organic m-PFC phase are combined at a volume ratio of approximately 80% m-PFC to 20% aqueous solution. The two phases are mixed using mechanical stirring or sonication for a period that may range from about 1 to 12 hours, depending on the desired droplet uniformity and stability. The stirring rate can vary within a broad range, typically between 500 and 1000 revolutions per minute, allowing adjustment of droplet size distribution and interfacial characteristics.

[0085] Following the mixing stage, the resulting m-PFC-in-water emulsion exhibits dispersed droplets stabilized by surfactant molecules at the interface, forming a consistent suspension suitable for subsequent hydrogenation. The emulsion is then exposed to a hydrogen environment under controlled conditions that promote gradual diffusion of hydrogen into the dispersed m-PFC phase. This process produces a hydrogenated emulsion while maintaining droplet integrity and preventing phase separation.

[0086] To recover hydrogen, the hydrogenated emulsion can be subjected to ultrasonic treatment or mild agitation. Ultrasonication facilitates the controlled release of hydrogen gas from within the droplets while preserving the emulsion’s reusability for subsequent hydrogenation cycles. This reversible process enables repetitive hydrogen uptake and release without requiring complete system reconstitution. The parameters described here, such as phase ratio, mixing duration, and agitation intensity, can be varied within the stated ranges to tailor droplet stability, hydrogen capacity, and recovery efficiency, making this formulation adaptable to diverse hydrogen storage or transport applications.

[0087] In one embodiment, for example and without limitation, the hydrogen storing emulsion disclosed herein is an all-in-liquid material (being metal-free) that can allow for sustainable and atmospheric hydrogen storage and can provide practical solutions. Such systems, devices, emulsions and process can help eliminate the need for high-pressure tanks and / or cryogenic temperatures, and can help to make hydrogen storage safer and more practical. In the embodiment disclosed herein, the system, device, emulsion and process can help store hydrogen at room temperature and pressure, thereby can help significantly reduce the energy required for storage and the associated costs.EXAMPLES

[0088] The above disclosure generally describes the present invention. A more complete understanding can be obtained by reference to the following specific Examples. These Examples are described solely for purposes of illustration and are not intended to limit the scope of the invention. Changes in form and substitution of equivalents are contemplated as circumstances may suggest or render expedient. Without further description, it is believed that one of ordinary skill in the art can, using the preceding description and the following illustrative examples, make and utilize the constructs of the present invention and practice the claimed methods. The following working examples therefore, specifically point out the typical aspects of the present invention and are not to be construed as limiting in any way in the remainder of the disclosure. Although specific terms have been employed herein, such terms are intended in a descriptive sense and not for purposes of limitation.

[0089] Experimental

[0090] This section describes the materials, sample preparation, hydrogenation process, and characterization techniques employed in this study to investigate the potential of perfluorodecalin (PFD) emulsions as a medium for hydrogen storage and transportation. The experimental approach is outlined in Figure 1 , as described herein.

[0091] Materials

[0092] Perfluorodecalin (PFD) at 90% purity (Sigma) was used, which consists of a mixture of cis and trans geometric isomers. Sodium Dodecyl Sulfate (SDS, Sigma) is used as the source of anionic surfactant.

[0093] Sample preparation

[0094] The experimental protocol is described herein with reference to Figure 1 . Samples consist of a single phase (PFD) and a two-phase (PFD in water emulsion). The SDS is used as emulsifier at the concentration of 10 critical micelle concentration (CMC). High internal phase emulsions were generated with volumetric ratios of 80% PFD and 20% SDS solution using a magnetic stirrer at 500 rpm for one hour. Then, emulsions are sonicated for 15 minutes to reduce their droplet size.

[0095] Hydrogenation

[0096] Hydrogenation was conducted using a hydrogen generator and pump, infusing hydrogen into the emulsions contained within a sealed pressure cell equipped with a relief valve. After hydrogenation, the emulsions were analyzed again using microscopy and / or rheometry to identify any morphological or rheological changes due to hydrogen infusion. The final step involved releasing hydrogen from the samples through sonication, facilitating the expulsion of the trapped gas.

[0097] Microscope

[0098] Microstructural analysis was performed using AmScope MU1403 optical Microscope with magnifications of 4x, 10x, and 20x with the resolution of 3.5 pm / pixel, to assess the stability and structure of the emulsions.

[0099] Rheometer

[0100] Rheological properties, primarily viscosity, were measured using aHR30 rheometer (TA Instruments), equipped with a 60 mm diameter parallel plate. Using the flow ramp method, the viscosity of pure PFD was measured across various shear rates, ranging from 1 to 1000 1 / s, with a gap size of 300 pm and at room temperature. The measurements are conducted for samples prehydrogenation, post-hydrogenation, and post-sonication.

[0101] RESULTS AND DISCUSSION

[0102] Rheology of pure PFD

[0103] 40 ml of pure PFD was subjected to hydrogen gas for a duration of 30 minutes, with the pressure maintained between 60 and 85 psi. Following hydrogenation, the PFD sample underwent one hour of sonication, which served to release the hydrogen that had been incorporated into the fluid. The objective of the sonication process was to expel the absorbed hydrogen, thus reversing the hydrogenation effect. The principle behind this technique is that the ultrasonic waves generate micro-vibrations within the emulsion, creating an environment conducive to the release of hydrogen gas from the emulsion droplets. The viscosity of the pure PFD was measured at three stages of the experiment: before hydrogen exposure, subsequently after the hydrogenation process, and finally following the sonication treatment. Each viscosity measurement was conducted three times to ensure the reproducibility and reliability of the results. These measurements were aimed at determining the impact of hydrogenation and subsequent sonication on the rheological properties of PFD, particularly focusing on changes in viscosity, which reflects the fluid’s resistance to flow under applied shear.

[0104] Figure 2 presents a semi-log plot of viscosity versus shear rate for PFD samples, before hydrogenation (blue circles), after hydrogenation (green triangles), and after sonication (red squares). The error bars represents the standard deviation of three measurements for each case. The samples show shear thinning behaviors at shear rates below 200 1 / s, while the viscosity remains constant at higher shear rates. The viscosity of PDF solution is increased upon the exposure to hydrogen, which could suggest that the hydrogenation process is causing changes within the PFC structure that lead to higher resistance to flow. The data indicates a further increase in viscosity after the sonication decrease. Although hydrogen is released from the solution after the sonication, some nanobubbles of air might be formed inside the solution that has resulted in an increase in the viscosity.

[0105] PFC emulsions characterization

[0106] The PFD in water emulsion samples were characterized using microscopic images, Figure 3, at the three different stages: pre-hydrogenation, posthydrogenation and post sonication. The emulsion structure remains unchanged after the exposure to hydrogen and also ultrasonication, indicating the emulsion stability during hydrogenation and dehydration cycles. The emulsion droplet size distribution, analyzed using Image J, is also presented in Figure 4.

[0107] Figure 4 shows the droplet size distribution of emulsions prepared with 80% PFC before hydrogenation and after four consecutive hydrogenation cycles. The frequency distribution curves (G(d)) show a gradual shift toward larger droplet diameters with cycling; however, the overall increase in droplet size is insignificant. The average droplet size is 135 ± 39 nm.

[0108] Figure 4 illustrates the droplet size distribution of emulsions containing 80% perfluorocarbon (PFC) before and after successive hydrogenation cycles. The x-axis represents the droplet size in nanometers, plotted on a logarithmic scale, while the y-axis shows the frequency of occurrence. The results demonstrate a gradual shift in the droplet size distribution toward larger diameters with increasing hydrogenation cycles. Specifically, the “Before Hydrogenation” curve peaks at smaller droplet sizes, whereas the curves corresponding to Cycle 1 through Cycle 3 exhibit broader and slightly right-shifted peaks. This behavior indicates that repeated hydrogenation slightly enlarges the average droplet diameter, most likely due to coalescence or partial aggregation occurring during hydrogen gas absorption and release. However, the overall change in droplet size remains modest, the average size increases to only 135 ± 39 nm, suggesting that the emulsion maintains structural stability even after multiple cycles. The importance of this result lies in its implications for hydrogen storage applications. Maintaining droplet integrity across hydrogenation, dehydrogenation cycles is critical for the reusability and efficiency of the emulsion system. Minimal droplet growth implies that the surfactant layer (SDS in this case) effectively prevents excessive coalescence and stabilizes the interface during gas transfer. This structural resilience ensures that the hydrogen storage and release process remains consistent across repeated uses, which can be useful for sustainable hydrogen transport in aviation and aerospace systems. In summary, the figure provides experimental evidence that hydrogenation-induced droplet size changes are minor and reversible, confirming that the emulsion system can endure cyclic operation without significant degradation of performance.

[0109] Hydrogen release profile

[0110] Figure 5 shows the hydrogen release profiles from samples saturated with hydrogen, wherein the sample include: PFD-emulsion, PFD, decan-emulsion, decane, and Dl-water. The concentration of dissolved hydrogen (micromole / L) wasmonitored over time. The cross mark on the horizontal axis indicates the application of sonication, which triggered a rapid release of hydrogen within 1 hour of sonication.

[0111] With reference to Figure 5, in the experiment, approximately 10 mL of each liquid sample (PFD-emulsion, pure PFD, decane-emulsion, pure decane, and deionized water) was introduced into a sealed chamber designed for hydrogenation tests. Prior to hydrogen exposure, the chamber was purged thoroughly with high- purity hydrogen gas to remove residual air and moisture, ensuring an inert environment. Following purging, hydrogen was continuously supplied to the system using a laboratory hydrogen generator. The injection flow rate was maintained within a typical range of 20 to 80 mL / min, to allow uniform hydrogen diffusion into the liquid phase. A calibrated hydrogen sensor positioned directly within the chamber and partially immersed in the liquid continuously measured the dissolved hydrogen concentration throughout the process.

[0112] The hydrogen injection was carried out for a controlled duration of approximately 10 to 60 minutes, ensuring the samples reached near-saturation conditions. Once the desired concentration was achieved, the injection was stopped, and the system was isolated to prevent additional gas exchange. From this point forward, only the real-time data from the hydrogen sensor were monitored to evaluate the natural release of hydrogen from each sample under quiescent conditions.

[0113] The resulting hydrogen release curves are presented in Figure 5. These profiles illustrate the time-dependent changes in hydrogen concentration for each medium, highlighting the effect of liquid composition and emulsion structure on gas retention and release behavior.

[0114] The figure presents the hydrogen release behavior of different liquid systems saturated with hydrogen, including PFD-emulsion, pure PFD, decaneemulsion, pure decane, and deionized (DI) water. The y-axis represents the concentration of dissolved hydrogen in micromoles per liter (pmol / L), while the x-axis shows the release time in hours. The profiles reveal distinct hydrogen retention and release kinetics for each medium.

[0115] Among all samples, the PFD-emulsion exhibits the slowest and most extended hydrogen release, maintaining a high dissolved hydrogen concentration(above 3500 pmol / L) for over 30 hours before showing a gradual decline. This prolonged retention demonstrates that emulsifying PFD within a continuous aqueous phase creates a barrier that limits hydrogen diffusion, effectively acting as a controlled-release system. In contrast, pure PFD begins to release hydrogen much earlier and shows a sharper decline, indicating higher diffusivity and faster degassing in the absence of the stabilizing aqueous layer.

[0116] The decane-emulsion and pure decane show significantly faster hydrogen loss compared to the PFD-based systems, confirming that PFD provides superior hydrogen solubility and retention. DI water, which serves as a control, exhibits an almost immediate hydrogen release with minimal retention capacity.

[0117] In Figure 5, the cross mark on the time axis, indicates the application of sonication. Once sonication was applied, a sharp drop in hydrogen concentration occurred within approximately one hour, corresponding to the rapid release of hydrogen triggered by acoustic cavitation and droplet disruption. This observation verifies that hydrogen stored within emulsified droplets can be quickly and controllably released through external stimulation.

[0118] Overall, this figure demonstrates that the PFD-emulsion configuration offers a unique balance between storage stability and controllable hydrogen release. The extended retention period under static conditions, combined with the ability to induce fast release through sonication, suggests that this emulsion-based system can function as a reversible, tunable hydrogen carrier suitable for on-demand applications in hydrogen energy or aerospace systems.

[0119] The study demonstrated the potential of PFD and other PFC emulsions as a promising medium for hydrogen storage. The generated emulsions remain stable under hydrogenation and sonication cycles. The increase in viscosity of PFD solution after hydrogenation signifies the role of rheological studies to characterize the amount of hydrogen storage and release in each cycle.

[0120] All publications, patents and patent applications cited above are herein incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.

[0121] Although preferred embodiments of the invention have been described herein in detail, it will be understood by those skilled in the art that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.

Claims

WE CLAIM:1 . A hydrogen storage and / or delivery system, comprising: a vessel configured to receive and provide hydrogen gas, the vessel containing a hydrogen storing emulsion, the hydrogen storing emulsion releasably retaining the hydrogen gas, the hydrogen storing emulsion being in a hydrogen containing emulsion state or a hydrogen absorbable emulsion state; the hydrogen storing emulsion comprising a perfluorocarbon (PFC) and a surfactant present in an aqueous medium.

2. The hydrogen storage and / or delivery system of claim 1 , comprising: the hydrogen storing emulsion in a hydrogen containing emulsion state; and sonicating the hydrogen storing emulsion to release hydrogen gas therefrom.

3. The hydrogen storage and / or delivery system of claim 1 or 2, comprising: the hydrogen storing emulsion in a hydrogen absorbable emulsion state; and providing hydrogen gas to the hydrogen storing emulsion state to form the hydrogen containing emulsion state.

4. The hydrogen storage and / or delivery system of any one of claims 1 to 3, wherein the system cycles between a hydrogen storage state and a hydrogen discharged state.

5. The hydrogen storage and / or delivery system of any one of claims 1 to 4, wherein the hydrogen storing emulsion is a high internal phase emulsion (HIPE).

6. The hydrogen storage and / or delivery system of any one of claims 1 to 5, wherein the PFC has from Ce - Cis atoms.

7. The hydrogen storage and / or delivery system of any one of claims 1 to 6, wherein the surfactant is an ionic surfactant or a non-ionic surfactant.

8. The hydrogen storage and / or delivery system of claim 7, wherein the non-ionic surfactant is Span™ or Tween™.

9. The hydrogen storage and / or delivery system of any one of claims 1 to 8, wherein the hydrogen storing emulsion is a nano-emulsion having a dispersed average droplet size of less than 200 nm.

10. The hydrogen storage and / or delivery system of any one of claims 1 to 8, wherein the hydrogen storing emulsion is a nano-emulsion having a dispersed average droplet size of less than 150 nm.

11. The hydrogen storage and / or delivery system of any one of claims 1 to 8, wherein the hydrogen storing emulsion is a micro-emulsion having a dispersed average droplet size of less than 1 pm.

12. The hydrogen storage and / or delivery system of any one of claims 1 to 8, wherein the hydrogen storing emulsion is a micro-emulsion having a dispersed average droplet size of from 300 - 1 pm.

13. The hydrogen storage and / or delivery system of any one of claims 1 to 12, wherein the hydrogen storing emulsion is stable for about two months at room temperature and atmospheric pressure.

14. The hydrogen storage and / or delivery system of any one of claims 1 to 13, wherein the hydrogen storing emulsion has a viscosity range of from about 1 to about 1000 mPas. sec.

15. The hydrogen storage and / or delivery system of any one of claims 1 to 13, wherein the hydrogen storing emulsion has a viscosity range of from about 1 to about 10 mPas.sec.

16. The hydrogen storage and / or delivery system of any one of claims 1 to 13, wherein the hydrogen storing emulsion has a viscosity range of from about 10 to about100 mPas.sec.

17. The hydrogen storage and / or delivery system of any one of claims 1 to 13, wherein the hydrogen storing emulsion has a viscosity range of from great than 100 to about 1000 mPas.sec.

18. A hydrogen storing emulsion comprising: a perfluorocarbon (PFC) and a surfactant present in an aqueous medium; and wherein the hydrogen storing emulsion releasably retains hydrogen gas.

19. The hydrogen storing emulsion of claim 18, wherein the hydrogen storing emulsion is in a hydrogen containing emulsion state and configured to release the hydrogen gas upon sonication, the hydrogen storing emulsion thereby switching to a hydrogen absorbable emulsion state upon release of the hydrogen gas.

20. The hydrogen storing emulsion of claim 18 or 19, wherein the hydrogen storing emulsion cycles between the hydrogen containing emulsion state and the hydrogen absorbable emulsion state.

21. The hydrogen storing emulsion of any one of claims 18 to 20, wherein the hydrogen storing emulsion is a high internal phase emulsion.

22. The hydrogen storing emulsion of any one of claims 18 to 21 , wherein the PFC has from Ce - Cis atoms.

23. The hydrogen storing emulsion of any one of claims 18 to 22, wherein the surfactant is an ionic surfactant or a non-ionic surfactant.

24. The hydrogen storing emulsion of any one of claims 18 to 23, wherein the nonionic surfactant is Span™ or Tween™.

25. The hydrogen storing emulsion of any one of claims 18 to 24, wherein the hydrogen storing emulsion is a nano-emulsion having a dispersed average droplet size of less than 200 nm.

26. The hydrogen storing emulsion of any one of claims 18 to 25, wherein the hydrogen storing emulsion is a nano-emulsion having a dispersed average droplet size of less than 150 nm.

27. The hydrogen storing emulsion of any one of claims 18 to 24, wherein the hydrogen storing emulsion is a micro-emulsion having a dispersed average droplet size of less than 1 pm.

28. The hydrogen storing emulsion of any one of claims 18 to 24, wherein the hydrogen storing emulsion is a micro-emulsion having a dispersed average droplet size of from 300 - 1 pm.

29. The hydrogen storing emulsion of any one of claims 18 to 28, wherein the hydrogen storing emulsion is stable for about two months at room temperature and atmospheric pressure.

30. The hydrogen storage emulsion of any one of claims 18 to 29, wherein the hydrogen storing emulsion has a viscosity range of from about 1 to about 1000 mPas. sec.

31. The hydrogen storage emulsion of any one of claims 18 to 29, wherein the hydrogen storing emulsion has a viscosity range of from about 1 to about 10 mPas.sec.

32. The hydrogen storage emulsion of any one of claims 18 to 29, wherein the hydrogen storing emulsion has a viscosity range of from about 10 to about 100 mPas.sec.

33. The hydrogen storage emulsion of any one of claims 18 to 29, wherein the hydrogen storing emulsion has a viscosity range of from great than 100 to about 1000 mPas.sec.

34. A process for storing and providing hydrogen gas, comprising: providing the hydrogen gas to a hydrogen storing emulsion in a hydrogen absorbable emulsion state to form the hydrogen storing emulsion in a hydrogencontaining emulsion state; the hydrogen storing emulsion comprising a perfluorocarbon (PFC) and a surfactant present in an aqueous medium.

35. The process of storing and providing hydrogen gas according to claim 34, further comprising: sonicating the hydrogen storing emulsion in the hydrogen containing emulsion state to release the hydrogen gas, and form the hydrogen storing emulsion in the hydrogen absorbable emulsion state.

36. The process of storing and providing hydrogen gas according to claim 34 or 35, wherein the hydrogen storing emulsion is a high internal phase emulsion.

37. The process of storing and providing hydrogen gas according to any one of claims 34 to 36, wherein the PFC has from Ce - Cis atoms.

38. The process of storing and providing hydrogen gas according to any one of claims 34 to 37, wherein the surfactant is an ionic surfactant or a non-ionic surfactant.

39. The process of storing and providing hydrogen gas according to any one of claims 34 to 38, wherein the non-ionic surfactant is Span™ or Tween™.

40. The process of storing and providing hydrogen gas according to any one of claims 34 to 39, wherein the hydrogen storing emulsion is a nano-emulsion having a dispersed average droplet size of less than 200 nm.

41. The process of storing and providing hydrogen gas according to any one of claims 34 to 39, wherein the hydrogen storing emulsion is a nano-emulsion having a dispersed average droplet size of less than 150 nm.

42. The process of storing and providing hydrogen gas according to any one of claims 34 to 39 wherein the hydrogen storing emulsion is a micro-emulsion having a dispersed average droplet size of less than 1 pm.

43. The process of storing and providing hydrogen gas according to any one of claims 34 to 39, wherein the hydrogen storing emulsion is a micro-emulsion having a dispersed average droplet size of from 300 - 1 pm.

44. The process of storing and providing hydrogen gas according to any one of claims 34 to 43, wherein the hydrogen storing emulsion is stable for about two months at room temperature and atmospheric pressure.

45. The process of storing and providing hydrogen gas according to any one of claims 34 to 44, wherein the hydrogen storing emulsion has a viscosity range of from about 1 to about 1000 mPas. sec.

46. The process of storing and providing hydrogen gas according to any one of claims 34 to 44, wherein the hydrogen storing emulsion has a viscosity range of from about 1 to about 10 mPas.sec.

47. The process of storing and providing hydrogen gas according to any one of claims 34 to 44, wherein the hydrogen storing emulsion has a viscosity range of from about 10 to about 100 mPas.sec.

48. The process of storing and providing hydrogen gas according to any one of claims 34 to 44, wherein the hydrogen storing emulsion has a viscosity range of from great than 100 to about 1000 mPas.sec.

49. A device for storing and providing hydrogen gas, the device comprising: a vessel configured to receive and provide hydrogen gas, the vessel containing a hydrogen storing emulsion, the hydrogen storing emulsion releasably retaining the hydrogen gas, the hydrogen storing emulsion being in a hydrogen containing emulsion state or a hydrogen absorbable emulsion state; the hydrogen storing emulsion comprising a perfluorocarbon (PFC) and a surfactant present in an aqueous medium.

50. The device of claim 49, wherein the hydrogen storing emulsion is a high internal phase emulsion (HIPE).51 . The device of claim 49 or 50, wherein the PFC has from Ce - Cis atoms.

52. The device of any one of claims 49 to 51 , wherein the surfactant is an ionic surfactant or a non-ionic surfactant.

53. The device of claim 52, wherein the non-ionic surfactant is Span™ orTween™.

54. The device of any one of claims 49 to 53, wherein the hydrogen storing emulsion is a nano-emulsion having a dispersed average droplet size of less than 200 nm.

55. The device of any one of claims 49 to 53, wherein the hydrogen storing emulsion is a nano-emulsion having a dispersed average droplet size of less than 150 nm.

56. The device of any one of claims 49 to 53, wherein the hydrogen storing emulsion is a micro-emulsion having a dispersed average droplet size of less than 1 pm.

57. The device of any one of claims 49 to 53, wherein the hydrogen storing emulsion is a micro-emulsion having a dispersed average droplet size of from 300 - 1 pm.

58. The device of any one of claims 49 to 57, wherein the hydrogen storing emulsion is stable for about two months at room temperature and atmospheric pressure.

59. The device of any one of claims 49 to 58, wherein the hydrogen storing emulsion has a viscosity range of from about 1 to about 1000 mPas. sec.

60. The device of any one of claims 49 to 58, wherein the hydrogen storing emulsion has a viscosity range of from about 1 to about 10 mPas.sec.

61. The device of any one of claims 49 to 58, wherein the hydrogen storing emulsion has a viscosity range of from about 10 to about 100 mPas.sec.

62. The device of any one of claims 49 to 58, wherein the hydrogen storing emulsion has a viscosity range of from great than 100 to about 1000 mPas.sec.

63. A process for preparation of a hydrogen storing emulsion, the process comprising:contacting a surfactant with a perfluorocarbon (PFC) and an aqueous medium to form the hydrogen storing emulsion, wherein the surfactant is present in an amount equal to or above the critical micelle concentration.

64. The process of claim 63, wherein the surfactant first contacts the PFC, prior to contacting the aqueous medium.

65. The process of claim 63, wherein the surfactant first contacts the aqueous medium, prior to contacting the PFC.

66. The process of claim 63, wherein the aqueous medium first contacts the PFC, prior to contacting the surfactant.

67. The process of any one of claims 63 to 66, comprising: mixing the surfactant with the perfluorocarbon (PFC) and the aqueous medium.

68. The process of any one of claims 63 to 67, comprising: sonicating the surfactant with the perfluorocarbon (PFC) and the aqueous medium.

69. The process of any one of claims 63 to 68, comprising:providing hydrogen gas to the PFC or the aqueous medium prior to forming the hydrogen storing emulsion.

70. The process of any one of claims 63 to 69, wherein the hydrogen storing emulsion is a high internal phase emulsion (HIPE).71 . The process of any one of claims 63 to 70, wherein the PFC has from Ce - Cis atoms.

72. The process of any one of claims 63 to 71 , wherein the surfactant is an ionic surfactant or a non-ionic surfactant.

73. The process of any one of claims 63 to 72, wherein the non-ionic surfactant is Span™ or Tween™.

74. The process of any one of claims 63 to 73, wherein the hydrogen storing emulsion is a nano-emulsion having a dispersed average droplet size of less than 200 nm.

75. The process of any one of claims 63 to 73, wherein the hydrogen storing emulsion is a nano-emulsion having a dispersed average droplet size of less than 150 nm.

76. The process of any one of claims 63 to 73, wherein the hydrogen storing emulsion is a micro-emulsion having a dispersed average droplet size of less than 1 pm.

77. The process of any one of claims 63 to 73, wherein the hydrogen storing emulsion is a micro-emulsion having a dispersed average droplet size of from 300 - 1 pm.

78. The process of any one of claims 63 to 77, wherein the hydrogen storing emulsion is stable for about two months at room temperature and atmospheric pressure.The process of any one of claims 63 to 78, wherein the hydrogen storing emulsion has a viscosity range of from about 1 to about 1000 mPas. sec.

80. The process of any one of claims 63 to 78, wherein the hydrogen storing emulsion has a viscosity range of from about 1 to about 10 mPas.sec.

81. The process of any one of claims 63 to 78, wherein the hydrogen storing emulsion has a viscosity range of from about 10 to about 100 mPas.sec.

82. The process of any one of claims 63 to 78, wherein the hydrogen storing emulsion has a viscosity range of from great than 100 to about 1000 mPas.sec.

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