Electrolyzers and systems comprising the same

Abstract

Disclosed herein are systems comprising one or more electro-synthesizer units (ESU) and at least one hydrogen compensation unit (HCU), wherein the system is configured to efficiently loop hydrogen within the ESU and compensate by any lost hydrogen with HCU.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims benefit to a U.S. Provisional Application No. 63 / 698,700 filed Sep. 25, 2024, the content of which is incorporated by reference, in its entirety, into the present application.TECHNICAL FIELD

[0002] This application relates generally to electrochemical cells and systems configured to form acid and base solutions in the desired concentrations.BACKGROUND

[0003] Direct electrosynthesis of sodium hydroxide (NaOH) and hydrochloric acid (HCl) or sulfuric acid (H2SO4) from sodium chloride (NaCl) or sodium sulfate (Na2SO4) brine can be a cost-effective process to generate both concentrated NaOH and HCl / H2SO4 solution for chemical industries. This electrosynthesis process usually uses the water splitting reaction to generate H+ and OH−, then combine with the Cl− and Na+ produced by separating the NaCl with two ion-exchange membranes for acid and base production. The half-reactions and their standard potential of anode (R2) and cathode (R1) are,At⁢ pH=14,2⁢ H2⁢O-2⁢ e-→H2+2⁢ OH-⁢ φ=-0.83⁢ V⁢ vs. SHE(R1)At⁢ pH=0,2⁢ H2⁢O+4⁢ e-→O2+2⁢ H+⁢ φ=1.23 V⁢ vs. SHE(R⁢2)

[0004] Various types of electrolyzers are known and used currently in the field. One of the challenges of using known electrolyzers is the high pH difference between multiple chambers of the device. As a result, the concentrations of electro-synthesized acid and base are limited to less than 0.5 mol / L. To solve the challenge of maintaining a high pH difference (0 to 14) in a single electrolyzer while still achieving a high concentration of acid and base, the bipolar membrane electrodialysis (BMED) method has been employed. While such a method allows obtaining acid / base concentrations up to 3 mol / L, it still suffers from low energy efficiency and high capital cost.

[0005] An additional challenge is the need to supply hydrogen to the anodic chamber for the efficient formation of the acid. Many known systems use an external hydrogen supply line. This is costly and inefficient. Some newer system use hydrogen looping within the system where the hydrogen formed in the cathode chamber is looped into the anode chamber for further use. However, those systems also suffer from inefficiencies due to the loss of hydrogen.

[0006] Thus, new, more efficient, and cost-effective electrolyzer systems are needed. New methods for using these systems and forming acid / base in desired concentrations are also needed. These needs and other needs are at least partially satisfied by the present disclosure.SUMMARY

[0007] The present disclosure is directed to a system comprising: one or more electro-synthesizer units (ESU) and at least one hydrogen compensation unit (HCU); wherein the one or more ESU are in fluid and electrical communication with at least one HCU; wherein the one or more ESUs comprises: (a) a first chamber comprising a first volume of a first solution that is in electrical communication with a first electrode; (b) a second chamber comprising a second volume of a second solution that is in electrical communication with a second electrode; (c) a third chamber positioned between and in fluid communication with the first and the second chamber, wherein the third chamber comprises a third volume of a third solution; and wherein the at least one HCU comprises (i) a fourth chamber comprising a fourth volume of a fourth solution that is in electrical communication with a fourth electrode; and (ii) a fifth chamber comprising a fifth volume of a fifth solution that is in electrical communication with a fifth electrode; wherein optionally, the fourth chamber and the first chamber are the same such that one shared chamber between the one or more ESUs and at least one HCU is formed; wherein the one or more ESUs are acid / base electrolyzers and the at least one HCU is an alkaline electrolyzer.

[0008] In further aspects, the system is a multistack of the one or more ESU and at least one HCU.

[0009] In still further aspects, the system is a recirculated-in-a-loop flow system.

[0010] Additional advantages will be set forth in part in the description that follows and in part will be evident from the description or can be learned by practice of the aspects described below. The advantages described below will be realized and attained using the chemical compositions, methods, and combinations thereof, particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.BRIEF DESCRIPTION OF DRAWINGS

[0011] FIG. 1A depicts an exemplary electro-synthesizer unit (ESU) in one aspect.

[0012] FIG. 1B depicts an exemplary hydrogen compensation unit (HCU) in one aspect.

[0013] FIG. 2 depicts an exemplary system comprising four (4) electro-synthesizer units (ESU).

[0014] FIG. 3A depicts an exemplary system comprising four (4) exemplary electro-synthesizer units (ESU) coupled with one terminal exemplary HCU unit in one aspect.

[0015] FIG. 3B depicts an exemplary system comprising four (4) exemplary electro-synthesizer units (ESU) coupled with two exemplary HCU units positioned in a middle of a multistack in one aspect.

[0016] FIGS. 4A and 4B depict the systems shown in FIGS. 3A-3B and their power connections in a different aspect.

[0017] FIG. 5 shows an exemplary system comprising disclosed herein ESUs and HCUs in one aspect.

[0018] FIG. 6 shows an exemplary system comprising disclosed herein ESUs and HCUs in a different aspect.

[0019] FIG. 7 shows exemplary experimental hydrogen looping test results.

[0020] FIG. 8 shows an exemplary hydrogen loss. H2% Loss=100*(1−Outlet Flow / Inlet Flow) in the system according to one aspect.

[0021] FIG. 9 shows an exemplary pressure in the system according to one aspect

[0022] The accompanying figures, which are incorporated in and constitute a part of this specification, illustrate several aspects described below.DETAILED DESCRIPTION

[0023] The present invention can be understood more readily by reference to the following detailed description, examples, drawings, and claims, and their previous and following description. However, before the present articles, systems, and / or methods are disclosed and described, it is to be understood that this invention is not limited to the specific or exemplary aspects of articles, systems, and / or methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

[0024] The following description of the invention is provided as an enabling teaching of the invention in its best, currently known aspect. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the invention described herein while still obtaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be obtained by selecting some of the features of the present invention without utilizing other features. Accordingly, those of ordinary skill in the pertinent art will recognize that many modifications and adaptations to the present invention are possible and may even be desirable in certain circumstances and are a part of the present invention. Thus, the following description is again provided as illustrative of the principles of the present invention and not in limitation thereof.Definitions

[0025] As used herein, the singular forms “a,”“an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a “device” or a “unit” includes aspects having two or more such devices or units unless the context clearly indicates otherwise.

[0026] It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate aspects, can also be provided in combination with a single aspect. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single aspect, can also be provided separately or in any suitable subcombination.

[0027] As used herein, the terms “optional” or “optionally” mean that the subsequently described event or circumstance may or may not occur and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0028] Throughout the description and claims of this specification, the word “comprise” and other forms of the word, such as “comprising” and “comprises,” means including but not limited to, and are not intended to exclude, for example, other additives, segments, integers, or steps. Furthermore, it is understood that the terms comprise, comprising, and comprises as they relate to various aspects, elements, and features of the disclosed invention also include the more limited aspects of “consisting essentially of” and “consisting of.”

[0029] Unless defined otherwise, 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 invention belongs. In this specification and in the claims which follow, reference will be made to a number of terms that shall be defined herein.

[0030] For the terms “for example” and “such as” and grammatical equivalences thereof, the phrase “and without limitation” is understood to follow unless explicitly stated otherwise. It is further understood that these phrases are used for explanatory purposes only. It is further understood that the term “exemplary,” as used herein, means “an example of” and is not intended to convey an indication of a preferred or ideal aspect.

[0031] The term “or” means “and / or.” Recitation of ranges of values is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. The endpoints of all ranges are included within the range and independently combinable. All methods described herein can be performed in a suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.

[0032] The expressions “ambient temperature” and “room temperature” as used herein are understood in the art and refer generally to a temperature from about 20° C. to about 35° C.

[0033] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Furthermore, when numerical ranges of varying scope are set forth herein, it is contemplated that any combination of these values inclusive of the recited values may be used. Further, ranges can be expressed herein as from “about” one particular value and / or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and / or to the other particular value.

[0034] Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint and independently of the other endpoint. Unless stated otherwise, the term “about” means within 5% (e.g., within 2% or 1%) of the particular value modified by the term “about.”

[0035] It is understood that the term “between,” when used in the context of ranges, includes the bordering values of the range. For example, a range described as being between 10 and 15 includes both 10 and 15 unless described otherwise.

[0036] When a range is expressed, a further aspect includes from the one particular value and to the other particular value. For example, where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure, e.g., the phrase “x to y” includes the range from ‘x’ to ‘y’ as well as the range greater than ‘x’ and less than ‘y’. The range can also be expressed as an upper limit, e.g., ‘x, y, z, or less’ and should be interpreted to include the specific ranges of ‘x,’‘y,’‘z,’‘about x,’‘about y,’ and ‘about z’ as well as the ranges of ‘less than x,’‘less than y, or ‘less than z,’ or ‘less than about x,’‘less than about y, and ‘less than about z.’ Likewise, the phrase ‘x, y, z, or greater’ should be interpreted to include the specific ranges of ‘x,’‘y,’′z,′‘about x,’‘about y,’ and ‘about z’ as well as the ranges of ‘greater than x,’ greater than y,′‘greater than z,’ or ‘greater than about x,’ greater than about y,′‘greater than about z.’ In addition, the phrase “‘x’ to ‘y’,” where ‘x’ and ‘y’ are numerical values, also includes “about ‘x’ to about ‘y’.”

[0037] Such a range format is used for convenience and brevity and, thus, should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a numerical range of “0.1% to 5%” should be interpreted to include not only the explicitly recited values of 0.1% to 5% but also include individual values (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.5% to 1.1%; 5% to 2.4%; 0.5% to 3.2%, and 0.5% to 4.4%, and other possible sub-ranges) within the indicated range.

[0038] Recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value recited or falling within the range unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited. Ranges provided herein are understood to be shorthand for all of the values within the range. For example, a range of 1 to 50 is understood to include any number, or combination of numbers, from the group consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 or sub-ranges from the group consisting of 10-40, 20-50, 5-35, etc. Similarly, numerical ranges recited herein by endpoints include subranges subsumed within that range (e.g., 1 to 5 includes 1-1.5, 1.5-2, 2-2.75, 2.75-3, 3-3.90, 3.90-4, 4-4.24, 4.24-5, 2-5, 3-5, 1-4, and 2-4).

[0039] In still further aspects, when the specific values are disclosed between two end values, it is understood that these end values can also be included.

[0040] In still further aspects, when the range is given, and exemplary values are provided, it is understood that any ranges can be formed between any exemplary values within the broadest range.

[0041] It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements or layers should be interpreted in a like fashion (e.g., “between” versus “directly between,”“adjacent” versus “directly adjacent,”“on” versus “directly on”). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0042] It will be understood that although the terms “first,”“second,” etc., may be used herein to describe various elements, components, regions, layers, and / or sections. These elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or a section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of example embodiments.

[0043] Spatially relative terms, such as “beneath,”“below,”“lower,”“above,”“upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein are interpreted accordingly.

[0044] As used herein, the term or phrase “effective,”“effective amount,” or “conditions effective to” refers to such amount or condition that is capable of performing the function or property for which an effective amount or condition is expressed. As will be pointed out below, the exact amount or particular condition required will vary from one embodiment to another, depending on recognized variables such as the materials employed and the processing conditions observed. Thus, it is not always possible to specify an exact “effective amount” or “condition effective to.” However, it should be understood that an appropriate effective amount will be readily determined by one of ordinary skill in the art using only routine experimentation.

[0045] As used herein, the term “substantially” means that the subsequently described event or circumstance completely occurs or that the subsequently described event or circumstance generally, typically, or approximately occurs.

[0046] Still further, the term “substantially” can, in some aspects, refer to at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% of the stated property, characteristic, component, composition, or other condition for which substantially is used to characterize or otherwise quantify an amount.

[0047] As used herein, the term “substantially,” in, for example, the context “substantially identical” or “substantially similar” refers to a method or a system, or a component that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% by similar to the method, system, or the component it is compared to.

[0048] Numerous other general purpose or special purpose computing device environments or configurations can be used. Examples of well-known computing devices, environments, and / or configurations that can be suitable for use include, but are not limited to, personal computers, server computers, handheld or laptop devices, smartphones, multiprocessor systems, microprocessor-based systems, network personal computers (PCs), minicomputers, mainframe computers, embedded systems, distributed computing environments that include any of the above systems or devices, and the like.

[0049] Computing devices, as disclosed herein, can contain communication connection(s) that allow the device to communicate with other devices if desired. Computing devices can also have input device(s) such as a keyboard, mouse, pen, voice input device, touch input device, etc. Output device(s) such as a display, speakers, printer, etc., can also be included. All these devices are well-known in the art and need not be discussed at length here.

[0050] Computer-executable instructions, such as program modules being executed by a computer, can be used. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. Distributed computing environments can be used where tasks are performed by remote processing devices that are linked through a communications network or other data transmission medium. In a distributed computing environment, program modules and other data can be located in both local and remote computer storage media, including memory storage devices.

[0051] In its most basic configuration, a computing device typically includes at least one processing unit and memory. Depending on the exact configuration and type of computing device, memory can be volatile (such as random-access memory (RAM)), non-volatile (such as read-only memory (ROM), flash memory, etc.), or some combination of the two.

[0052] Computing devices can have additional features / functionality. For example, a computing device can include additional storage (removable and / or non-removable), including, but not limited to, magnetic or optical disks or tape.

[0053] Computing device typically includes a variety of computer-readable media. Computer-readable media can be any available media that can be accessed by the device and includes both volatile and non-volatile media, removable and non-removable media.

[0054] Computer storage media include volatile and non-volatile and removable and non-removable media implemented in any method or technology for storage of information, such as computer-readable instructions, data structures, program modules, or other data. Memory, removable storage, and non-removable storage are all examples of computer storage media. Computer storage media include but are not limited to, RAM, ROM, electrically erasable program read-only memory (EEPROM), flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computing device. Any such computer storage media can be part of a computing device.

[0055] Computing devices, as disclosed herein, can contain communication connection(s) that allow the device to communicate with other devices. The connection can be wireless or wired. Computing devices can also have input device(s) such as a keyboard, mouse, pen, voice input device, touch input device, etc. Output device(s) such as a display, speakers, printer, etc., can also be included. All these devices are well-known in the art and need not be discussed at length here.

[0056] It should be understood that the various techniques described herein can be implemented in connection with hardware components or software components or, where appropriate, with a combination of both. Illustrative types of hardware components that can be used include Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (ASICs), Application-specific Standard Products (ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), etc. The methods and apparatus of the presently disclosed subject matter, or certain aspects or portions thereof, can take the form of program code (i.e., instructions) embodied in tangible media, such as CD-ROMs, hard drives, or any other machine-readable storage medium where, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the presently disclosed subject matter.

[0057] Also, it is further understood that the devices disclosed herein can be in communication with other computerized devices by various means. In certain aspects, the sensors can transfer the information to the computerized devices with cameras or any other devices configured to capture a visual response of the measuring device. In yet other aspects, where the measuring device response is a change of color, it is understood that the change of color can occur in the visual spectra of the light.

[0058] It is further understood, however, that the measuring response device can also occur in UV or IR spectra. In such aspects, the response can be further evaluated by additional means, and the final result can be presented to the device wearer. It is also understood that the response of the devices disclosed herein can include photo fluorescence, fluorescence, and / or luminescent responses.

[0059] While aspects of the present invention can be described and claimed in a particular statutory class, such as the system statutory class, this is for convenience only, and one of ordinary skill in the art will understand that each aspect of the present invention can be described and claimed in any statutory class. Unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that an order be inferred in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to the arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification.

[0060] Moreover, for the sake of simplicity, the attached figures cannot show the various ways (readily discernable, based on this disclosure, by one of ordinary skill in the art) in which the disclosed system, method, and apparatus can be used in combination with other systems, methods, and apparatuses. Additionally, the description sometimes uses terms such as “produce” and “provide” to describe the disclosed method. These terms are high-level abstractions of the actual operations that can be performed. The actual operations that correspond to these terms can vary depending on the particular implementation and are, based on this disclosure, readily discernible by one of ordinary skill in the art.

[0061] The present invention may be understood more readily by reference to the following detailed description of various aspects of the invention and the examples included therein and to the Figures and their previous and following description.System

[0062] In certain aspects disclosed herein is a system comprising: one or more electro-synthesizer units (ESU) and at least one hydrogen compensation unit (HCU).

[0063] It is understood that any known in the art ESUs can be used. Some of the exemplary and unlimiting ESU units are disclosed in International Patent Application Publication No. WO2024026394, or U.S. Patent Application No. 20240035172 the contents of which are incorporated in their entirety.

[0064] In still further aspects, the one or more ESUs can comprise a) a first chamber comprising a first volume of a first solution that is in electrical communication with a first electrode; (b) a second chamber comprising a second volume of a second solution that is in electrical communication with a second electrode; (c) a third chamber positioned between and in fluid communication with the first and the second chamber, wherein the third chamber comprises a third volume of a third solution.

[0065] An exemplary and unlimiting ESU is shown in FIG. 1 A. In such exemplary aspects, the unit is a flow unit comprising a number of chambers / compartments. For example, as shown in FIG. 1A, the electro-synthesizer unit 100 comprises a first chamber 102, a second chamber 104, and a third chamber 106. The first chamber, 102, comprises the first solution, 116. It is understood that the first volume of this solution can be determined by the desired application and, therefore, by the desired cell dimensions.

[0066] In still further aspects, the first solution is an alkaline solution. In other aspects, the first electrode is a cathode. In other aspects, the cathode positioned in the first chamber generates a first hydrogen gas and a hydroxide.

[0067] Since the ESU can be a flow unit the first chamber 102 can comprise a first inlet (not shown) configured to receive a first flow of the first solution and a cathode 108. The first solution can be an electrolyte solution.

[0068] The first electrolyte solution 116 is in electrical and fluid communication with the cathode 108.

[0069] In some aspects, the first electrolyte (solution) comprises a base. Any known in the art bases can be used. For example, the base can comprise one or more of sodium hydroxide, lithium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, ammonium hydroxide, amine-based bases, sodium acetate, or any combination thereof. In still further aspects, the bases can comprise amine-based bases, such as primary, secondary, tertiary amines, or any combination thereof. It is understood that other organic bases can be utilized. In still further aspects, the base can be strong or weak, depending on the desired pH, as commonly defined in chemical arts. In yet still further aspects, the bases can also comprise Lewis bases. It is understood that the base can be present in any concentration to provide the desired pH. The concentration can be measured in M, or it can be measured in wt %, depending on the desired application. In still further aspects, the base can be present in any concentration from 0 M to 20 M, including exemplary values 0.001 M, 0.005 M, 0.01 M, 0.05 M, 0.1 M, 0.5 M, 1 M, 2 M, 3 M, 4 M, 5 M, 6 M, 7 M, 8 M, 9 M, 10 M, 11 M, 12 M, 13 M, 14 M, 15 M, 16 M, 17 M, 18 M, and 19 M. It is understood that these values are only exemplary, and the base can be present in a concentration having any values between any two foregoing values or falling within a range formed by any two foregoing values. For example, and without limitations, the base can be present in any concentration from 0 M to 20 M, from greater than 0 M to 20 M, 0 M to 18 M, 0 M to 15 M, 0 M to 12 M, 0 M to 10 M, 0 M to 8 M, 0 M to 5 M, 0 M to 3 M, 0 M to 2 M, 0 M to 1 M, 0 M to 0.5 M, 0 M to 0.1 M, 0 M to 0.001 M, 0.001 M to 20 M, 0.001 M to 20 M, 0.005 M to 20 M, 0.01 M to 20 M, 0.05 M to 20 M, 0.1 M to 20 M, 0.5 M to 20 M, 1 M to 20 M, 3 M to 20 M, 5 M to 20 M, 8 M to 20 M, 10 M to 20 M, and so on.

[0070] In certain exemplary and unlimiting aspects, a pH of the first electrolyte solution can be 6≤pH≤15.5, including exemplary values of 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, and 15.5. It is understood that at any point, the first chamber can comprise the first solution having a pH value that falls within any two foregoing values or within the range formed by two foregoing values. For example, a pH of the first electrolyte solution can be 6≤pH≤15.5, 6≤pH≤15, 6≤pH≤14, 6≤pH≤13, 6≤pH≤12, 6≤pH≤10, 6≤pH≤8, 7≤pH≤15.5, 8≤pH≤15.5, 10≤pH≤15.5, 12≤pH≤15.5, 8≤pH≤12, 7≤pH≤13, and so on.

[0071] In yet still further aspects, the pH of the first electrolyte can change during the unit operation. While in yet still further aspects, the pH of the first electrolyte is kept substantially the same during the unit operation, depending on the desired outcome. In still further aspects, the cathode is configured to generate a hydrogen gas and a hydroxide. The first chamber further comprises one or more outlets (not shown in FIG. 1) configured to remove the generated hydrogen gas and / or a base solution comprising the generated hydroxide from the first chamber.

[0072] In still further aspects, the first electrolyte comprises one or more inorganic salts. In some exemplary and unlimiting aspects, the first electrolyte can comprise a salt without the presence of the base. Yet, in other aspects, the first electrolyte can comprise only a base. In yet still further aspects, the first electrolyte can comprise the salt and the base in any desired concentration. It is understood that the salt is present in the first electrolyte can be at any concentration before its saturation. In certain aspects, the salt and the base present in the electrolyte can have the same cation or a different cation. In yet other aspects, the combination of various salts (having the same cations but different anions or the same anions but different cations) can be present. Yet, in still further aspects, the combination of the various bases can also be present in the first electrolyte.

[0073] In still further aspects, the one or more inorganic salt can comprise chlorides, sulfates, nitrates, phosphates, citrates, formates, lactates, tartrates, malates, fumarates, oxalates, succinates, gluconates, ascorbates, acetates of alkaline metals and / or alkaline-earth metals, or mixtures thereof.

[0074] It is understood that a cathode can comprise any material capable of inducing an electrochemical generation of hydrogen. the cathode can comprise a Pt group metal or their alloys based electrode, a Ni- and its alloys-based electrode, a NiFe-based electrode, a NiTi-based electrode, a steel-based electrode, transition metal sulfates-based electrode, such as, for example, and without limitations, molybdenum sulfide, tungsten sulfide, transition metal phosphide-based electrode, for example, and without limitations cobalt phosphide, Fe-based catalysts, carbon-based materials, or any combination thereof.

[0075] The disclosed herein ESU 100, as shown in FIG. 1A further comprises a second chamber 104 that comprises a second volume of a second solution and a second electrode. It is understood again that the second volume can be selected based on the desired application and cell dimensions. In certain aspects, the second solution is a second electrolyte. In such exemplary aspects, the second electrolyte is an acid solution, and the second electrode is a gas diffusion anode. The second chamber, 104, as shown in FIG. 1A, comprises an anode 110. The anode 110 has a first surface 109 and a second surface 111. In aspects disclosed herein, the second chamber comprises a first compartment 117 and a second compartment 119, wherein the first compartment comprises the second solution 118 and the second compartment comprises a hydrogen gas (stream 120). In such aspects, and the first 117 and the second compartments 119 are separated by the anode 110. In aspects where the disclosed herein ESU is a flow unit, the second chamber 104 comprises a second inlet (not shown) configured to receive a second flow of a second electrolyte solution 118 and a third inlet (not shown) configured to receive a stream 120 comprising a hydrogen gas.

[0076] In still further aspects, the second electrolyte comprises an acid. Any known in the art acids can be used. For example, the acid can comprise one or more of hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfurous acid, sulfuric acid, nitric acid, phosphorous acid, phosphoric acid, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, formic acid, acetic acid, carbonic acid, or any combination thereof. In still further aspects, the acids can comprise organic acids. In still further aspects, the acid can be strong or weak, depending on the desired pH, as commonly defined in chemical arts. In yet still further aspects, the acid can also comprise Lewis's acids. It is understood that the acid can be present in any concentration to provide for the desired pH. The concentration can be measured in M, or it can be measured in wt %, depending on the desired application. In still further aspects, the acid can be present in any concentration from 0 M to 10 M, including exemplary values 0.001 M, 0.005 M, 0.01 M, 0.05 M, 0.1 M, 0.5 M, 1 M, 2 M, 3 M, 4 M, 5 M, 6 M, 7 M, 8 M, and 9 M. It is understood that these values are only exemplary, and the acid can be present in a concentration having any values between any two foregoing values or fall in the range formed by any two foregoing values. For example, and without limitations, the acid can be present in any concentration from 0 M to 10 M, 0 M to 8 M, 0 M to 5 M, 0 M to 3 M, 0 M to 1 M, 0 M to 0.5 M, 0 M to 0.1 M, 0 M to 0.05 M, 0 M to 0.001 M, 0.001 M to 10 M, 0.005 M to 10 M, 0.01 M to 10 M, 0.05 M to 10 M, 0.1 M to 10 M, 0.5 M to 10 M, 1 M to 10 M, 3 M to 10 M, 5 M to 10 M, 8 M to 10 M, 0.5 M to 8 M, 0.05 M to 9 M, and so on.

[0077] In still further aspects, the second electrolyte comprises one or more inorganic salts. In some exemplary and unlimiting aspects, the second electrolyte can comprise a salt without the presence of the acid. Yet, in other aspects, the second electrolyte can comprise only an acid. In yet still further aspects, the second electrolyte can comprise the salt and the acid in any desired concentration. It is understood that the salt present in the second electrolyte can be at any concentration before its saturation. In certain aspects, the salt and the acid present in the electrolyte can have the same cation or a different cation. In yet other aspects, the combination of various salts (having the same cations but different anions or the same anions but different cations) can be present. Yet in still further aspects, the combination of the various acids can also be present in the second electrolyte.

[0078] In still further aspects, the one or more inorganic salt can comprise chlorides, sulfates, nitrates, phosphates, citrates, formates, lactates, tartrates, malates, fumarates, oxalates, succinates, gluconates, ascorbates, acetates of alkaline metals and / or alkaline-earth metals, or mixtures thereof.

[0079] It is understood that using hydrogen to generate hydrogen ions (either by looping the hydrogen from the first chamber to the second chamber or using both streams of hydrogen) improves the overall efficiency of the process. The hydrogen-depolarized reaction reduces both the energy cost and the electrode polarization in this electrolysis process. For example, in aspects where the pH gradient between the chambers is extreme (for example, pH=14 in the first chamber and pH=0 in the second chamber), the hydrogen-induced loop will only cost 0.83 V for the pH gradient, which is 60% more efficient than the typical salt splitting process. The half-reactions and their standard potential of anode (R4) and cathode (R3) are,At⁢ pH=14,2⁢ H2⁢O-2⁢ e-→H2+2⁢ OH-⁢ φ=-0.83⁢ V⁢ vs. SHE(R3)At⁢ pH=0,H2+2⁢ e-→2⁢ H+⁢ φ=0⁢ V⁢ vs. SHE(R⁢4)

[0080] In one aspect, the second electrolyte solution 118 is in electrical and fluid communication with the anode. For example, the second electrolyte solution 118 is in electrical and fluid communication with the first surface 109 of the anode 110. In still further aspects, a pH of the second electrolyte solution is −1.5≤pH≤8, including exemplary values of −1.5, −1, −0.5, 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, and 8. Yet, in other aspects, the pH of the second electrolyte solution can fall within any range formed by any of two foregoing values. For examples, pH of the second electrolyte solution can be −1.5≤pH≤8, −1≤pH≤8, −0.5≤pH≤8, 0≤pH≤8, 0.5≤pH≤8, 1≤pH≤8, 2≤pH≤8, 4≤pH≤8, 5≤pH≤8, 6≤pH≤8, −1.5≤pH≤7, −1.5≤pH≤6, −1.5≤pH≤5, −1.5≤pH≤3, −1.5≤pH≤2, −1.5≤pH≤1, −1.5≤pH≤0, −0≤pH≤3, 1≤pH≤4, and so on.

[0081] It is understood that at any point the second chamber can comprise the second electrolyte having a pH value that falls within any two foregoing values. In yet still further aspects, the pH of the second electrolyte can change during the unit operation. While in yet still further aspects, the pH of the second electrolyte is kept substantially the same during the unit operation, depending on the desired outcome. In still further aspects, the anode is configured to oxidate the hydrogen gas to generate hydrogen ions. In yet still further aspects, the second chamber comprises an outlet (not shown) configured to remove an acid solution comprising the generated hydrogen ions from the second chamber.

[0082] In still further aspects, any known in the art gas diffusion anodes can be used in the second chamber. In certain aspects, the anode can comprise a gas diffusion layer. Yet in further aspects, the anode further comprises a hydrogen oxidation catalyst layer. It is understood that the gas diffusion layer assists with maintaining a stable gas-liquid interface. It is further understood that other configurations capable of maintaining a stable gas-liquid interface other than the disclosed herein gas diffusion layer can be used. For example, the stable gas-liquid interface can be formed by continuous bubbling of the gas through the second compartment of the second chamber.

[0083] In certain aspects, the gas diffusion layer comprises a carbon-based gas diffusion layer, a fluorocarbon-based gas diffusion layer, a hydrophobic material comprising a plurality of pores, or any combination thereof. It is understood that any hydrophobic material can be utilized. In certain aspects, the layer can be made from the materials that are not inherently hydrophobic but can comprise a hydrophobic coating that provides the desired utility. In certain aspects, the gas diffusion layer comprises a carbon-based paper, a carbon-based textile, a modified carbon-based paper, a modified carbon-based textile, micro-porous PTFE membrane, mesoporous PTFE membrane, macro-porous PTFE membrane, or a combination thereof. It is understood that the term “modified” as used herein refers to the disposed desired coatings on the surfaces or any other modification of the surfaces to introduce the desired surface properties. For example, the surface can be chemically, electrochemically, physically, and / or plasma modified to increase roughness, introduce the desired chemical moieties, and the like.

[0084] In still further aspects, the hydrogen oxidation catalyst layer comprises one or more Pt group metal (PGM) or alloys thereof-based catalysts, PGM-free catalysts, and any combination thereof. In still further exemplary and unlimiting aspects, the hydrogen oxidation catalyst layer comprises one or more of Pt / C, Pd and its alloys, Au and its alloys, Ru and its alloys, transition metal oxides and their alloys, transition metal carbides and nitrides, metal-organic frameworks, carbon-supported metal atoms, hydrogenase, hydrogenase mimic compounds, hydrogenase, or any combinations thereof.

[0085] In still further aspects, the second inlet of the chamber extends into a first compartment 117, and the third inlet extends into a second compartment 119.

[0086] In certain aspects, the second compartment 119 of the second chamber 104 receives the hydrogen gas generated in the first chamber as a gas stream 120.

[0087] The ESU 100 further comprises a third chamber 106 positioned between and in fluid communication with the first chamber 102 and the second chamber 104. The third chamber 106 comprises a third volume of a third solution 122. It is understood again that the third volume can be selected based on the desired application and cell dimensions. In still further aspects, the third electrolyte solution can comprise one or more inorganic salts. In still further aspects, the one or more inorganic salt comprises chlorides, sulfates, nitrates, phosphates, citrates, formates, lactates, tartrates, malates, fumarates, oxalates, succinates, gluconates, ascorbates, acetates of alkaline metals and / or alkaline-earth metals, or mixtures thereof. In yet still further aspects, the one or more inorganic salts in the third electrolyte can be referred to as brine.

[0088] In some aspects, the third electrolyte solution 122, can have a pH of 4≤pH≤10, including exemplary values of 4, 4.5, 5, 5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, and 10. It is understood that at any point of the third chamber can comprise the third electrolyte having a pH value that falls within any two foregoing values or falls within the range formed by any two foregoing values. For example, pH can be 4≤pH≤10, 3≤pH≤10, 5≤pH≤10, 7≤pH≤10, 8≤pH≤10, 4≤pH≤8, 4≤pH≤7, 4≤pH≤6, 4≤pH≤5, 5≤pH≤8, 6≤pH≤9, and so on.

[0089] In yet still further aspects, the pH of the third electrolyte can change during the unit operation. While in yet still further aspects, the pH of the third electrolyte is kept substantially the same during the unit operation, depending on the desired outcome.

[0090] In still further aspects, the third chamber 106 comprises a fourth inlet (not shown) configured to receive the third electrolyte solution 122. In still further aspects, the third chamber also can comprise an outlet configured (not shown) to remove the third electrolyte from the third chamber.

[0091] In still further aspects, the third chamber 106 is separated from the first chamber 102 with one or more cation exchange membranes (CEM) 112 and is separated from the second chamber 104 with one or more anion exchange membranes 114. In still further aspects, the first compartment 117 is positioned between the anion exchange membrane (AEM) 114 and the first surface 109 of the anode 110 and hosts the second electrolyte 118. While in other aspects, the second compartment 119 is positioned abut the second surface 111 of the anode 110 and is configured to receive the hydrogen gas stream 120.

[0092] It is also understood that any known in the art cation exchange membranes and anion exchange membranes can be used. In such aspects, any known and commercially available cation exchange membranes and anion exchange membranes can be used.

[0093] In certain aspects, the polymeric cation-exchange membranes comprise —SO3−, —COO−, —PO32−, —PO3H−, or —C6H4O− cation exchange functional groups. The polymers for the preparation of cation-exchange membranes can be perfluorinated ionomers such as NAFION (a perfluorosulfonic-based membrane), FLEMION, and NEOSEPTA-F, partially fluorinated polymers, non-fluorinated hydrocarbon polymers, non-fluorinated polymers with aromatic backbone, or acid-base blends. It will be appreciated that in some aspects, depending on the need to restrict or allow migration of a specific cation or an anion species between the electrolytes, a cation exchange membrane that is more restrictive and thus allows migration of one species of cations while restricting the migration of another species of cations may be used as, e.g., a cation exchange membrane that allows migration of potassium ions into the cathode electrolyte while restricting migration of other cations into the cathode electrolyte, may be used. Such restrictive cation exchange membranes are commercially available and can be selected by one ordinarily skilled in the art. Some exemplary and commercially available membranes, such as Nafion® N117, CMI-7000, CMH-PP Ralex, EMION PF1-HLF8-15-X, CEM-Type I and CEM-Type II, etc., can be used.

[0094] Anion exchange membranes (AEM) are conventionally known in the art. In some aspects, the polymeric anion-exchange membranes comprise —NH3+, —NRH2+, —NR2H+, —NR3+, or —SR2− anion exchange functional groups. The polymers for the preparation of anion-exchange membranes can be perfluorinated ionomers such as NAFION (a perfluorosulfonic-based membrane), FLEMION, and NEOSEPTA-F, partially fluorinated polymers, non-fluorinated hydrocarbon polymers, non-fluorinated polymers with aromatic backbone, or acid-base blends. It will be appreciated that in some aspects, depending on the need to restrict or allow migration of a specific cation or an anion species between the electrolytes, an anion exchange membrane that is more restrictive and thus allows migration of one species of anions while restricting the migration of another species of anions may be used as, e.g., an anion exchange membrane that allows migration of chloride ions into the anode electrolyte while restricting migration of other anions into the anode electrolyte, may be used. Such restrictive anion exchange membranes are commercially available and can be selected by one ordinarily skilled in the art. In still further aspects, any known and commercially available anion exchange membranes can be used. For example, and without limitations, Sustainion® 37-50, Nafion® 115, PiperION TP-85, Fumasep FAPQ-375, PBI, Neosepta ACN, etc. In certain aspects, the unit can comprise one or more of cation exchange membranes and / or anion exchange membranes. In still further aspects, the cation and anion exchange membranes can be unsupported. While in other aspects, the cation and anion exchange membranes can be supported or reinforced. For example, the cation and / or anion exchange membranes can be polymer-reinforced. In such aspects, the polymers that are used for reinforcement are inert to the first, second, and / or third electrolyte solutions present in the disclosed units. In still further aspects, the cation and / or anion exchange membranes can be PTFE-reinforced, PEEK reinforced, or any combination thereof.

[0095] In still further aspects, the cation and anion exchange membranes can have any desired thickness. In some aspects, the thickness of the membranes can be 15 μm to 450 μm, including exemplary values of 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, and 400 μm. It is understood that the thickness can have any value falling between any two foregoing values or within the range formed by any two foregoing values. For example, the thickness can be 5 μm to 450 μm, 10 μm to 450 μm, 50 μm to 450 μm, 75 μm to 450 μm, 100 μm to 450 μm, 125 μm to 450 μm, 150 μm to 450 μm, 175 μm to 450 μm, 200 μm to 450 μm, 225 μm to 450 μm, 250 μm to 450 μm, 275 μm to 450 μm, 300 μm to 450 μm, 325 μm to 450 μm, 350 μm to 450 μm, 375 μm to 450 μm, 5 μm to 450 μm, 5 μm to 400 μm, 5 μm to 350 μm, 5 μm to 300 μm, 5 μm to 250 μm, 5 μm to 200 μm, 5 μm to 100 μm, 5 μm to 50 μm, and so on.

[0096] In still further aspects, while the disclosed above inlets and outlets are not shown in FIG. 1, the skilled practitioner can understand that inlet and outlet can be positioned anywhere within the chamber to allow inflow and outflow of respective streams as described. For example, each of the chambers can have one or more inlets and / or one or more outlets. In some aspects, the generated in the first chamber hydrogen gas and the base solution comprising the generated hydroxide can be removed from the same outlet. Yet in other aspects, the first chamber can comprise two or more outlets. In such exemplary and unlimiting aspects, the generated hydrogen gas stream and the base solution comprising the generated hydroxide can be removed from separate outlets.

[0097] In still further aspects, the electro-synthesizer unit can be constructed by any known in the art methods. For example, and without limitations, each chamber can be any vessel configured to receive and retain disclosed above streams. In yet other aspects, the electro-synthesizer unit can comprise a plurality of plates positioned such that the disclosed above chambers are formed. For example, and without limitations, each of the first, second and third chambers can be defined by two or more plates. It is understood that all materials used to form the electro-synthesizer unit are chemically and physically compatible with the electrolytes used in the unit, as well as output streams formed in the unit chambers.

[0098] In still further aspects, each of the chambers can have any width, length and / or depth that can accommodate the desired flow rate of the described above streams. It is understood that these dimensions can form the desired volume. It is further understood that the depth (or volume) of each chamber can be varied by adding or removing gaskets, membranes, spacers / plates to accommodate the desired application. It is understood that the width and depth can be adjustable to accommodate the desired volume of the unit. It is further understood that the term “adjustable” means that it can be changed by the addition of the spacers, gaskets, membranes, and / or plates to arrive at the desirable value.

[0099] In some aspects, the first chamber can have a width (or depth) of 0.01 mm to 500 mm, including exemplary values of 0.05 mm, 0.1 mm, 0.5 mm, 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 50 mm, 75 mm, 100 mm, 125 mm, 150 mm, 175 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, and 450 mm. It is understood that the first chamber can also have any width value that falls within any of the disclosed above values. For example, and without limitations, the width of the first compartment can be 0.01 mm to 200 mm, 0.01 mm to 150 mm, 0.01 mm to 100 mm, 0.01 mm to 50 mm, 0.01 mm to 50 mm, 0.01 mm to 20 mm, 0.01 mm to 10 mm, 0.01 mm to 1 mm, 0.1 mm to 500 mm, 1 mm to 500 mm, 20 mm to 500 mm, 50 mm to 500 mm, 100 mm to 500 mm, 200 mm to 500 mm, 1 mm to 10 mm, or 5 mm to 100 mm, and so on.

[0100] In aspects where the second chamber has the first and second compartments, each compartment can have any desired width that suits the streams' preferred flow rates. For example, and without limitations, the first compartment present in the second compartment has a width (or depth) of 0.01 to 500 mm, including exemplary values of 0.05 mm, 0.1 mm, 0.5 mm, 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 50 mm, 75 mm, 100 mm, 125 mm, 150 mm, 175 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, and 450 mm. It is understood that the first compartment can also have any width value that falls within any of the disclosed above values. For example, and without limitations, the width of the first compartment can be 0.01 mm to 200 mm, 0.01 mm to 150 mm, 0.01 mm to 100 mm, 0.01 mm to 50 mm, 0.01 mm to 50 mm, 0.01 mm to 20 mm, 0.01 mm to 10 mm, 0.01 mm to 1 mm, 0.1 mm to 500 mm, 1 mm to 500 mm, 20 mm to 500 mm, 50 mm to 500 mm, 100 mm to 500 mm, 200 mm to 500 mm, 1 mm to 10 mm, or 5 mm to 100 mm, and so on.

[0101] In further aspects, the second compartment present in the second compartment has a width (or depth) of 0.01 to 500 mm, including exemplary values of 0.05 mm, 0.1 mm, 0.5 mm, 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 50 mm, 75 mm, 100 mm, 125 mm, 150 mm, 175 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, and 450 mm. It is understood that the second compartment can also have any width value that falls within any of the disclosed above values. For example, and without limitations, the width of the second compartment can be 0.01 mm to 200 mm, 0.01 mm to 150 mm, 0.01 mm to 100 mm, 0.01 mm to 50 mm, 0.01 mm to 50 mm, 0.01 mm to 20 mm, 0.01 mm to 10 mm, 0.01 mm to 1 mm, 0.1 mm to 500 mm, 1 mm to 500 mm, 20 mm to 500 mm, 50 mm to 500 mm, 100 mm to 500 mm, 200 mm to 500 mm, 1 mm to 10 mm, or 5 mm to 100 mm, and so on.

[0102] In still further aspects, the first compartment has a width that is smaller than the width of the second compartment. Yet in still further aspects, the first compartment has a width that is greater than the width of the second compartment. Yet in still further aspects, the first compartment and the second compartment can have the same width.

[0103] In certain aspects, the first compartment can have a width (or depth) of 0.01 mm to 10 mm, 0.01 mm to 8 mm, 0.01 mm to 5 mm, 0.05 mm to 10 mm, 0.1 mm to 10 mm, 1 mm to 10 mm, 2 mm to 10 mm, 5 mm to 10 mm, 0.05 mm to 8 mm, 0.05 mm to 5 mm, and so on. In certain aspects, the second compartment can have a width of 0.01 mm to 50 mm, 0.01 mm to 40 mm, 0.01 mm to 30 mm, 0.01 mm to 20 mm, 0.01 mm to 10 mm, 0.05 mm to 50 mm, 0.1 mm to 50 mm, 1 mm to 50 mm, 2 mm to 150 mm, 5 mm to 50 mm, 10 mm to 50 mm, 20 mm to 50 mm, 30 mm to 50 mm, 1 mm to 30 mm, 1 mm to 20 mm, 5 mm to 10 mm, 5 mm to 20 mm, and so on.

[0104] In still further aspects, the third chamber can have a width (or depth) of 0.01 to 500 mm, including exemplary values of 0.05 mm, 0.1 mm, 0.5 mm, 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 50 mm, 75 mm, 100 mm, 125 mm, 150 mm, 175 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, and 450 mm. It is understood that the third chamber can also have any width value that falls within any of the disclosed above values. For example, and without limitations, the width of the third chamber can be 0.01 mm to 200 mm, 0.01 mm to 150 mm, 0.01 mm to 100 mm, 0.01 mm to 50 mm, 0.01 mm to 50 mm, 0.01 mm to 20 mm, 0.01 mm to 10 mm, 0.01 mm to 1 mm, 0.1 mm to 500 mm, 1 mm to 500 mm, 20 mm to 500 mm, 50 mm to 500 mm, 100 mm to 500 mm, 200 mm to 500 mm, 1 mm to 10 mm, or 5 mm to 100 mm, and so on.

[0105] In still further aspects, all chambers can have the same width (or depth), while in other aspects, some of the chambers can have the same width, and some can have a different width. It is understood that the desired flow rate and coulombic efficiency of the cell can determine the width of the compartment. In yet still further aspects, the width of the chamber can be changed in the cell by introducing (or removing) additional plates, gaskets, membranes, and the like.

[0106] In certain aspects, the hydrogen gas stream 120 can comprise the hydrogen gas generated in the first chamber. In such aspects, the generated hydrogen gas is directly fed from the first chamber to the second chamber, forming the looping of the hydrogen gas between the unit's first and second chambers. Yet in other aspects, and as disclosed below in more detail, the hydrogen formed in the first chamber can be collected and purified before transferring it to the second chamber.

[0107] In certain aspects, more than one ESU can be present. For example, disclosed herein are systems comprising two or more of the ESUs disclosed herein. The exemplary system 200 is shown in FIG. 2 and comprises 4 different electro-synthesizer units 100 as described above. In certain aspects, wherein two or more electro-synthesizer units are present, these two or more electro-synthesizer units are designed to share a cathode 108. Yet in other aspects, when three or more electro-synthesizer units are present, these three or more electro-synthesizer units are configured to share the second compartment 119 of the second chamber.

[0108] In still further aspects, and as disclosed above, the system comprises at least one HCU. In such aspects, and as shown in FIG. 1B, each of the HCUs 150 that can be present in the system can comprise (i) a fourth chamber comprising a fourth volume of a fourth solution 154 that is in electrical communication with a fourth electrode 152 and (ii) a fifth chamber comprising a fifth volume of a fifth solution 158 that is in electrical communication with a fifth electrode 152′.

[0109] It is understood that HCU is coming to compensate for any hydrogen loss from ESU either through leakage or dissolution in the solvents.

[0110] In certain aspects, the HCU can be any known in the art alkaline electrolyzer. In certain aspects, exemplary alkaline electrolyzers that can be used herein are disclosed in U.S. Pat. Nos. 11,005,117, 10,637,068, U.S. patent application No. 20200083541, the contents of which are incorporated herein by reference.

[0111] In still further aspects, the fourth solution can be the fourth electrolyte. In still further aspects, the fourth solution is alkaline. In still further aspects, the fourth electrolyte can comprise an alkaline solution known in the art. For example, the fourth electrolyte can be selected from the first electrolyte solutions disclosed above. In yet in still further aspects, the fourth electrolyte can be the same as the first electrolyte, or it can be different.

[0112] In still further aspects, the fifth solution is an oxygen-enriched alkaline. In such aspects, the oxygen can be formed during the electrolysis, and the alkaline solution present in the fifth chamber gets enriched with this in-situ formed oxygen. In still further aspects, the alkaline solution of the fourth electrolyte and the fifth electrolyte can comprise any solution listed above under the definition of the first electrolyte. In still further aspects, the fourth electrolyte and the fifth electrolyte can be the same or different.

[0113] It is understood that the fourth and / or fifth electrolyte, if chosen from any of the alkaline solutions mentioned above, can be present in any concentration as listed above and can have any of the pH listed above.

[0114] In still further aspects, the fourth 154 and fifth 158 chambers can be separated from each other by any known elements 156. For example, it can be separated by membrane, separators, porous barriers, or any combination thereof.

[0115] In still further aspects, the one or more ESUs can be coupled with at least one HCU in any suitable manner. In certain aspects, one or more ESUs can be fluidically connected with at least one HCU with a fluidic path (line). In other aspects, the one or more ESUs can be physically coupled with HCU. In such exemplary aspects, the one or more ESUs and at least one HCU can form a multistack.

[0116] In such exemplary and unlimiting aspects, if the one or more ESUs are physically connected (coupled) with at least one HCU, optionally, the fourth chamber and the first chamber can be the same such that one shared chamber between the one or more ESUs and at least one HCU is formed. In other words, in certain aspects, the first and the fourth chambers are, in fact, forming one shared chamber.

[0117] In still further exemplary and unlimiting aspects, when the first chamber and the fourth chamber are the one shared chamber, the fourth electrode can be a shared electrode, i.e., the fourth electrode and the first electrode are the same one electrode shared between the ESU unit and HCU unit. Yet in other aspects, when the first chamber and the fourth chamber are the one shared chamber, the fourth electrode can be an additional electrode to the first electrode such that the one shared chamber comprises two separate electrodes: the first electrode and the fourth electrode, which are electrically isolated from each other. It is again understood that electrical isolation can be achieved by positioning gaskets / plates / separators / membranes, etc.

[0118] Yet in still further aspects, when the first chamber and the fourth chamber are the one shared chamber, the fourth volume of the fourth solution equals to the first volume of the first solution, and the first solution and the fourth solution are the same.

[0119] In still further aspects, the fourth electrode (a cathode) generates a second hydrogen gas. The fourth electrode can be the same or similar to the first electrode. In still further aspects, the second hydrogen gas is fed in the second chamber. It is understood that the second hydrogen gas can be directly fed into the second chamber, or it can be first collected, purified, and then fed into the second chamber. In certain aspects, the second hydrogen gas, similar to the first hydrogen gas, can be stored if needed instead of feeding into the second chamber or before feeding into the second chamber. In yet still further aspects, the first and / or second hydrogen gas can exist the ESU and / or HCU as a mixture of a gas and liquid.

[0120] In still further aspects, the fifth electrode is an anode. In such exemplary and unlimiting aspects, the anode can comprise a metallic or ceramic anode specifically designed for oxygen evolution. Suitable materials for this anode include OER-active catalysts such as mixed metal oxides (MMO), platinum, nickel-iron (NiFe) oxides, cobalt oxides (Co3O4), perovskite oxides (e.g., LaNiO3, LaCoO3), spinel oxides (e.g., CoFe2O4, Mn3O4), and transition metal phosphides (Ni2P, CoP).

[0121] FIGS. 3A and 3B show various variations of the possible multistack. For example, in FIG. 3A, four ESU 100 are coupled with one HCU 150. In this exemplary and unlimiting example, HCU is a terminal unit of the multistack and it can share its fourth chamber with the first chamber. It can also share cathode 108, or two cathodes can be present 108 and 152, as disclosed above. FIG. 3B shows a different configuration of the multistack, where two HCU 150 are positioned within the stack and are coupled with an additional ESU 100. In this example, two adjacent HCUs 150 can share the same anode 152′.

[0122] In certain aspects, the multistack can comprise a ratio of ESU to HCU of 10:1 to 500:1, 20:1, 40:1, 50:1, 60:1, 80:1, 100:1, 200:1, 200:1, or 400:1. Yet in still further aspects, the multistack comprises a ratio of ESU to HCU of 10:2 to 500:2, 20:2, 40:2, 50:2, 60:1, 80:2, 100:2, 200:2, 200:2, or 400:2. In still further aspects, the one or more ESUs and the at least one HCU are coupled in a parallel configuration. Yet in still further aspects, one or more ESUs and the at least one HCU are coupled in a series configuration.

[0123] In still further aspects, each of the cathode and anode are electrically connected to a power source. It is understood that the ESU and HCU can have separate power sources. For example, as shown in FIG. 4A-4B, the multistack similar to those described in FIGS. 3A and 3B are shown with connections to the power sources 140 for ESU and 160 for HCU.

[0124] In still further aspects, the power source can provide the desired current to achieve the electrochemical reaction at desired efficiencies. In certain aspects, the current can have a current density from 50 mA / cm2 to 5,000 mA / cm2, including exemplary values of 75 mA / cm2, 100 mA / cm2, 125 mA / cm2, 150 mA / cm2, t 175 mA / cm2, 200 mA / cm2, 225 mA / cm2, 250 mA / cm2, 275 mA / cm2, 300 mA / cm2, 325 mA / cm2, 350 mA / cm2, 375 mA / cm2, 400 mA / cm2, 425 mA / cm2, 450 mA / cm2, 475 mA / cm2, 500 mA / cm2, 600 mA / cm2, 700 mA / cm2, 800 mA / cm2, 900 mA / cm2, 1,000 mA / cm2, 1,250 mA / cm2, 1,500 mA / cm2, 1,750 mA / cm2, 2,000 mA / cm2, 2,250 mA / cm2, 2,500 mA / cm2, 2,750 mA / cm2, 3,000 mA / cm2, 3,250 mA / cm2, 3,500 mA / cm2, 3,750 mA / cm2, 4,000 mA / cm2, 4,250 mA / cm2, 4,500 mA / cm2, and 4,750 mA / cm2, In yet still further aspects, the current density can have any value between any two foregoing values or falls within a range formed by any two foregoing values. For example, 50 mA / cm2 to 5,000 mA / cm2, 100 mA / cm2 to 4,000 mA / cm2, 250 mA / cm2 to 5,000 mA / cm2, 1,000 mA / cm2 to 5,000 mA / cm2, 500 mA / cm2 to 1,000 mA / cm2, 50 mA / cm2 to 1,000 mA / cm2, 50 mA / cm2 to 600 mA / cm2, and so on.

[0125] In still further aspects, the power source is configured to provide a desired voltage between the cathode and anode material. In such aspects, the provided voltage can be from 0.5 V to 10 V, including exemplary values of 1 V, 1.5 V, 2 V, 2.5 V, 3 V, 3.5 V, 4 V, 4.5 V, 5 V, 5.5 V, 6 V, 6.5 V, 7 V, 7.5 V, 8 V, 8.5 V, 9 V, and 9.5 V. It is understood that any voltage having a value between any two foregoing values or that falls within a range formed by any two foregoing values can be used to achieve the desired outcome. For example, the voltage can be 0.5 V to 10 V, 1 V to 10 V, 0.5 V to 5 V, 2 V to 10 V, 1 V to 5 V, and so on.

[0126] In still further aspects, to collect the current through both electrodes, current collectors are used for both anode and cathode. In some aspects, the current collector can be presented as a bipolar plate, or a wire, or a plate, or any combination thereof. For example, and without limitations, the current collector / bipolar plates can be made of graphite (plain or porous), titanium, gold, or gold-coated metal plates, etc.

[0127] As discussed above, hydrogen recycling or looping can reduce the energy intensity of electrochemical acid and base synthesis. Hydrogen is formed in the electrosynthesizer's (ESU) cathode chamber. The fluid leaving the cathode chamber is a bubbly mixture of alkaline solution and hydrogen gas. The hydrogen gas must be removed and dried before it can be supplied to the anode for acid production.

[0128] The system disclosed herein can also be seen in FIGS. 5 and 6. The ESU 100 is connected through disclosed above inlets and outlets with acid tan 508, brine tank 510, and base tank 512 using acid pump 502, brine pump 504, and base pump 506. The ESU can be connected in series with HCU 150 (FIG. 5) or in parallel with HCU 150 (FIG. 6). The hydrogen flow formed in ESU and HCU goes through degasser 514.

[0129] In certain aspects, the degasser 514 receives a flow comprising the first hydrogen gas (for ESU 100) and / or second hydrogen gas (from HCU 150) if formed> The degasser separates the first hydrogen gas and / or second hydrogen from the liquid flow. In certain aspects, the degasser can comprise one or more membranes configured to separate a gas from a liquid. However, it is understood that there are no limitations to using any specific degasser. In certain aspects, the degasser can be gravity-based, centrifugation-based, vortex-based, vacuum-based, or any combination thereof.

[0130] For example, and without limitations, the flow comprising the first and / or the second hydrogen gas through a porous hollow fiber membrane degasser where sub-atmospheric pressure on the gas side of the hollow fiber membrane module pulls gas bubbles from the alkaline solution. Yet in still further aspects, the pressure can be atmospheric. Yet in still further aspects, the pressure can be above atmospheric pressure if needed. In certain exemplary aspects, it is understood that the alkaline solution needs to be at a higher pressure than the gas side of the membrane. The second hydrogen gas can be swept through the gas side of the hollow fiber membrane, or the two gas streams can be combined after the degasser.

[0131] The separated hydrogen gas then passes through a desiccant material to remove excess moisture. It is understood that the degasser can receive the first hydrogen gas separately from the second hydrogen gas. While in other aspects, the gases can be delivered simultaneously.

[0132] In still further aspects, the degasser further comprises at least one moisture-removing element. The moisture-removing element can be any element known in the art. For example, the degasser can have a trap capable of catching moisture.

[0133] In still further aspects, the system can comprise a compressor 520. The compressor can generate the vacuum pressure needed to separate the hydrogen gas bubbles and compress the dried hydrogen up to its service pressure. Hydrogen gas accumulates in the hydrogen reservoir 524 to ensure a constant supply of gas to the one or more ESU. A mass flow meter 518 (MFM) downstream of the compressor measures the flow rate of gas and helps determine the mass balance of the system.

[0134] Hydrogen looping with an integrated alkaline electrolyzer eliminates the need for external hydrogen input into the acid / base production system. Efficient and reliable separation of hydrogen gas from the alkaline liquid stream is critical to successful hydrogen looping. To ensure system reliability and longevity, multiple stages of separation may be needed. The degasser 514 is the primary separation device responsible for recovering gas from the bubbly alkaline fluid stream leaving the ES. Hydrogen gas permeates the degasser's hollow fiber membranes when an external vacuum is applied. While the hollow fiber membranes are selective to gases, some water accumulation occurs in the gas-side of the degasser. The solvent-based moisture trap removes water vapor from the recovered hydrogen stream, protecting the diaphragm pump (or a compressor) and ensuring high purity of gas entering the ES. A gravity-based moisture trap is placed after the ES to remove liquid water droplets mixed with the effluent hydrogen. Liquid droplets (which can be acidic) coalesce and sink to the bottom of the moisture trap, while the lighter hydrogen gas leaves from the top of the trap. This bulk liquid removal device keeps liquid water from entering the solvent trap, extending the life of the solvent. Multiple solvent columns can be used, which enables a single column to be regenerated when it becomes saturated without shutting down the system.

[0135] A mass flow controller (MFC) 516, for example and without limitations, supplies a precise amount of hydrogen gas to the ESU. It is understood that in this specific aspect, the MFC is described to supply a precise amount of hydrogen. However, it is understood that any valve capable of providing a desired amount of hydrogen to the system can be used. The anode receives an excess of hydrogen to prevent hydrogen starvation in the anode. In still further aspects, if the system has an excess of overall hydrogen gas in the system, this excess gas can be recycled. The excess gas is sent back through the compressor. An expansion valve is placed after the anode chamber to regulate the anode gas pressure. A valve, for example, can also be placed downstream of the membrane degasser to regulate the gas-side pressure. In certain aspects, the valve can be a needle valve. Yet in other aspects, it can be any valve capable of regulating the gas-side pressure. Check valves placed downstream of the MFM and the MFC can further prevent unexpected back-flow of gas and prevent loss of hydrogen gas when the system is turned off.

[0136] In still further aspects, the HCU present in the system can work constantly together with ESU. While in other aspects, the HCU can only be activated if the loss of hydrogen is detected. For example, it can be switched on and off to match the system's hydrogen demand. The additional hydrogen must also pass through the degasser to separate the gas from the alkaline solution.

[0137] In still further aspects, the system can also comprise a separate desiccant column, 522.

[0138] In still further aspects, a flow of the first solution, second solution, third solution, fourth solution, and / or fifth solution is 1 to 5,000,000 mL / h, including exemplary values of 50 mL / h, 100 mL / h, 200 mL / h, 300 mL / h, 400 mL / h, 500 mL / h, 600 mL / h, 700 mL / h, 800 mL / h, 900 mL / h, 1,000 mL / h, 5,000 mL / h, 10,000 mL / h, 50,000 mL / h, 100,000 mL / h, 250,000 mL / h, a00,000 mL / h, 750,000 mL / h, 1,000,000 mL / h, 2,000,000 mL / h, 3,000,000 mL / h, and 4,000,000 mL / h. It is also understood that the flow rate can have any value between any two foregoing values or within the range formed by any two foregoing values.

[0139] In still further aspects, the electro-synthesizer unit disclosed herein can produce the acid solution and the base solution at any desired pH. For example, the unit disclosed herein can produce the acid and base solutions at low concentrations. For example, when the pH in the first chamber is 8 to 14.5, including exemplary values of 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, and 14, and wherein the pH in the second chamber is −0.5 to 6, including exemplary values of 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, and 5.5, the base solution removed from the one or more outlets of the first chamber and the acid solution removed from the outlet of the second chamber has a molarity of greater than 0 to less than 3 M, including exemplary values of 0.001 M, 0.005 M, 0.01 M, 0.05 M, 0.1 M, 0.5 M, 1 M, 1.5 M, 2 M, and 2.5. It is understood that these values are only exemplary, and the base solution and acid solution can be present in a concentration having any values between any two foregoing values. It is further understood that in some aspects, the generated acid solution and the generated base solution can have substantially the same concentration. While in other aspects, the generated acid solution and the generated base solution can have a different concentrations falling with the disclosed values.

[0140] In further aspects, when the pH in the first chamber is 8 to 15.5, including exemplary values of 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, and 15, and wherein the pH in the second chamber is 1 to 6, including exemplary values of 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, and 5.5, the base solution removed from the one or more outlets of the first chamber has a molarity of greater than 0 to 20 M, including exemplary values of 0.001 M, 0.005 M, 0.01 M, 0.05 M, 0.1 M, 0.5 M, 1 M, 2 M, 3 M, 4 M, 5 M, 6 M, 7 M, 8 M, 9 M, 10 M, 12 M, 13 M, 14 M, 15 M, 16 M, 17 M, 18 M, and 19 M. It is understood that these values are only exemplary, and the base solution can be present in a concentration having any values between any two foregoing values or within the range formed by any two foregoing values.

[0141] In further aspects, when the pH in the first chamber is 8 to 15.5, including exemplary values of 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, and 15, and wherein the pH in the second chamber is 1 to less than 6, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, and 5.5, the acid solution removed from the outlet of the second chamber has a molarity of greater than 0 to 10 M, including exemplary values of 0.001 M, 0.005 M, 0.01 M, 0.05 M, 0.1 M, 0.5 M, 1 M, 2 M, 3 M, 4 M, 5 M, 6 M, 7 M, 8 M, and 9 M. It is understood that these values are only exemplary, and the acid solution can be present in a concentration having any values between any two foregoing values.

[0142] In still further aspects, the system is a recirculated-in-a-loop system. In still further aspects, the system can be connected to one or more pumps. It is understood that in some aspects, the desired flow of the electrolytes and other streams can be provided by any means known in the art. In some aspects, one or more pumps are used to deliver the desired stream. While in other aspects, pumps are not used. It is understood that any known in the art pumps can be utilized.

[0143] In still further aspects, if desired the disclosed herein one or more ESU can be driven by different cathodic and anodic reactions including but not limited to hydrogen oxidation reaction (HOR), hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR).

[0144] In still further aspects, the disclosed herein system unit can be in communication with a controller. The controller can comprise a processor that allows control of the desired process. In some aspects, the controller is a feedback loop base controller designed to adjust processing conditions based on an output. In still further aspects, the power source used to operate the disclosed herein system can be a conventional grid power source, a renewable power source or any combination thereof. In still further aspects, it is understood that the system can generate the acid solution and the base solution in a batch or a continuous operation. In yet still further aspects, the system generate the acid solution and the base solution utilizing an energy source configured to operate continuously or on demand. For example, in some aspects, the system can utilize off-peak periods when the energy is cheap. In such exemplary and unlimiting aspects, the system can be stopped when energy is expensive and operated only when energy is cheap. In certain aspects, the generated acids / bases can be utilized immediately. While in other aspects, the generated acids / bases can be collected for further desired applications.

[0145] In still further aspects, the system disclosed herein has a coulombic efficiency of greater than 80%, 85%, 90%, 95%, and 100%. In still other aspects, the system disclosed herein exhibits a coulombic efficiency of substantially 100%.

[0146] By way of a non-limiting illustration, examples of certain aspects of the present disclosure are given below.EXAMPLES

[0147] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices, and / or methods claimed herein are made and evaluated and are intended to be purely exemplary and are not intended to limit the disclosure. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is degrees C. or is at ambient temperature, and pressure is at or near atmospheric.Example 1

[0148] In these examples, the experiments were conducted to verify the performance of the proposed hydrogen looping system. A mass-flow controller (MFC) was used to deliver a precise amount of hydrogen gas into the simulated alkaline stream. The hydrogen gas generated in the electrolyzer was removed using the membrane degasser module. The mass flow rate of the hydrogen gas leaving the compressor was measured. The hydrogen gas reservoir pressure and the gas-side pressure in the membrane degasser module were also measured.

[0149] As shown in FIGS. 7 and 8, the closed mass balance (<2.5% H2 loss) of hydrogen for over three hours was demonstrated. Even further, no decrease in reservoir pressure over time (FIG. 9) was observed. It is understood, without wishing to be bound by any theory, that these results demonstrate a lack of hydrogen gas leak from the system. In fact, gas reservoir pressure increased. Without wishing to be bound by any theory, it is assumed that this pressure increase is due to the increase in suction-side reservoir pressure. The long time needed to achieve equilibrium is explained by the lack of the usage of automated pressure controls.

[0150] The devices, systems, and methods of the appended claims are not limited in scope by the specific devices, systems, and methods described herein, which are intended as illustrations of a few aspects of the claims. Any devices, systems, and functionally equivalent methods are intended to fall within the scope of the claims. Various modifications of the devices, systems, and methods, in addition to those shown and described herein, are intended to fall within the scope of the appended claims. Further, while only certain representative devices, systems, and method steps disclosed herein are specifically described, other combinations of the devices, systems, and method steps also are intended to fall within the scope of the appended claims, even if not specifically recited. Thus, a combination of steps, elements, components, or constituents may be explicitly mentioned herein or less; however, other combinations of steps, elements, components, and constituents are included, even though not explicitly stated.

[0151] Although several embodiments of the invention have been disclosed in the foregoing specification, it is understood by those skilled in the art that many modifications and other embodiments of the invention will come to mind to which the invention pertains, having the benefit of the teaching presented in the foregoing description and associated drawings. It is thus understood that the invention is not limited to the specific embodiments disclosed hereinabove and that many modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although specific terms are employed herein, as well as in the claims which follow, they are used only in a generic and descriptive sense and not for the purposes of limiting the described invention or the claims which follow.

[0152] Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of skill in the art to which the disclosed invention belongs. Publications cited herein and the materials for which they are cited are specifically incorporated by reference.

[0153] The claims are not intended to include, and should not be interpreted to include means-plus- or step-plus-function limitations unless such a limitation is explicitly recited in a given claim using the phrase(s) “means for” or “step for,” respectively.

[0154] In view of the described processes and compositions, hereinbelow are described certain more particularly described aspects of the inventions. These particularly recited aspects should not, however, be interpreted to have any limiting effect on any different claims containing different or more general teachings described herein or that the “particular” aspects are somehow limited in some way other than the inherent meanings of the language and formulas literally used therein.EXEMPLARY ASPECTS

[0155] In view of the described processes and compositions, hereinbelow are described certain more particularly described aspects of the disclosures. These particularly recited aspects should not, however, be interpreted to have any limiting effect on any different claims containing different or more general teachings described herein, or that the “particular” aspects are somehow limited in some way other than the inherent meanings of the language and formulas literally used therein.

[0156] Example 1. A system comprising: one or more electro-synthesizer units (ESU) and at least one hydrogen compensation unit (HCU); wherein the one or more ESU are in fluid and electrical communication with at least one HCU; wherein the one or more ESUs comprises: (a) a first chamber comprising a first volume of a first solution that is in electrical communication with a first electrode; (b) a second chamber comprising a second volume of a second solution that is in electrical communication with a second electrode; (c) a third chamber positioned between and in fluid communication with the first and the second chamber, wherein the third chamber comprises a third volume of a third solution; and wherein the at least one HCU comprises (i) a fourth chamber comprising a fourth volume of a fourth solution that is in electrical communication with a fourth electrode; and (ii) a fifth chamber comprising a fifth volume of a fifth solution that is in electrical communication with a fifth electrode; wherein optionally, the fourth chamber and the first chamber are the same such that one shared chamber between the one or more ESUs and at least one HCU is formed; wherein the one or more ESUs are acid / base electrolyzers and the at least one HCU is an alkaline electrolyzer.

[0157] Example 2. The system of example 1, wherein the first solution is an alkaline solution, and the first electrode is a cathode, and wherein the cathode generates a first hydrogen gas and a hydroxide.

[0158] Example 3. The system of any one of the examples herein, particularly example 1 or 2, wherein the second solution is an acid solution and the second electrode is a gas diffusion anode.

[0159] Example 4. The system of any one of the examples herein, particularly examples 1-3, wherein the second chamber comprises a first compartment and a second compartment, wherein the first compartment comprises the second solution and the second compartment comprises a hydrogen gas, and wherein the first and the second compartments are separated by the anode.

[0160] Example 5. The system of any one of the examples herein, particularly example 4, wherein the second compartment of the second chamber receives the hydrogen gas generated in the first chamber.

[0161] Example 6. The system of any one of the examples herein, particularly examples 1-5, wherein when the first chamber and the fourth chamber are the one shared chamber, the fourth electrode is either: (i) a shared electrode, i.e., the fourth electrode and the first electrode are the same one electrode shared between the ESU unit and HCU unit; or (ii) an additional electrode to the first electrode such that the one shared chamber comprises two separate electrodes: the first electrode and the fourth electrode, which are electrically isolated from each other.

[0162] Example 7. The system of any one of the examples herein, particularly examples 1-6, wherein when the first chamber and the fourth chamber are the one shared chamber, the fourth volume of the fourth solution equals to the first volume of the first solution, and the first solution and the fourth solution are the same.

[0163] Example 8. The system of any one of the examples herein, particularly examples 1-7, wherein the fourth solution is alkaline, and the fifth solution is an oxygen-enriched alkaline.

[0164] Example 9. The system of any one of the examples herein, particularly examples 1-8, wherein the fourth electrode generates a second hydrogen gas.

[0165] Example 10. The system of any one of the examples herein, particularly example 9, wherein the second hydrogen gas is fed in the second chamber.

[0166] Example 11. The system of any one of the examples herein, particularly examples 1-10, wherein the fifth electrode is an anode.

[0167] Example 12. The system of any one of examples 1-11, wherein at least one of the one or more ESU and the at least one HCU are physically coupled.

[0168] Example 13. The system of any one of the examples herein, particularly examples 1-12, wherein the system is a multistack of the one or more ESU and at least one HCU.

[0169] Example 14. The system of example 13, wherein the multistack comprises a ratio of ESU to HCU of 10:1 to 100:1.

[0170] Example 15. The system of example 14, wherein the multistack comprises a ratio of ESU to HCU of 10:2 to 500:1.

[0171] Example 16. The system of any one of the examples herein, particularly examples 12-14, wherein the at least one HCU is positioned at at least one end of the multistack.

[0172] Example 17. The system of any one of the examples herein, particularly examples 12-15, wherein the at least one HCU is positioned within the multistack between two or more ESUs.

[0173] Example 18. The system of any one of the examples herein, particularly examples 14-16, wherein the two or more HCUs are present, each of the two or more HCUs is adjacent to each other.

[0174] Example 19. The system of any one of the examples herein, particularly examples 1-18, wherein the one or more ESUs and the at least one HCU are coupled in a parallel configuration.

[0175] Example 20. The system of any one of the examples herein, particularly examples 1-18, wherein one or more ESUs and the at least one HCU are coupled in a series configuration.

[0176] Example 21. The system of any one of the examples herein, particularly examples 1-20, wherein the first chamber is separated from the third chamber with one or more cation exchange membranes (CEM).

[0177] Example 22. The system of any one of the examples herein, particularly examples 1-21, wherein the second chamber is separated from the third chamber with one or more anion exchange membranes (AEM).

[0178] Example 23. The system of any one of the examples herein, particularly examples 1-22, wherein the third solution comprises one or more inorganic salts comprising chlorides, sulfates, nitrates, phosphates, citrates, formates, lactates, tartrates, malates, fumarates, oxalates, succinates, gluconates, ascorbates, acetates of alkaline metals and / or alkaline-earth metals, or mixtures thereof.

[0179] Example 24. The system of any one of the examples herein, particularly examples 1-23, wherein the system further comprises a degasser.

[0180] Example 25. The system of any one of the examples herein, particularly example 24, wherein the degasser receives a flow comprising the first hydrogen gas and / or second hydrogen gas if formed, and where the degasser separates the first hydrogen gas and / or second hydrogen from the flow.

[0181] Example 26. The system of any one of the examples herein, particularly examples 24 or 25, wherein the degasser comprises one or more membranes configured to separate a gas from a liquid.

[0182] Example 27. The system of any one of the examples herein, particularly example 25, wherein the degasser is gravity-based, centrifugation-based, vortex-based, vacuum-based, or any combination thereof.

[0183] Example 28. The system of any one of the examples herein, particularly examples 24-27, wherein the degasser further comprises at least one moisture-removing element.

[0184] Example 29. The system of any one of the examples herein, particularly examples 1-28 further comprises a hydrogen storage unit, wherein the hydrogen storage unit stores the first hydrogen gas and / or second hydrogen gas if formed before it is fed into the second chamber.

[0185] Example 30. The system of any one of the examples herein, particularly examples 1-29, wherein the system is a recirculated-in-a-loop flow system.

[0186] Example 31. The system of any one of the examples herein, particularly example 30, wherein a flow of the first solution, second solution, third solution, fourth solution, and / or fifth solution is 1 to 5,000,000 mL / h.

Claims

1. A system comprising:one or more electro-synthesizer units (ESU) andat least one hydrogen compensation unit (HCU);wherein the one or more ESU are in fluid and electrical communication with at least one HCU;wherein the one or more ESUs comprises:a) a first chamber comprising a first volume of a first solution that is in electrical communication with a first electrode;b) a second chamber comprising a second volume of a second solution that is in electrical communication with a second electrode;c) a third chamber positioned between and in fluid communication with the first and the second chamber, wherein the third chamber comprises a third volume of a third solution; andwherein the at least one HCU comprisesi) a fourth chamber comprising a fourth volume of a fourth solution that is in electrical communication with a fourth electrode; andii) a fifth chamber comprising a fifth volume of a fifth solution that is in electrical communication with a fifth electrode;wherein optionally, the fourth chamber and the first chamber are the same such that one shared chamber between the one or more ESUs and at least one HCU is formed;wherein the one or more ESUs are acid / base electrolyzers and the at least one HCU is an alkaline electrolyzer.

2. The system of claim 1, whereinthe first solution is an alkaline solution, and the first electrode is a cathode, and wherein the cathode generates a first hydrogen gas and a hydroxide; and / orwherein the second solution is an acid solution and the second electrode is a gas diffusion anode.

3. The system of claim 1, wherein the second chamber comprises a first compartment and a second compartment, wherein the first compartment comprises the second solution and the second compartment comprises a hydrogen gas, and wherein the first and the second compartments are separated by the anode.

4. The system of claim 3, wherein the second compartment of the second chamber receives the hydrogen gas generated in the first chamber.

5. The system of claim 1, wherein when the first chamber and the fourth chamber are the one shared chamber, the fourth electrode is either:i) a shared electrode, i.e., the fourth electrode and the first electrode are the same one electrode shared between the ESU unit and HCU unit; orii) an additional electrode to the first electrode such that the one shared chamber comprises two separate electrodes: the first electrode and the fourth electrode, which are electrically isolated from each other;and / orwherein when the first chamber and the fourth chamber are the one shared chamber, the fourth volume of the fourth solution equals to the first volume of the first solution, and the first solution and the fourth solution are the same.

6. The system of claim 1, wherein the fourth solution is alkaline, and the fifth solution is an oxygen-enriched alkaline.

7. The system of claim 1, wherein the fourth electrode generates a second hydrogen gas.

8. The system of claim 7, wherein the second hydrogen gas is fed into the second chamber.

9. The system of claim 1, wherein the fifth electrode is an anode.

10. The system of claim 1, wherein at least one of the one or more ESU and the at least one HCU are physically coupled.

11. The system of claim 1, wherein the system is a multistack of the one or more ESU and at least one HCU, orwherein the multistack comprises a ratio of ESU to HCU of 10:1 to 500:1, orwherein the multistack comprises a ratio of ESU to HCU of 10:2 to 500:2.

12. The system of claim 11, whereinthe at least one HCU is positioned at at least one end of the multistack, orwherein the at least one HCU is positioned within the multistack between two or more ESUs;and / orwherein the two or more HCUs are present, each of the two or more HCUs is adjacent to each other;and / orwherein the one or more ESUs and the at least one HCU are coupled in a parallel configuration;and / orwherein one or more ESUs and the at least one HCU are coupled in a series configuration.

13. The system of claim 1, wherein the first chamber is separated from the third chamber with one or more cation exchange membranes (CEM).

14. The system of claim 1, wherein the second chamber is separated from the third chamber with one or more anion exchange membranes (AEM).

15. The system of claim 1, wherein the third solution comprises one or more inorganic salts comprising chlorides, sulfates, nitrates, phosphates, citrates, formates, lactates, tartrates, malates, fumarates, oxalates, succinates, gluconates, ascorbates, acetates of alkaline metals and / or alkaline-earth metals, or mixtures thereof.

16. The system of claim 1, wherein the system further comprises a degasser.

17. The system of claim 16, wherein the degasser receives a flow comprising the first hydrogen gas and / or second hydrogen gas if formed, and where the degasser separates the first hydrogen gas and / or second hydrogen from the flow, and wherein the degasser comprises one or more membranes configured to separate a gas from a liquid; or wherein the degasser is gravity-based, centrifugation-based, vortex-based, vacuum-based, or any combination thereof.

18. The system of claim 16, wherein the degasser further comprises at least one moisture removing element.

19. The system of claim 1, wherein the system further comprises a hydrogen storage unit, wherein the hydrogen storage unit stores the first hydrogen gas and / or second hydrogen gas if formed before it is fed into the second chamber.

20. The system of claim 1, wherein the system is a recirculated-in-a-loop flow system.

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