Electrolyzer dynamic seal

Abstract

In one aspect, the disclosure relates to a dynamic method for sealing an electrolyzer flow field, seals useful in the disclosed method, devices incorporating the seals, and methods of performing electrolysis using the same. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

Description

ELECTROLYZER DYNAMIC SEALCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Ser. No. 63 / 562,471 , filed March 7, 2024, and U.S. Provisional Application Ser. No. 63 / 557,270, filed February 23, 2024, each of which is incorporated herein by reference in its entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] This invention was made with government support under grant number 2119435 awarded by the National Science Foundation. The government has certain rights in the invention.BACKGROUND

[0003] Antarctic ice core studies indicate that the current atmospheric CO2 concentration (420 ppm) represents a maximum relative to the last 650,000-800,000 years, other works using proxies for CO2 indicate that the current concentration represents a maximum over the last 14 million years. In order to limit global warming by 1.5 °C, current greenhouse gas emission rates should be cut in half by 2030 and to zero by 2050. At present, chemical manufacturing processes including ethylene production (228 million metric tons per year) and ethanol production (22 million metric tons per year) are responsible for approximately 6% of global CO2 emissions. Thus, using CO2 as a chemical feedstock for electrolysis and renewable energy offers a sustainable path to make carbon products with zero or negative CO2 emissions.

[0004] Use of CO2 as a chemical feedstock will be enhanced by improvements in electrolyzers that can account for oscillation of pressures and / or flow rates during use of the electrolyzers, that reduce corrosion and / or degradation of instrument components allowing for a longer service life for instruments and longer period of continuous operation, and that reduce maintenance time and costs. For example, an ideal sealing system for an electrolyzer would ensure no undesired substances pass between compartments in the system, such as gases, electrolytes, or the like.

[0005] Despite advances in electrolyzer construction research, there is still a scarcity of sealing systems that are effective, adjustable to varying operation parameters, and long lasting, allowing for extended operation of the electrolyzer with minimal need for maintenance. These needs and other needs are satisfied by the present disclosure.SUMMARY

[0006] In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, the disclosure, in one aspect, relates to a dynamic method for sealing an electrolyzer flow field, seals useful in the disclosed method, devices incorporating the seals, and methods of performing electrolysis using the same.

[0007] Other systems, methods, features, and advantages of the present disclosure will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims. In addition, all optional and preferred features and modifications of the described embodiments are usable in all aspects of the disclosure taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with one another.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

[0009] FIG. 1 is a cross-sectional diagram of one side of an exemplary electrolyzer apparatus as described herein.

[0010] FIG. 2 is an exploded diagram in perspective view of a full electrolyzer apparatus as described herein.

[0011] FIG. 3 shows scanning electron microscopy (SEM) images of the synthesized Cu-based nanoparticles. (Left) Cu-Sno.o3 with 100 nm average particle size. (Middle) Cu-Po.o65 with 104 nm average particle size. (Right) Cu2Se with 110 nm average particle size. The nanoparticles were synthesized via a one pot approach with hydrazine as a reducing agent and polyvinylpyrrolidone as a capping agent.

[0012] FIG. 4 shows XRD patterns of undoped and doped Cu electrocatalysts. (Left) XRD of Cu and Cu-Po.o65 showing shifted peaks to lower 20 values for Cu-Po.o65. Inset shows a zoom-in ofthe (111) and (200) peaks. (Middle) XRD of Cu and Cu-Sno03 showing peak broadening and shifting for Cu-Sno.o3. Inset shows zoom-in of the (111) and (200) peaks. (Right) XRD of Cu and Cu2Se showing characteristic cubic Cu2Se peaks. Inset shows zoom-in of the Cu2Se peaks.

[0013] FIG. 5 shows Faradaic efficiencies of CO2reduction products on the Cu, Cu-Pooes, Cu- Sno.o3, and Cu2Se electrocatalysts at a constant cell potential of 4.0 (Left) 0.1 M KHCO3 (pH = 8.20) and (Right) 1 M KOH (pH = 14.05). Error bars represent the standard deviation from triplicate measurements on each electrocatalyst under identical testing conditions. The small error bars verify the reproducibility of the CO2reduction and observed trends in faradaic efficiency across the undoped, Sn-doped, P-doped copper and Cu2Se electrocatalyst.

[0014] FIG. 6 shows Faradaic efficiencies of CO2reduction products and current density at varied cell potentials from 3.6 V to 4.6 V. Results are shown for (Upper left) Cu, (Upper right) Cu-Po.oes, (Lower left) Cu-Sno.o3, and (Lower right) Cu2Se electrocatalysts. Error bars represent the standard deviation from triplicate measurements on each electrocatalyst under identical testing conditions. The small error bars verify the reproducibility of the CO2reduction and observed trends in faradaic efficiency across the undoped, Sn-doped, P-doped copper, and Cu2Se electrocatalyst.

[0015] FIG. 7 shows cell potential and Faradaic efficiency stability for CO2reduction on (Left) Cu- Po.oes, (Middle) Cu-Sno.03, and (Right) Cu2Se electrocatalysts. Galvanostatic experiments were conducted at 150 mA cm-2in 0.1 M KHCO3 electrolyte for over 200 h.

[0016] FIG. 8 shows scanning electron microscopy (SEM) images of Cu-Sno.03, Cu-Po.oes, and Cu2Se electrocatalysts deposited onto the gas diffusion electrode (GDE) with PVDF and Vulcan carbon support. The upper row shows SEM images before electrolysis, revealing densely packed spherical Cu-based nanoparticles for each electrocatalyst. The lower row displays SEM images after prolonged CO2electrolysis for over 200 h at 150 mA cm-2in KHCO3. After electrolysis, a structural transformation from spherical Cu nanoparticles into larger cubic shapes is evident.

[0017] FIG. 9 shows a Pourbaix diagram for Cu-Se including the CO2to CO reaction at 25 °C. Cu2Se reduction occurs at -0.58 V vs RHE and provides a stabile alkaline window for CO2reduction. Calculated using the HSC Chemistry 10.0 software package.

[0018] FIG. 10 shows a proposed reaction pathways for ethylene, ethanol, and acetate production from CO2electroreduction.

[0019] FIG. 11 shows an alternate configuration of the system of FIG. 2 including a gas diffusion electrode (GDE) and membrane.

[0020] FIGs. 12A-12B are photographs of several views of an exemplary membrane in use.

[0021] Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or can be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations 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.DETAILED DESCRIPTION

[0022] In one aspect, disclosed herein is a dynamic seal for an electrolyzer including at least the following components: a main housing plate comprising a central opening, wherein the central opening extends through the entire thickness of the main housing plate; a flexible sealing ring in contact with the central opening of the main housing plate; and a flow field electrode, wherein at least a portion of the flow field electrode is situated in the central opening of the main housing plate.

[0023] The flexible sealing ring can be made by injection molding or another method. In some aspects, the flexible sealing ring is further in contact with the flow field electrode. In another aspect, the flow field electrode can be a flow field cathode or a flow field anode. In some aspects, the dynamic seal further includes an anti-collapse ring made from poly(1 , 1 ,2,2- tetrafluoroethylene) or another suitable nonreactive material. In an aspect, the anti-collapse ring is adjacent to and in contact with the flow field electrode and the flexible sealing ring and prevents inward collapse of the flexible sealing ring.

[0024] In another aspect, the dynamic seal further includes a membrane retaining clip in contact with the main housing plate. In some aspects, the dynamic seal further includes a membrane, wherein the membrane is in contact with the flexible sealing ring and the main housing plate and is held in place by the membrane retaining clip. In some aspects, the dynamic seal further includes a gas diffusion electrode (GDE) in contact with the flow field electrode and the membrane.

[0025] In one aspect, a particular advantage of the dynamic seal disclosed herein is that the allows for an adjustable space for the GDE, so that different thicknesses of GDEs can be used.Further in this aspect, GDEs can be quickly and easily replaced by GDEs of other sizes without replacing other components of the system due to the adjustability of the seal. In some aspects, a GDE of a particular size or thickness may be used with a particular set of flow field conditions, while a different GDE can be suitable for a different set of flow field conditions. In one aspect, the disclosed dynamic seal is adjustable for any combination of GDE and flow field conditions.

[0026] In still a further aspect, the dynamic seal further includes a push strap in contact with an outer surface of the flow field electrode. Further in this aspect, the push strap includes at least one through hole, wherein a compression force adjustment screw is inserted into the at least one through hole. In one aspect, the compression force adjustment screw is configured to apply pressure on the flow field electrode, relieve pressure from the flow field electrode, or both, with adjustment of the position of the compression force adjustment screw.

[0027] In any of these aspects, the dynamic seal is stable for at least 225 hours of operation without replacement of any components and dose not degrade in the presence of an electrolyte including KOH, KHCO3, or any combination thereof. In still another aspect, the dynamic seal does not leak electrolytes, gases, reactants, or value-added products during pressure oscillations. In one aspect, value-added products include, but are not limited to, ethylene, ethanol, acetaldehyde, or another Ci or C2 containing species. In one aspect, the dynamic seal is stable at pressures up to 100 psi, or at about 10 psi.

[0028] Also disclosed herein is an electrolyzer including the disclosed dynamic seal, wherein the dynamic seal surrounds a flow field cathode, a flow field anode, or both a flow field cathode and a flow field anode.

[0029] Also disclosed herein is a method for sealing an electrolyzer, the method including at least the step of applying the dynamic seal disclosed herein to at least one flow field electrode such as, for example, a flow field anode or a flow field cathode. In some aspect, the method further includes adjusting the compression force adjustment screw to compensate for pressure oscillations and / or flow rate oscillations in the electrolyzer.

[0030] Turning to FIGs. 1-2, a cross-sectional diagram of an electrolyzer including the disclosed dynamic seal is shown. Main housing plate 100 extends around the dynamic seal 110 on all sides. A preload spring 102 is in contact on one side with flow field electrode 104 and main housing plate 100 to hold dynamic seal 110 in place. Dynamic seal 110 is also in contact with a Teflon anti-collapse ring 112 to preserve structure and function of the electrolyzer. A membrane retaining clip 114 also supports the structure. The position of the flow field electrode 104 inrelation to the dynamic seal 110 through use of a push strap 106 and position / com pression force adjustment screw 108. Flow field movement occurs in one or both directions marked by arrow A. As seen in FIG. 11 , membrane retaining clip 114 can be used to hold membrane 118 in place. The system can further include a gas diffusion electrode (GDE) 116.

[0031] Many modifications and other embodiments disclosed herein will come to mind to one skilled in the art to which the disclosed compositions and methods pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosures are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. The skilled artisan will recognize many variants and adaptations of the aspects described herein. These variants and adaptations are intended to be included in the teachings of this disclosure and to be encompassed by the claims herein.

[0032] Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0033] As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure.

[0034] Any recited method can be carried out in the order of events recited or in any other order that is logically possible. That is, 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 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 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.

[0035] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates ofpublication provided herein can be different from the actual publication dates, which can require independent confirmation.

[0036] While aspects of the present disclosure can be described and claimed in a particular statutory class, such as the system statutory class, this is for convenience only and one of skill in the art will understand that each aspect of the present disclosure can be described and claimed in any statutory class.

[0037] 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. 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 the disclosed compositions and methods belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0038] Prior to describing the various aspects of the present disclosure, the following definitions are provided and should be used unless otherwise indicated. Additional terms may be defined elsewhere in the present disclosure.Definitions

[0039] As used herein, “comprising” is to be interpreted as specifying the presence of the stated features, integers, steps, or components as referred to, but does not preclude the presence or addition of one or more features, integers, steps, or components, or groups thereof. Moreover, each of the terms “by”, “comprising,” “comprises”, “comprised of,” “including,” “includes,” “included,” “involving,” “involves,” “involved,” and “such as” are used in their open, non-limiting sense and may be used interchangeably. Further, the term “comprising” is intended to include examples and aspects encompassed by the terms “consisting essentially of” and “consisting of.” Similarly, the term “consisting essentially of” is intended to include examples encompassed by the term “consisting of.

[0040] As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a value added product,” “a flexible material,” or “an electrolyte,” include, but are not limited to, mixtures or combinations of two or more such value added products, flexible materials,or electrolytes, and the like.

[0041] It should be noted that ratios, concentrations, amounts, and other numerical data can be expressed herein in a range format. 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. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms a further aspect. For example, if the value “about 10” is disclosed, then “10” is also disclosed.

[0042] When a range is expressed, a further aspect includes from the one particular value and / or 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. 'about x, y, z, or less’ and should be interpreted to include the specific ranges of ‘about x’, 'about y’, and ‘about z’ as well as the ranges of ‘less than x’, less than y’, and ‘less than z’. Likewise, the phrase ‘about x, y, z, or greater’ should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘greater than x’, greater than y’, and ‘greater than z’. In addition, the phrase “about ‘x’ to ‘y’”, where ‘x’ and ‘y’ are numerical values, includes “about ‘x’ to about ‘y’”.

[0043] It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner 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 subranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a numerical range of “about 0.1 % to 5%” should be interpreted to include not only the explicitly recited values of about 0.1% to about 5%, but also include individual values (e.g., about 1%, about 2%, about 3%, and about 4%) and the sub-ranges (e.g., about 0.5% to about 1.1%; about 5% to about 2.4%; about 0.5% to about 3.2%, and about 0.5% to about 4.4%, and other possible sub-ranges) within the indicated range.

[0044] As used herein, the terms “about,” “approximate,” “at or about,” and “substantially” mean that the amount or value in question can be the exact value or a value that provides equivalentresults or effects as recited in the claims or taught herein. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and / or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art such that equivalent results or effects are obtained. In some circumstances, the value that provides equivalent results or effects cannot be reasonably determined. In such cases, it is generally understood, as used herein, that “about” and “at or about” mean the nominal value indicated ±10% variation unless otherwise indicated or inferred. In general, an amount, size, formulation, parameter or other quantity or characteristic is “about,” “approximate,” or “at or about” whether or not expressly stated to be such. It is understood that where “about,” “approximate,” or “at or about” is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless specifically stated otherwise.

[0045] As used herein, the terms “optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0046] Unless otherwise specified, temperatures referred to herein are based on atmospheric pressure (i.e. one atmosphere).

[0047] Now having described the aspects of the present disclosure, in general, the following Examples describe some additional aspects of the present disclosure. While aspects of the present disclosure are described in connection with the following examples and the corresponding text and figures, there is no intent to limit aspects of the present disclosure to this description. On the contrary, the intent is to cover all alternatives, modifications, and equivalents included within the spirit and scope of the present disclosure.ASPECTS

[0048] The present disclosure can be described in accordance with the following numbered aspects, which should not be confused with the claims.

[0049] Aspect 1. A dynamic seal for an electrolyzer, the dynamic seal comprising: a main housing plate comprising a central opening, wherein the central opening extends through the entire thickness of the main housing plate; a flexible sealing ring in contact with the central opening of the main housing plate; anda flow field electrode, wherein at least a portion of the flow field electrode is situated in the central opening of the main housing plate.

[0050] Aspect 2. The dynamic seal of aspect 1 , wherein the flexible sealing ring is further in contact with the flow field electrode.

[0051] Aspect 3. The dynamic seal of aspect 1 or 2, wherein the flow field electrode is a flow field cathode or a flow field anode.

[0052] Aspect 4. The dynamic seal of any one of aspects 1-3, further comprising an anti-collapse ring.

[0053] Aspect 5. The dynamic seal of aspect 4, wherein the anti-collapse ring comprises poly ( 1 , 1 ,2,2-tetrafluoroethylene).

[0054] Aspect 6. The dynamic seal of aspect 4 or 5, wherein the anti-collapse ring is adjacent to and in contact with the flow field electrode.

[0055] Aspect 7. The dynamic seal of any one of aspects 4-6, wherein the anti-collapse ring is further in contact with the flexible sealing ring.

[0056] Aspect 8. The dynamic seal of any one of aspects 4-7, wherein the anti-collapse ring prevents inward collapse of the flexible sealing ring.

[0057] Aspect 9. The dynamic seal of any one of aspects 1-8, further comprising a membrane retaining clip in contact with the main housing plate.

[0058] Aspect 10. The dynamic seal of aspect 9, further comprising a membrane, wherein the membrane is in contact with the flexible sealing ring and the main housing plate, and wherein the membrane is held in place by the membrane retaining clip.

[0059] Aspect 11. The dynamic seal of aspect 10, further comprising a gas diffusion electrode in contact with the flow field electrode and the membrane.

[0060] Aspect 12. The dynamic seal of any one of aspects 1-11, further comprising a push strap in contact with an outer surface of the flow field electrode.

[0061] Aspect 13. The dynamic seal of aspect 12, wherein the push strap comprises at least one through hole, wherein a compression force adjustment screw is inserted into the at least one through hole.

[0062] Aspect 14. The dynamic seal of aspect 13, wherein the compression force adjustment screw is configured to apply pressure on the flow field electrode, relieve pressure from the flow field electrode, or both, with adjustment of the position of the compression force adjustment screw.

[0063] Aspect 15. The dynamic seal of any one of aspects 1-14, wherein the dynamic seal is stable for at least 225 hours of operation without replacement of any components.

[0064] Aspect 16. The dynamic seal of any one of aspects 1-15, wherein the dynamic seal does not degrade in the presence of an electrolyte comprising KOH, KHCO3, or any combination thereof.

[0065] Aspect 17. The dynamic seal of aspect any one of aspects 1-16, wherein the dynamic seal does not leak electrolytes, gases, reactants, or value added products during pressure oscillations.

[0066] Aspect 18. The dynamic seal of any one of aspects 1-17, wherein the dynamic seal is stable at pressures up to 100 psi.

[0067] Aspect 19. An electrolyzer comprising the dynamic seal according to any one of aspects 1-18, wherein the dynamic seal prevents leakage of electrolyte solution, reactants, value-added products, or any combination thereof, from the flow field electrode.

[0068] Aspect 20. The electrolyzer of aspect 19, wherein the dynamic seal surrounds a flow field cathode, a flow field anode, or both a flow field cathode and a flow field anode.

[0069] Aspect 21. A method for sealing an electrolyzer, the method comprising applying the dynamic seal of any one of aspects 1-18 to at least one flow field electrode in the electrolyzer.

[0070] Aspect 22. The method of aspect 21 , wherein the at least one flow field electrode comprises a flow field cathode, a flow field anode, or both a flow field cathode and a flow field anode.

[0071] Aspect 23. The method of aspect 21 or 22, wherein the method further com prises adjusting the compression force adjustment screw to compensate for pressure oscillations in the electrolyzer.

[0072] Aspect 24. The method of any one of aspects 21-23, wherein the method further comprises adjusting the compression force adjustment screw to compensate for flow rate oscillations in the electrolyzer.EXAMPLES

[0073] 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 of the disclosure and are not intended to limit the scope of what the inventors regard as their 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 in °C or is at ambient temperature, and pressure is at or near atmospheric.Example 1 : Electrochemical Reduction of CO2

[0074] Example 1 describes an exemplary process performed using the disclosed dynamic seal.Chemicals and Materials

[0075] Copper chloride dihydrate (CuCI2-2H2O, 99%), Se powder (Se, 99.5%), stannous chloride (SnCh, 98 %) potassium bicarbonate (KHCO3, 99 %), potassium hydroxide (KOH, 99.95%), sodium hydroxide (NaOH), hydrazine hydrate aqueous solution (N2H4-H2O, 85%) and hydrochloric acid (36-38 %) were procured from ThermoFisher Scientific. Sodium hypophosphite (NaH2PO2, 99%) and iridium (IV) chloride hydrate (lrCl4-XH2O, 99.9 %) were procured from Sinopharm Chemical Reagent Co., Ltd. The Sustainion membranes (X37-50 Grade RT) characterized by a dry thickness of above 50 microns, carbon black vulcan, polyvinylidene fluoride (PVDF) with a pore size of 0.45 pm, and titanium (Ti) felt were purchased through Fuel Cell Store. All deionized (DI) water used was of Milli-Q grade (resistivity of 18.2 MQ-cm).Synthesis of Electrocatalyst

[0076] A one-pot approach was adapted from literature sources to synthesize copper phosphorus (Cu-Po.065) nanoparticles with a molar ratio of 1 :0.065. Initially, 10 mmol of CUCI2 2H2O was dissolved in 50 mL of deionized water with vigorous stirring. The solution was stabilized with 1 g of poly(vinylpyrrolidone) (PVP), and the pH was adjusted by gradually adding 12 M NaOH solution, forming a red liquid. The mixture was stirred at 80 °C for 2 h, and then 50 mL of a 1 mmol NaH2PO2solution was added. Subsequently, 3 mL of N2H4-H2O was injected, and the mixture was heated and stirred for 3 h. The resulting Cu-Po.o65 nanoparticles were collected by centrifugation, washed with deionized water, ethanol, and acetone, and dried at 60 °C for 12 h.

[0077] Copper selenide (CihSe) nanoparticles were synthesized according to a colloidal approach. 5 mmol of elemental Se was dissolved in a NaOH solution, leading to an orange-red solution. 50 mL Cu2+solution obtained from 10 mmol of CuCl2-2H2O was added to the Se solution with rapid stirring. Afterward, 3 mL of N2H4 H2O was injected, and the mixture was stirred and heated for 3 h, producing black Cu2Se nanoparticles. The precipitate was collected by centrifugation, washed with water, and dried at 150 °C under vacuum for 24 h.

[0078] Similarly, Cu-Sno.03 nanoparticles were synthesized by dissolving 10 mmol of CuCl2'2H2O and 0.25 mmol of SnCh in 50 mL of deionized water, then stabilization with 1 g of PVP. The pH was adjusted using NaOH solution, and 3 mL of N2H4 H2O was added. The mixture was stirred and heated for 3 h, and the resulting Cu-Sno.o3 alloy nanoparticles were collected, washed, and dried at 60 °C under vacuum for 12 h.Characterization

[0079] Crystal and electronic structures of the samples were comprehensively analyzed using an X-ray diffractometer (XRD, PANanalytical XRD), X-ray photoelectron spectroscopy (XPS, ScientaOmicron XPS), scanning electron microscope and energy dispersive X-ray spectroscopy (SEIWEDS, ThermoFisher PFIBSEM). The XRD operated at a voltage of 40 kV and a current of 40 mA. Data collection within a range from 20° to 100° angles allowed the identification of diffraction peaks. The samples’ morphology and grain size information of the samples were examined using a field emission SEM equipped with an energy dispersive X-ray spectrometer. XPS enabled precise analysis of the samples’ surface elemental composition and oxidation states of the samples.Electrode Preparation

[0080] The cathode was prepared using a spray-coating technique with electrocatalyst slurry containing approximately 100 mg of each electrocatalyst, 5 mg of Vulcan Carbon, and 5.53 mg of PVDF powder in 20 mL of 1 :1 H2O-isopropanol solution. After sonication for 1 h, the slurry was sprayed onto 50 cm2microporous hydrophobic side of gas diffusion carbon paper carbon (Sigracet 39BB). Electrocatalyst loading was measured using a balance until a loading of 1 mg cm-2was achieved. For the anode electrode, the process involved dip-coating iridium chloride onto titanium felt, followed by thermal decomposition to lrO2. The titanium felt, covering an area of 6.64 cm2, was initially etched in boiling 0.5 M oxalic acid for 30 minutes. Subsequently, the etched titanium felt was coated with a solution comprising 75 mg of IrCU xH2© dissolved in 6.76 ml of 37 % HCI and 18.24 ml of isopropanol. The titanium felt coated with lrCI4was then oven-dried at 100 °C for 20 minutes and then calcinated at 500 °C for 20 minutes to produce an I rC>2 catalyst layer. The dipping and oxidation process was repeated until a suitable loading of 3 mg cm-2was achieved.Electrochemical CO2 Reduction Measurements

[0081] CO2 reduction reaction (CO2RR) experiments were carried out in a zero-gap EA using a titanium mesh anode and a stainless-steel cathode flow field. The cathode flow field is made of 2205 stainless steel with a serpentine flow channel to promote CO2transport across the GDE. The anode flow field was milled from grade 2 Ti and had a serpentine flow channel for electrolyte flow. CO2 was delivered to the cathode side of the electrolytic cell at a flow rate of 20 seem, while the anode was supplied with an aqueous 0.1 M KHCO3 electrolyte at 10 mL min-1using a peristaltic pump (CHEM-TECH). Both cathode and anode flow rates were controlled using mass flow controllers (Alicat MC-500SCCM) and monitored using Flow Vision 2.0 software. Faradaic efficiencies were determined using outlet flow rates and concentrations based on calibrated GC and N analyses.Computation of Partial Atomic Charges on Cu

[0082] Density functional theory calculations were performed using the Vienna Ab initio Simulation Package (VASP) to compute partial charges on the Cu sites in bulk structures representing the different electrocatalysts examined in the experiments. The Lbwdin partial charges were calculated using a basis set of quasi-atomic orbitals determined from the occupied bands computed in the electronic ground state of each material. This was done using an extension to the VASP code developed previously.

[0083] Partial charges were calculated for five bulk structures representing the different electrocatalysts. The Cu-P electrocatalyst was modeled using a 2*2*2 supercell of Fm3m Cu with one Cu atom substituted by P. Three bulk structures were used to represent the Cu-Sn electrocatalyst the hexagonal P63 / mmc and orthogonal Pmmn unit cells of Cu3Sn, as well as a 2*2*2 supercell of Fm3m Cu with one Cu atom substituted by Sn. The Cu2Se electrocatalyst was represented by the cubic F-43m unit cell. For all structures, the reported partial charge on Cu was computed as the average partial charge of all Cu atoms directly adjacent to the P, Sn, or Se heteroatom.Results: Electrocatalyst Synthesis and Characterization

[0084] All electrocatalysts shown in FIGs. 3A-3C were synthesized in a one pot process using hydrazine as a reducing agent and polyvinylpyrrolidone (PVP) as capping agent. Scanning electron microscopy (SEM) analyses of the electrocatalyst shows similar spherical nanoparticles of Cu, Cu- Po065, Cu-Sno.o3, and Cu2Se with diameters near 100 nm. Energy dispersive X-ray spectroscopy (EDS) elemental mapping shows a uniform distribution of Sn, P and Se dopant elements. Structural phases and chemical properties of the Cu, Cu-P0.065, Cu-Sno.03, and Cu2Se electrocatalysts were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) before and after their use as electrocatalysts.

[0085] As shown in FIGs. 4A-4C, XRD analyses show incorporation of P, Sn, or Se alters the crystal structure. Undoped Cu and Cu-Po.o65 electrocatalysts show characteristic peaks corresponding to the (111), (200), (220), (311) and (222) planes of face-centered cubic Cu. Analysis of the Cu-Po.o65 electrocatalyst shows characteristic Cu peaks are shifted to lower 20 values compared to the undoped Cu. This systematic shift indicates that the incorporation of P induces an expansion of the Cu crystal lattice. The gradual peak displacements and increased d- spacings with increasing P confirm a monotonic increase in the Cu-Cu interatomic distances. XRD patterns of the Cu-Sno.o3 electrocatalyst showed similar diffraction peaks to undoped Cu with no crystalline Sn species detected; however, all diffraction peaks were widened and shifted to a lower 20 angle. Similar Cu-Snxalloy XRD patterns have been found in the literature. The XRD diffraction peaks of the Cu2Se electrocatalyst are associated with the cubic Cu2-xSe. XPS analyses were performed to help elucidate the electronic properties of the electrocatalysts. The Cu 2p core photoemission levels reside at near 932 eV (Cu 2p3 / 2) and 952 eV (Cu 2p1 / 2) binding energies for all the samples. The Cu 2p3 / 2 core levels of all samples are deconvoluted into two peaks corresponding to the ~ 932 eV Cu° / Cu+states, differing less than 0.2 eV binding energy (only distinguished by inspecting their respective Cu LLM Auger parameter) and a second shoulder peak at ~ 934 eV corresponding to the Cu2+oxidation state. A curve fitting analysis of the XPS peaks and Cu Auger spectrum indicates that before the electroreduction the Cu-Po.o65 and Cu- Sno.o3 electrocatalysts comprise mostly Cu° and Cu2Se nanoparticles comprise mostly Cu+.Results: Impact of pH

[0086] FIG. 5 shows the FEs of CO2 reduction at Cu, Cu-Po.o65, Cu-Sno.03, and Cu2Se electrocatalysts at a constant cell potential of 4.0 V using a 0.1 M KHCO3 electrolyte (pH 8.2). The undoped Cu electrocatalyst (resistivity ~ 2.30 O cm) yields the greatest current density, i= 188 mA cm-2, and ethylene is the primary product at an FE of 37%. Other products include CO(FE 13%) and ethanol (FE 11 %). Evaluation of the Cu-Pooes electrocatalyst (r ~ 2.42 pQ cm) showed an ethylene FE 1.4 times greater (52%) and ethanol FE 1.9 times greater (21%) relative to undoped Cu electrocatalyst at a cell potential of 4.0 V (i = 150 mA cm-2). The Cu-Sno.o3 electrocatalyst (r ~ 2.37 Q cm) resulted in a slightly lower current density at the same cell potential (i = 171 mA cm'2at 4.0 V); however, ethanol production increased by 2.2-fold (FE 24%) relative to undoped Cu. At this same cell potential, the Cu2Se electrocatalyst (r ~ 98.62 pQ cm) resulted in a cathodic current density of 148 mA cm-2and demonstrated selectivity to acetate. At this pH, the FE for acetate production at Cu2Se electrocatalysts was 32%. This value is approximately 6 to 10 times greater than undoped Cu or other electrocatalysts (Cu-P0065, and Cu- Sno.03). Likewise, ethanol was the secondary product at Cu2Se electrocatalysts (FE 28%) marking a 2.5-fold increase relative to undoped Cu. It is also important to note that the current densities at the same cell potentials were inversely related to electrocatalyst’s resistivity trends.

[0087] In more alkaline electrolytes, 1 M KOH (pH 14) and at a constant cell potential of 4.0 the selectivity shifts to oxygenates with increasing electropositive Cu+ become more apparent. Under these conditions, the Cu-Po.o65 electrocatalyst enhanced ethylene and ethanol FEs to 43% and 35%, respectively (relative to 26% and 13%, respectively, for undoped Cu). The Cu-Sno.o3 electrocatalyst yielded ethanol as a primary product with an FE of 48%. The Cu2Se electrocatalyst resulted in acetate as a primary product with an FE of 35%.Results: Impact of Potential

[0088] The influence of cell potential on CO2reduction was evaluated by evaluating all four electrocatalysts (Cu, Cu-Pooes, Cu-Sno.o3, and Cu2Se) at constant cell potentials of 3.6 V, 4.0 V, and 4.6 V in a KHCO3 electrolyte (pH 8.2). As shown in FIGs. 6A-6D, the resulting cathode current densities ranged from 138 to 246 mA cm-2and generally followed the resistivity trends of doped electrocatalysts as noted previously.

[0089] As expected, ethylene is the primary product of the Cu electrocatalyst at all potentials in this potential range with the Faradaic efficiencies (FE) increasing from 35% to 37% as the cell potential increases from 3.6 V to 4.0 V. Meanwhile, the FE for the hydrogen evolution reaction (HER) decreased from 19% to 17% over the same range. At the greatest cell potential of 4.6 V, ethylene FE at undoped Cu electrocatalysts dropped to 31 % while HER FE rose to 24%. In the case of Cu-Po.oes electrocatalysts, ethylene FE increased from 50% to 52% as the cell potential increased from 3.6 V to 4.0 V. The FE for ethanol remained near 22% and the HER FE remained near 10 %. At the higher cell potential of 4.6 V, ethylene and ethanol FEs were maintained near51% and 21%, respectively while HER FE increased to 12%. In the case of Cu-Sno03 electrocatalysts, the ethanol FE increased from 13% to 24% as the cell potential increased from 3.6 V to 4.0 V, while CO FE decreased from 30% to 18% over the same potential range. At a cell potential of 4.6 V, the ethanol FE remained near 21% while the CO FE increased to 19% and the HER FE increased to 10%. In the case of Cu2Se, increasing cell potentials from 3.6 V to 4.0 V resulted in decreased acetate production, FEs fell from 35% to 32%, while ethylene FEs increased from 12% to 18%. At a cell potential of 4.6 V, acetate and ethanol FEs decrease to 26% and 9%, respectively while the FE for HER increases to 30%.Results: Stability Measurement

[0090] Durability of MEA cells including Cu-Po.o65, Cu-Sno.os, and Cu2Se electrocatalysts was evaluated in galvanostatic mode (150 mA cm-2) for over 200 h. As shown in FIGs. 7A-7D, the Cu- Po.o65 electrocatalysts showed a steady decline in ethylene Faradaic efficiency (FE) at a rate of - 0.04% per h, dropping from 52% to 43% over 220 h and ethanol FEs decreased from 22% to 18% (-0.01% per h) over 200 h along with concurrent increases in H2FEs from 14% to 19% (+0.03 % per h).

[0091] During the galvanostatic durability experiment, the cell potential increased from 4 to 5 V at a rate of approximately 2 mV h'1. In this case, the decrease in C2 selectivity and increasing HER is likely associated with electrocatalyst deactivation and / or degradation of the AEM. Durability testing of the Cu-Sno.o3 electrocatalyst showed a relatively lower growth rate in cell potential (1 mV IT1), while the ethanol FE decreased from 24% to 18% over 200 h (-0.02 % per h). The Cu2Se electrocatalysts also showed a slow rise in cell potential (1 mV IT1) and a steady decline in acetate FE from 35% to 30% over 250 h (0.02% per h).

[0092] As shown in FIG. 8, post-electrolysis SEM analyses of the electrocatalysts show agglomeration in the case of Cu-P and Cu Sn electrocatalysts; however, the Cu-Se electrocatalyst remained relatively intact. This sort of agglomeration is typically associated with reshaping. XPS analyses of electrocatalysts post-electrolysis (150 mA cm-2for over 200 h) show the relative surface concentrations of Cu° increases in all cases. These ex-situ XPS results provide some relative sense of the level of Cud+species; however, they are limited in that the electrocatalysts were evaluated several hours after electrolysis and are subject to oxidation in air before XPS analysis. Although some reduction in the Cu oxidation state is expected, ex situ investigations limit the interpretation of the post XPS measurements.

[0093] As reported in other operand© time-resolved X-ray absorption spectroscopy and in situ Raman spectroscopy studies, the Cu+species in oxide-derived Cu are mostly reduced to Cu°. Recent works using in situ X-ray absorption spectroscopy (XAS) quantified this time-dependent reduction behavior showing 84% Cu+on the electrocatalyst surface decreases to 77% Cu+after 10 minutes of CO2 reduction at -1.2 V vs RHE. It is important to note that some (~23%) Cu+persisted even after 1 h at the same cathodic potential. However, the nature of this dynamic oxidation of Cu while under cathodic potentials is unusual. The behavior could be related to O2 crossover and chemical oxidation of electrically-isolated Cu particles at the cathode. For example, in a study of the stability of residual oxides in oxide-derived Cu electrocatalyst using18O isotopic labeling on a Cu2O electrocatalyst along with secondary ion mass spectrometry measurements for CO2 electroreduction. When held at -1 .0 V vs RHE in 0.1 M KHCO3 electrolyte for 5 hours, the results showed that18O content was reduced entirely. This indicates a complete reduction of the initial copper oxide layer under the potential required for CO2 electroreduction.

[0094] Further, in-situ X-ray absorption near edge structure (XANES) studies were conducted to investigate the oxidation state of Cu electrocatalyst on carbon black and showed Cu° under CO2RR, however, the fragmented Cu nanoparticles were more easily oxidized at open circuit potentials. Electronegative dopants other than O such as P, Sn, or Se may provide relatively more active and more stable Cu+species.

[0095] From a purely thermodynamic perspective, electrocatalyst stability depends on the reduction potential of oxidized or doped Cu electrocatalysts. In the case of Cu oxides, CU2O is expected to be reduced (E= 0.52 V vs. RHE) as the reduction to the first intermediate, CO (E= - 0.11 V vs. RHE) is over 600mV more negative. However, as shown in the Cu2Se Pourbaix diagram in FIG. 9, Cu2Se reduction to Cu and HSe- occurs at a potential -0.58 V vs RHE. This allows a stable overpotential window for CO2reduction without reduction of Cu5+electrocatalyst. A comparison of the disclosed system to previous electrolyzers for multi-carbon products is shown in Table 1.General Mechanistic Considerations

[0096] Electrochemical reduction of CO2 to C2 products begins with the reduction of CO2 to adsorbed CO. It is generally agreed that C-C coupling occurs by dimerization of two CO adsorbates to form the OCCO intermediate, while Ci products such as methane and methanol proceed from hydrogenation of CO. It is also noted that a minority of studies propose C-Ccoupling occurs through other Ci intermediates such as CHO, COH, CH, and CH2. From this point forward the mechanistic details are poorly understood, with almost every possible pathway from the OCCO intermediate to various C2 products having been proposed.

[0097] The most important aspects of this latter part of the mechanism relate to the branching points that dictate selectivity between the different C2 products. In particular, all C2 products observed in these experiments (ethylene, ethanol, and acetate) require the removal of one oxygen from the OCCO intermediate. Most mechanistic proposals in the literature propose this to occur by reduction of the OCCO intermediate to HOCCO followed by hydroxide elimination to yield a ketene (HXCCO, x = 0,1 ,2) intermediate. Ethanol is proposed to be produced directly from this intermediate without the formation or cleavage of any additional C-0 bonds. In contrast, production of acetate requires formation of an additional C-0 bond (by hydroxide addition either from a surface intermediate or a desorbed ethenone) while production ethylene requires cleavage of the remaining C-0 bond.Nature of the Selectivity Shifts

[0098] To explain the selectivity trends in this study, it is proposed that the degree of partial positive charge on the Cu5+atom influences the pathway taken by a common acetyl intermediate (H3CCO), which has not yet been proposed. Using DFT, it is estimated that the partial charges on Cu in Cu-P, Cu-Snoo3, and Cu2Se are +0.13, +0.27, and + 0.47, respectively. Note these are calculated partial atomic charges rather than formal charges; thus, Cu in Cu2Se has a positive charge that is significantly less than the formal charge of +1 due to the covalency of the Cu-Se bond.

[0099] As shown in FIG. 10, the first step involves the reduction of CO2followed by coupling of two CO species to form the OCCO intermediate. This intermediate undergoes reduction and hydroxide elimination to a common acetyl intermediate (H3CCO) that is equilibrated with hydroxyethylidene (H3CCOH) via a proton-coupled electron transfer step to the oxygen. Since the protonation of oxygen is typically rapid and equilibrated, this is considered as a single intermediate. The acetyl / hydroxyethylidene intermediate can then undergo one of three selectivity determining steps leading to either acetate, ethanol or ethylene. Hydroxide addition to acetyl leads to the elimination of acetate (path A), two-electron reduction of hydroxyethylidene (path B) leads to ethanol, while hydroxide elimination (coupled with a one-electron reduction) leads to ethylidene which then undergoes an additional one-electron reduction to produce ethylene (path C).

[0100] The influence of positively charged Cu on the selectivity can be explained by considering its effect on the hydroxide addition and elimination steps that lead to acetate and ethylene, respectively. Hydroxide addition (path A) becomes more favorable when the carbonyl carbon of the acetyl intermediate is more electrophilic, as is expected to occur when the associated Cu atom is more positively charged. Essentially, a positive charge on Cu destabilizes the partial positive charge on the carbonyl carbon in the acetyl intermediate, making it more susceptible to hydroxide addition. Thus, acetate is favored at surfaces which have the greatest relative positive Cud+or Cu2Se electrocatalysts in this case. In contrast, the transition state for hydroxide elimination (path C) results in a partial positive charge on the carbon atom that is destabilized by a positive charge on the Cu site. Thus, the pathway leading to ethylene (path C) is not favored at Cu2Se and CuSno.o3 electrocatalysts compared to CuPo.oes due to the greater positive charge on Cu in the former two surfaces.

[0101] One alternative pathway (path D) for acetate formation is also considered that has been proposed to occur through a ketene, ethenone (H2CCO). This pathway is also expected to become more favorable on surfaces with a more positively charged on Cu because such surfaces are likely to weakly bind the electron deficient carbonyl carbon of ethenone. Thus, ethenone is more likely to desorb and undergo hydroxide addition to yield acetate.Conclusion

[0102] These results demonstrate the stability and tunability of C2products as a function partial positive site (Cu5+) of doped-Cu electrocatalysts. Experiments using MEA cells with GDEs and alkaline anolytes reveal Cu-Po.oes electrocatalysts yield ethylene as a primary product (FE 43%) while Cu-Sno.03 electrocatalysts favored ethanol (FE 48%) and Cu2Se electrocatalysts yield acetate as a primary product (FE 40%) at high current density (350 mA cm-2). Selective formation of acetate is believed to be associated with more electropositive Cu5+sites that favor OH- addition to acetyl or ethenone intermediates. Conversely, less electropositive Cu sites favor OH- elimination and yield either ethylene or ethanol depending on the relative level of partial positive Cu5+. In addition to influencing selectivity, the electropositive Cu electrocatalysts considered here also show excellent stability for more than 200 h of continuous CO2reduction at a current density of 150 mA cm-2.

[0103] It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.REFERENCES1. A.E. Baber, et al, Journal of the American Chemical Society, 135 (45), 16781-16784 (2013).2. A. Roine, Vol. November, 1 2023. Metso, Pori, 2023.3. A. Saxena, et al, Journal of Materials Chemistry A, 9 (11), 7150-7161 (2021).4. B. Hbnisch, et al, Science, 382 (6675), eadi5177 (2023).5. C. E. Tornow, et al, Journal of the American Chemical Society, 134 (48), 19520-19523 (2012).6. C. M. Gabardo, et al, Joule, 3 (11), 2777-2791 (2019).7. C.-J. 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Claims

CLAIMSWhat is claimed is:

1. A dynamic seal for an electrolyzer, the dynamic seal comprising: a main housing plate comprising a central opening, wherein the central opening extends through the entire thickness of the main housing plate; a flexible sealing ring in contact with the central opening of the main housing plate; and a flow field electrode, wherein at least a portion of the flow field electrode is situated in the central opening of the main housing plate.

2. The dynamic seal of claim 1 , wherein the flexible sealing ring is further in contact with the flow field electrode.

3. The dynamic seal of claim 1 , wherein the flow field electrode is a flow field cathode or a flow field anode.

4. The dynamic seal of claim 1 , further comprising an anti-collapse ring.

5. The dynamic seal of claim 4, wherein the anti-collapse ring comprises poly(1 , 1 ,2,2- tetrafluoroethylene).

6. The dynamic seal of claim 4, wherein the anti-collapse ring is adjacent to and in contact with the flow field electrode.

7. The dynamic seal of claim 4, wherein the anti-collapse ring is further in contact with the flexible sealing ring.

8. The dynamic seal of claim 4, wherein the anti-collapse ring prevents inward collapse of the flexible sealing ring.

9. The dynamic seal of claim 1 , further comprising a membrane retaining clip in contact with the main housing plate.

10. The dynamic seal of claim 9, further comprising a membrane, wherein the membrane is in contact with the flexible sealing ring and the main housing plate, and wherein the membrane is held in place by the membrane retaining clip.

11. The dynamic seal of claim 10, further comprising a gas diffusion electrode in contact with the flow field electrode and the membrane.

12. The dynamic seal of claim 1 , further comprising a push strap in contact with an outer surface of the flow field electrode.

13. The dynamic seal of claim 12, wherein the push strap comprises at least one through hole, wherein a compression force adjustment screw is inserted into the at least one through hole.

14. The dynamic seal of claim 13, wherein the compression force adjustment screw is configured to apply pressure on the flow field electrode, relieve pressure from the flow field electrode, or both, with adjustment of the position of the compression force adjustment screw.

15. The dynamic seal of claim 1, wherein the dynamic seal is stable for at least 225 hours of operation without replacement of any components.

16. The dynamic seal of claim 1 , wherein the dynamic seal does not degrade in the presence of an electrolyte comprising KOH, KHCO3, or any combination thereof.

17. The dynamic seal of claim 1 , wherein the dynamic seal does not leak electrolytes, gases, reactants, or value added products during pressure oscillations.

18. The dynamic seal of claim 1 , wherein the dynamic seal is stable at pressures up to 100 psi.

19. An electrolyzer comprising the dynamic seal according to any one of claims 1-18, wherein the dynamic seal prevents leakage of electrolyte solution, reactants, value-added products, or any combination thereof, from the flow field electrode.

20. The electrolyzer of claim 19, wherein the dynamic seal surrounds a flow field cathode, a flow field anode, or both a flow field cathode and a flow field anode.

21. A method for sealing an electrolyzer, the method comprising applying the dynamic seal of any one of claims 1-18 to at least one flow field electrode in the electrolyzer.

22. The method of claim 21 , wherein the at least one flow field electrode comprises a flow field cathode, a flow field anode, or both a flow field cathode and a flow field anode.

23. The method of claim 21 , wherein the method further comprises adjusting the compression force adjustment screw to compensate for pressure oscillations in the electrolyzer.

24. The method of claim 21 , wherein the method further comprises adjusting the compression force adjustment screw to compensate for flow rate oscillations in the electrolyzer.

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