Electrolysis water device and method for membrane-free hydrogen-oxygen separation

Abstract

The application discloses a membrane-free hydrogen-oxygen separation electrolytic water device and method. The electrolytic water device comprises an electrolytic water base element. The electrolytic water base element comprises a hydrogen production chamber, an oxygen production chamber, a buffer chamber, a power supply and a flow channel. The hydrogen production chamber comprises a hydrogen evolution catalytic electrode and a hydrogen outlet. The oxygen production chamber comprises an oxygen evolution catalytic electrode and an oxygen outlet. The buffer chamber comprises a medium electrode. The power supply supplies power to the hydrogen evolution catalytic electrode, the medium electrode and the oxygen evolution catalytic electrode. The hydrogen production chamber, the oxygen production chamber and the buffer chamber are connected through a controllable flow channel. The application designs a simple structure of a step-by-step electrolytic water device, and realizes large-scale and continuous step-by-step electrolytic water through a series connection method, thereby solving the problems of complex mechanical maintenance, high operation cost and inability to realize large-scale and continuous hydrogen production in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrolytic water hydrogen production, in particular to a membrane-free water electrolysis device and method for hydrogen-oxygen separation. BACKGROUND

[0002] Hydrogen energy has the advantages of being clean, efficient and renewable, and is expected to replace fossil fuels as the main energy form in the green era. Using renewable energy such as wind, light and nuclear power to further electrolyze water to produce hydrogen can achieve "zero emissions" in the whole process, which is an effective means to achieve the "double carbon" goal. Traditional water electrolysis technology usually requires the use of expensive ion exchange membranes to prevent gas mixing, which increases the system cost and electrolysis resistance. In addition, the pressure difference between H2 and O2 (theoretical H2 / O2 = 2:1) during electrolysis reduces the service life of the ion exchange membrane, exacerbating the decline (or destruction) of the membrane. Most importantly, the production and mixing of H2 and O2 at the same time and in the same space increase the safety problems in large-scale water electrolysis applications.

[0003] By using a redox mediator, the water decomposition reaction can be divided into two half-reactions, thereby realizing the production of hydrogen and oxygen at different times or (and) spaces. This electrolysis method has many advantages, such as reducing the gas separation step and reducing the risk of gas mixing. This technology is currently still in the laboratory stage and is a newly developed water electrolysis hydrogen production technology.

[0004] However, in actual application, the production of pure hydrogen and oxygen by the step-by-step electrolysis device requires a large amount of gas purging of the entire chamber after the production of hydrogen or oxygen in each step to remove the mixed gas in the previous step, which undoubtedly increases the operating cost. At the same time, the continuous operation of the reported step-by-step water electrolysis device is still in the experimental stage. SUMMARY

[0005] To solve the problems existing in the prior art, the present application provides a membrane-free water electrolysis device and method for hydrogen-oxygen separation. The present application designs a simple structure of step-by-step water electrolysis device, which only needs a small amount of gas purging of the buffer chamber during operation, and realizes a large-scale, membrane-free water electrolysis device for hydrogen-oxygen separation by a series connection method, solving the problems of complex mechanical maintenance, high operating cost and inability to produce hydrogen continuously in large scale in the existing step-by-step water electrolysis technology.

[0006] In order to achieve the above purpose, the present application provides the following technical scheme.

[0007] In a first aspect, the present application provides a membrane-free water electrolysis device for hydrogen-oxygen separation, comprising: a water electrolysis unit;

[0008] The water electrolysis unit comprises a hydrogen production chamber, an oxygen production chamber, a buffer chamber, a power supply and a flow channel.

[0009] The hydrogen production chamber comprises a hydrogen evolution catalytic electrode and a hydrogen outlet;

[0010] The oxygen production chamber comprises an oxygen evolution catalytic electrode and an oxygen outlet;

[0011] The buffer chamber comprises a mediator electrode,

[0012] The power supply is connected to the hydrogen evolution catalytic electrode, the mediator electrode and the oxygen evolution catalytic electrode.

[0013] The hydrogen production chamber, the oxygen production chamber and the buffer chamber are connected through controllable flow channels.

[0014] As a further improvement, the hydrogen production chamber, the oxygen production chamber and the buffer chamber are provided with a partition, and the flow channels are arranged on the partition. All the chambers are sealed.

[0015] As a further improvement, the flow channels are controlled by a piston structure, and the electrolyte in each chamber is connected to form a loop by controlling the flow channel switch.

[0016] As a further improvement, the volume of the buffer chamber is much smaller than that of the hydrogen production chamber and the oxygen production chamber.

[0017] As a further improvement, the hydrogen evolution catalytic electrode is connected to the negative pole of the first power supply, the oxygen evolution catalytic electrode is connected to the positive pole of the second power supply, and the mediator electrode is located between the hydrogen evolution catalytic electrode and the oxygen evolution catalytic electrode, with the two ends connected to the positive pole of the first power supply and the negative pole of the second power supply, respectively, to form a loop with the hydrogen evolution catalytic electrode and the oxygen evolution catalytic electrode.

[0018] As a further improvement, the buffer chamber is provided with an argon inlet and an argon outlet.

[0019] As a further improvement, the mediator electrode is selected from ion balance type mediator electrodes.

[0020] The ion balance mediator electrode is selected from solid materials that store and release H + through redox reactions, including at least one of inorganic solid mediator materials NiOOH, MoO3, MnOOH and organic solid mediator materials PTO, PANI.

[0021] As a further improvement, n electrolytic water base units are connected in series, and adjacent electrolytic water base units are connected through a buffer chamber, where n≥2.

[0022] In a second aspect, the present application provides an electrolytic water method for a membrane-free hydrogen-oxygen separation electrolytic water device, comprising the following steps:

[0023] The flow channels between the hydrogen production chamber and the buffer chamber, and between the oxygen production chamber and the buffer chamber are closed, and the buffer chamber is purged with gas to remove hydrogen and oxygen; the hydrogen evolution catalytic electrode is connected to the medium electrode, and the flow channel switch between the hydrogen production chamber and the buffer chamber is opened to produce hydrogen;

[0024] Close the flow channels between the hydrogen production chamber and the buffer chamber, and between the oxygen production chamber and the buffer chamber, purge the buffer chamber with gas to remove hydrogen and oxygen, connect the oxygen evolution catalytic electrode to the medium electrode, and open the flow channel switch between the oxygen production chamber and the buffer chamber to produce oxygen.

[0025] Optionally, when multiple water electrolysis units are connected in series, both ends of the hydrogen production chamber and the oxygen production chamber are buffer chambers, and the hydrogen production chamber is connected to the buffer chamber at one end to produce hydrogen while the buffer chamber at the other end is connected to the oxygen production chamber to produce oxygen;

[0026] After the above steps are completed, the hydrogen production chamber is connected to the buffer chamber at the other end to produce hydrogen. At this time, the hydrogen production chamber in the device can realize continuous step-by-step electrolysis of water to produce hydrogen; the oxygen production chamber is connected to the buffer chamber at one end to produce oxygen, while the buffer chamber at the other end is connected to the hydrogen production chamber to produce hydrogen. After the above steps are completed, the oxygen production chamber is connected to the buffer chamber at the other end to produce oxygen; this cycle is repeated, and the oxygen production chamber realizes continuous step-by-step electrolysis of water to produce oxygen.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention provides a membraneless hydrogen and oxygen separation electrolysis device. On the basis of the traditional step-by-step water electrolysis device, a buffer chamber is added to separate the hydrogen production chamber and the oxygen production chamber. The buffer chamber is connected to the hydrogen production chamber and the oxygen production chamber through a flow channel to form a loop. Compared with the traditional step-by-step water electrolysis device, the present invention only needs to purge the buffer chamber with argon gas to solve the problem of hydrogen and oxygen mixing in the device electrolyte, greatly reducing the operating cost of the device. The present invention uses the oxidation reaction H + Compared with the traditional medium electrode, the ion-balanced medium electrode can store and release H generated during the step-by-step electrolysis of water to produce oxygen. + , H is released during the step-by-step electrolysis of water to produce hydrogen + Compared to conventional step-by-step water electrolysis devices, the present invention solves the problem of electrolyte ion balance. The present invention designs a simple step-by-step water electrolysis unit and, by connecting these units in series, achieves large-scale, continuous step-by-step water electrolysis for hydrogen production. Compared to conventional step-by-step water electrolysis devices, the present invention solves the problems of complex mechanical maintenance and the inability to produce hydrogen on a large scale through continuous step-by-step water electrolysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced, and the shapes and proportional sizes of the components in the drawings are only schematic, which are used to help the understanding of the present application, and are not specifically limited to the shapes and proportional sizes of the components in the present application. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0030] Figure 1 A schematic diagram of a membrane-free hydrogen-oxygen separation electrolytic water device of the present application;

[0031] In the figure, 1. hydrogen outlet, 2. hydrogen evolution catalytic electrode, 3. separator, 4. argon inlet, 5. medium electrode, 6. flow channel (S), 7. oxygen evolution catalytic electrode, 8. oxygen outlet, 9. oxygen production chamber (B), 10. circuit switch (K), 11. power supply (V), 12. argon outlet, 13. buffer chamber (M), 14. hydrogen production chamber (A);

[0032] Figure 2 A one-stage working schematic diagram of a membrane-free hydrogen-oxygen separation electrolytic water device in Example 1;

[0033] Figure 3 A two-stage working schematic diagram of a membrane-free hydrogen-oxygen separation electrolytic water device in Example 1;

[0034] Figure 4 A gas chromatogram of the gas produced by the oxygen production chamber in Example 1;

[0035] Figure 5 A gas chromatogram of the gas produced by the hydrogen production chamber in Example 1;

[0036] Figure 6 A PH change diagram of the electrolyte in the oxygen production chamber and the hydrogen production chamber in Example 1 after 100 cycles of electrolysis;

[0037] Figure 7 A one-stage working schematic diagram of a membrane-free hydrogen-oxygen separation electrolytic water device in Example 2;

[0038] Figure 8 A two-stage working schematic diagram of a membrane-free hydrogen-oxygen separation electrolytic water device in Example 2. DETAILED DESCRIPTION

[0039] In order to make the technical scheme in the present application better understood by the person skilled in the art, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative effort should fall within the scope of the present application.

[0040] In the description of the present application, the codes "A n ", "B n ", "M n ", "V n ", "K n ", "S n " after the device components are only for the purpose of description and distinguishing similar objects, facilitating the description of the present application and simplifying the description, and are not intended to refer to chemical elements or other professional terms. In addition, in the description of the present application, the terms "first", "second", etc. are only for the purpose of description and distinguishing similar objects, and there is no sequence or relative importance between them. In addition, in the description of the present application, the meaning of "multiple" is two or more, unless otherwise specified and limited. In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "connected", "connected" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements.

[0041] Unless otherwise defined, 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 application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0042] As Figure 1 shown, the first object of the present application is to provide a membrane-free hydrogen-oxygen separation electrolytic water device, comprising: a hydrogen production chamber 14, an oxygen production chamber 9, a buffer chamber 13, a power supply 11, a circuit switch 10 and a flow channel 6;

[0043] The hydrogen production chamber 14 comprises a hydrogen evolution catalytic electrode 2 and a hydrogen gas outlet 1;

[0044] The oxygen production chamber 9 comprises an oxygen evolution catalytic electrode 7 and an oxygen gas outlet 8;

[0045] The buffer chamber 13 comprises the mediator electrode 5, the argon gas inlet 4 and the argon gas outlet 13, and the volume of the buffer chamber 13 is far less than that of the hydrogen production chamber 14 and the oxygen production chamber 9;

[0046] The hydrogen production chamber 14, the oxygen production chamber 9 and the buffer chamber 13 are connected through the flow channel 6, and the flow channel 6 is provided with corresponding switches for connecting electrolyte in different chambers. No diaphragm is needed between different chambers, and the electrolyte is shared.

[0047] The switch of the flow channel 6 of the device adopts a piston structure for control. The middle flow channel 6 is below the electrolyte liquid level of each chamber. The electrolyte in each chamber is connected to form a loop by controlling the switch of the flow channel 6. The piston is rotated out of the flow channel 6 to open it, and the electrolyte in the chambers at both ends of the flow channel 6 is communicated. The piston is rotated into the flow channel 6 to close it, and the electrolyte in the chambers at both ends of the flow channel 6 is isolated from each other. The opening and closing of the switch can be controlled through an automatic program.

[0048] The power supply supplies power to the hydrogen production chamber, the oxygen production chamber and the buffer chamber, mainly providing the required power for step-by-step electrolysis of water. The current loop between the chambers is controlled by a circuit switch. The hydrogen evolution catalytic electrode 2 is connected to the negative pole of the power supply 11, the oxygen evolution catalytic electrode 7 is connected to the positive pole of the power supply 11, the mediator electrode 5 is located between the hydrogen evolution catalytic electrode 2 and the oxygen evolution catalytic electrode 7, and the two ends are connected to the positive pole and the negative pole of the power supply 11 respectively, and form a loop with the hydrogen evolution catalytic electrode 2 and the oxygen evolution catalytic electrode 7 respectively.

[0049] The mediator electrode 5 is selected from an ion balance type mediator electrode, i.e. in the oxygen production process, the mediator electrode 5 can store H + in the oxygen production process, the mediator electrode 5 can release the stored H + for hydrogen production, and the transportation of H + by the ion balance type mediator electrode can ensure the ion balance of the electrolyte in the entire device.

[0050] As an optional solution, the ion balance mediator electrode is selected from solid materials that store and release H + through redox reaction, including at least one of inorganic solid mediator materials NiOOH, MoO3 and MnOOH, and organic solid mediator materials PTO and PANI.

[0051] The device realizes the production of hydrogen and oxygen at different times and in different spaces through the design of the buffer chamber and the flow channel, and solves the problem of mixing of hydrogen and oxygen in the electrolyte. The device uses an ion balance type mediator electrode to replace the traditional mediator electrode, realizes the transfer of H+ between the hydrogen production chamber and the oxygen production chamber, and solves the problem of ion balance of the electrolyte.

[0052] The principle of the electrolytic water device of the present application is: hydrogen production chamber, oxygen production chamber, buffer chamber, power supply, circuit switch and flow channel; the hydrogen production chamber comprises a hydrogen evolution catalytic electrode and a hydrogen outlet; the oxygen production chamber comprises an oxygen evolution catalytic electrode and an oxygen outlet; the buffer chamber comprises a mediator electrode, an argon inlet and an argon outlet, and the volume of the buffer chamber is much smaller than that of the hydrogen production chamber and the oxygen production chamber; a partition is arranged between the hydrogen production chamber, the oxygen production chamber and the buffer chamber, and is connected through the flow channel, and a corresponding switch is arranged in the flow channel for connecting the electrolyte of different chambers, and no diaphragm is needed between different chambers, and the electrolyte is shared; the hydrogen evolution catalytic electrode is connected to the negative electrode of the power supply, the oxygen evolution catalytic electrode is connected to the positive electrode of the power supply, the mediator electrode is located between the hydrogen evolution catalytic electrode and the oxygen evolution catalytic electrode, and the two ends are respectively connected to the positive electrode and the negative electrode of the power supply, and form a loop with the hydrogen evolution catalytic electrode and the oxygen evolution catalytic electrode; the mediator electrode is selected from ion balance type mediator electrode, i.e. in the oxygen production process, the mediator electrode can store H + In the hydrogen production process, the mediator electrode can release the H + stored in the oxygen production process for hydrogen production; the present application designs a simple structure of step-by-step electrolytic water device, and realizes large-scale and continuous step-by-step electrolytic water through the method of series connection, solves the problems of complex mechanical maintenance, high operation cost and inability to produce hydrogen in large scale and continuously in the existing step-by-step electrolytic water technology.

[0053] The second object of the present application is to provide a membrane-free hydrogen-oxygen separation electrolytic water device capable of continuous electrolysis: comprising: n electrolytic water units; n said electrolytic water units are sequentially connected in series, and can be designed in series in the combination of hydrogen production chamber 14, buffer chamber 13, oxygen production chamber 9 and buffer chamber 13, to achieve a continuous step-by-step electrolysis process.

[0054] As shown in Figure 2 and Figure 3 , the membrane-free hydrogen-oxygen separation electrolytic water device "hydrogen production chamber 14, buffer chamber 13, oxygen production chamber 9" is an electrolytic water unit, and the two electrolytic water units are separated by the buffer chamber 13, and the two ends of the buffer chamber 13 are the hydrogen production chamber 14 and the oxygen production chamber 9.

[0055] The electrolytic water method based on the above-mentioned membrane-free hydrogen-oxygen separation electrolytic water device comprises the following steps:

[0056] 1) Hydrogen production step:

[0057] Close the flow channel between the hydrogen production chamber 14 and the buffer chamber 13, the oxygen production chamber 9 and the buffer chamber 13, and perform gas purging on the buffer chamber 13 to ensure that there is no hydrogen and oxygen in the buffer chamber 13. Thereafter, the hydrogen evolution catalytic electrode 2 is connected to the mediator electrode 5, and the flow channel 6 switch between the hydrogen production chamber 14 and the buffer chamber 13 is opened to perform the hydrogen production step;

[0058] 2) Oxygen production step:

[0059] The flow passages 6 between the hydrogen production chamber 14 and the buffer chamber 13, and between the oxygen production chamber 9 and the buffer chamber 13, are closed, and the buffer chamber 13 is purged with gas to ensure that no hydrogen or oxygen is present in the buffer chamber 13. Thereafter, the oxygen evolution catalytic electrode 7 is connected to the medium electrode 5, and the flow passage 6 between the oxygen production chamber 9 and the buffer chamber 13 is opened to proceed with the oxygen production step;

[0060] 3) Continuous step-by-step electrolysis steps:

[0061] When multiple water electrolysis units are connected in series, both ends of the hydrogen production chamber 14 and the oxygen production chamber 9 are buffer chambers 13. The hydrogen production chamber 14 is connected to the buffer chamber 13 at one end to perform the hydrogen production step while the buffer chamber 13 at the other end is connected to the oxygen production chamber 9 to perform the oxygen production step. After the above steps are completed, the hydrogen production chamber 14 is connected to the buffer chamber 13 at the other end to perform the hydrogen production step. At this time, the hydrogen production chamber 14 in the device can achieve continuous step-by-step water electrolysis to produce hydrogen. Similarly, the oxygen production chamber is connected to the buffer chamber 13 at one end to perform the oxygen production step while the buffer chamber 13 at the other end is connected to the hydrogen production chamber 13 to perform the hydrogen production step. After the above steps are completed, the oxygen production chamber 9 is connected to the buffer chamber 13 at the other end to perform the oxygen production step. At this time, the oxygen production chamber 9 in the device can achieve continuous step-by-step water electrolysis to produce oxygen.

[0062] During the water electrolysis method, only the buffer chamber 13 needs to be purged to remove the hydrogen and oxygen remaining in the hydrogen and oxygen production steps, without purging the entire device.

[0063] This method connects the step-by-step water electrolysis units in series, achieving continuous step-by-step water electrolysis in the hydrogen production chamber and the oxygen production chamber, solving the problem that traditional step-by-step water electrolysis devices cannot produce hydrogen through large-scale and continuous step-by-step water electrolysis.

[0064] The following will further describe a membraneless hydrogen and oxygen separation electrolysis device and method. This embodiment is carried out on the premise of the technical solution of the present invention, and a detailed implementation method and specific operation process are given. However, the protection scope of the present invention is not limited to the following embodiments. Those skilled in the art can modify and polish it without changing the spirit and content of the present invention.

[0065] Example 1

[0066] In this embodiment, the electrolyte used by all chambers is 0.5M H2SO4 solution, and the hydrogen evolution catalytic electrode is a commercial platinum mesh electrode (2x2.5 cm 2 ), the oxygen evolution catalytic electrode uses commercial IrO2 / RuO2 electrode, and the ion balance medium electrode uses MoO3 material.

[0067] wherein the MoO3 material is prepared as follows: 3.62 g of sodium molybdate tetrahydrate and 5.25 g of thiourea are first dissolved in 50 mL of deionized water at room temperature to form a homogeneous solution by vigorous stirring. The solution is then transferred to a 100 ml stainless steel autoclave lined with polytetrafluoroethylene, heated at 240°C for 24 h to obtain black molybdenum disulfide nanosheets. After natural cooling to room temperature, the molybdenum disulfide nanosheets are repeatedly washed with deionized water and ethanol, and collected by centrifugation at a speed of 8000 revolutions per minute and dried at 80°C overnight. The collected dried MoO3 nanosheets are heated in air to 500°C for 40 minutes to obtain white MoO3 powder. The obtained MoO3 powder is mixed with conductive carbon black and polytetrafluoroethylene binder in a ratio of 8:1:1 to form a paste-like substance, which is then rolled into a film by a roll press machine with a density of 100 mg / cm 2 , and cut into 2x2.5 cm 2 rectangular blocks to be pressed on a metal titanium mesh at a pressure of 10 MPa for 1 min to make a MoO3 mediator electrode for further testing.

[0068] As shown in Figure 2 , the first stage of work is performed by the continuous step-by-step electrolysis water device consisting of two electrolysis water base elements in series: closing the circuit switch K2 opens the flow channel S2, and a direct current power source is used as an external power source, at this time the buffer chamber M1 and the oxygen production chamber B1 constitute a loop, the MoO3 mediator electrode is connected to the negative electrode of the power source V2, and the oxygen evolution catalytic electrode is connected to the positive electrode of the power source V2. The oxygen evolution catalytic electrode in the oxygen production chamber B1 loses electrons and undergoes an oxidation reaction, and water is electrolyzed to generate O2 and H + ; the MoO3 mediator electrode in the buffer chamber M1 gains electrons and undergoes a reduction reaction, and MoO3 stores H + in the electrolyte; due to the concentration difference of H + between the oxygen production chamber and the buffer chamber, H + diffuses from the oxygen production chamber B1 to the buffer chamber M1 through the flow channel S2.

[0069] Closing the circuit switch K4 opens the flow channel S4, and a direct current power source is used as an external power source, at this time the buffer chamber M2 and the hydrogen production chamber A2 constitute a loop, the MoO3 mediator electrode is connected to the positive electrode of the power source V4, and the oxygen evolution catalytic electrode is connected to the negative electrode of the power source V4. The oxygen evolution hydrogen catalytic electrode in the hydrogen production chamber A2 gains electrons and undergoes a reduction reaction, and catalyzes H + to generate H2; the MoO3 mediator electrode in the buffer chamber M2 loses electrons and undergoes an oxidation reaction, and MoO3 releases H + stored in itself; due to the concentration difference of H + between the hydrogen production chamber and the buffer chamber, H + diffuses from the buffer M2 to the hydrogen production chamber A2 through the flow channel S4.

[0070] Close the circuit switch K6 to open the flow channel S6, and use the DC power supply as the external power supply. At this time, the buffer chamber M3 and the oxygen production chamber B2 form a loop, the MoO3 medium electrode is connected to the negative pole of the power supply V6, and the oxygen evolution catalytic electrode is connected to the positive pole of the power supply V6. The oxygen evolution catalytic electrode in the oxygen production chamber B2 loses electrons and undergoes an oxidation reaction, electrolyzing water to produce O2 and H + The MoO3 medium electrode in the buffer chamber M3 receives electrons to undergo a reduction reaction, and MoO3 stores H in the electrolyte. + ; Due to the presence of H between the oxygen producing chamber and the buffer chamber + Concentration difference, H + Diffusion from the oxygen producing chamber B2 into the buffer chamber M3 through the flow channel S6.

[0071] like Figure 3 As shown, the membraneless hydrogen and oxygen separation water electrolysis device composed of two water electrolysis units connected in series performs the second stage of operation: the circuit switch K1 is closed to open the flow channel S1, and a DC power supply is used as an external power supply. At this time, the buffer chamber M1 and the hydrogen production chamber A1 form a loop, the MoO3 medium electrode is connected to the positive electrode of the power supply V1, and the hydrogen evolution catalytic electrode is connected to the negative electrode of the power supply V1. The hydrogen evolution catalytic electrode in the hydrogen production chamber A1 receives electrons to undergo a reduction reaction, reducing the H in the electrolyte. + Generate H2; the MoO3 medium electrode in the buffer chamber M1 loses electrons and undergoes oxidation reaction, and MoO3 releases the H stored in itself + ; Due to the presence of H between the hydrogen production chamber and the buffer chamber + Concentration difference, H + Diffusion from the buffer chamber M1 through the flow channel S1 into the hydrogen production chamber A1.

[0072] Close the circuit switch K3 to open the flow channel S3, and use the DC power supply as the external power supply. At this time, the buffer chamber M2 and the oxygen production chamber B1 form a loop, the MoO3 medium electrode is connected to the negative pole of the power supply V3, and the oxygen evolution catalytic electrode is connected to the positive pole of the power supply V3. The oxygen evolution catalytic electrode in the oxygen production chamber B1 loses electrons and undergoes an oxidation reaction, electrolyzing water to produce O2 and H + The MoO3 medium electrode in the buffer chamber M2 receives electrons to undergo a reduction reaction, and MoO3 stores H in the electrolyte. + ; Due to the presence of H between the oxygen producing chamber and the buffer chamber + Concentration difference, H + Diffusion from the oxygen-generating chamber B1 through the flow channel S6 into the buffer chamber M2.

[0073] Close the circuit switch K5 to open the flow channel S5, and use the DC power supply as the external power supply. At this time, the buffer chamber M3 and the hydrogen production chamber A2 form a loop, the MoO3 medium electrode is connected to the positive pole of the power supply V5, and the hydrogen evolution catalytic electrode is connected to the negative pole of the power supply V5. The hydrogen evolution catalytic electrode in the hydrogen production chamber A2 receives electrons to undergo a reduction reaction, reducing the H in the electrolyte. +Generate H2; the MoO3 medium electrode in the buffer chamber M3 loses electrons and undergoes oxidation reaction, and MoO3 releases the H stored in itself + ; Due to the presence of H between the hydrogen production chamber and the buffer chamber + Concentration difference, H + Diffusion from the buffer chamber M3 through the flow channel S5 into the hydrogen production chamber A2.

[0074] The continuous step-by-step water electrolysis device, which consists of two water electrolysis units connected in series, operates cyclically in the first and second stages. During the cycle, the oxygen production chamber B1 and the hydrogen production chamber A2 can achieve continuous step-by-step water electrolysis. The gas collected by the oxygen production chamber is passed into a gas chromatograph, and the test results are as follows: Figure 4 As shown, the collected gas is pure oxygen; the gas collected in the hydrogen production chamber is passed into the gas chromatograph, and the test results are as follows Figure 5 As shown in the figure, the gas collected is pure hydrogen. The above membraneless hydrogen and oxygen separation electrolysis device was cycled for 100 times. After each cycle, the pH values ​​of the electrolyte in the hydrogen production chamber and the oxygen production chamber were recorded. The pH change curve is shown in the figure below. Figure 6 As shown, the above device achieves electrolyte ion balance in the hydrogen production chamber and the oxygen production chamber during cyclic operation.

[0075] Example 2

[0076] In this embodiment, the electrolyte used by all chambers is 0.5M H2SO4 solution, and the hydrogen evolution catalytic electrode is a commercial platinum mesh electrode (2x2.5 cm 2 ), the oxygen evolution catalytic electrode uses commercial IrO2 / RuO2 electrode, and the ion balance medium electrode uses MoO3 material.

[0077] The preparation method of MoO3 material is as follows: first, 3.62g of sodium molybdate tetrahydrate and 5.25g of thiourea are dissolved in 50mL of deionized water at room temperature, and a uniform solution is formed by vigorous stirring. The solution is then transferred to a 100ml stainless steel autoclave lined with polytetrafluoroethylene and heated at 240℃ for 24h to obtain black molybdenum disulfide nanosheets. After naturally cooling to room temperature, the molybdenum disulfide nanosheets are repeatedly washed with deionized water and ethanol, collected by centrifugation at 8000 rpm and dried at 80℃ overnight. The collected dry MoO3 nanosheets are heated to 500℃ in air and oxidized for 40 minutes to obtain white MoO3 powder. The obtained MoO3 powder is mixed with conductive carbon black and polytetrafluoroethylene binder in a ratio of 8:1:1 to form a paste, and then the paste is rolled into a film using a roller press with a density of 100mg / cm 2 , and cut into 2x2.5cm 2The rectangular block was pressed onto a metal titanium mesh at a pressure of 10 MPa for 1 min to make a MoO3 medium electrode for further testing.

[0078] like Figure 7 As shown, the continuous step-by-step water electrolysis device composed of n water electrolysis units connected in series performs the first stage of work: closing the circuit switch K 2N (N=1, 2, 3..., 2n-1) Open flow channel S 2N (N=1,2,3……,2n-1), using DC power supply V 2N (N=1, 2, 3..., 2n-1) acts as an external power source, at this time the buffer chamber M N (N=1, 2, 3..., 2n-1) and oxygen production chamber B respectively n (n=1, 2, 3..., n) and hydrogen production chamber A n (n=2, 3..., n) form a circuit. When the buffer chamber is connected to the oxygen production chamber to form a circuit, the oxygen evolution catalytic electrode is connected to the positive pole of the power supply, and the MoO3 medium electrode is connected to the negative pole of the power supply. The oxygen evolution catalytic electrode in the oxygen production chamber loses electrons and undergoes an oxidation reaction, electrolyzing water to produce O2 and H + The MoO3 medium electrode in the buffer chamber obtains electrons to undergo a reduction reaction, and MoO3 stores H in the electrolyte. + ; Due to the presence of H between the oxygen producing chamber and the buffer chamber + Concentration difference, H + The oxygen diffuses from the oxygen production chamber through the flow channel to the buffer chamber. When the buffer chamber is connected to the hydrogen production chamber to form a circuit, the MoO3 medium electrode is connected to the positive pole of the power supply, and the hydrogen evolution catalytic electrode is connected to the negative pole of the power supply. The hydrogen evolution catalytic electrode in the hydrogen production chamber receives electrons to undergo a reduction reaction, reducing the H in the electrolyte. + Generate H2; the MoO3 medium electrode in the buffer chamber loses electrons and undergoes oxidation reaction, and MoO3 releases the H stored in itself + ; Due to the presence of H between the hydrogen production chamber and the buffer chamber + Concentration difference, H + Diffusion from the buffer chamber through the flow channel into the hydrogen production chamber.

[0079] like Figure 8 As shown, the continuous step-by-step water electrolysis device composed of n water electrolysis units connected in series performs the first stage of work: closing the circuit switch K 2N-1 (N=1, 2, 3..., 2n-1) Open flow channel S 2N-1 (N=1,2,3……,2n-1), using DC power supply V 2N-1 (N=1, 2, 3..., 2n-1) acts as an external power source, at this time the buffer chamber M N-1 (N=1, 2, 3..., 2n-1) and oxygen production chamber B respectively n(n=1, 2, 3..., n-1) and hydrogen production chamber A n (n=1,2,3……,n) form a circuit. When the buffer chamber is connected to the oxygen production chamber to form a circuit, the oxygen evolution catalytic electrode is connected to the positive pole of the power supply, and the MoO3 medium electrode is connected to the negative pole of the power supply. The oxygen evolution catalytic electrode in the oxygen production chamber loses electrons and undergoes an oxidation reaction, electrolyzing water to produce O2 and H + The MoO3 medium electrode in the buffer chamber obtains electrons to undergo a reduction reaction, and MoO3 stores H in the electrolyte. + ; Due to the presence of H between the oxygen producing chamber and the buffer chamber + Concentration difference, H + The oxygen diffuses from the oxygen production chamber through the flow channel to the buffer chamber. When the buffer chamber is connected to the hydrogen production chamber to form a circuit, the MoO3 medium electrode is connected to the positive pole of the power supply, and the hydrogen evolution catalytic electrode is connected to the negative pole of the power supply. The hydrogen evolution catalytic electrode in the hydrogen production chamber receives electrons to undergo a reduction reaction, reducing the H in the electrolyte. + Generate H2; the MoO3 medium electrode in the buffer chamber loses electrons and undergoes oxidation reaction, and MoO3 releases the H stored in itself + ; Due to the presence of H between the hydrogen production chamber and the buffer chamber + Concentration difference, H + Diffusion from the buffer chamber through the flow channel into the hydrogen production chamber.

[0080] The continuous step-by-step water electrolysis device composed of n water electrolysis units connected in series operates cyclically in the first and second stages. During the cycle, the oxygen production chamber B n (n=1, 2, 3..., n-1) and hydrogen production chamber A n (n = 2, 3 ..., n) can achieve continuous step-by-step water electrolysis. The value of n can be determined according to actual implementation conditions. The continuous step-by-step water electrolysis device with n water electrolysis units connected in series has a simple structure, reduces the cost of the device and achieves large-scale continuous step-by-step water electrolysis.

[0081] It should be understood that the above description is for illustrative purposes only and is not intended to be limiting. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the preceding claims and the full scope of equivalents to which such claims are entitled. For the purpose of completeness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein from the preceding claims is not a disclaimer of such subject matter, nor should it be considered that the applicants did not consider such subject matter to be part of the disclosed inventive subject matter.

Claims

1. An electrolytic water device for membraneless hydrogen-oxygen separation, characterized by It comprises: an electrolysis water base unit; the electrolysis water base unit comprises a hydrogen production chamber (14), an oxygen production chamber (9), a buffer chamber (13), a power supply (11) and a flow channel (6); the hydrogen production chamber (14) comprises a hydrogen evolution catalytic electrode (2) and a hydrogen outlet (1); the oxygen production chamber (9) comprises an oxygen evolution catalytic electrode (7) and an oxygen outlet (8); the buffer chamber (13) comprises a mediator electrode (5), wherein the power supply (11) supplies power to the hydrogen evolution catalytic electrode (2), the mediator electrode (5) and the oxygen evolution catalytic electrode (7); the hydrogen production chamber (14), the oxygen production chamber (9) and the buffer chamber (13) are connected through a controllable flow channel (6); the volume of the buffer chamber (13) is much smaller than the volume of the hydrogen production chamber (14) and the oxygen production chamber (9); the mediator electrode (5) is selected from ion balance type mediator electrodes; The ion balance medium electrode is selected from at least one of solid materials whose redox reaction is storage and release of H + including inorganic solid medium materials NiOOH, MoO3, MnOOH and organic solid medium materials PTO, PANI. the buffer chamber (13) is provided with an argon inlet (4) and an argon outlet (12).

2. The electrolysis water device without a membrane for separating hydrogen and oxygen according to claim 1, characterized by, A baffle (3) is arranged between the hydrogen production chamber (14), the oxygen production chamber (9) and the buffer chamber (13), and the flow channel (6) is arranged on the baffle (3), and all the chambers are sealed.

3. The electrolysis water device without a membrane for separating hydrogen and oxygen according to claim 1, characterized by, The flow channel (6) adopts a piston structure for control, and the electrolyte in each chamber is connected to form a loop by controlling the opening and closing of the flow channel (6).

4. The electrolysis water device without a membrane for separating hydrogen and oxygen according to claim 1, characterized by The hydrogen evolution catalytic electrode (2) is connected to the negative electrode of a first power supply, the oxygen evolution catalytic electrode (7) is connected to the positive electrode of a second power supply, the mediator electrode (5) is located between the hydrogen evolution catalytic electrode (2) and the oxygen evolution catalytic electrode (7), and the two ends are respectively connected to the positive electrode of the first power supply and the negative electrode of the second power supply, and respectively form a loop with the hydrogen evolution catalytic electrode (2) and the oxygen evolution catalytic electrode (7).

5. The electrolysis water device without membrane for separating hydrogen and oxygen according to any one of claims 1 to 4, characterized in that, n electrolysis water base units are connected in series, and adjacent electrolysis water base units are connected through a buffer chamber (13), and n≥2.

6. The method of claim 1 to 5, wherein the method of electrolysis of water of the device for electrolysis of water without membranes for separation of hydrogen and oxygen is characterized by that, It comprises the following steps: close the flow channels between the hydrogen production chamber (14) and the buffer chamber (13), and between the oxygen production chamber (9) and the buffer chamber (13), and perform gas purging on the buffer chamber (13) to remove hydrogen and oxygen; connect the hydrogen evolution catalytic electrode (2) and the mediator electrode (5), and open the flow channel (6) between the hydrogen production chamber (14) and the buffer chamber (13) to produce hydrogen; close the flow channels between the hydrogen production chamber (14) and the buffer chamber (13), and between the oxygen production chamber (9) and the buffer chamber (13), and perform gas purging on the buffer chamber (13) to remove hydrogen and oxygen; connect the oxygen evolution catalytic electrode (7) and the mediator electrode (5), and open the flow channel (6) between the oxygen production chamber (9) and the buffer chamber (13) to produce oxygen.

7. The electrolysis water method of the membrane-free hydrogen-oxygen separation electrolysis water device according to claim 6, wherein when a plurality of electrolysis water base units are connected in series, the hydrogen production chamber (14) and the oxygen production chamber (9) are both buffer chambers (13), the hydrogen production chamber (14) is connected to the buffer chamber (13) at one end to produce hydrogen, and the buffer chamber (13) at the other end is connected to the oxygen production chamber (9) to produce oxygen. ​ After the above steps, the hydrogen production chamber (14) is connected with the buffer chamber (13) at the other end to produce hydrogen, at which time the hydrogen production chamber (14) in the device can realize continuous step-by-step electrolysis of water to produce hydrogen; the oxygen production chamber (9) is connected with the buffer chamber (13) at one end to produce oxygen, at the same time, the buffer chamber (13) at the other end is connected with the hydrogen production chamber (14) to produce hydrogen, after the above steps, the oxygen production chamber (9) is connected with the buffer chamber (13) at the other end to produce oxygen; such a cycle, the oxygen production chamber (9) realizes continuous step-by-step electrolysis of water to produce oxygen.

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