CN114045509B

CN114045509B - Seawater electrolysis device with sodium ion conduction and application thereof

Info

Publication number: CN114045509B
Application number: CN202111423333.1A
Authority: CN
Inventors: 王谭源; 石灏; 李箐
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2021-11-26
Filing date: 2021-11-26
Publication date: 2023-02-14
Anticipated expiration: 2041-11-26
Also published as: CN114045509A

Abstract

The invention discloses a seawater electrolysis device conducted by sodium ions and application thereof. The device comprises an anode electrode plate, a cathode electrode plate, a sodium ion exchange membrane, anode chamber electrolyte and cathode chamber electrolyte; wherein the anode electrode plate comprises an anode catalyst, and the cathode electrode plate comprises a cathode catalyst; the anode catalyst and the cathode catalyst are both noble metal catalysts loaded on NiFeP; the anolyte and the catholyte are separated by the sodium ion exchange membrane; the electrolyte in the anode chamber is alkaline solution, and the electrolyte in the cathode chamber is neutral seawater. The invention utilizes the design of the pH asymmetric electrolytic cell conducted by the sodium ion exchange membrane and adopts the noble metal monatomic catalyst on the amorphous NiFeP nanowire, realizes the hydrogen production by electrolyzing the seawater at a large current under an extremely low voltage, and solves the technical problems of catalyst corrosion, low anode oxygen production efficiency and large energy consumption caused by the competitive reaction of chlorine precipitation of the anode which is easy to occur in the electrolyzed seawater.

Description

Seawater electrolysis device with sodium ion conduction and application thereof

Technical Field

The invention belongs to the technical field of seawater electrolysis, and particularly relates to a seawater electrolysis device with sodium ion conduction and application thereof.

Background

The energy crisis and the environmental problem are becoming more severe, and the search for new renewable clean energy is urgent. Hydrogen energy, which is the simplest energy source with the most abundant resources on the earth, has attracted people's attention greatly. Hydrogen has a high energy density and is pollution-free and is considered to be currently the most promising renewable clean energy source. The greatest challenge that currently limits large-scale application of hydrogen energy is the cost and energy consumption in the hydrogen production process. The electrolytic water reaction consists of an Oxygen Evolution Reaction (OER) at the anode and a Hydrogen Evolution Reaction (HER) at the cathode. The electrolytic seawater hydrogen production has the application prospect of abundant earth seawater resources, and can also absorb abandoned water, abandoned wind energy and the like. Conventional electrolytic seaWater units are typically at 100mA/cm ² The current density of (2) requires a voltage of 1.8V or more, and it is difficult to produce an effective yield. Therefore, it is important to design the catalyst properly to reduce the electrolytic seawater. The current noble metal catalyst materials based on Pt, ir and Ru show good electrochemical performance, but their high price and scarcity limit their wide application. It is necessary to select inexpensive non-noble metals or extremely low content of noble metal monatomics to achieve high efficiency electrolysis of water. Therefore, it is important to design the catalyst properly to reduce the electrolytic seawater.

In order to avoid poor catalytic activity of a catalyst in neutrality, conventional seawater electrolysis hydrogen production is generally carried out by adding alkali into natural seawater for pretreatment so as to regulate pH, which increases cost on one hand and increases Ca in natural seawater on the other hand ²⁺ And Mg ²⁺ Will react with OH ^- Form a precipitate and consume OH ^- . Meanwhile, a large amount of chloride ions in the seawater can generate chlorine precipitation competition reaction on the anode side, so that the catalyst is corroded, the service life of the catalyst is shortened, and the oxygen production efficiency of the anode is reduced. Although at present there are also asymmetric water electrolysis devices separated by bipolar membranes, H ⁺ And OH ^- Self-discharge occurs through the bipolar membrane, greatly losing energy.

Disclosure of Invention

Aiming at the defects or improvement requirements of the prior art, the invention provides a seawater electrolysis device conducted by sodium ions and application thereof, aiming at utilizing the design of a pH asymmetric electrolytic cell conducted by a sodium ion exchange membrane, applying a noble metal monatomic catalyst loaded on an amorphous NiFeP nanowire to an anode and a cathode, and reducing the theoretical decomposition potential through the potential difference formed by the asymmetric pH of the cathode and the anode, so that the hydrogen production of natural seawater by direct electrolysis of large current under extremely low voltage is realized, and the technical problems that the seawater needs to be pretreated by adding alkali in the seawater electrolysis, the anode generates a chlorine precipitation competition reaction, the catalyst is corroded, the oxygen production efficiency of the anode is reduced, and the energy consumption is large are solved.

To achieve the above objects, according to one aspect of the present invention, there is provided a seawater electrolysis apparatus with sodium ion conductivity, comprising an anode electrode sheet, a cathode electrode sheet, a sodium ion exchange membrane, an anode chamber electrolyte and a cathode chamber electrolyte; the anode electrode plate comprises an anode catalyst, and the cathode electrode plate comprises a cathode catalyst; the anode catalyst and the cathode catalyst are both noble metal catalysts loaded on NiFeP; the anolyte and the catholyte are separated by the sodium ion exchange membrane; the electrolyte in the anode chamber is alkaline solution, and the electrolyte in the cathode chamber is neutral seawater.

Preferably, the electrolyte in the anode chamber is 0.5-4 mol/L NaOH solution, and preferably, the electrolyte in the anode chamber is 1mol/L NaOH solution.

Preferably, the anode catalyst and the cathode catalyst are both noble metal monoatomic catalysts supported on amorphous NiFeP nanowires, and the noble metal monoatomic catalyst is one of Pt, pd, ru, rh, au and Ir.

Preferably, the atomic content x of P in the amorphous NiFeP nanowire is less than or equal to 10%, and x is not zero, the atomic content of Fe in the amorphous NiFeP nanowire is 15% -25%, and the atomic content of Ni in the amorphous NiFeP nanowire is 60% -70%; the atomic content of the noble metal monoatomic catalyst loaded on the amorphous NiFeP nanowire is less than or equal to 1% and is not zero.

Preferably, the noble metal monatomic catalyst supported on the amorphous NiFeP nanowire is prepared by the following method:

(1) Taking foamed nickel as a cathode and a Pt sheet as an anode, and depositing on the foamed nickel by adopting an electroplating method to obtain a NiFe alloy;

(2) Immersing the NiFe alloy into an organic solution dissolved with a red phosphorus simple substance, heating for 5-7 hours at 230-270 ℃, and washing to obtain an amorphous NiFeP nanowire;

(3) And depositing noble metal monoatomic ions on the surface of the amorphous NiFeP nanowire by adopting an electroplating method or a pyrolysis method to obtain the noble metal monoatomic catalyst loaded on the amorphous NiFeP nanowire.

Preferably, in the step (1), an electroplating method is adopted to deposit the NiFe alloy on the foamed nickel, and the method specifically comprises the following steps: placing foamed nickel and Pt sheets in NiSO ₄ 、FeSO ₄ And NH ₄ In the mixed solution of Cl, at 0.8-1.1A cm ^-2 Electrolyzing for 5-6min under current density; the organic solution dissolved with the red phosphorus simple substance in the step (2) is obtained by dissolving 580-620mg of red phosphorus in 10ml of diethylene glycol. Wherein, the component concentration in the mixed solution is as follows: 0.07mol/L NiSO ₄ 、0.03mol/L FeSO ₄ 、2.0mol/L NH ₄ Cl。

Preferably, the step (3) adopts an electroplating method, which specifically comprises: taking amorphous NiFeP nano-wires as a cathode, a carbon rod as an anode, a calomel electrode as a reference electrode, and NaOH solution containing noble metal salt as a deposition medium, scanning by adopting a cyclic voltammetry method, and scanning for 200-450 CV cycles at a potential of-1.04-1.54V vs.

Preferably, the step (3) adopts a pyrolysis method, specifically: and (3) dropwise adding noble metal salt diluted by ethanol on the amorphous NiFeP nanowire, and then pyrolyzing the noble metal salt for 2-3h in a tubular furnace at 200-250 ℃.

Preferably, the washing mode is washing in deionized water for 5-10min, and then washing in absolute ethyl alcohol for 5-10min; and finally washing in deionized water for 5-10min.

Preferably, the foamed nickel is foamed nickel after acid washing, specifically, the foamed nickel is soaked in 20wt% hydrochloric acid for 5-10min, and is washed with deionized water for 5-10min after soaking.

Preferably, the sodium ion exchange membrane is prepared by the following method:

(1) Placing the proton exchange membrane in 3-5 vol% H ₂ O ₂ Treating at 70-80 deg.C for 2-3 hr, taking out, and washing;

(2) And (2) placing the membrane washed in the step (1) in 0.8-1.2mol/L NaOH solution, treating for 2-3h at the temperature of 70-80 ℃, taking out and washing to obtain the sodium ion exchange membrane.

Preferably, the cathode chamber electrolyte is natural seawater having a pH of 6 to 8, and preferably, the cathode chamber electrolyte is natural seawater having a pH of 7.

According to another aspect of the invention, a sodium ion conductive seawater electrolysis device is provided for producing hydrogen and/or electrolyzing seawaterThe electrolytic cell reaches 10 mA-cm under the potential of 1.40V ^-2 The current density of (1). Reaches 100mA cm at the potential of 1.60V ^-2 The current density of (2).

In general, at least the following advantages can be obtained by the above technical solution conceived by the present invention compared to the prior art.

(1) The seawater electrolysis device with sodium ion conduction provided by the invention adopts an asymmetric pH electrolytic cell, and the working principle is that the theoretical decomposition voltage of electrolyzed water is reduced by the energy difference caused by different chemical potentials of the cathode and anode chambers, so that the actual voltage of hydrogen production by electrolyzed water is reduced, and the cost and energy consumption of hydrogen production by electrolyzed water can be reduced. Meanwhile, the sodium ion exchange membrane is adopted in the invention, and the electrolysis process is realized through the conduction of sodium ions, so that firstly, the explosion danger caused by the mixing of hydrogen and oxygen generated by electrolysis is avoided; secondly, cl in the seawater is avoided ^- Generation of Cl by a competitive reaction at the anode ₂ 。

In addition, the invention can directly electrolyze neutral seawater, and the catalyst firstly shows excellent catalytic activity in neutral environment, secondly shows extremely low over potential in alkaline OER and also shows lower over potential in neutral seawater HER due to the adoption of the noble metal monatomic catalyst loaded on the amorphous NiFeP nanowire at the anode and the cathode. Thereby avoiding the need of regulating the seawater to be alkaline and Ca in the natural seawater for conventional seawater electrolysis hydrogen production ²⁺ And Mg ²⁺ Will react with OH ^- Form a precipitate and consume OH ^- To (3) is described.

(2) Compared with the traditional asymmetric water electrolysis device adopting bipolar membrane separation, pure water without electrolyte can be generated in the middle of the bipolar membrane due to the neutralization of hydrogen ions and hydroxyl ions, so that the resistance between the bipolar membranes is too large, and the large current application cannot be realized. The sodium ion exchange membrane adopted by the invention can realize the ion exchange membrane in the cathode chamber and the anode chamber through sodium ions, and simultaneously, because a large amount of hydrogen ions do not exist in the cathode chamber, the neutralization of the hydrogen ions and hydroxyl ions can not occur, and pure water without electrolyte can not be generated, so that the problem can be solved, and the high-current application can be realized.

(3) The seawater electrolysis device with sodium ion conduction provided by the invention reaches 10 mA-cm under the potential of 1.40V ^-2 The current density of (2) is 100mA/cm at a potential of 1.60V ^-2 Current density of (1) and under industrial conditions (400 mA cm) ^-2 The current density, 85 ℃) and the potential of 1.80V electrolyze seawater to produce hydrogen, and the electrolysis generates 1m ³ The power consumption of the hydrogen is 4.3 kW.h, which is far lower than that of commercial Raney nickel, and the energy consumption is greatly reduced.

(4) The preparation method of the noble metal catalyst loaded on NiFeP and the sodium ion exchange membrane in the seawater electrolysis device with sodium ion conduction is simple, has low cost and is suitable for industrial popularization.

Drawings

FIG. 1 is an X-ray diffraction pattern of a Pt monatomic catalyst supported on amorphous NiFeP nanowires in example 1 of the present invention;

fig. 2 is a scanning electron microscope picture of Pt monatomic catalyst supported on amorphous NiFeP nanowires in example 1 of the present invention;

fig. 3 is a scanning electron microscope picture of Pt monatomic catalyst supported on amorphous NiFeP nanowires in example 2 of the present invention;

FIG. 4 is a polarization curve diagram of oxygen evolution process of Pt monatomic catalyst supported on amorphous NiFeP nanowires in alkaline medium in catalytic performance test examples 1 and 2 of the present invention;

FIG. 5 is a polarization curve diagram of a Pt monatomic catalyst loaded on amorphous NiFeP nanowires in neutral seawater medium during hydrogen evolution in catalytic performance tests of example 1 and example 2 of the present invention;

FIG. 6 is a schematic diagram of the electrolysis of seawater to produce hydrogen and oxygen by the electrolytic cell of the present invention;

FIG. 7 is a graph of cell potential versus time for example 1 of the present invention, in which the test current density was 10mA cm ^-2 The testing temperature is 25 ℃;

FIG. 8 is a graph of cell potential versus time for example 1 of the present invention, wherein the test current density is 100mA cm ^-2 The test temperature is 25 ℃;

FIG. 9 is a graph of cell potential versus time for example 1 of the present invention, wherein the test current density is 400mA cm ^-2 The test temperature is 85 ℃;

FIG. 10 is a graph of cell potential versus time for comparative example 1 of the present invention, in which the test current was 100mA cm ^-2 The testing temperature is 25 ℃;

FIG. 11 is a graph of cell potential versus time for comparative example 2 of the present invention, in which the test current was 100mA cm ^-2 The test temperature was 25 ℃.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Unless otherwise specified, the raw materials in the examples of the present invention were purchased commercially and used as they were without treatment; the test conditions of the instrument all adopt the parameters recommended by the manufacturer.

In the embodiment, the natural seawater is collected from Bohai sea in China.

In the examples, proton exchange membranes were obtained from DuPont, USA.

In the examples, X-ray diffraction analysis (XRD) of the samples was characterized using DMAX-2400X.

In the examples, the scanning electron micrograph of the sample is characterized by S-4800.

In the examples, the polarization profiles of the samples were obtained from the electrochemical workstation (CHI 760E) test of chenhua corporation, shanghai.

Example 1

The embodiment provides a seawater electrolysis device with sodium ion conduction.

(1) Preparation of Pt monatomic catalyst supported on amorphous NiFeP nanowires:

cutting foamed nickel into small pieces of 1cm × 1cm, soaking in 20wt% dilute hydrochloric acid for 10min, taking out, and collectingWashing with deionized water for 10min, and air drying to obtain foamed nickel substrate. 1.840g of NiSO are respectively weighed by a balance ₄ ·6H ₂ O、0.834g FeSO ₄ ·7H ₂ O、10.698g NH ₄ Cl was dissolved in 100ml deionized water and stirred until well dispersed. Then, the acid-washed nickel foam was used as a cathode and a Pt sheet was used as an anode in the above solution at 1A cm ^-2 And (3) electrolyzing for 5min under the current density, taking down the foamed nickel, and washing for 10min in deionized water to obtain the NiFe alloy.

Weighing 600mg of the red phosphorus simple substance by an analytical balance, dissolving the red phosphorus simple substance in 10ml of diethylene glycol, and carrying out ultrasonic treatment in an ultrasonic machine for 30min to uniformly disperse the red phosphorus simple substance in the diethylene glycol.

And (3) putting the cleaned nickel-iron alloy into a polytetrafluoroethylene inner container of a 50ml reaction kettle, pouring the uniformly stirred mixed solution, sealing the reaction kettle, and then putting the reaction kettle in a blast oven to keep the temperature at 250 ℃ for 6 hours. And (3) waiting for the temperature to be reduced to normal temperature, taking out the catalyst, washing the catalyst for 10min by using deionized water, then washing the catalyst for 10min by using absolute ethyl alcohol, then washing the catalyst for 10min by using deionized water, and finally drying the catalyst in the air to obtain the amorphous NiFeP nanowire catalyst. Then 50. Mu.l of 10mg/mL H was aspirated with a pipette ₂ PtCl ₆ Dissolving the catalyst in 50ml of 1mol/L NaOH solution, uniformly mixing, then taking the NiFeP catalyst as a cathode, taking a carbon rod as the cathode, taking a calomel electrode as a reference electrode, and sweeping 450 CV circles under the potential of-1.04 to-1.54V vs. And then washing the catalyst by deionized water for 10min to obtain the Pt monatomic catalyst loaded on the amorphous NiFeP nanowire.

(2) The sodium ion exchange membrane is prepared by the following method:

placing the proton exchange membrane at 3% vol H ₂ O ₂ Treating at 70 deg.C for 2 hr, taking out, and washing;

and (3) placing the washed membrane in 1mol/L NaOH solution, treating for 2h at the temperature of 70 ℃, taking out and washing to obtain the sodium ion exchange membrane.

(3) The seawater electrolysis apparatus was assembled in the manner shown in fig. 6.

The Pt monatomic catalyst loaded on the amorphous NiFeP nanowire is respectively used as an anode catalyst and a cathode catalyst and is used for assembling a seawater electrolysis device.

Diaphragm: a sodium ion exchange membrane is used.

The anode chamber and the cathode chamber are separated from the anolyte and the catholyte by a sodium ion exchange membrane.

Electrolyte in anode chamber: 1mol/L NaOH solution.

Electrolyte in cathode chamber: neutral seawater.

After an electrolytic cell is assembled, 1mol/L NaOH solution and neutral seawater are respectively injected into the anode chamber and the cathode chamber through peristaltic pumps to obtain the seawater electrolysis device.

Example 2

The embodiment provides a seawater electrolysis device with sodium ion conduction. The device provided in this example was obtained in the same manner as in example 1, but the present example was different from example 1 in the preparation method of the Pt monatomic catalyst on the amorphous NiFeP nanowire, specifically:

cutting the foamed nickel into small blocks of 1cm multiplied by 1cm, soaking for 10min by using 20wt% of dilute hydrochloric acid, taking out, washing for 10min by using deionized water, and airing in the air to obtain the foamed nickel substrate. 1.840g of NiSO are respectively weighed by a balance ₄ ·6H ₂ O、0.834g FeSO ₄ ·7H ₂ O、10.698g NH ₄ Cl was dissolved in 100ml deionized water and stirred until well dispersed. Then, the acid-washed nickel foam was used as a cathode and a Pt sheet was used as an anode in the above solution at 1A cm ^-2 And (3) electrolyzing for 5min under the current density, taking down the foamed nickel, and washing for 10min in deionized water to obtain the NiFe alloy.

Putting the cleaned nickel-iron alloy into a polytetrafluoroethylene inner container of a 50ml reaction kettle, pouring the uniformly stirred mixed solution, sealing the reaction kettle, putting the reaction kettle into a blast oven, and putting the reaction kettle into the blast ovenKeeping the temperature at 250 ℃ for 6h. And (3) waiting for the temperature to be reduced to normal temperature, taking out the catalyst, washing the catalyst for 10min by using deionized water, then washing the catalyst for 10min by using absolute ethyl alcohol, then washing the catalyst for 10min by using deionized water, and finally drying the catalyst in the air to obtain the amorphous NiFeP nanowire catalyst. Pipette 10. Mu.l of 10mg/ml H with pipette ₂ PtCl ₆ Dropping the catalyst solution on the surface of an amorphous NiFeP nanowire catalyst in 1ml of absolute ethyl alcohol. And then placing the catalyst in a tubular furnace, heating to 250 ℃ at the heating rate of 10 ℃/min, preserving the heat for 2h, and taking out after cooling to obtain the Pt monatomic catalyst loaded on the amorphous NiFeP nanowire catalyst and obtained by a pyrolysis method.

Comparative example 1 this example provides a sodium ion conducting seawater electrolysis apparatus.

(1) The sodium ion exchange membrane is prepared by the following method:

placing the proton exchange membrane at 3% vol of H ₂ O ₂ Treating at 70 deg.C for 2 hr, taking out, and washing;

and (3) placing the washed membrane in a 1mol/L NaOH solution, treating for 2h at the temperature of 70 ℃, taking out and washing to obtain the sodium ion exchange membrane.

(2) The seawater electrolysis apparatus was assembled in the manner shown in fig. 5.

Commercial Pt/C and commercial IrO ₂ and/C is respectively used as a cathode catalyst and an anode catalyst and is used for assembling the seawater electrolysis device.

A diaphragm: a sodium ion exchange membrane is used.

Electrolyte in the anode chamber: 1mol/L NaOH solution.

Electrolyte in cathode chamber: neutral seawater.

Comparative example 2

The present embodiment provides a conventional apparatus for electrolyzing alkaline seawater.

cutting the foamed nickel into small blocks of 1cm multiplied by 1cm, soaking for 10min by 20wt% of dilute hydrochloric acid, taking out, washing for 10min by deionized water, and airing in the air to obtain the foamed nickel substrate. 1.840g of NiSO are respectively weighed by a balance ₄ ·6H ₂ O、0.834g FeSO ₄ ·7H ₂ O、10.698g NH ₄ Cl was dissolved in 100ml deionized water and stirred until well dispersed. Then, the acid-washed nickel foam was used as a cathode and a Pt sheet was used as an anode in the above solution at 1A cm ^-2 And (3) electrolyzing for 5min under the current density, taking down the foamed nickel, and washing for 10min in deionized water to obtain the NiFe alloy.

And (3) putting the cleaned nickel-iron alloy into a polytetrafluoroethylene inner container of a 50ml reaction kettle, pouring the uniformly stirred mixed solution, sealing the reaction kettle, and then putting the reaction kettle in a blast oven to keep the temperature at 250 ℃ for 6 hours. And (3) after the temperature is reduced to normal temperature, taking out the catalyst, washing the catalyst with deionized water for 10min, then washing the catalyst with absolute ethyl alcohol for 10min, then washing the catalyst with deionized water for 10min, and finally drying the catalyst in the air to obtain the amorphous NiFeP nanowire catalyst. Then 50. Mu.l of 10mg/mL H was aspirated with a pipette ₂ PtCl ₆ Dissolving the catalyst in 50ml of 1mol/L NaOH solution, uniformly mixing, then taking the NiFeP catalyst as a cathode, taking a carbon rod as the cathode, taking a calomel electrode as a reference electrode, and sweeping 450 CV circles under the potential of-1.04 to-1.54V vs. And then washing the Pt single-atom catalyst on the amorphous NiFeP nanowire for 10min by using deionized water to obtain the Pt single-atom catalyst loaded on the amorphous NiFeP nanowire.

(2) And respectively taking Pt monatomic catalysts loaded on the amorphous NiFeP nanowires as cathode and anode catalysts.

Natural seawater containing 1M NaOH was used as the cathode and anode compartment electrolytes.

Results and analysis:

the Pt monatomic catalyst on the amorphous NiFeP nanowires in examples 1 and 2 was characterized.

X-ray diffraction analysis was performed on Pt monatomic catalysts on amorphous NiFeP nanowires. It can be seen from fig. 1 that the Pt monatomic catalyst supported on amorphous NiFeP nanowires prepared in example 1 is amorphous, and there is no Pt diffraction peak in the XRD pattern, indicating that there is no Pt particle, but the Pt monatomic catalyst.

Scanning electron microscopy analysis was performed on the Pt monatomic catalyst supported on amorphous NiFeP nanowires prepared by the electroplating method and the pyrolysis method of examples 1 and 2. As can be seen from FIG. 2, the Pt monatomic catalyst loaded on the amorphous NiFeP nanowire prepared by the electroplating method is in the shape of a nanowire, and the thickness of the Pt monatomic catalyst is about 200nm. It can be seen from fig. 3 that the pyrogenically prepared Pt monatomic catalyst supported on amorphous NiFeP nanowires is in the form of nanowires, with a thickness of about 200nm.

The oxygen generation performance of the Pt monatomic catalyst on the amorphous NiFeP nanowire in a 1M NaOH solution was tested, and the results are shown in fig. 4. As can be seen from fig. 4, the Pt monatomic catalysts supported on amorphous NiFeP nanowires prepared by the electroplating method and the pyrolysis method are closer in performance, and both have certain advantages in performance compared to the commercial IrO2 catalyst.

The hydrogen production performance of the Pt monatomic catalyst on the amorphous NiFeP nanowire in neutral natural seawater was tested, and the results are shown in fig. 5. As can be seen in fig. 5, the performance of the Pt monatomic catalyst supported on amorphous NiFeP nanowires of the electroplating method and the pyrolyzation vegetation is relatively close, and the performance of the Pt monatomic catalyst supported on amorphous NiFeP nanowires is greatly improved compared with that of the commercial Pt/C. We can achieve better performance than Pt/C with very low Pt content.

The seawater electrolysis apparatus of example 1 was subjected to a potential-time test under the following conditions: the current density is 10mA cm ^-2 The test temperature was 25 ℃. As a result, as shown in FIG. 7, the current density was 10mA cm ^-2 When the voltage of the electrolyzed seawater is 1.40V, the voltage is 10mA cm ^-2 Under the current density, the hydrogen production by electrolyzing seawater at 1.40V can be stably realized.

Apparatus for electrolyzing seawater according to example 1Under the following conditions: the current density is 100mA cm ^-2 The test temperature was 25 ℃. As a result, as shown in FIG. 8, the current density was 100mA cm ^-2 The voltage of the electrolyzed seawater is 1.60V.

The seawater electrolysis device in comparative example 1 was subjected to potential-time test under the following conditions: the current density is 100 mA-cm ^-2 The test temperature was 25 ℃. As a result, as shown in FIG. 10, the current density was 100mA cm ^-2 The voltage of the electrolyzed seawater was 1.67V. Compared with example 1, the Pt monatomic catalyst loaded on the amorphous NiFeP nanowire is compared with commercial Pt/C and IrO ₂ The current density of the/C catalyst is 100mA cm ^-2 When the potential is lowered by 70mV.

The conventional seawater electrolysis apparatus of comparative example 2 was subjected to potential-time test under the following conditions: the current density is 100mA cm ^-2 The test temperature was 25 ℃. As a result, as shown in FIG. 11, the current density was 100mA cm ^-2 The voltage of the electrolyzed seawater is 1.76V. Compared with the embodiment 1, the pH asymmetric electrolytic cell has the current density of 100 mA-cm compared with the conventional alkaline electrolytic seawater ^-2 The potential may be lowered by 160mV. This potential difference illustrates the advantage of the asymmetric electrolytic cell over conventional alkaline seawater electrolytic cells in practical applications.

The apparatus for electrolyzing seawater in example 1 was subjected to a potential-time test under industrial conditions (current density 400 mA. Cm) ^-2 The test temperature was 85 deg.C). As a result, as shown in FIG. 9, under industrial conditions, the voltage of the electrolyzed seawater was 1.80V, and the electrolyzed seawater was 1m ³ Hydrogen required 4.3 kW.h. Has wide application prospect in industrial mass production.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. The application of the device for electrolyzing seawater conducted by sodium ions is characterized in that the device is used for electrolyzing seawater to produce hydrogen and/or oxygen;

the seawater electrolysis device comprises an anode electrode plate, a cathode electrode plate, a sodium ion exchange membrane, anode chamber electrolyte and cathode chamber electrolyte;

wherein the anode electrode plate comprises an anode catalyst, and the cathode electrode plate comprises a cathode catalyst; the anode catalyst and the cathode catalyst are both noble metal catalysts loaded on NiFeP;

the anolyte and the catholyte are separated by the sodium ion exchange membrane;

the electrolyte in the anode chamber is alkaline solution, and the electrolyte in the cathode chamber is neutral seawater.

2. The use according to claim 1, wherein the electrolyte in the anode compartment is a 0.5 to 4mol/L NaOH solution.

3. The use according to claim 2, wherein the electrolyte in the anode compartment is a 1mol/L NaOH solution.

4. The use according to claim 1 or 2, wherein the anode catalyst and the cathode catalyst are each a noble metal monoatomic catalyst supported on amorphous NiFeP nanowires, the noble metal monoatomic being one of Pt, pd, ru, rh, au, and Ir.

5. The use of claim 4, wherein the amorphous NiFeP nanowires have a P atom content, x, of less than or equal to 10% and not zero, and a Fe atom content of 15% to 25% and a Ni atom content of 60% to 70%; the atomic content of the noble metal monoatomic catalyst loaded on the amorphous NiFeP nanowire is less than or equal to 1% and is not zero.

6. The use of claim 4, wherein the noble metal monatomic catalyst supported on amorphous NiFeP nanowires is prepared by:

(3) And depositing a noble metal monoatomic layer on the surface of the amorphous NiFeP nanowire by adopting an electroplating method or a pyrolysis method to obtain the noble metal monoatomic catalyst loaded on the amorphous NiFeP nanowire.

7. The use according to claim 6, wherein in step (1) the NiFe alloy is deposited on the foamed nickel by electroplating, specifically: placing foamed nickel and Pt sheets in NiSO ₄ 、FeSO ₄ And NH ₄ In the mixed solution of Cl, at 0.8-1.1A cm ^-2 Electrolyzing for 5-6min under current density; the organic solution dissolved with the red phosphorus simple substance in the step (2) is obtained by dissolving 580-620mg of red phosphorus in 10-15ml of diethylene glycol.

8. The use according to claim 6, wherein said step (3) uses an electroplating method, in particular: taking an amorphous NiFeP nanowire as a cathode, a carbon rod as an anode, a calomel electrode as a reference electrode, and NaOH solution containing noble metal salt as a deposition medium, scanning by adopting a cyclic voltammetry method, and scanning for 200-450 CV cycles at a potential of-1.04-1.54V vs. SCE; the pyrolysis method in the step (3) specifically comprises: and dropwise adding noble metal salt diluted by ethanol on the amorphous NiFeP nanowire, and then pyrolyzing the amorphous NiFeP nanowire for 2 to 3 hours in a tubular furnace at the temperature of between 200 and 250 ℃.

9. The use according to claim 1, wherein the sodium ion exchange membrane is prepared by:

(2) And (2) placing the membrane washed in the step (1) into 0.8-1.2mol/L NaOH solution, treating for 2-3h at the temperature of 70-80 ℃, taking out and washing to obtain the sodium ion exchange membrane.

10. The use according to claim 1, wherein the cathode compartment electrolyte is natural seawater having a pH of 6 to 8.

11. The use of claim 10 wherein the cathode compartment electrolyte is natural seawater at pH 7.

12. Use according to claim 1, characterized in that the electrolytic cell reaches 10 mA-cm at a potential of 1.40V ^-2 Current density of (d); reaches 100mA cm at the potential of 1.60V ^-2 The current density of (1).