A nickel-doped molybdenum dioxide composite seawater electrocatalyst and its preparation method and application

Abstract

The present invention discloses a nickel-doped molybdenum dioxide composite seawater electrocatalyst and a preparation method and application thereof, and relates to the field of catalyst technology. The preparation method comprises the following steps: (1) preparation of a transparent solution; (2) preparation of a Ni-Mo-O precursor; (3) preparation of a Ni-MoO2 electrocatalyst. The present invention also discloses the application of the nickel-doped molybdenum dioxide composite electrocatalyst in electrocatalytic cracking of seawater to produce hydrogen. The Ni-MoO2 electrocatalyst provided by the present invention has uniform size, regular morphology, large specific surface area, and high activity and stability. In addition, the present invention has mild preparation conditions, simple operation, strong repeatability, and low requirements for instruments and equipment, providing a good technical basis and material guarantee for large-scale applications.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a nickel-doped molybdenum dioxide composite seawater electrocatalyst and a preparation method and application thereof. Background Art

[0002] In recent years, hydrogen energy has received extensive attention, and electrocatalytic water splitting to produce hydrogen, especially electrocatalytic seawater splitting, provides an effective means to solve the energy crisis and develop new energy. However, electrocatalyst materials are affected by their high price, difficulty in synthesis and scarce reserves, which has led to their lack of rapid development.

[0003] Among traditional transition metal materials, transition metal oxides, such as nickel oxide, cobalt oxide, and manganese oxide, have received extensive attention in the field of electrocatalytic hydrogen production due to their abundant reserves and low prices. However, their poor electrical conductivity and high adsorption energy currently limit their performance in electrocatalytic water splitting to produce hydrogen. At the same time, in the prior art, there are few reports on the rapid heating synthesis of oxide electrocatalysts, and no related tests on the performance of electrocatalytic seawater splitting have been conducted. There is still much room for improvement in terms of synthesis methods and design strategies.

[0004] Therefore, how to provide an economical and efficient electrocatalyst to promote the rapid development of oxide-based materials in the field of electrocatalytic cracking of seawater and ultimately realize its industrialization is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of the above-mentioned defects in the prior art, the present invention provides a nickel-doped molybdenum dioxide composite seawater electrocatalyst and a preparation method and application thereof.

[0006] To achieve the above object, the present invention proposes the following technical solutions:

[0007] A method for preparing a nickel-doped molybdenum dioxide composite seawater electrocatalyst comprises the following steps:

[0008] 1) adding tetrahydrated ammonium molybdate and hexahydrated nickel chloride to deionized water respectively and mixing them, then placing the foamed nickel in the obtained mixed solution and letting it stand, heating it, cooling it to room temperature, washing it, and vacuum drying it to obtain a Ni-Mo-O precursor;

[0009] 2) reacting the Ni-Mo-O precursor in an inert atmosphere at 400-800° C. for 0.5-30 min to obtain a nickel-doped molybdenum dioxide composite seawater electrocatalyst.

[0010] Furthermore, in step 1), the mass ratio of the tetrahydrated ammonium molybdate to the hexahydrated nickel chloride is 1:(0.1-5.0).

[0011] Furthermore, in step 1), the standing time is 5-10 minutes.

[0012] Furthermore, in step 1), the parameters of the heating treatment are: temperature 150-200° C., time 5-10 h.

[0013] Furthermore, in step 1), the parameters of the vacuum drying are: temperature 5-100°C, time 8-72h, vacuum degree 133-267Pa.

[0014] Furthermore, in step 2), the inert atmosphere refers to an Ar / H2 mixed gas.

[0015] The present invention also provides a nickel-doped molybdenum dioxide composite seawater electrocatalyst prepared by the method for preparing the nickel-doped molybdenum dioxide composite seawater electrocatalyst.

[0016] The present invention also provides an application of a nickel-doped molybdenum dioxide composite seawater electrocatalyst in electrocatalytic cracking of seawater to produce hydrogen.

[0017] Furthermore, the nickel-doped molybdenum dioxide composite seawater electrocatalyst is used as a working electrode, the calomel electrode is used as a reference electrode, the graphite electrode is used as a counter electrode, and the electrolyte is alkaline seawater; the pH of the electrolyte is 10-14.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention uses tetrahydrated ammonium molybdate to provide a molybdenum source and hexahydrated nickel chloride to provide a nickel source, which are loaded on a foamed nickel substrate, and a precursor is prepared by heating and deposition, and then a heating reaction is performed under an inert atmosphere to obtain a catalyst for electrocatalytic cracking of seawater to produce hydrogen. Metal doping can optimize the electronic structure of the molybdenum dioxide material, exert a synergistic effect, and accelerate the transfer speed of electrons. Water molecules in seawater are adsorbed on the surface of the catalyst, and the water molecules obtain electrons to generate hydrogen protons. Two hydrogen protons combine to generate hydrogen, which accelerates the reaction process.

[0020] The Ni-MoO2 electrocatalyst prepared by the present invention has the characteristics of large specific surface area, high activity and high stability, and has excellent hydrogen production performance in alkaline seawater. In addition, the preparation of the Ni-MoO2 electrocatalyst in the present invention is short in time, simple in operation and highly repeatable, providing a good technical basis and material guarantee for large-scale application.

[0021] The Ni-MoO2 electrocatalyst prepared by the invention has a rod-shaped nanostructure, can provide abundant specific surface area, and thus improves its catalytic activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 is a scanning electron microscope image of the Ni-MoO2 electrocatalyst prepared in Example 1;

[0024] Figure 2 is the X-ray diffraction spectrum of the Ni-MoO2 electrocatalyst prepared in Example 1;

[0025] Figure 3 This is a performance diagram of the Ni-MoO2 electrocatalyst prepared in Example 1 for splitting seawater to produce hydrogen in alkaline seawater. DETAILED DESCRIPTION

[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0027] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0028] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0029] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0030] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0031] The raw materials used in the embodiments of the present invention are all purchased from the market.

[0032] A method for preparing a nickel-doped molybdenum dioxide composite seawater electrocatalyst comprises the following steps:

[0033] 1) adding ammonium molybdate tetrahydrate and nickel chloride hexahydrate into deionized water to obtain an ammonium molybdate tetrahydrate solution and a nickel chloride hexahydrate solution, respectively; adding the ammonium molybdate tetrahydrate solution dropwise into the nickel chloride hexahydrate solution; and continuously stirring to obtain a mixed solution;

[0034] Putting nickel foam into the obtained mixed solution and allowing it to stand, heating it, cooling it to room temperature, washing the obtained solid product, and vacuum drying it to obtain a Ni-Mo-O precursor;

[0035] 2) reacting the Ni-Mo-O precursor in an inert atmosphere at 400-800°C for 0.5-30 min to obtain a nickel-doped molybdenum dioxide composite seawater electrocatalyst, i.e., a Ni-MoO2 electrocatalyst. The temperature is preferably 500°C.

[0036] In some preferred embodiments, in step 1), the mass ratio of ammonium molybdate tetrahydrate to nickel chloride hexahydrate is 1:(0.1-5.0). The concentration of the ammonium molybdate tetrahydrate solution is 0.02 mol / L, and the concentration of the nickel chloride hexahydrate solution is 0.01-0.10 mol / L.

[0037] In some preferred embodiments, in step 1), the standing time is 5-10 min.

[0038] In some preferred embodiments, in step 1), the parameters of the heating treatment are: temperature 150-200° C., time 5-10 h.

[0039] In some preferred embodiments, in step 1), the parameters of the vacuum drying are: temperature 5-100° C., time 8-72 h, and vacuum degree 133-267 Pa.

[0040] In some preferred embodiments, in step 1), the nickel foam has a thickness of 1.5 mm and an area of ​​1-4 cm 2 .

[0041] In some preferred embodiments, in step 2), the inert atmosphere refers to an Ar / H2 mixed gas, and the volume ratio of the two is 9:1.

[0042] The present invention also provides a nickel-doped molybdenum dioxide composite seawater electrocatalyst prepared by the preparation method of the nickel-doped molybdenum dioxide composite seawater electrocatalyst, namely a Ni-MoO2 electrocatalyst, the chemical composition of which is Ni-MoO2, the structure is rod-shaped, and the length is 3 μm. The structure can provide a rich specific surface area, thereby improving its catalytic activity.

[0043] The present invention also provides an application of a nickel-doped molybdenum dioxide composite seawater electrocatalyst in electrocatalytic cracking of seawater to produce hydrogen.

[0044] In some preferred embodiments, the nickel-doped molybdenum dioxide composite seawater electrocatalyst is used as a working electrode, a calomel electrode is used as a reference electrode, a graphite electrode is used as a counter electrode, and the electrolyte is alkaline seawater; the pH of the electrolyte is 10-14.

[0045] The seawater used in the embodiment of the present invention is alkaline seawater taken from the Yellow Sea of ​​China, wherein the concentration of KOH is 1.0 mol / L.

[0046] The "room temperature" described in the present invention refers to 25°C.

[0047] Example 1

[0048] A method for preparing a nickel-doped molybdenum dioxide composite seawater electrocatalyst, comprising the following steps:

[0049] 1) dispersing nickel chloride hexahydrate in deionized water at room temperature to obtain a green transparent nickel chloride hexahydrate solution with a concentration of 0.015 mol / L;

[0050] 2) dissolving ammonium molybdate tetrahydrate in deionized water at room temperature to obtain a colorless and transparent ammonium molybdate tetrahydrate solution having a concentration of 0.02 mol / L;

[0051] 3) adding the tetrahydrate ammonium molybdate solution of step (2) dropwise into the hexahydrate nickel chloride solution of step (1), and continuously stirring to obtain a green transparent solution; wherein the mass ratio of the tetrahydrate ammonium molybdate to the hexahydrate nickel chloride is 1:1;

[0052] 4) 1.5mm thick and 2cm in area 2 The nickel foam is added to the transparent solution of step (3) and allowed to stand for 5 min (so that the transparent solution completely immerses the nickel foam), then transferred to a reactor, reacted at 150° C. for 6 h to obtain a nickel foam material, which is fully washed with deionized water and ethanol, and vacuum dried (temperature 80° C., time 12 h, vacuum degree 150 Pa) to obtain a nickel foam material with an area of ​​2 cm 2 Ni-Mo-O precursor;

[0053] 5) The area obtained in step (4) is 2 cm 2The Ni-Mo-O precursor was placed in a molybdenum boat, which was transferred to a Joule heating instrument and reacted at 500°C for 1 min under an Ar / H2 mixed atmosphere to obtain a black Ni-MoO2 electrocatalyst.

[0054] Figure 1 This is a scanning electron microscope image of the Ni-MoO2 electrocatalyst prepared in Example 1. It can be seen that the Ni-MoO2 electrocatalyst prepared in this example is a rod-like structure and grows on nickel foam.

[0055] Figure 2 This is the X-ray diffraction spectrum of the Ni-MoO2 electrocatalyst prepared in Example 1. It can be seen that the chemical composition of the prepared product is Ni-doped MoO2.

[0056] Example 2

[0057] A method for preparing a nickel-doped molybdenum dioxide composite seawater electrocatalyst, comprising the following steps:

[0058] 1) dispersing nickel chloride hexahydrate in deionized water at room temperature to obtain a green transparent nickel chloride hexahydrate solution with a concentration of 0.015 mol / L;

[0059] 2) dissolving ammonium molybdate tetrahydrate in deionized water at room temperature to obtain a colorless and transparent ammonium molybdate tetrahydrate solution having a concentration of 0.02 mol / L;

[0060] 3) adding the tetrahydrate ammonium molybdate solution of step (2) dropwise into the hexahydrate nickel chloride solution of step (1), and continuously stirring to obtain a green transparent solution; wherein the mass ratio of the tetrahydrate ammonium molybdate to the hexahydrate nickel chloride is 1:1;

[0061] 4) 1.5mm thick and 2cm in area 2 The nickel foam was added to the transparent solution of step (3) and allowed to stand for 5 min, then transferred to a reactor and reacted at 150° C. for 6 h to obtain a nickel foam material (Ni loading: 13.4 mg / cm -2 , Mo loading: 21.9 mg / cm -2 ), washed thoroughly with deionized water and ethanol, and vacuum dried (temperature 80°C, time 12h, vacuum degree 150Pa) to obtain a 2cm 2 Ni-Mo-O precursor;

[0062] 5) The area obtained in step (4) is 2 cm 2 The Ni-Mo-O precursor was placed in a molybdenum boat, which was transferred to a Joule heating instrument and reacted at 400 °C for 1 min under an Ar / H2 mixed atmosphere to obtain a black Ni-MoO2 electrocatalyst.

[0063] Example 3

[0064] A method for preparing a nickel-doped molybdenum dioxide composite seawater electrocatalyst, comprising the following steps:

[0065] 1) dispersing nickel chloride hexahydrate in deionized water at room temperature to obtain a green transparent nickel chloride hexahydrate solution with a concentration of 0.015 mol / L;

[0066] 2) dissolving ammonium molybdate tetrahydrate in deionized water at room temperature to obtain a colorless and transparent ammonium molybdate tetrahydrate solution having a concentration of 0.02 mol / L;

[0067] 3) adding the tetrahydrate ammonium molybdate solution of step (2) dropwise into the hexahydrate nickel chloride solution of step (1), and continuously stirring to obtain a green transparent solution; wherein the mass ratio of the tetrahydrate ammonium molybdate to the hexahydrate nickel chloride is 1:1;

[0068] 4) 1.5mm thick and 2cm in area 2 The nickel foam was added to the transparent solution of step (3) and allowed to stand for 5 min, then transferred to a reactor and reacted at 150° C. for 6 h to obtain a nickel foam material, which was fully washed with deionized water and ethanol and vacuum dried (temperature 80° C., time 12 h, vacuum degree 150 Pa) to obtain a nickel foam material with an area of ​​2 cm 2 Ni-Mo-O precursor;

[0069] 5) The area obtained in step (4) is 2 cm 2 The Ni-Mo-O precursor was placed in a molybdenum boat, which was transferred to a Joule heating instrument and reacted at 600°C for 1 min under an Ar / H2 mixed atmosphere to obtain a black Ni-MoO2 electrocatalyst.

[0070] Example 4

[0071] Same as Example 2, except that step 5) is: the area obtained in step (4) is 2 cm 2 The Ni-Mo-O precursor was placed in a molybdenum boat, which was transferred to a Joule heating instrument and reacted at 500°C for 0.5 min under an Ar / H2 mixed atmosphere to obtain a black Ni-MoO2 electrocatalyst.

[0072] Example 5

[0073] Same as Example 2, except that step 5) is: the area obtained in step (4) is 2 cm 2 The Ni-Mo-O precursor was placed in a molybdenum boat, which was transferred to a Joule heating instrument and reacted at 500°C for 1.5 min under an Ar / H2 mixed atmosphere to obtain a black Ni-MoO2 electrocatalyst.

[0074] Example 6

[0075] A method for preparing a nickel-doped molybdenum dioxide composite seawater electrocatalyst, comprising the following steps:

[0076] 1) dispersing nickel chloride hexahydrate in deionized water at room temperature to obtain a green transparent nickel chloride hexahydrate solution with a concentration of 0.015 mol / L;

[0077] 2) dissolving ammonium molybdate tetrahydrate in deionized water at room temperature to obtain a colorless and transparent ammonium molybdate tetrahydrate solution having a concentration of 0.02 mol / L;

[0078] 3) adding the tetrahydrate ammonium molybdate solution of step (2) dropwise into the hexahydrate nickel chloride solution of step (1), and continuously stirring to obtain a green transparent solution; wherein the mass ratio of the tetrahydrate ammonium molybdate to the hexahydrate nickel chloride is 1:2;

[0079] 4) 1.5mm thick and 2cm in area 2 The nickel foam was added to the transparent solution of step (3) and allowed to stand for 5 min, then transferred to a reactor and reacted at 150° C. for 6 h to obtain a nickel foam material (Ni loading: 13.4 mg / cm -2 , Mo loading: 21.9 mg / cm -2 ), washed thoroughly with deionized water and ethanol, and vacuum dried (temperature 80°C, time 12h, vacuum degree 150Pa) to obtain a 2cm 2 Ni-Mo-O precursor;

[0080] 5) The area obtained in step (4) is 2 cm 2 The Ni-Mo-O precursor was placed in a molybdenum boat, which was transferred to a Joule heating instrument and reacted at 500°C for 1 min under an Ar / H2 mixed atmosphere to obtain a black Ni-MoO2 electrocatalyst.

[0081] Example 7

[0082] A method for preparing a nickel-doped molybdenum dioxide composite seawater electrocatalyst, comprising the following steps:

[0083] 1) dispersing nickel chloride hexahydrate in deionized water at room temperature to obtain a green transparent nickel chloride hexahydrate solution with a concentration of 0.015 mol / L;

[0084] 2) dissolving ammonium molybdate tetrahydrate in deionized water at room temperature to obtain a colorless and transparent ammonium molybdate tetrahydrate solution having a concentration of 0.02 mol / L;

[0085] 3) adding the tetrahydrate ammonium molybdate solution of step (2) dropwise into the hexahydrate nickel chloride solution of step (1), and continuously stirring to obtain a green transparent solution; wherein the mass ratio of the tetrahydrate ammonium molybdate to the hexahydrate nickel chloride is 1:3;

[0086] 4) 1.5mm thick and 2cm in area 2 The nickel foam was added to the transparent solution of step (3) and allowed to stand for 5 min, then transferred to a reactor and reacted at 150° C. for 6 h to obtain a nickel foam material (Ni loading: 13.4 mg / cm -2 , Mo loading: 21.9 mg / cm -2 ), washed thoroughly with deionized water and ethanol, and vacuum dried (temperature 80°C, time 12h, vacuum degree 150Pa) to obtain a 2cm 2 Ni-Mo-O precursor;

[0087] 5) The area obtained in step (4) is 2 cm 2 The Ni-Mo-O precursor was placed in a molybdenum boat, which was transferred to a Joule heating instrument and reacted at 500°C for 1 min under an Ar / H2 mixed atmosphere to obtain a black Ni-MoO2 electrocatalyst.

[0088] Example 8

[0089] A method for preparing a nickel-doped molybdenum dioxide composite seawater electrocatalyst, comprising the following steps:

[0090] 1) dispersing nickel chloride hexahydrate in deionized water at room temperature to obtain a green transparent nickel chloride hexahydrate solution with a concentration of 0.015 mol / L;

[0091] 2) dissolving ammonium molybdate tetrahydrate in deionized water at room temperature to obtain a colorless and transparent ammonium molybdate tetrahydrate solution having a concentration of 0.02 mol / L;

[0092] 3) adding the tetrahydrate ammonium molybdate solution of step (2) dropwise into the hexahydrate nickel chloride solution of step (1), and continuously stirring to obtain a green transparent solution; wherein the mass ratio of the tetrahydrate ammonium molybdate to the hexahydrate nickel chloride is 1:4;

[0093] 4) 1.5mm thick and 2cm in area 2 The nickel foam was added to the transparent solution of step (3) and allowed to stand for 5 min, then transferred to a reactor and reacted at 150° C. for 6 h to obtain a nickel foam material (Ni loading: 13.4 mg / cm -2 , Mo loading: 21.9 mg / cm -2), washed thoroughly with deionized water and ethanol, and vacuum dried (temperature 80°C, time 12h, vacuum degree 150Pa) to obtain a 2cm 2 Ni-Mo-O precursor;

[0094] 5) The area obtained in step (4) is 2 cm 2 The Ni-Mo-O precursor was placed in a molybdenum boat, which was transferred to a Joule heating instrument and reacted at 500°C for 1 min under an Ar / H2 mixed atmosphere to obtain a black Ni-MoO2 electrocatalyst.

[0095] Example 9

[0096] A method for preparing a nickel-doped molybdenum dioxide composite seawater electrocatalyst, comprising the following steps:

[0097] 1) dispersing nickel chloride hexahydrate in deionized water at room temperature to obtain a green transparent nickel chloride hexahydrate solution with a concentration of 0.015 mol / L;

[0098] 2) dissolving ammonium molybdate tetrahydrate in deionized water at room temperature to obtain a colorless and transparent ammonium molybdate tetrahydrate solution having a concentration of 0.02 mol / L;

[0099] 3) adding the tetrahydrate ammonium molybdate solution of step (2) dropwise into the hexahydrate nickel chloride solution of step (1), and continuously stirring to obtain a green transparent solution; wherein the mass ratio of the tetrahydrate ammonium molybdate to the hexahydrate nickel chloride is 1:5;

[0100] 4) 1.5mm thick and 2cm in area 2 The nickel foam was added to the transparent solution of step (3) and allowed to stand for 5 min, then transferred to a reactor and reacted at 150° C. for 6 h to obtain a nickel foam material (Ni loading: 13.4 mg / cm -2 , Mo loading: 21.9 mg / cm -2 ), washed thoroughly with deionized water and ethanol, and vacuum dried (temperature 80°C, time 12h, vacuum degree 150Pa) to obtain a 2cm 2 Ni-Mo-O precursor;

[0101] 5) The area obtained in step (4) is 2 cm 2 The Ni-Mo-O precursor was placed in a molybdenum boat, which was transferred to a Joule heating instrument and reacted at 500°C for 1 min under an Ar / H2 mixed atmosphere to obtain a black Ni-MoO2 electrocatalyst.

[0102] Example 10

[0103] A method for preparing a nickel-doped molybdenum dioxide composite seawater electrocatalyst, comprising the following steps:

[0104] 1) dispersing nickel chloride hexahydrate in deionized water at room temperature to obtain a green transparent nickel chloride hexahydrate solution with a concentration of 0.015 mol / L;

[0105] 2) dissolving ammonium molybdate tetrahydrate in deionized water at room temperature to obtain a colorless and transparent ammonium molybdate tetrahydrate solution having a concentration of 0.02 mol / L;

[0106] 3) adding the tetrahydrate ammonium molybdate solution of step (2) dropwise into the hexahydrate nickel chloride solution of step (1), and continuously stirring to obtain a green transparent solution; wherein the mass ratio of the tetrahydrate ammonium molybdate to the hexahydrate nickel chloride is 1:5;

[0107] 4) 1.5mm thick and 2cm in area 2 The nickel foam was added to the transparent solution of step (3) and allowed to stand for 5 min, then transferred to a reactor and reacted at 175° C. for 6 h to obtain a nickel foam material (Ni loading: 13.4 mg / cm -2 , Mo loading: 21.9 mg / cm -2 ), washed thoroughly with deionized water and ethanol, and vacuum dried (temperature 80°C, time 12h, vacuum degree 150Pa) to obtain a 2cm 2 Ni-Mo-O precursor;

[0108] 5) The area obtained in step (4) is 2 cm 2 The Ni-Mo-O precursor was placed in a molybdenum boat, which was transferred to a Joule heating instrument and reacted at 500°C for 1 min under an Ar / H2 mixed atmosphere to obtain a black Ni-MoO2 electrocatalyst.

[0109] Embodiment 11

[0110] A method for preparing a nickel-doped molybdenum dioxide composite seawater electrocatalyst, comprising the following steps:

[0111] 1) dispersing nickel chloride hexahydrate in deionized water at room temperature to obtain a green transparent nickel chloride hexahydrate solution with a concentration of 0.015 mol / L;

[0112] 2) dissolving ammonium molybdate tetrahydrate in deionized water at room temperature to obtain a colorless and transparent ammonium molybdate tetrahydrate solution having a concentration of 0.02 mol / L;

[0113] 3) adding the tetrahydrate ammonium molybdate solution of step (2) dropwise into the hexahydrate nickel chloride solution of step (1), and continuously stirring to obtain a green transparent solution; wherein the mass ratio of the tetrahydrate ammonium molybdate to the hexahydrate nickel chloride is 1:5;

[0114] 4) 1.5mm thick and 2cm in area 2 The nickel foam was added to the transparent solution of step (3) and allowed to stand for 5 min, then transferred to a reactor and reacted at 200° C. for 6 h to obtain a nickel foam material (Ni loading: 13.4 mg / cm -2 , Mo loading: 21.9 mg / cm -2 ), washed thoroughly with deionized water and ethanol, and vacuum dried (temperature 80°C, time 12h, vacuum degree 150Pa) to obtain a 2cm 2 Ni-Mo-O precursor;

[0115] 5) The area obtained in step (4) is 2 cm 2 The Ni-Mo-O precursor was placed in a molybdenum boat, which was transferred to a Joule heating instrument and reacted at 500°C for 1 min under an Ar / H2 mixed atmosphere to obtain a black Ni-MoO2 electrocatalyst.

[0116] Test Example 1

[0117] The black Ni-MoO2 electrocatalyst prepared in Examples 1-5 was applied to the production of hydrogen by cracking seawater. Specifically, the Ni-MoO2 electrocatalyst was directly used as the working electrode, the calomel electrode was used as the reference electrode, the graphite electrode was used as the counter electrode, and the electrolyte was alkaline seawater (KOH+real seawater, the real seawater was taken from the Yellow Sea of ​​China, and the concentration of KOH was 1.0 mol / L). The test results are shown in Table 1. Figure 3 This is a performance diagram of the Ni-MoO2 electrocatalyst prepared in Example 1 for splitting seawater to produce hydrogen in alkaline seawater.

[0118] Table 1 Electrocatalytic performance of Ni-MoO2 electrocatalyst

[0119]

[0120]

[0121] From Table 1 and Figure 3 It can be seen that the Ni-Mo-O precursor is obtained by reacting tetrahydrate ammonium molybdate and nickel chloride hexahydrate in a mass ratio of 1:1 at 150°C for 6 hours, and the Ni-MoO2 electrocatalyst obtained by reacting at 500°C for 1 minute has excellent electrocatalytic performance in hydrogen production from seawater.

[0122] Comparative Example 1

[0123] Same as Example 2, except that in step 5), the reaction gas is argon.

[0124] Comparative Example 2

[0125] Same as Example 2, except that in step 5), the reaction temperature is 800°C.

[0126] Table 2

[0127] Overpotential Overpotential Comparative Example 1 <![CDATA[640mV@1Acm -2 ]]> <![CDATA[200mV@10mAcm -2 ]]> Comparative Example 2 <![CDATA[509mV@1Acm -2 ]]> <![CDATA[32mV@10mAcm -2 ]]>

[0128] It can be seen that the black Ni-MoO2 electrocatalyst obtained by reaction at 500°C under Ar / H2 mixed atmosphere has the best electrocatalytic performance for hydrogen production from seawater.

[0129] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a nickel-doped molybdenum dioxide composite seawater electrocatalyst, characterized in that: The following steps are involved: 1) adding tetrahydrated ammonium molybdate and hexahydrated nickel chloride to deionized water respectively and mixing them, then placing the foamed nickel in the obtained mixed solution and letting it stand, heating it, cooling it to room temperature, washing it, and vacuum drying it to obtain a Ni-Mo-O precursor; 2) In a Joule heat instrument, reacting a Ni-Mo-O precursor in an inert atmosphere at 400-600° C. for 0.5-1.5 min to obtain a nickel-doped molybdenum dioxide composite seawater electrocatalyst; In step 1), the mass ratio of the tetrahydrated ammonium molybdate and the hexahydrated nickel chloride is 1:(1-4); In step 1), the parameters of the heating treatment are: temperature 150° C., time 6 h.

2. The method for preparing the nickel-doped molybdenum dioxide composite seawater electrocatalyst according to claim 1, characterized in that: In step 1), the standing time is 5-10 min.

3. The method for preparing the nickel-doped molybdenum dioxide composite seawater electrocatalyst according to claim 1, characterized in that: In step 1), the parameters of vacuum drying are: temperature 5-100°C, time 8-72h, vacuum degree 133-267Pa.

4. The method for preparing the nickel-doped molybdenum dioxide composite seawater electrocatalyst according to claim 1, characterized in that: In step 2), the inert atmosphere refers to an Ar / H2 mixed gas.

5. Use of the nickel-doped molybdenum dioxide composite seawater electrocatalyst prepared by the preparation method according to any one of claims 1 to 4 in electrocatalytic cracking of seawater to produce hydrogen.

6. The use according to claim 5, characterized in that: The nickel-doped molybdenum dioxide composite seawater electrocatalyst is used as a working electrode, a calomel electrode is used as a reference electrode, a graphite electrode is used as a counter electrode, and the electrolyte is alkaline seawater; the pH value of the electrolyte is 10-14.

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