A method for hydrogen production by hydrazine borane-assisted electrolytic water

Abstract

The present invention provides a method for hydrogen production by hydrazine borane-assisted electrolysis of water. Using an alkaline solution as the electrolyte and hydrazine borane as the auxiliary electrolyte, the cathode and anode are respectively placed in the electrolyte solution, and under an externally applied direct current, hydrazine borane-assisted electrolysis of water is carried out. The electrocatalytic oxidation of hydrazine borane in the present invention requires a lower voltage than the oxygen evolution reaction. Replacing the oxygen evolution reaction with the electrocatalytic oxidation reaction of hydrazine borane can overcome the disadvantage of high potential in traditional electrolytic water hydrogen production and has the effect of reducing the electrolytic cell voltage. The method for hydrazine borane-assisted electrolysis of water proposed by the present invention has a simple process and can produce hydrogen at a lower voltage, which is a method with great development prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalytic hydrogen production by electrolysis, and relates to a method for energy-saving electrolytic water hydrogen production. More specifically, the present invention relates to a method for hydrazine borane-assisted electrolytic water hydrogen production. Background Art

[0002] Hydrogen energy is a clean and renewable energy source with high energy density and easy transportation and storage characteristics. Electrolytic water hydrogen production is considered an important means for preparing high-purity hydrogen. Currently, the bottleneck of electrolytic water hydrogen production mainly lies in the oxygen evolution reaction (OER) at the anode. Since the oxygen evolution reaction involves a four-electron transfer process, it is inherently kinetically slow, and the thermodynamic energy barrier for the formation of the O-O bond is relatively high, resulting in the need for a high voltage of more than 1.23 V for electrochemical water splitting to produce hydrogen, which severely restricts the large-scale application of electrolytic water hydrogen production. Therefore, introducing a more easily oxidized reaction to replace the oxygen evolution reaction to significantly reduce the electrolytic cell voltage is considered a promising strategy.

[0003] In recent years, people have tried to find other alternative reactions to overcome the obstacles of electrolytic water hydrogen production, mostly small molecules. For urea-assisted electrolytic water hydrogen production, urea is easily obtained from sewage, but the reaction involves a six-electron process, and the required voltage is far higher than the theoretical potential. Studies on ethanol-assisted electrolytic water show that its oxidation products contain carbon substances, which may lead to catalyst poisoning and the generation of greenhouse gases. Hydrazine hydrate-assisted electrolytic water is currently one of the reactions with the lowest reported voltage, but hydrazine is toxic and unstable, which is not conducive to application and safety.

[0004] Hydrazine borane (N2H4BH3) is a solid that is easy to prepare, does not contain carbon atoms, and is stable and non-toxic. The theoretical potential of hydrazine borane electrooxidation is (-0.4 V vs. RHE), which is a very promising small molecule to replace the oxygen evolution reaction, thereby achieving efficient hydrogen production at low voltage. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for hydrazine borane-assisted electrolytic water hydrogen production.

[0006] The method for hydrazine borane-assisted electrolytic water hydrogen production proposed by the present invention is based on traditional electrolytic water hydrogen production, uses water-soluble hydrazine borane as an auxiliary electrolyte, replaces the oxygen evolution reaction through the electrochemical oxidation reaction of hydrazine borane, places the cathode and anode in the electrolyte respectively, and realizes hydrazine borane-assisted electrolytic water hydrogen production under an externally applied direct current.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for producing hydrogen by hydrazine borane-assisted electrolysis of water uses an alkaline solution as the electrolyte and hydrazine borane as the auxiliary electrolyte. The cathode and anode are respectively placed in the electrolyte solution, and under an externally applied direct current, hydrazine borane-assisted electrolysis of water is carried out.

[0009] The working principle of hydrazine borane-assisted electrolysis of water is as follows:

[0010] Anode: N2H4BH3 + 10OH - = HBO2 + N2 + 8H2O + 10e - (1)

[0011] Cathode: 4H2O + 4e - = 2H2 + 4OH - (2)

[0012] Total reaction: N2H4BH3 + 6OH - = HBO2 + N2 + 2H2 + 4H2O + 6e - (3)

[0013] Preferably, the voltage of the direct current is -0.5 - 1V.

[0014] Preferably, the alkaline solution is NaOH or KOH.

[0015] Preferably, the concentration of the alkaline solution is 0.5 - 3 mol / L.

[0016] Preferably, the concentration of the auxiliary electrolyte is 0.001 - 1 mol / L.

[0017] Preferably, the substrates of the anode and cathode are glassy carbon electrodes, nickel foam or carbon cloth.

[0018] Preferably, the anode and cathode catalysts are noble metals or transition metal phosphides.

[0019] Preferably, the noble metal is one or more combinations of Pd, Au, Pt, Ag.

[0020] Preferably, the transition metal phosphide is one or more combinations of NiP, CoP, FeP.

[0021] The advantages of the present invention are: The voltage required for the electrocatalytic oxidation of hydrazine borane is lower than that of the oxygen evolution reaction. When the electrocatalytic oxidation of hydrazine borane replaces the oxygen evolution reaction, it can reduce the voltage of traditional electrolysis of water for hydrogen production. When CoNiFeP is used as a bifunctional catalyst for hydrazine borane-assisted hydrolysis, at 10 mA / cm 2At a current density, its decomposition voltage is 0.078 V, which is much lower than the decomposition voltage of pure electrolyzed water (1.478 V), and it is a potential application method for low-energy-consuming and efficient hydrogen production by electrolyzing water. In addition, hydrazine borane is an easily prepared solid. Compared with small molecules such as urea, ethanol, and hydrazine hydrate, the product does not contain carbon atoms, is safe and non-toxic, and has good stability in solution. Brief Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0023] Figure 1 It is the working principle diagram of hydrogen production by hydrazine borane-assisted electrolysis of water.

[0024] Figure 2 It is the linear sweep voltammetry curve of CoNiFeP as a bifunctional catalyst for hydrazine borane-assisted electrolysis of water for hydrogen evolution and pure electrolysis of water for hydrogen evolution in Example 1. Detailed Embodiments

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0026] For hydrazine borane-assisted electrolysis of water, using a hydrazine borane alkaline solution as the electrolyte, its working principle is as Figure 1 shown.

[0027] The working principle of hydrazine borane-assisted electrolysis of water is as follows:

[0028] Anode: N2H4BH3 + 10OH - = HBO2 + N2 + 8H2O + 10e - (1)

[0029] Cathode: 4H2O + 4e - = 2H2 + 4OH - (2)

[0030] Total reaction: N2H4BH3 + 6OH - = HBO2 + N2 + 2H2 + 4H2O + 6e - (3)

[0031] The following provides a specific implementation manner of a method for producing hydrogen by hydrazine borane-assisted electrolysis of water according to the present invention.

[0032] Example 1:

[0033] In a self-made electrolytic cell, an auxiliary electrolyte hydrazine borane and a strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of KOH was 1 mol / L. The nickel foam loaded with CoNiFeP was used as the cathode and anode respectively and placed in the electrolytic cell to construct a test device for producing hydrogen by hydrazine borane-assisted electrolysis of water according to the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of producing hydrogen by hydrazine borane-assisted electrolysis of water.

[0034] Example 2:

[0035] In a self-made electrolytic cell, an auxiliary electrolyte hydrazine borane and a strong base NaOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of NaOH was 1 mol / L. The nickel foam loaded with CoNiFeP was used as the cathode and anode respectively and placed in the electrolytic cell to construct a test device for producing hydrogen by hydrazine borane-assisted electrolysis of water according to the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of producing hydrogen by hydrazine borane-assisted electrolysis of water.

[0036] Example 3:

[0037] In a self-made electrolytic cell, an auxiliary electrolyte hydrazine borane and a strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of KOH was 0.5 mol / L. The nickel foam loaded with CoNiFeP was used as the cathode and anode respectively and placed in the electrolytic cell to construct a test device for producing hydrogen by hydrazine borane-assisted electrolysis of water according to the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of producing hydrogen by hydrazine borane-assisted electrolysis of water.

[0038] Example 4:

[0039] In a self-made electrolytic cell, an auxiliary electrolyte hydrazine borane and a strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of KOH was 3 mol / L. The nickel foam loaded with CoNiFeP was used as the cathode and anode respectively and placed in the electrolytic cell to construct a test device for producing hydrogen by hydrazine borane-assisted electrolysis of water according to the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of producing hydrogen by hydrazine borane-assisted electrolysis of water.

[0040] Example 5:

[0041] In a self-made electrolytic cell, the auxiliary electrolyte hydrazine borane and the strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.001 mol / L, and the concentration of KOH was 1 mol / L. The nickel foam loaded with CoNiFeP was used as the cathode and anode respectively in the electrolytic cell to construct the test device for hydrogen production by hydrazine borane-assisted electrolysis of water of the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of hydrogen production by hydrazine borane-assisted electrolysis of water.

[0042] Example 6:

[0043] In a self-made electrolytic cell, the auxiliary electrolyte hydrazine borane and the strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 1 mol / L, and the concentration of KOH was 1 mol / L. The nickel foam loaded with CoNiFeP was used as the cathode and anode respectively in the electrolytic cell to construct the test device for hydrogen production by hydrazine borane-assisted electrolysis of water of the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of hydrogen production by hydrazine borane-assisted electrolysis of water.

[0044] Example 7:

[0045] In a self-made electrolytic cell, the auxiliary electrolyte hydrazine borane and the strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of KOH was 1 mol / L. The nickel foam loaded with Pd was used as the cathode and anode respectively in the electrolytic cell to construct the test device for hydrogen production by hydrazine borane-assisted electrolysis of water of the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of hydrogen production by hydrazine borane-assisted electrolysis of water.

[0046] Example 8:

[0047] In a self-made electrolytic cell, the auxiliary electrolyte hydrazine borane and the strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of KOH was 1 mol / L. The nickel foam loaded with Au was used as the cathode and anode respectively in the electrolytic cell to construct the test device for hydrogen production by hydrazine borane-assisted electrolysis of water of the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of hydrogen production by hydrazine borane-assisted electrolysis of water.

[0048] Example 9:

[0049] In a self-made electrolytic cell, the auxiliary electrolyte hydrazine borane and the strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of KOH was 1 mol / L. The nickel foam loaded with Pt was used as the cathode and anode respectively in the electrolytic cell to construct the test device for hydrogen production by hydrazine borane-assisted electrolysis of water of the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of hydrogen production by hydrazine borane-assisted electrolysis of water.

[0050] Example 10:

[0051] In a self-made electrolytic cell, the auxiliary electrolyte hydrazine borane and the strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of KOH was 1 mol / L. The nickel foam loaded with Ag was used as the cathode and anode respectively in the electrolytic cell to construct the test device for hydrogen production by hydrazine borane-assisted electrolysis of water of the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of hydrogen production by hydrazine borane-assisted electrolysis of water.

[0052] Example 11:

[0053] In a self-made electrolytic cell, the auxiliary electrolyte hydrazine borane and the strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of KOH was 1 mol / L. The nickel foam loaded with cobalt PdAu was used as the cathode and anode respectively in the electrolytic cell to construct the test device for hydrogen production by hydrazine borane-assisted electrolysis of water of the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of hydrogen production by hydrazine borane-assisted electrolysis of water.

[0054] Example 12:

[0055] In a self-made electrolytic cell, the auxiliary electrolyte hydrazine borane and the strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of KOH was 1 mol / L. The nickel foam loaded with NiP was used as the cathode and anode respectively in the electrolytic cell to construct the test device for hydrogen production by hydrazine borane-assisted electrolysis of water of the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of hydrogen production by hydrazine borane-assisted electrolysis of water.

[0056] Example 13:

[0057] In a self-made electrolytic cell, the auxiliary electrolyte hydrazine borane and the strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of KOH was 1 mol / L. The nickel foam loaded with CoP was used as the cathode and anode respectively in the electrolytic cell to construct the test device for hydrogen production by hydrazine borane-assisted electrolysis of water of the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of hydrogen production by hydrazine borane-assisted electrolysis of water.

[0058] Example 14:

[0059] In a self-made electrolytic cell, the auxiliary electrolyte hydrazine borane and the strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of KOH was 1 mol / L. The nickel foam loaded with FeP was used as the cathode and anode respectively in the electrolytic cell to construct the test device for hydrogen production by hydrazine borane-assisted electrolysis of water of the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of hydrogen production by hydrazine borane-assisted electrolysis of water.

[0060] Example 15:

[0061] In a self-made electrolytic cell, the auxiliary electrolyte hydrazine borane and the strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of KOH was 1 mol / L. The glassy carbon electrode loaded with CoNiFeP was used as the cathode and anode respectively and placed in the electrolytic cell to construct the test device for producing hydrogen by hydrazine borane-assisted electrolysis of water of the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of producing hydrogen by hydrazine borane-assisted electrolysis of water.

[0062] Example 16:

[0063] In a self-made electrolytic cell, the auxiliary electrolyte hydrazine borane and the strong base KOH were added to form an aqueous solution. The concentration of hydrazine borane in the solution was 0.1 mol / L, and the concentration of KOH was 1 mol / L. The carbon cloth loaded with CoNiFeP was used as the cathode and anode respectively and placed in the electrolytic cell to construct the test device for producing hydrogen by hydrazine borane-assisted electrolysis of water of the present invention. At room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of producing hydrogen by hydrazine borane-assisted electrolysis of water.

[0064] Example 17:

[0065] For the test device for producing hydrogen by hydrazine borane-assisted electrolysis of water constructed according to Example 1, at room temperature, a DC voltage of -0.5 - 1 V was applied to realize the process of producing hydrogen by hydrazine borane-assisted electrolysis of water. The data of the cell voltage and current during the hydrogen production process were recorded by Chenhua CHI760E. It was found that compared with the traditional electrolysis of water without hydrazine borane, as Figure 2 shown, when tested in a 1 mol / L KOH solution containing 0.1 mol / L N2H4BH3, at a current density of 10 mA / cm 2 its decomposition voltage was 0.078 V, which was much lower than the decomposition voltage of traditional electrolysis of water (1.478 V).

[0066] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and reference can be made to the description in the method part for relevant parts.

[0067] The foregoing description of the disclosed embodiments enables those skilled in the art to practice or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for hydrogen production by hydrazine borane-assisted electrolytic water, characterized in that, Using an alkaline solution as the electrolyte and hydrazine borane as the auxiliary electrolyte, the cathode and anode are respectively placed in the electrolyte solution, and hydrogen is produced by electrolyzing water assisted by hydrazine borane under an externally applied direct current of -0.5 - 1V; the cathode and anode are loaded with nickel foam of CoNiFeP.

2. The method for hydrogen production by hydrazine borane-assisted electrolytic water according to claim 1, characterized in that, The alkaline solution is NaOH or KOH.

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