A method for preparing high-efficiency hydrogen evolution electrocatalyst by regulating iron corrosion using urea

Abstract

The present invention discloses a method for preparing an efficient hydrogen evolution electrocatalyst by regulating iron corrosion with urea. The method regulates the spontaneous corrosion process of foamed iron and RuCl3 at room temperature by adding urea molecules containing amino groups to the corrosive solution, and finally grows an efficient hydrogen evolution electrocatalyst in situ on the foamed iron. The prepared efficient hydrogen evolution electrocatalyst has a pine needle-like morphology, has abundant active sites, and effectively reduces the overpotential of the hydrogen evolution reaction. The regulation of the corrosion process by urea mainly includes the following two aspects: first, the urea molecules can be adsorbed on the metal surface, blocking the direct contact between the metal and the corrosive agent, improving the reaction environment between the foamed iron and RuCl3, reducing the intensity of the reaction, and indirectly regulating the morphology of the corrosion layer; second, the amino groups in the urea molecules can react with Cl ‑ The combination can slow down corrosion and ensure that the corrosion layer grows more uniformly and orderly, and ultimately produce an efficient hydrogen evolution electrocatalyst with abundant active sites.

Description

Technical Field

[0001] The invention belongs to the technical field of preparing electrocatalysts for hydrogen evolution by electrolysis of water, and particularly relates to a method for preparing a high-efficiency electrocatalyst for hydrogen evolution by regulating iron corrosion using urea. Background Art

[0002] Since the first industrial revolution, people have consumed a large amount of fossil fuels, causing serious environmental pollution and energy crisis. Therefore, there is an urgent need to develop clean and sustainable energy to solve these problems. H2, as an eco-friendly energy carrier, is expected to play an important role in future sustainable energy. The hydrogen evolution reaction (HER) in water decomposition is considered to be an ideal process for hydrogen production without by-products. As an important component of the water decomposition device, hydrogen evolution electrocatalysts are used to reduce the overpotential caused by polarization and improve the energy transfer efficiency. However, the HER reaction energy barrier is relatively high and the kinetics are slow, resulting in huge energy consumption. Therefore, the development of efficient and inexpensive HER electrocatalysts has become one of the most urgent needs in water electrolysis hydrogen production technology.

[0003] Currently, powdered catalysts commonly used in water electrolysis suffer from low electrical conductivity and binder-encapsulated active sites, resulting in low electrocatalytic activity. While abundant transition metal-based catalysts offer strong electron transport and high surface area, their catalytic activity still needs to be further improved. Precious metal-based catalysts offer excellent catalytic activity, but their high cost significantly hinders their large-scale application. The emergence of self-supporting catalysts has effectively addressed these issues. The metal or carbon substrates of self-supporting catalysts possess excellent conductivity, ensuring rapid electron transfer. Their binder-free nature allows for greater exposure of active sites, enhancing electrocatalytic activity. Furthermore, the composite of transition metals with precious metals reduces precious metal usage, significantly saving costs. Ruthenium-based catalysts, in particular, exhibit excellent H-OH bond cleavage during the HER process, due to their similar hydrogen bonding strength to that of platinum and their competitive price. Therefore, the preparation of self-supporting transition metal and precious metal Ru composite catalysts is advantageous for achieving high catalytic performance. Common methods for preparing self-supporting catalysts are hydrothermal and electrochemical deposition. However, the specialized solution preparation and complex reaction apparatus require additional electrical and thermal energy, resulting in high cost and difficulty in fabricating HER electrodes. The metal corrosion strategy offers a simple process and low energy consumption, effectively addressing the aforementioned issues. This study uses foamed iron as a substrate and modulates the iron corrosion environment by adding urea to the corrosion solution, thereby preparing a Ru-modified iron-based self-supporting hydrogen evolution electrocatalyst with excellent electrocatalytic activity. Summary of the Invention

[0004] The technical problem solved by the present invention is to provide a method for preparing an efficient hydrogen evolution electrocatalyst by regulating iron corrosion with urea. The method regulates the spontaneous corrosion process of foamed iron and RuCl3 at room temperature by adding urea molecules containing amino groups to the corrosive solution, and finally grows an efficient hydrogen evolution electrocatalyst in situ on the foamed iron. The prepared efficient hydrogen evolution electrocatalyst has a pine needle-like morphology, has abundant active sites, and effectively reduces the overpotential of the hydrogen evolution reaction. The regulation of the corrosion process by urea mainly includes the following two aspects: first, the urea molecules can be adsorbed on the metal surface, blocking the direct contact between the metal and the corrosive agent, improving the reaction environment between the foamed iron and RuCl3, reducing the intensity of the reaction, and indirectly regulating the morphology of the corrosion layer; second, the amino groups in the urea molecules can react with Cl - The combination can slow down corrosion and ensure that the corrosion layer grows more uniformly and orderly, and ultimately produce an efficient hydrogen evolution electrocatalyst with abundant active sites.

[0005] The present invention adopts the following technical solution to solve the above technical problems, a method for preparing a high-efficiency hydrogen evolution electrocatalyst by regulating iron corrosion with urea, characterized in that the specific process is as follows:

[0006] Step S1: cutting the foam iron, ultrasonically cleaning it in anhydrous ethanol for 3 to 5 minutes to remove organic pollutants on the surface, then ultrasonically cleaning it in dilute hydrochloric acid for 30 to 50 minutes to remove oxides, and then rinsing it with deionized water and ethanol to obtain material A;

[0007] Step S2: adding urea to deionized water and mixing and stirring for 10 to 20 minutes, then adding RuCl3 and mixing and stirring for 1 to 3 hours to obtain a mixed solution B;

[0008] Step S3: adding the material A obtained in step S1 to the mixed solution B obtained in step S2, stirring at room temperature for 120 to 150 minutes, and obtaining material C through a metal corrosion reaction;

[0009] Step S4: washing the material C obtained in step S3 with deionized water and anhydrous ethanol, and then drying the material C at 80° C. for 3 h to obtain the target product, a high-efficiency hydrogen evolution electrocatalyst having a pine needle-like morphology.

[0010] Further defined, the size of the foam iron in step S1 is 2×2 cm 2 .

[0011] It is further defined that the rotation speed of the mixing and stirring in step S2 is 100 rpm.

[0012] It is further defined that the molar concentration of RuCl3 in the mixed solution B in step S2 is 1-3 mM, and the molar concentration of urea is 100-200 mM.

[0013] The method of the present invention for preparing a high-efficiency hydrogen evolution electrocatalyst by regulating iron corrosion with urea is characterized by the following steps:

[0014] Step S1: Cut to size 2×2cm 2 The foamed iron was ultrasonically cleaned in anhydrous ethanol for 5 minutes to remove organic pollutants on the surface, and then ultrasonically cleaned in dilute hydrochloric acid for 40 minutes to remove surface oxides, and then rinsed with deionized water and ethanol to obtain material A;

[0015] Step S2: adding urea to deionized water and mixing and stirring for 10 minutes, then adding RuCl3 and mixing and stirring for 1 hour to obtain a mixed solution B1, wherein the molar concentration of RuCl3 is 2 mM and the molar concentration of urea is 100 mM;

[0016] Step S3: adding the material A obtained in step S1 to the mixed solution B obtained in step S2, stirring at room temperature for 120 minutes, and obtaining material C through a spontaneous metal corrosion process;

[0017] Step S4: The material C obtained in step S3 was washed with deionized water and anhydrous ethanol, and then dried at 80°C for 3h to obtain a high-efficiency hydrogen evolution electrocatalyst with a pine needle-like morphology. The hydrogen evolution electrocatalyst was -2 The overpotential of hydrogen evolution reaction at the current density is only 116~130mV.

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

[0019] 1. The present invention produces a highly efficient hydrogen evolution electrocatalyst with foamed iron as the metal substrate through the spontaneous corrosion reaction of foamed iron in a mixed solution of urea and RuCl3 at room temperature. The corrosion layer of the highly efficient hydrogen evolution electrocatalyst exhibits a pine needle-like morphology, providing abundant active sites for the electrocatalytic reaction.

[0020] 2. The present invention adds urea molecules containing amino groups into the mixed solution, and the amino groups can react with Cl - The combination improves the reaction environment of foamed iron and RuCl3, slows down corrosion, makes the corrosion layer grow more uniformly, and indirectly regulates the morphology and electrochemical catalytic performance of hydrogen evolution electrocatalyst;

[0021] 3. The high-efficiency hydrogen evolution electrocatalyst prepared by the present invention is 1 mol L -1 Electrochemical tests were carried out in KOH electrolyte at 100 mA cm -2 The overpotential of hydrogen evolution reaction under the current density is only 116-130mV. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a scanning electron microscope image of the product D1 prepared in Example 1;

[0023] Figure 2 Corrosion polarization curves of products D1 to D4 prepared in Examples 1 to 4;

[0024] Figure 3 Electrochemical impedance spectroscopy (EIS) of products D1 to D4 prepared in Examples 1 to 4;

[0025] Figure 4 The linear sweep voltammetry curves of products D1 to D4 prepared in Examples 1 to 4 are shown. DETAILED DESCRIPTION

[0026] The above contents of the present invention are further described in detail below through examples, but this should not be understood as limiting the scope of the above subject matter of the present invention to the following examples. All technologies implemented based on the above contents of the present invention fall within the scope of the present invention.

[0027] Example 1

[0028] Step S1: Cut to size 2×2cm 2 The foamed iron was ultrasonically cleaned in anhydrous ethanol for 5 min, then ultrasonically cleaned in dilute hydrochloric acid for 40 min, and then washed with deionized water and ethanol to obtain material A1;

[0029] Step S2: adding urea to deionized water and mixing and stirring for 10 minutes, then adding RuCl3 and mixing and stirring for 1 hour to obtain a mixed solution B1, wherein the molar concentration of RuCl3 is 2 mM and the molar concentration of urea is 100 mM;

[0030] Step S3: Add material A1 to material B1 and stir at room temperature for 120 minutes to obtain material C1 through spontaneous metal corrosion reaction;

[0031] Step S4: Wash the material C1 with pure water and anhydrous ethanol, and then place the material C1 in an 80° C. forced air drying oven and dry it for 3 h to obtain the product D1.

[0032] Example 2

[0033] Step S1: Cut to size 2×2cm 2 The foamed iron was ultrasonically cleaned in anhydrous ethanol for 5 min, then ultrasonically cleaned in dilute hydrochloric acid for 40 min, and then washed with deionized water and ethanol to obtain material A2;

[0034] Step S2: adding RuCl 3 into deionized water and stirring for 1 h to obtain a mixed solution B2, wherein the molar concentration of RuCl 3 is 2 mM;

[0035] Step S3: Add material A2 to material B2 and stir at room temperature for 120 minutes to obtain material C2 through spontaneous metal corrosion reaction;

[0036] Step S4: Wash the material C2 with pure water and anhydrous ethanol, and then place the material C2 in an 80° C. forced air drying oven and dry it for 3 h to obtain the product D2.

[0037] Example 3

[0038] Step S1: Cut to size 2×2cm 2 The foamed iron was ultrasonically cleaned in anhydrous ethanol for 5 min, then ultrasonically cleaned in dilute hydrochloric acid for 40 min, and then washed with deionized water and ethanol to obtain material A3;

[0039] Step S2: adding thiourea to deionized water and mixing and stirring for 10 minutes, then adding RuCl3 and mixing and stirring for 1 hour to obtain a mixed solution B3, wherein the molar concentration of RuCl3 is 2 mM and the molar concentration of thiourea is 100 mM;

[0040] Step S3: Add material A3 to material B3 and stir at room temperature for 120 minutes to obtain material C3 through spontaneous metal corrosion reaction;

[0041] Step S4: Wash the material C3 with pure water and anhydrous ethanol, and then place the material C3 in an 80° C. forced air drying oven and dry it for 3 h to obtain the product D3.

[0042] Example 4

[0043] Step S1: Cut to size 2×2cm 2 The foamed iron was ultrasonically cleaned in anhydrous ethanol for 5 min, then ultrasonically cleaned in dilute hydrochloric acid for 40 min, and then washed with deionized water and ethanol to obtain material A4;

[0044] Step S2: adding thiosemicarbazide to deionized water and mixing and stirring for 10 minutes, then adding RuCl3 and mixing and stirring for 1 hour to obtain a mixed solution B3, wherein the molar concentration of RuCl3 is 2 mM and the molar concentration of thiosemicarbazide is 100 mM;

[0045] Step S3: Add material A4 to material B4 and stir at room temperature for 120 minutes to obtain material C4 through spontaneous metal corrosion reaction;

[0046] Step S4: Wash the material C4 with pure water and anhydrous ethanol, and then place the material C4 in an 80° C. forced air drying oven and dry it for 3 h to obtain the product D4.

[0047] Example 5

[0048] Cut 1×0.5cm 2 The target product, efficient hydrogen evolution electrocatalyst D1, was fixed as a working electrode with a platinum electrode clamp, so that its effective area was 0.4×0.5cm 2The same method was used to prepare the working electrodes of products D2, D3, and D4, which were used to compare with the target product D1. All electrochemical tests used a three-electrode system, with Hg / HgO electrode and carbon rod as reference electrode and counter electrode respectively, and the electrolyte was 1 mol L -1 The linear sweep voltammetry (LSV) test was performed at a scan rate of 5 mV s -1 The scanning range is 0~-0.4V(vs.RHE). During the impedance (EIS) test, the target product D1 was cut to make its effective area 0.4×0.5cm 2 , using 1 mol L -1 KOH solution as electrolyte, the frequency range is 0.01~10 5 Hz.

[0049] The performance characteristics of the samples in all examples are as follows: Figure 1 As shown in FIG. 1 , the scanning electron microscope image of the product D1 obtained in Example 1 has a distinct pine needle-like structure. Figure 2 As shown in Figure 1, the corrosion polarization curves of products D1 to D4 prepared in Examples 1 to 4 are shown. The corrosion degree of product D1 is between that of products D2, D3, and D4. Figure 4 As shown in the figure, the linear sweep voltammetry curves of products D1 to D4 prepared in Examples 1 to 4 are shown. Products D1 to D3 are at 100 mA cm -2 The overpotentials of the hydrogen evolution reaction at these current densities were 116 mV, 171 mV, and 266 mV, respectively. These results indicate that product D1 exhibits excellent electrocatalytic hydrogen evolution performance, and its preparation process is clean, efficient, green, and simple, demonstrating its broad prospects for practical applications.

[0050] The above embodiments describe the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the scope of the principles of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for preparing an efficient hydrogen evolution electrocatalyst by regulating iron corrosion using urea, characterized in that The specific process is: Step S1: cutting the foam iron, ultrasonically cleaning it in anhydrous ethanol for 3-5 minutes to remove organic pollutants on the surface, then ultrasonically cleaning it in dilute hydrochloric acid for 30-50 minutes to remove oxides, and then rinsing it with deionized water and ethanol to obtain material A; Step S2: adding urea to deionized water and mixing and stirring for 10-20 minutes, then adding RuCl3 and mixing and stirring for 1-3 hours to obtain a mixed solution B, wherein the molar concentration of RuCl3 in the mixed solution B is 1-3 mM and the molar concentration of urea is 100-200 mM; Step S3: adding the material A obtained in step S1 to the mixed solution B obtained in step S2, stirring at room temperature for 120-150 minutes, and obtaining material C through a metal corrosion reaction; Step S4: washing the material C obtained in step S3 with deionized water and anhydrous ethanol, and then drying the material C at 80° C. for 3 h to obtain the target product, a high-efficiency hydrogen evolution electrocatalyst having a pine needle-like morphology.

2. The method for preparing an efficient hydrogen evolution electrocatalyst by regulating iron corrosion using urea according to claim 1, characterized in that: The size of the foam iron in step S1 is 2×2 cm 2 .

3. The method for preparing an efficient hydrogen evolution electrocatalyst by regulating iron corrosion using urea according to claim 1, characterized in that: The rotation speed of the mixing and stirring in step S2 is 100 rpm.

4. The method for preparing an efficient hydrogen evolution electrocatalyst by regulating iron corrosion using urea according to claim 1, characterized in that The steps are: Step S1: Cut to size 2×2cm 2 The foamed iron was ultrasonically cleaned in anhydrous ethanol for 5 minutes to remove organic pollutants on the surface, and then ultrasonically cleaned in dilute hydrochloric acid for 40 minutes to remove surface oxides, and then rinsed with deionized water and ethanol to obtain material A; Step S2: adding urea to deionized water and mixing and stirring for 10 minutes, then adding RuCl3 and mixing and stirring for 1 hour to obtain a mixed solution B1, wherein the molar concentration of RuCl3 is 2 mM and the molar concentration of urea is 100 mM; Step S3: adding the material A obtained in step S1 to the mixed solution B obtained in step S2, stirring at room temperature for 120 minutes, and obtaining material C through a spontaneous metal corrosion process; Step S4: The material C obtained in step S3 was washed with deionized water and anhydrous ethanol, and then dried at 80°C for 3h to obtain a high-efficiency hydrogen evolution electrocatalyst with a pine needle-like morphology. The hydrogen evolution electrocatalyst was -2 The overpotential of hydrogen evolution reaction at the current density is only 116~130mV.

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