A twin-phase nano-structured alloy hydrogen evolution catalyst, and a preparation method and application thereof

Abstract

The present application relates to hydrogen evolution catalyst and heterogeneous structure alloy material technical field, specifically relates to a kind of bimorph nanostructure alloy hydrogen evolution catalyst and its preparation method and application.Bimorph nanostructure alloy hydrogen evolution catalyst includes substrate and the bimorph nanostructure alloy of deposition on the substrate surface, bimorph nanostructure alloy is composed of the following elements:Ru 56%~62%, Mn 5%~30%, Nb 8%~30% and O 5%~6%, total 100%;The bimorph nanostructure alloy includes Mn-rich phase and Mn-lean phase, and forms O-rich interface between Mn-rich phase and Mn-lean phase, and O-rich interface has catalytic active site;The size of Mn-rich phase is 1nm~6nm.The present application solves the problem that the strong interaction between Ru and H atom in existing Ru-based catalyst will hinder H2 desorption, resulting in the problem of hydrogen production rate reduction.

Description

Technical Field

[0001] This invention relates to the field of hydrogen evolution electrocatalysts and heterogeneous phase alloy materials, specifically to a bicrystalline nanostructured alloy hydrogen evolution catalyst, its preparation method, and its application. Background Technology

[0002] The widespread combustion of fossil fuels has led to numerous pollution and development problems, drawing widespread attention. However, this technology boasts zero carbon emissions and a maximum energy density of 142 MJ·kg⁻¹. -1 Hydrogen has become an ideal solution to energy shortages and environmental pollution. Among various hydrogen production methods, electrochemical water splitting, especially electrocatalytic hydrogen evolution reaction (HER), is considered an efficient, sustainable, and green synthesis strategy. HER is a high-performance, low-cost electrocatalyst for hydrogen evolution. Platinum, due to its superior hydrogen binding affinity, is widely recognized as the most advanced HER catalyst; however, its low reserves and high price significantly hinder its industrial application. Therefore, the key challenge at present is to develop high-performance and low-cost electrocatalysts for hydrogen evolution.

[0003] Ruthenium, as a precious metal, not only boasts an ideal price (approximately 5% of Pt) but also exhibits excellent water dissociation capabilities, making it a theoretically suitable substitute for Pt. However, the application of Ru-based catalysts faces limitations due to the strong interaction between Ru and H atoms. According to catalyst adsorption kinetics, this strong interaction hinders H2 desorption, leading to a decrease in hydrogen production. Summary of the Invention

[0004] To address the problem that the strong interaction between Ru and H atoms in existing Ru-based catalysts hinders H2 desorption, leading to a decrease in hydrogen production, the present invention aims to provide a bicrystalline nanostructured alloy hydrogen evolution catalyst, its preparation method, and its application.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows.

[0006] A first aspect of this invention provides a bicrystalline nanostructured alloy hydrogen evolution catalyst, comprising a substrate and a bicrystalline nanostructured alloy deposited on the surface of the substrate; the bicrystalline nanostructured alloy is composed of the following elements by atomic percentage:

[0007] The alloy comprises 56%–62% Ru, 5%–30% Mn, 8%–30% Nb, and 5%–6% O, totaling 100%. The bicrystalline nanostructure alloy includes a Mn-rich phase and a Mn-poor phase, with an O-rich interface formed between the Mn-rich and Mn-poor phases. The O-rich interface serves as a catalytic active site. The size of the Mn-rich phase is 1 nm–6 nm.

[0008] This invention primarily achieves Mn-rich and Mn-poor phases of varying sizes by controlling the content of Mn and Ru elements. The synergistic effect of these two phases promotes the formation of an O-rich interface. This O-rich interface enhances charge transfer and water dissociation kinetics, optimizes hydrogen adsorption and desorption processes, and thus improves HER performance. Furthermore, the high-density O-rich interface provides abundant catalytic active sites, improving HER catalytic performance and addressing the problem in existing Ru-based catalysts where the strong interaction between Ru and H atoms hinders H2 desorption, leading to reduced hydrogen production.

[0009] In this invention, Ru significantly affects catalytic activity. Excessive Ru content reduces the amount of Mn-rich phase, thereby decreasing the number of active interfaces formed in the Mn-rich phase. Conversely, Ru, as an active element, plays a crucial role in enhancing catalyst activity. Insufficient Ru content reduces catalytic sites, thus decreasing catalytic activity. Therefore, the Ru content should be controlled between 55% and 65%.

[0010] DFT calculations revealed that in the O-rich interface, O atoms can lower the energy barrier for the conversion of active hydrogen to H2. Simultaneously, O atoms can also improve the efficiency of the H2O dissociation step, resulting in RuMnNbO exhibiting superior electrochemical H2 release compared to Pt-based catalysts. The lower the cavity vacuum, the lower the O content. The O content affects the formation of the O-rich interface; excessively low O content leads to insufficient interface formation and reduces active sites. Conversely, excessively high O content causes over-oxidation of metal elements, excessively reducing the adsorption energy of active sites for H, which is detrimental to catalytic activity. Therefore, the O content should be controlled between 3% and 10%.

[0011] Preferably, the size of the Mn-rich phase is 1 nm to 2 nm. At this size, it helps to influence the size and number of highly active O-rich interfaces, thereby improving catalytic performance.

[0012] Preferably, the atomic percentage of Mn in the Mn-rich phase is 20% to 30%, and the atomic percentage of Mn in the Mn-poor phase is 10% to 15%.

[0013] In this invention, the content of Mn element can affect the size of Mn-rich phase, and thus affect the size and number of highly active O-rich interfaces. The resulting high-density O-rich interfaces can provide abundant active sites, thereby improving catalytic performance.

[0014] Preferably, the Mn-rich phase is composed of the following elements by atomic percentage:

[0015] Ru 50%–60%, Mn 20%–30%, Nb 20%–22%, and O 3%–8%, totaling 100%.

[0016] Preferably, the Mn-depleted phase is composed of the following elements by atomic percentage:

[0017] Ru 60%–75%, Mn 10%–15% and Nb 22%–24%, totaling 100%.

[0018] The composition of the bicrystalline hydrogen evolution catalyst prepared by this invention is the average composition of the bicrystalline hydrogen evolution catalyst, which is different from the composition of the Mn-rich phase and the Mn-poor phase; and the ratio of the Mn-rich phase and the Mn-poor phase will affect the total composition of the bicrystalline hydrogen evolution catalyst.

[0019] A second aspect of this invention provides a method for preparing the bicrystalline nanostructured alloy hydrogen evolution catalyst described in the first aspect, comprising the following steps:

[0020] Using magnetron sputtering technology, a bicrystalline nanostructure alloy containing Mn-rich and Mn-poor phases is deposited on the substrate surface by controlling the content of Mn and Ru elements, and an O-rich interface is formed between the Mn-rich and Mn-poor phases of the bicrystalline nanostructure alloy. By adjusting the size of the Mn-rich phase, the size and number of the O-rich interface are adjusted to provide catalytic active sites.

[0021] In this invention, high-purity argon gas is used in the experiment. The oxygen forming the O-rich interface mainly originates from the air present in the vacuum chamber of the magnetron sputtering system. The amount of residual air in the chamber varies under different vacuum levels. Of course, it is also possible that the oxygen comes from the pores in the target material. Therefore, a mixture of argon and air exists in the sputtering chamber under a certain vacuum level.

[0022] Preferably, the process parameters for depositing bicrystalline phase nanostructured alloys are as follows:

[0023] Ru, Mn, and Nb were used as the target materials; the background vacuum was 1 × 10⁻⁶. -5 Pa ~ 5 × 10 -5The working pressure is 0.2 Pa to 0.4 Pa, and the distance between the substrate and the target is 15 cm; the sputtering temperature is 20 °C to 30 °C; when Ru is used as the target, the sputtering power is 50 watt to 80 watt; when Mn is used as the target, the sputtering power is 50 watt to 80 watt, and the sputtering voltage is 270 V to 430 V; when Nb is used as the target, the sputtering power is 50 watt to 80 watt, and the sputtering voltage is 175 V to 280 V; the deposition time is 45 min to 60 min.

[0024] Preferably, before using magnetron sputtering technology, the substrate is further subjected to pretreatment, which involves acid immersion of the cleaned substrate to improve its hydrophilicity; the substrate is a carbon cloth substrate.

[0025] Preferably, argon is used as the working gas, and the mass flow rate of sputtered argon is in the range of 30 sccm to 50 sccm.

[0026] The third aspect of this invention provides an application of the bicrystalline nanostructured alloy hydrogen evolution catalyst described in the second aspect in the electrocatalytic hydrogen evolution process.

[0027] Preferably, the specific application method includes the following steps:

[0028] A modified electrode was prepared by depositing a bicrystalline nanostructured alloy hydrogen evolution catalyst on the surface of a carbon cloth electrode. The modified electrode was used as the working electrode, a graphite rod as the counter electrode, and a saturated calomel electrode as the reference electrode to form a three-electrode system for electrocatalytic hydrogen evolution.

[0029] The beneficial effects of this invention are:

[0030] 1. This invention primarily achieves Mn-rich phases of varying sizes by controlling the Mn and Ru elemental composition. The synergistic effect of the Mn-rich / Mn-poor biphase promotes the formation of an O-rich interface. This O-rich interface enhances charge transfer and water dissociation kinetics, optimizing the hydrogen adsorption / desorption process and thus improving HER performance. Furthermore, the high-density O-rich interface provides abundant active sites, improving catalytic performance and addressing the problem in existing Ru-based catalysts where the strong interaction between Ru and H atoms hinders H2 desorption, leading to reduced hydrogen production.

[0031] 2. In this invention, the content of Mn element can affect the size of Mn-rich phase, and thus affect the size of the highly active O-rich interface. The resulting high-density O-rich interface can provide abundant active sites, thereby improving catalytic performance. Attached Figure Description

[0032] Figure 1These are the linear voltammetric scan curves of the three-electrode systems assembled using the bicrystalline nanostructured alloy hydrogen evolution catalysts of Examples 1 to 3 as the working electrode.

[0033] Figure 2 This is a Tafel slope diagram of the three-electrode system assembled using the bicrystalline nanostructured alloy hydrogen evolution catalysts of Examples 1 to 3 as the working electrode. The horizontal axis represents the logarithm of the current density, and the vertical axis represents the potential.

[0034] Figure 3 These are electrochemical impedance spectroscopy (EIS) spectra of three-electrode systems assembled using the bicrystalline nanostructured alloy hydrogen evolution catalysts of Examples 1-3 as working electrodes. Where Z' represents the real part of the impedance; -Z” represents the negative of the imaginary part of the impedance. Figure 3 The illustration is an equivalent circuit diagram drawn based on EIS data. Wherein, R... s R is the resistance of the solution. ct It is a charge transfer resistor, and CPF 1 is a constant phase angle element.

[0035] Figure 4 The three-electrode system assembled using the bicrystalline nanostructured alloy hydrogen evolution catalyst of Example 3 as the working electrode at 1.2 A·cm -2 The following is a stability test chart.

[0036] Figure 5 These are TEM images of the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 2. In the images, a is a low-magnification SEM image; b is a high-magnification SEM image; c–c5 are EDS elemental analysis results in SEM mode; and d and e are TEM images at different magnifications.

[0037] Figure 6 yes Figure 5 An enlarged view of the illustration in d.

[0038] Figure 7 These are TEM images of the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 1. In the images, h is a low-magnification SEM image; i is a high-magnification SEM image; j to j5 are EDS elemental analysis results in SEM mode; and k and l are TEM images at different magnifications.

[0039] Figure 8 yes Figure 7 An enlarged view of the illustration in the middle of the image.

[0040] Figure 9These are TEM images of the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 3. In the images, a is a low-magnification SEM image; b is a high-magnification SEM image; c is a low-magnification TEM image; d1 and d2 are magnified views of the selected portion in c; d3 is the three-dimensional atomic overlap Gaussian function fitting mapping diagram of the selected portion in c; and e to e4 are EDS elemental analysis diagrams in TEM mode.

[0041] Figure 10 These are TEM images of the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 3 in HAADF mode. In the images, a and b are low-magnification TEM images in HAADF mode; c is a high-magnification TEM image in HAADF mode; and d is the EDS elemental line scan analysis in image c.

[0042] Figure 11 yes Figure 10 An enlarged view of the illustration in section b. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0044] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] The full name of the electrocatalytic hydrogen evolution reaction is Electrocatalytic Hydrogen Evolution reaction, abbreviated as HER.

[0046] The full name of linear voltammetry is Linear Sweep Voltammetry, abbreviated as LSV.

[0047] The application of Ru-based catalysts is limited due to the strong interaction between Ru and H atoms. According to catalyst adsorption kinetics, this strong interaction hinders H2 desorption, leading to a decrease in hydrogen production. Therefore, it is crucial to rationally adjust the electronic structure of ruthenium-based catalysts and the H2 desorption / desorption energy.

[0048] Heterogeneous phase structures, with their different electronegativity and work functions, allow for directional electron transfer at the phase interface, inducing charge redistribution and optimizing their electronic structure and charge transport properties, thereby enhancing their catalytic activity. This invention primarily utilizes the synergistic effect of the heterogeneous phase structure and the ruthenium-based catalyst to rationally adjust the electronic structure and H2 desorption / resorption energy of the bicrystalline nanostructured alloy hydrogen evolution catalyst, resulting in a catalyst exhibiting excellent catalytic performance in electrochemical water splitting.

[0049] The technical solution of the present invention will be further described below through specific embodiments.

[0050] In the following embodiments, unless otherwise specified, the methods described are conventional methods; and unless otherwise specified, the reagents and materials described are commercially available.

[0051] In the following examples, the volume percentage of the HNO3 solution is 50 vol.%. The purity of the high-purity argon gas is ≥99.9%.

[0052] Example 1

[0053] A method for preparing a bicrystalline nanostructured alloy hydrogen evolution catalyst includes the following steps:

[0054] Step 1, Pretreatment of carbon cloth substrate:

[0055] To remove grease and impurities from the surface of the carbon cloth substrate, the surface of the carbon cloth substrate was cleaned sequentially with distilled water and anhydrous ethanol; then it was immersed in 50 vol.% HNO3 solution and kept at 60°C for 2 hours to improve the hydrophilicity of the carbon cloth substrate; after that, the immersed carbon cloth substrate was taken out, the acid solution was washed off with distilled water, and it was vacuum dried at 60°C to obtain the pretreated carbon cloth substrate.

[0056] Step 2, Preparation of the bicrystalline nanostructured alloy hydrogen evolution catalyst:

[0057] Ru, Mn, and Nb were used as targets. Before deposition, the distance between the pretreated carbon cloth substrate and the target was adjusted to 15 cm. The magnetron sputtering system was evacuated to achieve a vacuum level of 5 × 10⁻⁶ within the cavity. -5 Pa; Before starting deposition, high-purity argon gas is introduced into the sputtering chamber to bring the working pressure to 0.2 Pa, and the mass flow rate of the sputtering argon gas is set to 50 sccm; the substrate temperature is maintained at 25°C.

[0058] Sputtering begins. The sputtering power for the Ru target is set to 80 watts; the sputtering power for the Nb target is set to 50 watts, and the sputtering voltage is 270V; the sputtering power for the Mn target is set to 80 watts, and the sputtering voltage is 430V.

[0059] Under the influence of an electric field, electrons collide with argon atoms as they fly toward the substrate, causing the argon gas to ionize. Under high voltage, Ar atoms ionize into Ar atoms. + Ions and electrons; Ar + Ions, as incident ions, bombard the target material under the influence of an electric field, causing neutral atoms or molecules on the target surface to gain sufficient kinetic energy to detach from the target surface and deposit on the pretreated carbon cloth substrate to form a thin film. The deposition rate was set to 12.5 nm / min and the deposition time to 60 min, achieving the deposition of a crystal-crystal nanostructured thin film on the carbon cloth substrate, thus preparing a bicrystalline nanostructured alloy hydrogen evolution catalyst.

[0060] The bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 1 was obtained by depositing a bicrystalline nanostructured alloy on the surface of a carbon cloth substrate. The bicrystalline nanostructured alloy consists of a Mn-rich phase and a Mn-poor phase, with an O-rich interface formed between the Mn-rich and Mn-poor phases. The chemical formula of the Mn-rich phase is Ru. 50～60 Mn 20～30 Nb 20～22 O 3～8 The chemical formula of the Mn-depleted phase is Ru. 75～60 Mn 10～15 Nb 22～24 The size of the Mn-rich phase is 4 nm to 6 nm.

[0061] The bicrystalline nanostructure alloy in Example 1 can be used as Ru 56 Mn 30 A Nb8O6 bicrystalline hydrogen evolution catalyst was developed for ampere-level hydrogen evolution. Example 1 showed that by controlling the Mn and Ru elemental composition, Mn-rich phases of different sizes were obtained. The synergistic effect of the Mn-rich and Mn-depleted phases promoted the formation of an O-rich interface. The O-rich interface enhanced charge transfer and water dissociation kinetics, optimized the hydrogen adsorption / desorption process, and thus improved HER performance. Furthermore, the high-density O-rich interface provided abundant active sites, further enhancing catalytic performance.

[0062] Example 2

[0063] A method for preparing a bicrystalline nanostructured alloy hydrogen evolution catalyst includes the following steps:

[0064] Step 1, Pretreatment of carbon cloth substrate:

[0065] To remove grease and impurities from the surface of the carbon cloth substrate, the surface of the carbon cloth substrate was cleaned sequentially with distilled water and anhydrous ethanol; then it was immersed in 50 vol.% HNO3 solution and kept at 60°C for 2 hours to improve the hydrophilicity of the carbon cloth substrate; after that, the immersed carbon cloth substrate was taken out, the acid solution was washed off with distilled water, and it was vacuum dried at 60°C to obtain the pretreated carbon cloth substrate.

[0066] Step 2, Preparation of the bicrystalline nanostructured alloy hydrogen evolution catalyst:

[0067] Ru, Mn, and Nb were used as targets. Before deposition, the distance between the pretreated carbon cloth substrate and the target was adjusted to 15 cm. The magnetron sputtering system was evacuated to achieve a vacuum level of 5 × 10⁻⁶ within the cavity. -5 Pa; Before starting deposition, high-purity argon gas is introduced into the sputtering chamber to bring the working pressure to 0.3 Pa, and the mass flow rate of the sputtering argon gas is set to 40 sccm; the substrate temperature is maintained at 25°C.

[0068] Sputtering begins. The sputtering power for the Ru target is set to 80 watts; the sputtering power for the Nb target is set to 80 watts, and the sputtering voltage is 280V; the sputtering power for the Mn target is set to 50 watts, and the sputtering voltage is 270V.

[0069] Under the influence of an electric field, electrons collide with argon atoms as they fly toward the substrate, causing the argon gas to ionize. Under high voltage, Ar atoms ionize into Ar atoms. + Ions and electrons; Ar + Ions, as incident ions, bombard the target material under the influence of an electric field, causing neutral atoms or molecules on the target surface to gain sufficient kinetic energy to detach from the target surface and deposit on the pretreated carbon cloth substrate to form a thin film. The deposition rate was set to 12.5 nm / min and the deposition time to 60 min, achieving the deposition of a crystal-crystal nanostructured thin film on the carbon cloth substrate, thus preparing a bicrystalline nanostructured alloy hydrogen evolution catalyst.

[0070] The bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 2 was obtained by depositing a bicrystalline nanostructured alloy on the surface of a carbon cloth substrate. The bicrystalline nanostructured alloy consists of a Mn-rich phase and a Mn-poor phase, with an O-rich interface formed between the Mn-rich and Mn-poor phases. The chemical formula of the Mn-rich phase is Ru. 50～60 Mn 20～30 Nb 20～22 O 3～8 The chemical formula of the Mn-depleted phase is Ru. 75～60 Mn 10～15 Nb 22～24 The size of the Mn-rich phase is 1 nm to 2 nm.

[0071] The bicrystalline nanostructure alloy in Example 2 can be used as Ru 60 Mn5Nb 30An O5 biphase hydrogen evolution catalyst was used for ampere-level hydrogen evolution. Example 2, by controlling the Mn and Ru elemental composition, yielded Mn-rich phases of different sizes. The synergistic effect of the Mn-rich and Mn-depleted phases promoted the formation of an O-rich interface. The O-rich interface enhanced charge transfer and water dissociation kinetics, optimized the hydrogen adsorption / desorption process, and thus improved HER performance. Furthermore, the high-density O-rich interface provided abundant active sites, further enhancing catalytic performance.

[0072] Example 3

[0073] A method for preparing a bicrystalline nanostructured alloy hydrogen evolution catalyst includes the following steps:

[0074] Step 1, Pretreatment of carbon cloth substrate:

[0075] To remove grease and impurities from the surface of the carbon cloth substrate, the surface of the carbon cloth substrate was cleaned sequentially with distilled water and anhydrous ethanol; then it was immersed in 50 vol.% HNO3 solution and kept at 60°C for 2 hours to improve the hydrophilicity of the carbon cloth substrate; after that, the immersed carbon cloth substrate was taken out, the acid solution was washed off with distilled water, and it was vacuum dried at 60°C to obtain the pretreated carbon cloth substrate.

[0076] Step 2, Preparation of the bicrystalline nanostructured alloy hydrogen evolution catalyst:

[0077] Ru, Mn, and Nb were used as targets. Before deposition, the distance between the pretreated carbon cloth substrate and the target was adjusted to 15 cm. The magnetron sputtering system was evacuated to achieve a vacuum level of 5 × 10⁻⁶ within the cavity. -5 Pa; Before starting deposition, high-purity argon gas is introduced into the sputtering chamber to bring the working pressure to 0.4 Pa, and the mass flow rate of the sputtering argon gas is set to 30 sccm; the substrate temperature is maintained at 25°C.

[0078] Sputtering begins. The sputtering power for the Ru target is set to 80 watts; the sputtering power for the Nb target is set to 80 watts, and the sputtering voltage is 280 V; the sputtering power for the Mn target is set to 80 watts, and the sputtering voltage is 430 V.

[0079] Under the influence of an electric field, electrons collide with argon atoms as they fly toward the substrate, causing the argon gas to ionize. Under high voltage, Ar atoms ionize into Ar atoms. + Ions and electrons; Ar + Ions, as incident ions, bombard the target material under the influence of an electric field, causing neutral atoms or molecules on the target surface to gain sufficient kinetic energy to detach from the target surface and deposit on the pretreated carbon cloth substrate to form a thin film. With a deposition rate of 16 nm / min and a deposition time of 45 min, a crystal-crystal nanostructured thin film was deposited on the carbon cloth substrate, thus preparing a bicrystalline nanostructured alloy hydrogen evolution catalyst.

[0080] The bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 3 was obtained by depositing a bicrystalline nanostructured alloy on the surface of a carbon cloth substrate. The average molecular formula of the bicrystalline nanostructured alloy was Ru. 62 Mn 12 Nb 21 O5. The bicrystalline nanostructured alloy consists of a Mn-rich phase and a Mn-depleted phase, with an O-rich interface formed between the two phases. The chemical formula of the Mn-rich phase is Ru. 50～60 Mn 20～30 Nb 20～22 O 3～8 The chemical formula of the Mn-depleted phase is Ru. 75～60 Mn 10～15 Nb 22～24 The size of the Mn-rich phase is 1 nm to 2 nm.

[0081] The bicrystalline nanostructure alloy in Example 3 can be used as Ru 62 Mn 12 Nb 21 An O5 biphase hydrogen evolution catalyst was used for ampere-level hydrogen evolution. Example 3 showed that by controlling the Mn and Ru elemental composition, Mn-rich phases of different sizes were obtained, and the synergistic effect of the Mn-rich and Mn-depleted phases promoted the formation of an O-rich interface. The O-rich interface enhanced charge transfer and water dissociation kinetics, optimized the hydrogen adsorption / desorption process, and thus improved HER performance. Furthermore, the high-density O-rich interface provided abundant active sites, further enhancing catalytic performance.

[0082] For ease of description, the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in the above embodiments is referred to as the bicrystalline hydrogen evolution catalyst; the specific preparation conditions and product comparison are shown in Table 1 and Table 2.

[0083] Table 1 Comparison of preparation conditions for bicrystalline hydrogen evolution catalysts

[0084]

[0085] Table 2 Comparison of products from bicrystalline phase hydrogen evolution catalysts

[0086]

[0087]

[0088] Note: The Mn-rich phase is composed of the following elements in atomic percentage: Ru 50%–60%, Mn 20%–30%, Nb 20%–22%, and O 3%–8%, totaling 100%.

[0089] Preferably, the Mn-depleted phase, by atomic percentage, is composed of the following elements: Ru 60%–75%, Mn 10%–15%, and Nb 22%–24%, totaling 100%.

[0090] Therefore, with Ru 50～60 Mn 20～30 Nb 20～22 O 3～8 As a Mn-rich phase, Ru 60～75 Mn 10～15 Nb 22～24 As a Mn-poor phase, the composition of the bicrystalline hydrogen evolution catalyst prepared in the embodiments of the present invention is the average composition of the bicrystalline hydrogen evolution catalyst, which is different from the composition of the Mn-rich phase and the Mn-poor phase; and the ratio of the Mn-rich phase to the Mn-poor phase will affect the total composition of the bicrystalline hydrogen evolution catalyst.

[0091] The following tests were conducted on the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in the above embodiments.

[0092] Test 1: TEM characterization. Transmission electron microscope, abbreviated as TEM.

[0093] The bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 1 was characterized by TEM, and the results are shown in the figure. Figure 7 and Figure 8 As shown.

[0094] Figure 7 These are TEM images of the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 1. In the images, h is a low-magnification SEM image; i is a high-magnification SEM image; j to j5 are EDS elemental analysis results in SEM mode; and k and l are TEM images at different magnifications.

[0095] Figure 8 yes Figure 7 An enlarged view of the illustration in the middle of the image.

[0096] Figure 7 Elemental composition analysis of h showed that the proportions of Ru, Nb and Mn in the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 1 were Ru 56%, Nb 8%, Mn 30%, and O 6%, totaling 100%. Figure 7 k-graph and Figure 8 The size range of the Mn-rich phase is shown, and the average size of the Mn-rich phase is 4.85 nm.

[0097] The bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 2 was characterized by TEM, and the results are shown in the figure. Figure 5 and Figure 6 As shown.

[0098] Figure 5 These are TEM images of the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 2. In the images, a is a low-magnification SEM image; b is a high-magnification SEM image; c–c5 are EDS elemental analysis results in SEM mode; and d and e are TEM images at different magnifications.

[0099] Figure 6 yes Figure 5 An enlarged view of the illustration in d.

[0100] Figure 5 Elemental composition analysis in Figure a shows that the proportions of Ru, Nb, and Mn in the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 2 are Ru 60%, Nb 30%, Mn 5%, and O 5%, totaling 100%. Figure 5 d-graph and Figure 6 The size range of the Mn-rich phase is shown, and the average size of the Mn-rich phase is 1.45 nm.

[0101] As can be seen from the above analysis, compared with Example 1, the average size of the Mn-rich phase in Example 2 is smaller than that in Example 1. Therefore, the number of Mn-rich phases in Example 2 is relatively low.

[0102] The bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 3 was characterized by TEM, and the results are shown in the figure. Figures 9-11 As shown.

[0103] Figure 9 These are TEM images of the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 3. In the images, a is a low-magnification SEM image; b is a high-magnification SEM image; c is a low-magnification TEM image; d1 and d2 are magnified views of the selected portion in c; d3 is the three-dimensional atomic overlap Gaussian function fitting mapping diagram of the selected portion in c; and e to e4 are EDS elemental analysis diagrams in TEM mode.

[0104] Figure 9 Images d1 and d2 show the presence of transient dislocations and distortions caused by lattice mismatch at the two-phase interface. d3 is a three-dimensional atomic overlap Gaussian function fitting map, further illustrating that the black area in the TEM image is a Mn-rich phase.

[0105] Figure 10 These are TEM images of the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 3, in HAADF mode. In the images, a and b are low-magnification TEM images in HAADF mode; c is a high-magnification TEM image in HAADF mode; and d is the EDS elemental line scan analysis in image c. HAADF mode, or High Angle Ring Dark Field Mode, is a working mode of scanning transmission electron microscopy.

[0106] Figure 11 yes Figure 10 An enlarged view of the illustration in section b.

[0107] Depend on Figure 10 The d-plot further illustrates that the black phase in the HADDF mode is an Mn-rich phase. Meanwhile, O is mainly distributed at the interface. Figure 10 Figure b in the middle and Figure 11 The size range of the Mn-rich phase is shown, and the average size of the Mn-rich phase is 1.38 nm.

[0108] Depend on Figure 9 and Figure 10 It can be seen that the surface of the carbon cloth substrate is completely covered by the bicrystalline nanostructured alloy hydrogen evolution catalyst. High-magnification scanning electron microscopy shows that the surface of the film in Example 3 is rough, which leads to a large specific exposed area. A black phase with an average size of 1.38 nm is present in the material, and the black phase is uniformly distributed in the matrix. Elemental analysis of the black phase by EDS confirms that it is a Mn-rich phase. We successfully prepared a novel Mn-rich / Mn-poor catalyst by magnetron sputtering, which exhibits significantly improved catalytic activity and stability compared to commercial Pt / C catalysts.

[0109] In summary, the analysis shows that the nano-sized Mn-rich phase is dispersed within the Mn-poor phase, providing abundant O-rich interfaces. Compared to Examples 1 and 2, Example 3 exhibits an increased number of O-rich interfaces. The smaller size and greater number of Mn-rich phases result in a greater number of O-rich interfaces. These high-density O-rich interfaces provide abundant catalytic active sites, thus improving the HER catalytic performance.

[0110] Test 2: Hydrogen evolution performance test of the bicrystalline hydrogen evolution catalyst of Example 1.

[0111] The bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 1 was deposited on the surface of a carbon cloth electrode to prepare a modified electrode. This modified electrode was used as the working electrode to promote the hydrogen evolution reaction. The Ru content of Example 1 was tested. 56 Mn 30 Hydrogen evolution performance of Nb8O6 biphase hydrogen evolution catalyst.

[0112] The test conditions were as follows: linear voltammetry was performed in a 1M KOH solution using a three-electrode system; a graphite rod was used as the counter electrode, a saturated calomel electrode as the reference electrode, and a modified electrode prepared by depositing the bicrystalline nanostructured alloy hydrogen evolution catalyst of Example 1 on the surface of a carbon cloth electrode was used as the working electrode. The scan rate was 5 mV / s, and 100% iR correction was applied.

[0113] Test results are as follows Figure 1 As shown. From Figure 1 As can be seen from the data, Ru prepared with parameters of deposition distance of +15 cm, deposition rate of 12.5 nm / min, and deposition time of 60 min yielded [a specific product / process]. 56 Mn 30 Nb8O6 dual-phase hydrogen evolution catalyst at a current density of 10 mA·cm -2 The overpotential is 25.3mV.

[0114] Test 3: Hydrogen evolution performance test of the bicrystalline phase hydrogen evolution catalyst of Example 2.

[0115] A modified electrode, prepared by depositing the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 2 onto the surface of a carbon cloth electrode, was used as the working electrode to promote the hydrogen evolution reaction. The Ru from Example 2 was tested. 60 Mn5Nb 30 Hydrogen evolution performance of O5 biphase hydrogen evolution catalyst.

[0116] The test conditions were as follows: linear voltammetry was performed using a three-electrode system in 1M KOH solution; a graphite rod was used as the counter electrode, a saturated calomel electrode as the reference electrode, and a modified electrode prepared by depositing the bicrystalline nanostructured alloy hydrogen evolution catalyst of Example 2 onto the surface of a carbon cloth electrode was used as the working electrode. The scan rate was 5 mV / s, and 100% iR correction was applied.

[0117] Test results are as follows Figure 1 As shown, from Figure 1 As can be seen from the data, with a condensation distance of +15 cm, a deposition rate of 12.5 nm / min, and a deposition time of 60 min, the Ru prepared was... 60 Mn5Nb 30 O5 biphase hydrogen evolution catalyst at 10 mA·cm -2 The overpotential is 20.3mV.

[0118] Test 4: Hydrogen evolution performance test of the bicrystalline phase hydrogen evolution catalyst of Example 3.

[0119] A modified electrode, prepared by depositing the bicrystalline nanostructured alloy hydrogen evolution catalyst prepared in Example 3 onto the surface of a carbon cloth electrode, was used as the working electrode to promote the hydrogen evolution reaction. The Ru content of Example 3 was tested. 62 Mn 12 Nb 21 Hydrogen evolution performance of O5 biphase hydrogen evolution catalyst.

[0120] The test conditions were as follows: linear voltammetry was performed in a 1M KOH solution using a three-electrode system; a graphite rod was used as the counter electrode, a saturated calomel electrode as the reference electrode, and a modified electrode prepared by depositing the bicrystalline nanostructured alloy hydrogen evolution catalyst of Example 3 onto the surface of a carbon cloth electrode was used as the working electrode. The scan rate was 5 mV / s, and 100% iR correction was applied.

[0121] Test results are as follows Figure 1 As shown. From Figure 1 As can be seen from the data, with a condensation distance of +15 cm, a deposition rate of 16 nm / min, and a deposition time of 45 min, the prepared Ru... 62 Mn 12 Nb 21 O5 biphase hydrogen evolution catalyst at 10 mA·cm -2 The overpotential is 18mV.

[0122] Table 3. Dimensions and hydrogen evolution performance test results of bicrystalline nanostructured alloy hydrogen evolution catalysts.

[0123] Example Mn-rich phase size / nm <![CDATA[10mA·cm -2 Overpotential / mV <![CDATA[Tafel slope / mV dec -1 > Example 1 4～6 25.3 36.7 Example 2 1～2 20.3 29.4 Example 3 1～2 18 21.6

[0124] Note: Although the size of the Mn-rich phase in Example 2 is similar to that in Example 3, the number of Mn-rich phases formed in Example 2 is less than that in Example 3 because the Mn content is lower. Therefore, the performance is lower than that of Example 3.

[0125] The Tafel slope, or Tafel gradient, is the slope of the straight line segment on a semi-logarithmic curve obtained by plotting the potential versus the logarithm of current density. The Tafel slope reflects the rate-determining step of the electrocatalytic hydrogen evolution and oxygen evolution reactions. The magnitude of the slope reflects the catalytic strength of the catalyst; a smaller value indicates better catalytic performance.

[0126] like Figure 2 As shown, Ru in Example 3 62 Mn 12 Nb 21 The O5 two-phase hydrogen evolution catalyst exhibits the lowest Tafel slope, at 21.6 mVdec. -1 ;Ru of Example 2 60 Mn5Nb 30 The Tafel slopes of the O5 two-phase hydrogen evolution catalyst were 29.4 mV dec. -1 ;Ru of Example 1 56 Mn 30 The Tafel slope of the Nb8O6 two-phase hydrogen evolution catalyst is 36.7 mV dec. -1 This indicates that it has good electrocatalytic performance.

[0127] Electrochemical impedance spectroscopy (EIS) is a crucial parameter for evaluating the performance of electrocatalytic hydrogen evolution. Z' represents the real part of the impedance, parallel to the x-axis, reflecting the resistive response of the electrochemical system to AC signals. -Z" represents the negative of the imaginary part of the impedance, parallel to the y-axis, related to capacitance or inductance effects, and used to describe the non-resistive response of the electrochemical system. Analyzing the changes in Z' and -Z" in electrochemical impedance spectroscopy provides insights into the kinetic processes and interfacial reaction characteristics of the electrochemical system.

[0128] Figure 3 These are electrochemical impedance spectroscopy (EIS) spectra of three-electrode systems assembled using the bicrystalline nanostructured alloy hydrogen evolution catalysts of Examples 1-3 as working electrodes. Where Z' represents the real part of the impedance; -Z” represents the negative of the imaginary part of the impedance. Figure 3 The illustration is an equivalent circuit diagram drawn based on EIS data. Wherein, R... s R is the resistance of the solution. ct It is a charge transfer resistor, and CPF 1 is a constant phase angle element. Figure 3 It was fitted according to this equivalent circuit diagram.

[0129] like Figure 3 As shown, Ru in Example 3 62 Mn 12 Nb 21 The O5 biphase hydrogen evolution catalyst exhibits a lower charge transfer resistance than the other two biphase hydrogen evolution catalysts, and R ct =1.96Ω, which indicates that Ru in Example 3 62 Mn 12 Nb 21 The O5 biphase hydrogen evolution catalyst has a stronger charge transfer capability.

[0130] Test 5: Long-term stability test. Long-term stability is another key indicator for evaluating the electrochemical performance of electrocatalysts, especially in industrial applications.

[0131] Figure 4 The three-electrode system assembled using the bicrystalline nanostructured alloy hydrogen evolution catalyst of Example 3 as the working electrode at 1.2 A·cm -2 The following is a stability test chart.

[0132] like Figure 4 As shown, Ru in Example 3 62 Mn 12 Nb 21 O5 two-phase hydrogen evolution catalyst can be used at 1.2 A·cm -2It can operate stably for 300 hours at current density, and has great potential for industrial applications.

[0133] In summary, in the biphase hydrogen evolution catalysts of the above embodiments, by controlling the Mn and Ru elemental composition, Mn-rich phases of different sizes were obtained. The synergistic effect of the Mn-rich / Mn-poor biphases promoted the formation of an O-rich interface. The O-rich interface enhanced charge transfer and water dissociation kinetics, optimized the hydrogen adsorption / desorption process, and thus improved HER performance. Furthermore, the high-density O-rich interface provided abundant active sites, further enhancing catalytic performance.

[0134] The experimental results in Tables 2 and 3 demonstrate that the content of Mn can affect the size of the Mn-rich phase, and thus the size of the highly active O-rich interface.

[0135] Density Functional Theory (DFT) is a theoretical framework for HER reactions. DFT calculations have shown that the adsorption energy of *OH at Ru sites adjacent to Nb is significantly higher than that at other Ru sites, indicating that Nb enhances the *OH adsorption efficiency of Ru. In the first step of HER, *OH undergoes proton transfer with H₂O to form *H₂O; the high *OH adsorption efficiency promotes this first-step reaction.

[0136] Ru significantly affects catalytic activity. Excessive Ru content reduces the amount of Mn-rich phase, thus decreasing the number of active interfaces. Conversely, Ru itself plays a crucial role in enhancing catalyst activity. Insufficient Ru content reduces catalytic sites, thereby decreasing catalytic activity. Therefore, the Ru content should be controlled between 55% and 65%.

[0137] DFT calculations revealed that in O-rich interfaces, O atoms can lower the energy barrier for the conversion of active hydrogen to H2. Simultaneously, O atoms can also improve the efficiency of the H2O dissociation step, resulting in RuMnNbO exhibiting superior electrochemical H2 release compared to Pt-based catalysts. The O content affects the formation of O-rich interfaces; excessively low O content leads to insufficient interface formation and reduces active sites. Conversely, excessively high O content causes over-oxidation of metal elements, excessively reducing the adsorption energy of active sites for H, which is detrimental to catalytic activity. Therefore, the O content should be controlled between 3% and 10%.

[0138] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bicrystalline nanostructured alloy hydrogen evolution catalyst, characterized in that, Includes a substrate and a bicrystalline phase nanostructure alloy deposited on the surface of the substrate; the average molecular formula of the bicrystalline phase nanostructure alloy is Ru. 62 Mn 12 Nb 21 O5; The bicrystalline nanostructure alloy is composed of a Mn-rich phase and a Mn-poor phase, with an O-rich interface formed between the Mn-rich and Mn-poor phases. The O-rich interface is a catalytic active site. The size of the Mn-rich phase is 1 nm to 2 nm.

2. The bicrystalline nanostructured alloy hydrogen evolution catalyst according to claim 1, characterized in that, The atomic percentage of Mn in the Mn-rich phase is 20% to 30%; the atomic percentage of Mn in the Mn-poor phase is 10% to 15%.

3. The bicrystalline nanostructured alloy hydrogen evolution catalyst according to claim 2, characterized in that, The Mn-rich phase, by atomic percentage, is composed of the following elements: Ru 50%–60%, Mn 20%–30%, Nb 20%–22% and O 3%–8%, totaling 100%.

4. The bicrystalline nanostructured alloy hydrogen evolution catalyst according to claim 2, characterized in that, The Mn-depleted phase, by atomic percentage, is composed of the following elements: Ru 60%–75%, Mn 10%–15% and Nb 22%–24%, totaling 100%.

5. A method for preparing a bicrystalline nanostructured alloy hydrogen evolution catalyst according to any one of claims 1 to 4, characterized in that, Includes the following steps: Using magnetron sputtering technology, a bicrystalline nanostructure alloy containing Mn-rich and Mn-poor phases is deposited on the substrate surface by controlling the content of Mn and Ru elements, and an O-rich interface is formed between the Mn-rich and Mn-poor phases of the bicrystalline nanostructure alloy. By adjusting the size of the Mn-rich phase, the size and number of the O-rich interface are adjusted to provide catalytic active sites.

6. The method for preparing the bicrystalline nanostructured alloy hydrogen evolution catalyst according to claim 5, characterized in that, The process parameters for depositing bicrystalline phase nanostructured alloys are as follows: Ru, Mn, and Nb were used as target materials; The background vacuum is 1×10⁻⁶ -5 Pa ~ 5 × 10 -5 Pa, working gas pressure is 0.2Pa~0.4Pa, distance between substrate and target is 15cm; sputtering temperature is 20℃~30℃; Using Ru as the target material, the sputtering power is 50 watt to 80 watt; Using Mn as the target material, the sputtering power is 50 watt to 80 watts, and the sputtering voltage is 270 V to 430 V; Using Nb as the target material, the sputtering power is 50 watt to 80 watts, and the sputtering voltage is 175 V to 280 V; The deposition time is 45 min to 60 min.

7. The application of the bicrystalline nanostructured alloy hydrogen evolution catalyst according to any one of claims 1 to 4 in electrocatalytic hydrogen evolution.

8. The application of the bicrystalline nanostructured alloy hydrogen evolution catalyst according to claim 7 in electrocatalytic hydrogen evolution, characterized in that, The application method includes the following steps: A modified electrode was prepared by depositing a bicrystalline nanostructured alloy hydrogen evolution catalyst onto the surface of a carbon cloth electrode. A three-electrode system was constructed using a modified electrode as the working electrode, a graphite rod as the counter electrode, and a saturated calomel electrode as the reference electrode to perform electrocatalytic hydrogen evolution.

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