A Ni-Si intermetallic compound porous material and its preparation method and electrocatalytic application

Abstract

The present invention belongs to the technical field of porous materials, and discloses a Ni-Si intermetallic compound porous material and its preparation method and electrocatalytic application. The Ni-Si intermetallic compound porous material of the present invention is doped with Mo, Fe, Mn, Ti, W, Co, Cu or Cr elements, and comprises Ni: 30-80at.%, Si: 20-70at.%, Mo: 0-10at.%, Fe: 0-10at.%, Mn: 0-10at.%, Ti: 0-10at.%, W: 0-10at.%, Co: 0-10at.%, Cu: 0-10at.%, Cr: 0-10at.%. This kind of intermetallic compound porous material can be directly used in electrolysis of water, without the need to use carbon cloth, nickel foam or binder, and in order to further improve electrocatalytic activity, the present invention obtains more active sites and better catalytic activity by combining doping with a three-dimensional porous structure.

Description

Technical Field

[0001] The present invention relates to the technical field of porous materials, and in particular to a Ni-Si intermetallic compound porous material, a preparation method thereof, and electrocatalytic applications thereof. Background Art

[0002] Hydrogen (H2) is a renewable energy carrier with high energy density and zero carbon emissions, and is considered an ideal alternative to fossil fuels. Currently, the main routes for producing H2 include steam reforming / partial oxidation of hydrocarbons, coal gasification, and water electrolysis. Water electrolysis uses 71% of the Earth's surface water as a feedstock, does not require high temperatures, and does not emit greenhouse gases or other pollutants, making it a low-cost technology for producing high-purity H2.

[0003] Electrocatalysts with earth-abundant properties, high catalytic activity, and high stability at high current densities are crucial for industrial production. Furthermore, bubbles generated by gas evolution at high current densities often coat the electrode surface and prevent electrolyte access to the reaction sites, further increasing the electrocatalyst's overpotential, a significant issue for industrial applications. However, the most effective electrocatalysts currently are noble metals, whose high cost and scarcity limit their widespread application.

[0004] Nickel is one of the most widely used elements in transition metal-based catalysts, boasting advantages such as abundance, low price, high strength, excellent corrosion resistance, high electrical conductivity, and high catalytic activity. One feasible approach is to improve catalytic activity by adjusting the catalyst composition by adding a second foreign atom. Silicon, the second most abundant element in the Earth's crust (27.7%), has some electrical conductivity, but not as high as metals. A nickel-silicon-based electrocatalyst could significantly address the current challenges of high catalyst costs and material scarcity in the electrocatalytic field. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the aforementioned background technology by providing a porous Ni-Si intermetallic compound material, its preparation method, and its electrocatalytic application. The porous intermetallic compound material of the present invention can be directly used for water electrolysis without the use of carbon cloth, nickel foam, or a binder. To further enhance electrocatalytic activity, the present invention combines doping with a three-dimensional porous structure to obtain more active sites and better catalytic activity.

[0006] To achieve the purpose of the present invention, the Ni-Si intermetallic compound porous material of the present invention is doped with Mo, Fe, Mn, Ti, W, Co, Cu or Cr elements, and contains Ni: 30-80at.%, Si: 20-70at.%, Mo: 0-10at.%, Fe: 0-10at.%, Mn: 0-10at.%, Ti: 0-10at.%, W: 0-10at.%, Co: 0-10at.%, Cu: 0-10at.%, Cr: 0-10at.%.

[0007] Preferably, in some embodiments of the present invention, the Ni—Si intermetallic compound porous material comprises Ni: 65-80 at.%, Si: 20-35 at.%, and Mo: 3-10 at.% in atomic ratio.

[0008] Preferably, in some embodiments of the present invention, the Ni-Si intermetallic compound porous material contains Ni: 65-80at.%, Si: 20-35at.%, Mo: 3-10at.%, Fe: 3-10at.%, Mn: 3-10at.%, Ti: 3-10at.%, W: 3-10at.%, Co: 3-10at.%, Cu: 3-10at.%, Cr: 3-10at.%.

[0009] Furthermore, the present invention also provides a method for preparing the aforementioned Ni-Si intermetallic compound porous material, the method comprising the following steps:

[0010] (1) Composition ratio: The raw materials contain Ni and Si element powders, which are mixed according to the following composition ratio: Ni: 30-80 at.%, Si: 20-70 at.%;

[0011] (2) Powder mixing: Mix the powders evenly;

[0012] (3) forming: forming the uniformly mixed powder into a green compact;

[0013] (4) Sintering: vacuum sintering the green body obtained in step (3);

[0014] (5) Cooling stage: After the sintering process is completed, the product is cooled to room temperature along with the furnace.

[0015] Furthermore, in some embodiments of the present invention, the powder in step (1) is alloy powder.

[0016] Preferably, in some embodiments of the present invention, the raw materials in step (1) further contain Mo, Fe, Mn, Ti, W, Co, Cu or Cr element powders, and are mixed according to the following composition ratio: Ni: 30-80at.%, Si: 20-70at.%, Mo: 0-10at.%, Fe: 0-10at.%, Mn: 0-10at.%, Ti: 0-10at.%, W: 0-10at.%, Co: 0-10at.%, Cu: 0-10at.%, Cr: 0-10at.%.

[0017] More preferably, in some embodiments of the present invention, the raw materials in step (1) further comprise Mo element powder, and the raw materials are mixed according to the following composition ratio: Ni: 65-80 at.%, Si: 20-35 at.%, Mo: 3-10 at.%.

[0018] More preferably, in some embodiments of the present invention, the raw materials in step (1) further comprise Mo, Fe, Mn, Ti, W, Co, Cu and Cr element powders, and are mixed according to the following composition ratio: Ni: 65-80at.%, Si: 20-35at.%, Mo: 3-10at.%, Fe: 3-10at.%, Mn: 3-10at.%, Ti: 3-10at.%, W: 3-10at.%, Co: 3-10at.%, Cu: 3-10at.%, Cr: 3-10at.%.

[0019] Furthermore, in some embodiments of the present invention, in step (2), the powder is mixed uniformly on a V-type mixer under the protection of an inert gas.

[0020] Furthermore, in some embodiments of the present invention, the mixing time in step (2) is 24-72 hours.

[0021] Furthermore, in some embodiments of the present invention, the forming method in step (3) is molding or cold isostatic pressing; preferably, the pressing pressure is 50-200 MPa, the pressing time is 10-20 s, and the pressing method is determined by the size and shape of the product.

[0022] Furthermore, in some embodiments of the present invention, the forming method in step (3) is loose sintering.

[0023] Furthermore, in some embodiments of the present invention, the sintering process of vacuum sintering in step (4) is a step-by-step heating process. When Mo powder and Ni, Si element powders are used as raw materials or Ni, Si element powders are used as raw materials, when the temperature is lower than 700°C, the temperature is increased at a heating rate of 1-6°C / min; when the temperature is higher than 700°C, the temperature is increased at a heating rate of 0.7-2.5°C / min.

[0024] On the other hand, the present invention also provides an application of the aforementioned Ni-Si intermetallic compound porous material, wherein the application is to use the Ni-Si intermetallic compound porous material for electrocatalysis.

[0025] Compared with the prior art, the advantages of the present invention are as follows:

[0026] (1) The Ni-Si intermetallic compound porous material prepared by the present invention can be synthesized by the reaction method of element powder, with element powder as raw material. The raw material cost is low, the content is rich, and it has good pressing performance, low cost and low energy consumption.

[0027] (2) The composition of the Ni-Si intermetallic compound porous material prepared by the present invention can be precisely adjusted, the pore structure is adjustable, the open porosity is high, the pores are abundant, the open porosity range is 20-65%, and the connection between the grains is good.

[0028] (3) In terms of material design, the Ni-Si intermetallic compound porous material of the present invention has the advantages of abundant content, low price, high strength, good corrosion resistance, high conductivity and high catalytic activity, while silicon can improve the corrosion resistance of the material. The intermetallic compound porous material has good corrosion resistance and catalytic activity and can be applied to the field of electrocatalytic materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the XRD pattern of the Ni2Si intermetallic compound porous material prepared in Example 1 of the present invention.

[0030] Figure 2 This is an SEM image of the Ni2Si intermetallic compound porous material prepared in Example 1 of the present invention.

[0031] Figure 3 This is a diagram showing the full electrolysis water performance of the Ni2Si intermetallic compound porous material prepared in Example 1 of the present invention in an alkaline electrolyte.

[0032] Figure 4 This is a diagram showing the full water electrolysis performance of the NiSi intermetallic compound porous material prepared in Example 2 of the present invention in an alkaline electrolyte.

[0033] Figure 5 This is a diagram showing the full electrolysis water performance of the NiSi2 intermetallic compound porous material prepared in Example 3 of the present invention in an alkaline electrolyte.

[0034] Figure 6 This is the XRD pattern of the Mo-doped Ni2Si intermetallic compound porous material prepared in Example 4 of the present invention.

[0035] Figure 7This is a graph showing the full water electrolysis performance of the Mo-doped Ni2Si intermetallic compound porous material prepared in Example 4 of the present invention in an alkaline electrolyte.

[0036] Figure 8 This is a diagram of the full water electrolysis performance of the high entropy porous material prepared in Example 5 of the present invention in an alkaline electrolyte. DETAILED DESCRIPTION

[0037] In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples. Additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be understood through practice of the present invention. It should be understood that the following description is only intended to explain the present invention and is not intended to limit the present invention.

[0038] As used herein, the terms "comprises," "including," "having," "containing" or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a listed element is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0039] The conjunction "consisting of" excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim, rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0040] When amount, concentration or other value or parameter is represented with range, preferred range or the range that a series of upper preferred value and lower preferred value limit are expressed, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value, no matter whether this range is disclosed separately.For example, when disclosing scope "1 to 5", described scope should be interpreted as including scope "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc.When numerical range is described in this article, unless otherwise stated, otherwise this scope is intended to include its end value and all integers and fractions within this range.

[0041] The singular includes plural references unless the context clearly dictates otherwise. "Optional" or "either" means that the subsequently described event or incident can or cannot occur, and that the description includes instances where the event occurs and instances where it does not.

[0042] In addition, the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" described below mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the technical features involved in the various embodiments of the present invention may be combined with each other as long as they do not conflict with each other.

[0043] Example 1

[0044] Ni and Si elemental powders were used as raw materials and mixed according to atomic percentage: 242.08g Ni and 57.92g Si. The Ni and Si powders were mixed in a V-type mixer under inert gas protection for 48 hours. The materials were compacted using a die pressing method with a pressing pressure of 100 MPa and a holding time of 10 seconds. Sintering was performed in a vacuum sintering furnace. The first stage sintering temperature was 120°C, the heating rate was 4°C / min, and the holding time was 30 minutes. The second stage sintering temperature was 500°C, the heating rate was 4°C / min, and the holding time was 30 minutes. The third stage sintering temperature was 700°C, the heating rate was 2°C / min, and the holding time was 210 minutes. The fourth stage sintering temperature was 750°C, the heating rate was 1°C / min, and the holding time was 120 minutes. The sintering temperature of the fifth stage is 800℃, the heating rate is 1℃ / min, and the holding time is 120min. The sintering temperature of the sixth stage is 850℃, the heating rate is 1℃ / min, and the holding time is 120min. The cooling process is carried out with the furnace cooling, and the vacuum degree is controlled at 10 -3 -10 - 2 Pa. A 60×10×2.5mm bulk Ni2Si intermetallic compound porous material was prepared. The total porosity of the prepared Ni2Si intermetallic compound porous material was 55.36%, the open porosity was 54.13%, and the permeability was 13.92m 3 ·m -2 kPa -1 ·h -1 , the maximum pore size is 4.36μm.

[0045] Figure 1 This is the XRD pattern of the Ni2Si intermetallic compound porous material prepared in Example 1 of the present invention. It can be seen from the figure that a high-purity Ni2Si phase is generated.

[0046] Figure 2This is an SEM image of the Ni2Si intermetallic compound porous material prepared in Example 1 of the present invention. From the image, we can see abundant pores and good connection between the grains.

[0047] Figure 3 This is a diagram showing the full electrolysis water performance of the Ni2Si intermetallic compound porous material prepared in Example 1 of the present invention in an alkaline electrolyte. It can be seen from the figure that Ni2Si has excellent electrocatalytic performance.

[0048] Example 2

[0049] Ni and Si elemental powders were used as raw materials and mixed according to atomic percentage: 202.91g Ni and 97.09g Si. The Ni and Si powders were mixed in a V-type mixer under inert gas protection for 48 hours. The materials were compacted using a die pressing method with a pressing pressure of 100 MPa and a holding time of 10 seconds. Sintering was performed in a vacuum sintering furnace. The first stage was sintering at a temperature of 120°C, a heating rate of 4°C / min, and a holding time of 30 minutes. The second stage was sintering at a temperature of 500°C, a heating rate of 4°C / min, and a holding time of 30 minutes. The third stage was sintering at a temperature of 700°C, a heating rate of 2°C / min, and a holding time of 210 minutes. The fourth stage was sintering at a temperature of 750°C, a heating rate of 1°C / min, and a holding time of 120 minutes. The sintering temperature of the fifth stage is 800℃, the heating rate is 1℃ / min, and the holding time is 120min. The sintering temperature of the sixth stage is 850℃, the heating rate is 1℃ / min, and the holding time is 120min. The sintering temperature of the seventh stage is 950℃, the heating rate is 2℃ / min, and the holding time is 120min. The cooling process is carried out with the furnace cooling, and the vacuum degree is controlled at 10 -3 -10 -2 Pa. Thus, a bulk NiSi intermetallic compound porous material with a size of 60×10×2.5 mm was prepared. The open porosity of the prepared NiSi intermetallic compound porous material was 25.41%.

[0050] Figure 4 This is a graph showing the full water electrolysis performance of the NiSi intermetallic compound porous material prepared in Example 2 of the present invention in an alkaline electrolyte. It can be seen from the graph that NiSi has excellent electrocatalytic performance.

[0051] Example 3

[0052] Ni and Si elemental powders were used as raw materials and mixed according to atomic percentage: 153.29g Ni and 146.71g Si. The Ni and Si powders were mixed in a V-type mixer under inert gas protection for 48 hours. The materials were compacted using a die pressing method with a pressing pressure of 100 MPa and a holding time of 10 seconds. Sintering was performed in a vacuum sintering furnace. The first stage sintering temperature was 120°C, the heating rate was 4°C / min, and the holding time was 30 minutes. The second stage sintering temperature was 500°C, the heating rate was 4°C / min, and the holding time was 30 minutes. The third stage sintering temperature was 700°C, the heating rate was 2°C / min, and the holding time was 210 minutes. The fourth stage sintering temperature was 750°C, the heating rate was 1°C / min, and the holding time was 120 minutes. The sintering temperature of the fifth stage is 800℃, the heating rate is 1℃ / min, and the holding time is 120min. The sintering temperature of the sixth stage is 850℃, the heating rate is 1℃ / min, and the holding time is 120min. The sintering temperature of the seventh stage is 950℃, the heating rate is 2℃ / min, and the holding time is 120min. The cooling process is carried out with the furnace cooling, and the vacuum degree is controlled at 10 -3 -10 -2 Pa. Thus, a bulk NiSi2 intermetallic compound porous material with a size of 60×10×2.5 mm was prepared. The open porosity of the prepared NiSi2 intermetallic compound porous material was 47.73%.

[0053] Figure 5 This is a diagram showing the full electrolysis water performance of the NiSi2 intermetallic compound porous material prepared in Example 3 of the present invention in an alkaline electrolyte. It can be seen from the figure that NiSi2 has excellent electrocatalytic performance.

[0054] Example 4

[0055] Mo powder, Ni powder, and Si powder were used as raw materials and mixed according to the following composition ratio: Mo: 60g, Ni: 242.08g, Si: 57.92g. The Mo powder, Ni powder, and Si powder were mixed in a V-type mixer under inert gas protection for 48 hours. The product was compacted using a die press with a pressing pressure of 100 MPa and a hold time of 10 seconds. Sintering was performed in a vacuum sintering furnace. The first stage was sintering at a temperature of 120°C, a heating rate of 4°C / min, and a hold time of 30 minutes. The second stage was sintering at a temperature of 500°C, a heating rate of 4°C / min, and a hold time of 30 minutes. The third stage was sintering at a temperature of 700°C, a heating rate of 2°C / min, and a hold time of 210 minutes. The fourth stage was sintering at a temperature of 750°C, a heating rate of 1°C / min, and a hold time of 120 minutes. The sintering temperature of the fifth stage is 800℃, the heating rate is 1℃ / min, and the holding time is 120min. The sintering temperature of the sixth stage is 850℃, the heating rate is 1℃ / min, and the holding time is 120min. The cooling process is carried out with the furnace cooling, and the vacuum degree is controlled at 10 -3 -10 -2 A bulk Mo-doped Ni2Si intermetallic compound porous material with a size of 60×10×2.5 mm was prepared. The open porosity of the prepared Mo-doped Ni2Si intermetallic compound porous material was 56.59%.

[0056] Figure 6 This is the XRD pattern of the Mo-doped Ni2Si intermetallic compound porous material prepared in Example 4 of the present invention. It can be seen from the figure that the main phase is Ni2Si phase.

[0057] Figure 7 This is a diagram showing the full water electrolysis performance of the Mo-doped Ni2Si intermetallic compound porous material prepared in Example 4 of the present invention in an alkaline electrolyte. It can be seen from the figure that the Mo-doped Ni2Si intermetallic compound porous material has excellent electrocatalytic performance.

[0058] Example 5

[0059] Ni, Si, Mo, Fe, Mn, Ti, W, Co, Cu, and Cr elemental powders were used as raw materials and mixed according to the following composition ratio: Ni: 19.65g, Si: 4.70g, Mo: 4.02g, Fe: 2.34g, Mn: 2.30g, Ti: 2.00g, W: 7.69g, Co: 2.47g, Cu: 2.66g, and Cr: 2.18g. Ni and Si powders were mixed with Mo, Fe, Mn, Ti, W, Co, Cu, and Cr powders in a V-type mixer under inert gas for 2 hours. Sintering was performed in a vacuum sintering furnace. The first stage sintering temperature was 120°C, the heating rate was 5°C / min, and the holding time was 30 minutes. The second stage sintering temperature was 750°C, the heating rate was 5°C / min, and the holding time was 120 minutes. The third stage sintering temperature is 900℃, the heating rate is 5℃ / min, and the holding time is 120min. The fourth stage sintering temperature is 1000℃, the heating rate is 5℃ / min, and the holding time is 120min. The cooling process is carried out with the furnace cooling, and the vacuum degree is controlled at 10 -3 -10 -2 Pa. Thus, a bulk high-entropy porous material was prepared. The open porosity of the prepared high-entropy porous material was 61.8%.

[0060] Figure 8 This is a diagram of the full water electrolysis performance of the high entropy porous material prepared in Example 5 of the present invention in an alkaline electrolyte. It can be seen from the figure that it has excellent electrocatalytic performance.

[0061] Example 6

[0062] All other conditions were the same as in Example 1, except that the forming method was loose sintering. Since the porous material was not affected by the pressing pressure, the porosity was larger, the area in contact with the solution was larger, and more active sites were exposed, which was more conducive to the electrochemical performance of the material.

[0063] Comparative Example 1

[0064] All other conditions were the same as in Example 1, except that the heating rate was 5°C / min when the sintering temperature was above 700°C. Due to the excessively fast heating rate, a self-propagating reaction occurred during the reaction process, which was violent and rapid, resulting in defects and melting of the material.

[0065] It will be easily understood by those skilled in the art that the above description is merely an example of the present invention and is 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 in the scope of protection of the present invention.

Claims

1. A porous Ni-Si intermetallic compound material, characterized in that: The elements in the Ni-Si intermetallic compound porous material are mixed according to the following composition ratio: Ni: 19.65g, Si: 4.70g, Mo: 4.02g, Fe: 2.34g, Mn: 2.30g, Ti: 2.00g, W: 7.69g, Co: 2.47g, Cu: 2.66g and Cr: 2.18g.

2. A method for preparing a porous Ni-Si intermetallic compound material, characterized in that: The method comprises the following steps: (1) Ingredient ratio: The elements in the raw materials are mixed according to the following ingredient ratio: Ni: 19.65g, Si: 4.70g, Mo: 4.02g, Fe: 2.34g, Mn: 2.30g, Ti: 2.00g, W: 7.69g, Co: 2.47g, Cu: 2.66g and Cr: 2.18g; (2) Powder mixing: Mix the powders evenly; (3) forming: forming the uniformly mixed powder into a green compact; (4) Sintering: vacuum sintering the green body obtained in step (3); (5) Cooling stage: After the sintering process is completed, the product is cooled to room temperature along with the furnace.

3. The method for preparing the porous Ni-Si intermetallic compound material according to claim 2, wherein: In the step (2), the powders are mixed uniformly on a mixer.

4. The method for preparing the porous Ni-Si intermetallic compound material according to claim 2, wherein: In the step (2), the powders are mixed uniformly on a V-type mixer under the protection of an inert gas.

5. The method for preparing the porous Ni-Si intermetallic compound material according to claim 2, wherein: The mixing time in step (2) is 24-72 hours.

6. The method for preparing the porous Ni-Si intermetallic compound material according to claim 2, wherein: The forming method in step (3) is molding or cold isostatic pressing.

7. The method for preparing the porous Ni-Si intermetallic compound material according to claim 6, wherein: The pressing pressure of the molding or cold isostatic pressing is 50-200 MPa, the pressing time is 10-20 seconds, and the pressing method is determined by the size and shape of the product.

8. The method for preparing the porous Ni-Si intermetallic compound material according to claim 2, wherein: The forming method in step (3) is loose sintering.

9. The use of the Ni-Si intermetallic compound porous material according to claim 1, characterized in that: The application is to use Ni-Si intermetallic compound porous materials for electrocatalysis.

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