Method for preparing uniform porous nickel particles through self-template

Abstract

The invention provides a method for preparing uniform porous nickel particles through a self-template. The method comprises the following steps that firstly, nickel salt and a precipitator are mixed according to a preset proportion to prepare a solution, and the solution is placed in a reactor to prepare a layered basic nickel carbonate precursor (NiCO3.2N i (OH) 2.4 H2O); 2, calcining the prepared precursor in a high-temperature environment to obtain mesoporous nickel protoxide (NiO); and 3, the mesoporous nickel protoxide is subjected to high-temperature reduction in the H2 atmosphere, and the final product porous nickel particles are obtained. The novel preparation method is provided for producing the porous nickel particles, the raw materials are low in cost and easy to obtain, the prepared porous nickel particles are stable in structure and controllable in pore diameter, the production cost and the market price of the porous nickel particles are expected to be further reduced, and application of the porous nickel particles in the field of catalysis is expanded.

Description

Technical Field

[0001] This invention belongs to the field of nanoporous catalytic materials, specifically a method for preparing uniform porous nickel particles using a self-template. Background Technology

[0002] Porous nickel particles, as a metal-based functional material possessing high specific surface area, excellent conductivity, and tunable pore structure, have shown significant application potential in fields such as hydrogen production through water electrolysis, lithium-ion battery electrodes, sensors, and high-temperature filtration. The core feature of their preparation lies in forming a nanoscale porous network through specific processes, endowing the material with unique physicochemical properties. However, existing preparation methods still somewhat limit their industrial application.

[0003] Traditional template methods (such as the sol-gel method) require the use of surfactants or organic template agents, and subsequent removal processes involve strong acid / alkali treatments, which can easily generate toxic waste liquids. Wu Qiang et al., in their paper "Nickel-based composite nanomaterials and their preparation methods, porous nickel nanomaterials and their preparation methods and applications" (patent publication number: CN102423708A), prepared nickel-based composite nanomaterials with a flower-like structure consisting of a solid core covered by nanosheets via solution-phase co-precipitation. However, the nanosheets had rough edges and uneven surface pore distribution. Jiao Jiqing et al., in their paper "A method for preparing regular porous nickel oxide nanosheets without templates" (patent publication number: CN118724087A), disclosed a hydrothermal method that requires the addition of hexadecyltrimethylammonium bromide (CTAB) as a structure directing agent, resulting in residual organic matter on the product surface, and high-temperature calcination easily triggers a phase transition in nickel oxide. Furthermore, the electrodeposition method used by Wang Xiaotian et al. in "A Porous Nanoparticle Nickel and Its Preparation Method and Application" (Patent Publication No.: CN117127204A) relies on chlorine-containing complexing agents (such as choline chloride), posing risks of plating bath toxicity and hydrogen embrittlement. Existing powder metallurgy methods require the addition of pore-forming agents such as PMMA, resulting in low porosity (typically <35%) and uneven distribution after sintering, with residual pore-forming agents reducing the material's corrosion resistance. While the nickel-manganese alloy dealloying method described by Kang Jianli et al. in "A Preparation Method of High-Strength Nanoporous Nickel Film" (Patent Publication No.: CN103774149A) can form nanopores, the corrosion rate is uncontrollable, leading to a pore size distribution spanning 0.5-100 nm and insufficient mechanical strength (compressive strength <200 MPa).

[0004] The nickel oxide nanosheets prepared by Jiao Jiqing et al. using chemical etching in their paper "A Method for Preparing Regular Porous Nickel Oxide Nanosheets Without Template" (Patent Publication No.: CN118724087A) exhibit mixed crystal structures (such as the coexistence of NiO and Ni(OH)2), affecting the stability of catalytic activity. Therefore, developing a green and structurally controllable porous nickel particle preparation technology, while simultaneously achieving large-scale continuous production and improved adaptability for functional applications, has become a pressing technical challenge in this field. This invention innovatively proposes a sacrificial self-template pore-forming process design, overcoming the technical bottleneck of uneven pore formation caused by uncontrollable structure, and providing a new approach for the efficient preparation of porous nickel particles and their application in the new energy field. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing uniform porous nickel particles using a self-templating technique. This method, drawing on the self-templating method, first prepares a precursor, and then, through subsequent processing, sacrifices other non-product components from the precursor to obtain the target product. This method can obtain the target product without the need for an external template, and the particle size and porosity of the product can be controlled by adjusting parameters during the preparation process.

[0006] To achieve the above-mentioned objectives, the present invention proposes the following technical solution:

[0007] A method for preparing uniform porous nickel particles using a self-templating method, characterized by comprising the following steps:

[0008] Step 1: Preparation of basic nickel carbonate precursor from mixed solution;

[0009] A layered basic nickel carbonate precursor (NiCO3·2Ni(OH)2·4H2O) is prepared by mixing nickel salt and precipitant in a certain proportion and placing the solution in a reactor. The reactor consists of (1) an electric motor, (2) a feed inlet, (3) a temperature measuring port, (4) a pressure measuring port, (5) a stirring blade, (6) a heating jacket, and (7) a discharge port.

[0010] Step 2: Calcination of the precursor yields nickel oxide (NiO);

[0011] The obtained precursor was calcined at high temperature to obtain mesoporous nickel oxide (NiO);

[0012] Step 3: Nickel suboxide is reduced at high temperature with H2 to obtain porous nickel particles;

[0013] Mesoporous nickel oxide was reduced at high temperature under H2 atmosphere to obtain the final product, porous nickel particles.

[0014] Principle of this invention

[0015] When urea is used as the precipitant, during the high-pressure hydrothermal reaction, divalent nickel ions react with urea (CO(NH2)2) and water (H2O) to generate a basic nickel carbonate precursor, as shown in equation (1). When other precipitants are used, the target product of this step is still basic nickel carbonate, which will not be elaborated here.

[0016] NiSO4+2CO(NH2)2+H2O→NiCO3·2Ni(OH)2·4H2O+(NH4)2SO4 (1)

[0017] Basic nickel carbonate undergoes a decomposition reaction upon calcination at high temperatures, producing nickel oxide (NiO), carbon dioxide (CO2), and water (H2O). The reaction equation is shown in (2). Since this reaction occurs at high temperatures, the generated carbon dioxide and water are discharged from the system in gaseous form, thus creating a large number of uniform pores and achieving the first step of pore formation.

[0018] NiCO3·2Ni(OH)2·4H2O=3NiO+CO2↑+6H2O↑ (2)

[0019] Nickel oxide and hydrogen undergo a reduction reaction at high temperature, producing metallic nickel (Ni) and water. The reaction equation is shown in (3). During this reduction process, oxygen in nickel oxide escapes as water vapor, which further generates uniform pores, thus achieving the second step of pore formation.

[0020] NiO + H2 = Ni + H2O (3)

[0021] Both steps of the reaction (reactions 2-3) achieve pore formation by sacrificing the template. That is, the C, H and O elements are gradually removed to create pores based on the overall structure of the basic nickel carbonate precursor as the structural basis of the final product. While maintaining the overall structure from collapsing and deforming, uniform pore formation is achieved, and finally, uniform porous nickel particles are prepared. The prepared porous nickel particles are not only structurally stable, but also have uniform pore size and distribution. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the reactor used to prepare porous nickel particles in Example 1 of the present invention;

[0024] Figure 2 This is a scanning electron microscope image of the porous nickel particle material prepared in Example 1 of the present invention;

[0025] Figure 3 The XRD pattern of the porous nickel particle material prepared in Example 1 of this invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0027] It should be understood that the step numbers used in the text are for ease of description only and are not intended to limit the order in which the steps are performed.

[0028] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0029] The terms “comprising” and “including” indicate the presence of the described feature, whole, step, operation, element and / or component, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0030] The term “and / or” refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes these combinations.

[0031] Example 1

[0032] Nickel sulfate and urea were mixed in a 1:2 ratio (Ni 2+ The nickel carbonate precursor (NiCO3·2Ni(OH)2·4H2O) was dissolved in a reactor at a molar ratio of urea and reacted at 300℃ for 24 h to obtain a basic nickel carbonate precursor. The basic nickel carbonate precursor was placed in a tube furnace, nitrogen gas was introduced, and the temperature was maintained at 800℃ for 1 h to obtain an intermediate nickel oxide (NiO). The intermediate nickel oxide was placed in a high-temperature hydrogen reduction reactor and maintained at 500℃ in H2 atmosphere for 8 h to obtain a uniform porous nickel particle product.

[0033] Example 2

[0034] Nickel nitrate solution and hydrazine hydrate were placed in a reactor, and the pH was adjusted to 8-9 with sodium carbonate. The reaction was carried out at 150℃ for 48 h to obtain a basic nickel carbonate precursor (NiCO3·2Ni(OH)2·4H2O). The basic nickel carbonate precursor was then placed in a tube furnace, argon gas was introduced, and the furnace was held at 300℃ for 4 h to obtain an intermediate.

[0035] Nickel suboxide (NiO); The intermediate nickel suboxide was placed in a high-temperature hydrogen reduction reactor and kept at 300℃ in H2 atmosphere for 18 hours to obtain a uniform porous nickel particle product.

[0036] Example 3

[0037] Nickel sulfate is mixed with a gas of NH3 and CO2 (Ni 2+ A mixture of NH3 and CO2 (2:2:1) was placed in a reactor and reacted at 400℃ for 12 hours to obtain a basic nickel carbonate precursor (NiCO3·2Ni(OH)2·4H2O). The basic nickel carbonate precursor was placed in a tube furnace, nitrogen gas was introduced, and the furnace was kept at 600℃ for 2 hours to obtain an intermediate nickel oxide (NiO). The intermediate nickel oxide was placed in a high-temperature hydrogen reduction reactor and kept at 200℃ in an H2 atmosphere for 24 hours to obtain a uniform porous nickel particle product.

[0038] The present invention has the following beneficial effects:

[0039] I. Compared with traditional processes for preparing porous nano-nickel, this invention generates no pollutants and conforms to the concept of green preparation.

[0040] Second, the by-products of this invention can be used in other fields, such as the preparation of fertilizers or as raw materials for the preparation of other products.

[0041] Third, in this invention, a stable self-supporting porous structure can be achieved by controlling the heat treatment temperature, and the structure itself serves as both a template and a product.

[0042] Fourth, compared with other existing preparation methods, the porous nickel particles produced by this invention have higher porosity and more balanced pore distribution, more uniform pore size, and more stable pore structure that is less prone to collapse.

[0043] This invention provides a method for preparing uniform porous nickel particles using a self-templating method.

[0044] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing uniform porous nickel particles using a self-templating method, characterized in that, Includes the following steps: Step 1: Preparation of basic nickel carbonate precursor from mixed solution; A layered basic nickel carbonate precursor (NiCO3·2Ni(OH)2·4H2O) is prepared by mixing nickel salt and precipitant in a certain proportion and placing the solution in a reactor. The reactor consists of (1) an electric motor, (2) a feed inlet, (3) a temperature measuring port, (4) a pressure measuring port, (5) a stirring blade, (6) a heating jacket, and (7) a discharge port. Step 2: Calcination of the precursor yields nickel oxide (NiO); The obtained precursor was calcined at high temperature to obtain mesoporous nickel oxide (NiO); Step 3: Nickel suboxide is reduced at high temperature with H2 to obtain porous nickel particles; Mesoporous nickel oxide was reduced at high temperature under H2 atmosphere to obtain the final product, porous nickel particles.

2. The method for preparing uniform porous nickel particles using a self-templating method according to claim 1, characterized in that, In step one, the nickel salt can be nickel sulfate (NiSO4), but it is not limited to this; other soluble nickel salts can also be used.

3. The method for preparing uniform porous nickel particles using a self-templating method according to claim 1, characterized in that, In step one, the precipitant can be urea (CO(NH2)2), but is not limited to this; it can also be hydrazine hydrate (N2H4·H2O) or a mixture of NH3 and CO2.

4. The method for preparing uniform porous nickel particles using a self-templating method according to claim 1, characterized in that, In step one, the ratio of nickel salt to precipitant is 1:2 to 1:

5.

5. The method for preparing uniform porous nickel particles using a self-templating method according to claim 1, characterized in that, In step one, the temperature inside the reactor is 50–800℃, and the time is 4–48 hours.

6. The method for preparing uniform porous nickel particles using a self-templating method according to claim 1, characterized in that, In step two, the decomposition temperature of basic nickel carbonate is 200–900°C.

7. The method for preparing uniform porous nickel particles using a self-templating method according to claim 1, characterized in that, In step three, the high-temperature reduction temperature is 200–600℃, and the time is 3–24 hours.

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