Carbon supported platinum-nickel catalyst, its preparation method and application

Abstract

The application provides a carbon-supported platinum-nickel catalyst, a preparation method and application thereof. The preparation method comprises the following steps: obtaining a nickel source through a double decomposition reaction of a first ammonium salt and a smelting nickel sulfate salt; obtaining activated carbon black through plasma treatment of carbon powder; obtaining a precursor product through mixing and contacting of the nickel source, the activated carbon black, a platinum source, a second ammonium salt, a complexing agent and a first reducing agent and through a combination reaction; and obtaining the carbon-supported platinum-nickel catalyst through calcination treatment of the precursor product and a second reducing agent. The application adopts a double decomposition reaction of a smelting nickel sulfate salt and an ammonium salt to prepare a high-purity nickel source, and adopts plasma to modify a carbon carrier, so that the controllable optimization of oxygen / nitrogen-containing functional groups and pore structures on the surface of the carbon carrier is realized, the interaction between the carrier and the active component is enhanced, and the obtained carbon-supported platinum-nickel catalyst has superior pore size structure and good catalytic activity.

Description

Technical Field

[0001] This invention relates to the field of electrochemical catalysts, and more specifically, to a carbon-supported platinum-nickel catalyst, its preparation method, and its application. Background Technology

[0002] With the global energy structure transformation and increasing environmental awareness, hydrogen-oxygen fuel cells, as a clean and efficient energy conversion device, are gradually becoming an important technological path to solve the energy crisis and environmental pollution problems. However, the commercial application of hydrogen-oxygen fuel cells still faces the bottleneck of slow cathode oxygen reduction reaction (ORR) kinetics, mainly due to the lack of efficient and stable catalyst materials.

[0003] Currently, platinum (Pt) and platinum-based materials are widely considered the most effective catalysts for the ORR reaction. However, pure platinum catalysts are scarce and costly, making it difficult to meet the needs of large-scale commercialization. To reduce platinum usage and improve catalytic activity, researchers have developed various platinum-based alloy catalysts, among which platinum-nickel (Pt-Ni) alloy catalysts have attracted much attention due to their excellent catalytic performance. CN119869586A discloses a supported platinum-nickel alloy catalyst and its preparation method. This method involves mixing a platinum source, a nickel source, and an organic ligand in an organic solvent to form a platinum-nickel complex, which is then supported on nitrogen-doped porous carbon and subjected to reduction calcination to obtain a platinum-nickel alloy catalyst with high catalytic activity.

[0004] To further improve the performance of platinum-nickel catalysts, core-shell structure design has become an effective strategy. CN118659001A describes a method for preparing a carbon-supported core-shell structured platinum-nickel catalyst for proton exchange membrane fuel cells. This method involves a two-step pressurized hydrogen reduction process, first preparing carbon-supported nickel nanoparticles, and then depositing a platinum layer on their surface to form a core-shell structure, enabling the catalyst to achieve a mass activity exceeding 0.70 A·mg. Pt -1 .

[0005] Carbon coating technology is also widely used in the preparation of platinum-nickel catalysts. CN116207280A, CN116207274A and CN116207279A disclose different types of carbon-coated platinum-nickel alloy nanomaterials and their preparation methods. These materials all have a core-shell structure with platinum-nickel alloy nanoparticles as the core and a carbon layer as the outer shell. The morphology of the alloy nanoparticles (such as porous structure, hollow structure) and the composition of the carbon layer (such as nitrogen doping) can be controlled.

[0006] However, existing methods for preparing platinum-nickel catalysts still suffer from the following problems: First, traditional methods such as co-precipitation, sol-gel, and impregnation struggle to achieve uniform dispersion of the platinum-nickel active metal on the support surface, easily leading to metal nanoparticle aggregation and reduced utilization of catalytic active sites. Second, the interaction between the support and the active component is weak; during fuel cell operation, especially under high temperature and high potential conditions, the active component easily detaches from the support surface, resulting in decreased catalyst stability. Furthermore, an unreasonable pore structure design of the catalyst restricts the rapid transport and diffusion of reactant gases, thus affecting battery performance.

[0007] Regarding nickel source selection, existing technologies mostly employ high-purity nickel salts (such as nickel chloride hexahydrate) as nickel precursors, neglecting the utilization potential of crude nickel sulfate, a low-cost nickel source and a byproduct of smelting. Crude nickel sulfate, a typical byproduct of copper smelting, boasts advantages such as high yield and low acquisition cost; however, its complex composition, containing numerous impurity metal ions and ions outside of stoichiometry, presents significant challenges for its direct use in catalyst preparation. Traditional crude nickel sulfate purification processes are lengthy, energy-intensive, have low recovery rates, and easily cause environmental pollution, necessitating the development of simple and efficient purification methods.

[0008] Pretreatment of the carrier carbon powder is also a key factor affecting catalyst performance. Untreated carbon powder has a highly inert surface, insufficient binding force with active components, and may have defects in its pore structure. Although traditional acid treatment methods can improve the surface properties of carbon powder to some extent, they have problems such as long treatment time, generation of large amounts of acidic waste liquid, and excessive etching leading to damage to the pore structure of the carbon powder.

[0009] Therefore, developing a method for preparing carbon-supported platinum-nickel catalysts that can simultaneously solve problems such as poor dispersion of active components, weak interaction between the support and active components, and unsatisfactory pore structure, and can efficiently utilize low-cost smelting of crude nickel sulfate, thereby preparing catalysts with superior electrocatalytic activity, is an important technical problem that urgently needs to be solved in this field. Summary of the Invention

[0010] The main objective of this invention is to provide a carbon-supported platinum-nickel catalyst, its preparation method, and its application, so as to realize the high-value utilization of nickel resources associated with copper smelting and improve the comprehensive utilization rate of nickel resources. At the same time, it solves the problem that the electrochemical catalysts in the prior art have low electrocatalytic activity due to poor pore structure and poor dispersion of active metals.

[0011] To achieve the above objectives, a first aspect of the present invention provides a method for preparing a carbon-supported platinum-nickel catalyst, comprising: step S1, a first ammonium salt and smelted nickel sulfate undergo a metathesis reaction to obtain a nickel source; step S2, plasma treatment of carbon powder to obtain activated carbon black; step S3, the nickel source, activated carbon black, platinum source, second ammonium salt, complexing agent, and first reducing agent are mixed and contacted and undergo a chemical reaction to obtain a precursor product; step S4, the precursor product and the second reducing agent are calcined to obtain a carbon-supported platinum-nickel catalyst; wherein the first ammonium salt is selected from one or more of ammonium carbonate, ammonium bicarbonate, ammonium sulfate, ammonium oxalate, ammonium acetate, ammonium chloride, and ammonia water; and the pyrolysis product of the nickel source is nickel oxide.

[0012] Further, step S1 includes: preparing a nickel sulfate solution by mixing smelting nickel sulfate with water, and adding a first ammonium salt to the nickel sulfate solution, and obtaining a nickel source through a metathesis reaction; the weight ratio of smelting nickel sulfate, the first ammonium salt and water is (1~30):(0.01~10):(4~1200); and / or, the molar concentration of nickel sulfate in the nickel sulfate solution is 0.1mol / L~1.5mol / L; and / or, the smelting nickel sulfate is a by-product of the copper ore smelting process, and the nickel grade in the smelting nickel sulfate is 15wt%~18wt%.

[0013] Further, in step S1, the first ammonium salt is added in the form of a salt solution, and the molar concentration of the first ammonium salt in the salt solution is 0.05 mol / L to 3.0 mol / L; and / or, the salt solution is added to the nickel sulfate solution at a dropping rate of 1 mL / min to 30 mL / min; and / or, the reaction temperature of the metathesis reaction is 50℃ to 80℃, and the time is 10 min to 180 min.

[0014] Further, step S2 includes: laying carbon powder in a reaction boat with a thickness of 1 mm to 2 mm, and treating it with plasma in a plasma reaction chamber to obtain activated carbon black; the working gas used for plasma treatment is selected from one or more of oxygen, nitrogen, argon and ammonia; and / or, the gas flow rate of plasma treatment is 20 mL / min to 50 mL / min, and the plasma treatment is carried out at 10 Pa to 50 Pa; and / or, the discharge voltage of plasma treatment is 20 V to 60 V, the electrode spacing is 5 mm to 30 mm, and the discharge time is 15 s to 120 s.

[0015] Further, step S3 includes: step S3-1, where activated carbon black and solvent are first dispersed to obtain a first suspension; step S3-2, where a platinum source is added to the first suspension, and a second dispersion is performed to obtain a second suspension; step S3-3, where a second ammonium salt is added to the second suspension to obtain a third suspension with a pH of 7-10; step S3-4, where a nickel source and a complexing agent are added to the third suspension, and a third dispersion is performed to obtain a fourth suspension; and step S3-5, where a first reducing agent is added to the fourth suspension, and a chemical reaction is performed to obtain a precursor product.

[0016] Further, in the first suspension, the solid content of activated carbon black is 30 g / L to 100 g / L; and / or, the weight ratio of activated carbon black to platinum source is (1~20):1; and / or, the molar ratio of the second ammonium salt to platinum source is (1~3):1; and / or, the molar ratio of nickel source to platinum source is (1~3):1; and / or, the molar ratio of complexing agent to nickel source is (1~2):1; and / or, the ratio of the total molar amount of nickel source and platinum source to the molar amount of the first reducing agent is 1:(2~5).

[0017] Further, in step S3-1, the first dispersion is carried out by ultrasound, with a frequency of 5kHz to 30kHz and a duration of 30min to 60min; and / or, in step S3-2, the second dispersion is carried out by stirring, with a stirring speed of 300±50rpm and a duration of 1h to 2h; and / or, in step S3-4, the third dispersion is carried out by stirring, with a stirring time of 1h to 2h; and / or, in step S3-5, the first reducing agent is added in the form of a reducing agent solution, with a molar concentration of the first reducing agent in the reducing agent solution of 1.0±0.2mol / L; the reaction temperature is 20℃ to 50℃, and the reaction time is 1h to 3h.

[0018] Furthermore, in step S4, the second reducing agent is selected from one or more of elemental carbon, CO, and hydrogen.

[0019] Furthermore, in step S4, the heating rate of the calcination treatment is 5℃ / min~30℃ / min, the holding temperature is 200℃~1000℃, and the holding time is 3h~10h.

[0020] A second aspect of the present invention provides a carbon-supported platinum-nickel catalyst, which is prepared by the above-described method for preparing a carbon-supported platinum-nickel catalyst; the carbon-supported platinum-nickel catalyst includes a support carbon black and an active metal supported on the support carbon black, and the total loading of the active metal is 20wt% to 40wt%.

[0021] Furthermore, the carbon-supported platinum-nickel catalyst has a porous structure, and the pore volume of the carbon-supported platinum-nickel catalyst is 1.0 cm³. 3 / g~10.0cm3 / g, pore size 2nm~50nm, specific surface area 500m² 2 / g~800m 2 / g.

[0022] A third aspect of the present invention provides an application of the above-mentioned carbon-supported platinum-nickel catalyst as a catalyst in an electrochemical reaction, wherein the electrochemical reaction is an oxygen reduction reaction, a hydrogen evolution reaction, or an oxygen evolution reaction.

[0023] By applying the technical solution of this invention, a high-purity nickel source is prepared through the metathesis reaction of smelting-grade nickel sulfate and ammonium salt. Plasma is used to modify the surface of the carbon support, achieving controllable optimization of the oxygen / nitrogen-containing functional groups and pore structure on the carbon support surface. This enhances the interaction between the support and the active component, avoiding the environmental pollution problem caused by the large amount of acidic waste liquid generated by traditional acid treatment methods. Through complexation technology and a stepwise reduction strategy, the release rate of metal ions is controlled while the reducing agent is used in stages, achieving uniform deposition of platinum-nickel ions on the carbon support surface. This solves the problem of uneven metal ion deposition in traditional co-precipitation methods. The resulting carbon-supported platinum-nickel catalyst exhibits superior pore structure and good catalytic activity. Meanwhile, the method provided by this invention can efficiently purify, enrich and refine smelted nickel sulfate, and achieve phase transformation of nickel salts. This not only shortens the process flow and improves the purity of nickel salts, but also prepares high-performance platinum-nickel oxygen reduction catalysts. This realizes the high-value utilization of nickel resources associated with copper smelting, improves the comprehensive utilization rate of nickel resources, and solves the industry technical problems of "high-cost pure nickel source dependence" and "low-cost crude nickel sulfate cannot be directly applied" in the field of platinum-nickel-based oxygen reduction electrocatalysts. Attached Figure Description

[0024] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0025] Figure 1 The transmission electron microscopy (TEM) characterization results of the carbon-supported platinum-nickel catalyst obtained in Example 1 of this invention are shown below.

[0026] Figure 2 The nitrogen adsorption-desorption curve of the carbon-supported platinum-nickel catalyst obtained in Example 1 of this invention is shown below.

[0027] Figure 3 The nitrogen adsorption-desorption curve of the carbon-supported platinum-nickel catalyst obtained in Comparative Example 2 of this invention is shown below.

[0028] Figure 4 This is a pore size distribution diagram of the carbon-supported platinum-nickel catalyst obtained in Example 1 of the present invention;

[0029] Figure 5This is a pore size distribution diagram of the carbon-supported platinum-nickel catalyst obtained in Comparative Example 2 of the present invention;

[0030] Figure 6 The cyclic voltammetry (CV) curves of the carbon-supported platinum-nickel catalyst obtained in Example 1 of this invention and commercial Pt / C are shown.

[0031] Figure 7 The linear sweep voltammetry (LSV) curves of the carbon-supported platinum-nickel catalyst obtained in Example 1 of this invention and commercial Pt / C are shown. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0033] As described in the background section, existing electrochemical catalysts suffer from low electrocatalytic activity due to poor pore structure and poor dispersion of active metals. To address this problem, a first aspect of the present invention provides a method for preparing a carbon-supported platinum-nickel catalyst, comprising: step S1, a first ammonium salt and smelted nickel sulfate undergo a metathesis reaction to obtain a nickel source; step S2, plasma treatment of carbon powder to obtain activated carbon black; step S3, mixing and contacting the nickel source, activated carbon black, platinum source, second ammonium salt, complexing agent, and first reducing agent to undergo a combination reaction to obtain a precursor product; and step S4, calcining the precursor product and the second reducing agent to obtain the carbon-supported platinum-nickel catalyst; wherein the first ammonium salt is selected from one or more of ammonium carbonate, ammonium bicarbonate, ammonium sulfate, ammonium oxalate, ammonium acetate, ammonium chloride, and ammonia water; and the pyrolysis product of the nickel source is nickel oxide.

[0034] This invention utilizes the metathesis reaction of smelting-grade nickel sulfate and ammonium salt to prepare a high-purity nickel source. Plasma is employed to modify the surface of the carbon support, achieving controllable optimization of the oxygen / nitrogen functional groups (oxygen- or nitrogen-containing functional groups can be introduced depending on the discharge gas; oxygen plasma treatment introduces oxygen-containing functional groups such as hydroxyl and carbonyl groups, increasing surface acidity; nitrogen plasma treatment introduces nitrogen-containing functional groups such as amino groups, enhancing surface alkalinity) and pore structure on the carbon support surface. Through complexation technology and a stepwise reduction strategy, the release rate of metal ions is controlled while the reducing agent is used in stages, achieving uniform deposition of platinum-nickel ions on the carbon support surface. This solves the problem of uneven metal ion deposition in traditional co-precipitation methods. The resulting carbon-supported platinum-nickel catalyst exhibits superior pore structure and excellent catalytic activity.

[0035] Specifically: In step S1, the first ammonium salt undergoes a metathesis reaction with smelting nickel sulfate, generating a nickel-containing composite salt in the reaction system. This composite salt is then used as the nickel source for preparing the platinum-nickel alloy catalyst. In this step, the type of the first ammonium salt is controlled, and the principle of ion exchange (i.e., Ni...) is applied.2+ With anions in ammonium salts (such as CO3) 2+ C2O4 2- The reaction produces nickel-containing complex salts, while releasing water-soluble byproducts (such as (NH4)2SO4), thus achieving the separation and purification of nickel from complex-component smelting nickel sulfate and converting it into a precursor form suitable for alloy catalyst preparation. Simultaneously, the generated nickel-containing complex salts and water-soluble byproducts are easily separated by filtration, facilitating subsequent purification.

[0036] In particular, by strictly limiting the type of the first ammonium salt, the resulting nickel source can avoid introducing other impurities into the system during subsequent preparation processes. Furthermore, it is preferable to use carbonate-containing ammonium salts, namely ammonium carbonate and / or ammonium bicarbonate, which, when reacting with nickel sulfate, can avoid the formation of Ni(OH)₂ precipitate (because Ni…). 2+ With CO3 2+ The NiCO3 generated in the reaction is relatively more stable under weakly alkaline conditions and is less prone to hydrolysis. Furthermore, after the reaction is complete, through steps such as filtration, washing, and vacuum drying, a nickel-containing compound with higher purity can be obtained, providing a higher purity nickel source for the subsequent preparation of catalysts.

[0037] In step S2, plasma treatment is used to activate the carbon powder surface and optimize its pore structure, resulting in activated carbon black. Plasma treatment technology utilizes the synergistic effects of high-energy electrons, active ions, and free radicals to selectively etch the carbon powder surface, introduce functional groups (promoting the formation of -C=O functional groups), or construct surface defect sites, thereby improving the interfacial bonding force between the carbon powder and the active metal components and significantly enhancing the structural stability of the catalyst. Compared to traditional acid etching methods, this method avoids the generation of corrosive waste liquid, has a shorter processing time, and directionally introduces oxygen-containing functional groups, increasing the surface roughness of the carbon material, forming more active sites, and simultaneously altering the pore structure and increasing the specific surface area. This provides an excellent microenvironment for the uniform dispersion of subsequent metal ions and the efficient loading of the catalyst, thereby improving catalyst performance.

[0038] In step S3, the nickel source obtained in step S1, plasma-treated activated carbon black, platinum source, second ammonium salt, complexing agent, and first reducing agent are mixed and a catalyst precursor is prepared through contact and chemical reaction. Utilizing the abundant active sites and optimized pore structure on the activated carbon black, platinum-nickel ions can be uniformly deposited on the carbon powder surface. The second ammonium salt can control the solubility of the metal salt by adjusting the pH value of the system, allowing the metal ions to fully contact the support and form a stable precursor structure. The application of the complexing agent further regulates the release rate and morphology of the metal ions, improving their dispersibility and stability on the support. The first reducing agent can initially reduce the metal salt at this stage, avoiding metal migration and agglomeration at high temperatures, which is beneficial for forming nanoscale alloy particles.

[0039] Finally, during the calcination heat treatment in step S4, the active metals platinum and nickel are further reduced, and the overall structure of the catalyst is further stabilized, thus exhibiting superior catalytic activity and cycle stability.

[0040] In addition, this invention directly uses smelting-grade nickel sulfate as raw material, eliminating the need for high-purity reagent-grade raw materials and significantly reducing raw material costs. Through the synergistic effect of complexation and reduction, the utilization rate of the precious metal platinum is greatly improved, significantly reducing the catalyst preparation cost. Furthermore, the use of plasma pretreatment instead of traditional acid treatment avoids the use of strong acids and the generation of waste liquid. Compared with traditional acid treatment methods, it also has advantages such as shorter processing time and precise control of surface functional groups.

[0041] In summary, this invention, through the organic combination of material design, process innovation, and step optimization, produces a carbon-supported platinum-nickel catalyst that exhibits high catalytic activity and high stability while significantly reducing production costs and increasing product added value.

[0042] It should be noted in advance that, in order to avoid ambiguity, the water used in the technical solution of this invention is deionized water or ultrapure water with a resistivity ≥18.2MΩ·cm.

[0043] Furthermore, to improve the kinetic efficiency of the metathesis reaction and further reduce the possibility of heterogeneous precipitation, step S1 preferably includes: preparing a nickel sulfate solution by mixing smelting nickel sulfate with water, and adding a first ammonium salt to the nickel sulfate solution, followed by a metathesis reaction to obtain a nickel source. In several typical embodiments, the preferred weight ratio of smelting nickel sulfate, the first ammonium salt, and water is (1~30):(0.01~10):(4~1200), more preferably (1~3):(5~8):(10~20). In this case, the amount of the first ammonium salt added is preferably about 1.5~3 times the theoretical molar amount of nickel sulfate, thereby more effectively avoiding the formation of by-products. Taking ammonium carbonate as the first ammonium salt as an example, since Ni 2+ It is a weakly basic cation, CO3 2- It is a weak acid anion and readily undergoes trace hydrolysis in aqueous solution, namely:

[0044]

[0045]

[0046] The aforementioned hydrolysis reaction can be suppressed by controlling the excess of ammonium salt, thereby controlling the pH of the system. However, an excess of the first ammonium salt will also alter the reaction kinetics, making the reaction difficult to control. Based on this, the inventors, through extensive experimentation, optimized the weight ratio of the above-mentioned nickel sulfate smelting process, the first ammonium salt, and water, specifically the NH4 produced by the dissociation of excess ammonium salt. +Ni is neutralized through proton transfer. 2+ H generated by hydrolysis + At the same time, it inhibits CO3 2- The stepwise hydrolysis maintains the weak alkalinity of the reaction system, thereby improving the uniformity of the product and more effectively reducing the probability of Ni(OH)2 impurity phase formation.

[0047] To more effectively balance the reaction rate and product purity, and obtain a nickel source with higher purity, the preferred molar concentration of nickel sulfate in the nickel sulfate solution is 0.1 mol / L to 1.5 mol / L. In practical applications, the smelting nickel sulfate salt used is a byproduct of copper ore smelting, and the nickel content in the smelting nickel sulfate salt is 15 wt% to 18 wt%. Furthermore, step S1 preferably includes adding sulfuric acid to the nickel sulfate solution to adjust the pH of the nickel sulfate solution to 2 to 3, thereby removing Fe. 3+ Al 3+ Impurity ions are added to further improve the purity of the nickel source and optimize the catalytic activity of the catalysts prepared subsequently.

[0048] To further improve the purity of the nickel source, in practical applications, the preparation method provided by this invention also includes the processes of filtration, washing, and drying of the nickel source obtained in step S1. Preferably, washing includes washing the nickel source product with deionized water 3-5 times (until the pH of the filtrate is 7); drying is performed under vacuum at 60℃-80℃ for 3-5 hours. Of course, the post-processing is not limited to the above methods, as long as solid-liquid separation and product drying can be achieved.

[0049] In the metathesis reaction, an excessively rapid dropping rate can lead to overly intense local reactions, resulting in the formation of aggregates (an excessively rapid dropping rate can cause extremely high local supersaturation, leading to the rapid generation of a large number of crystal nuclei. These nuclei, before sufficient growth and dispersion, are prone to agglomeration due to collision and adhesion); while an excessively slow dropping rate may affect the chemical reaction kinetics (an excessively slow dropping rate may result in insufficient formation of the target product or alteration of the reaction pathway, thus affecting the overall reaction rate). Therefore, in step S1, it is preferable that: the first ammonium salt is added in the form of a salt solution, and the molar concentration of the first ammonium salt in the salt solution is 0.05 mol / L to 3 mol / L; and / or, the salt solution is added to the nickel sulfate solution at a dropping rate of 1 mL / min to 30 mL / min. By optimizing the above reaction conditions, more efficient ion exchange can be promoted during the reaction, resulting in nickel salt precipitates with better dispersibility and purity.

[0050] Furthermore, in the above-mentioned metathesis reaction process, the preferred reaction temperature is 50℃~80℃, and the time is 10min~180min, so as to obtain a nickel source with higher purity at a faster reaction rate. More preferably, the metathesis reaction is carried out under stirring conditions, and the stirring speed is 300rpm~500rpm, which can promote more uniform mixing of the reactants, reduce the phenomenon of local over-concentration (affecting the mass transfer process, making it difficult for reactant molecules to reach the reactive sites in time, thereby reducing the reaction rate), and thus more effectively improve the particle size uniformity of the obtained nickel source.

[0051] In step S2, the carbon powder is activated by plasma treatment. Specifically, the carbon powder is laid in a reaction boat with a thickness of 1 mm to 2 mm and then subjected to plasma treatment in the plasma reaction chamber to obtain activated carbon black. In practical applications, before plasma treatment of the carbon powder, in order to reduce the interference of moisture, vacuum drying can also be used to dry the carbon powder to be treated at 60℃ to 80℃ for 5 h to 10 h.

[0052] During plasma treatment, high-energy particles bombard the surface of the carrier carbon powder, breaking the original inert CC and CH chemical bonds and generating a large number of oxygen-containing functional groups (such as hydroxyl -OH, carboxyl -COOH, and carbonyl C=O) and defect sites. These active sites enhance the interaction between the carbon powder and platinum ions (Pt). 2+ / Pt 4+ Nickel ions (Ni) 2+ The interaction between the plasma and the carbon powder reduces the aggregation of active components. Simultaneously, the etching effect of plasma can unclog blocked micropores (pore size <2nm) within the carbon powder, increase the proportion of mesopores (2~50nm), and improve the specific surface area, providing more channels for oxygen diffusion and reaction, thereby enhancing the electrocatalytic activity of the catalyst. Furthermore, compared to traditional acid treatments (such as HNO3 immersion or concentrated sulfuric acid reflux), plasma treatment eliminates the need for strong acid solutions and generates no waste liquid; it also has a shorter processing time (acid treatment requires 4~6 hours) and can simultaneously achieve surface modification and pore structure optimization. In addition, by adjusting the working gas, power, and time, the types and contents of functional groups on the carbon powder surface can be precisely controlled, avoiding the destruction of the carbon powder pore structure caused by excessive etching during acid treatment.

[0053] Based on this, in step S2, preferably: the working gas used for plasma treatment is selected from one or more of oxygen, nitrogen, argon, and ammonia; and / or, the gas flow rate for plasma treatment is 20 mL / min to 50 mL / min (more preferably 30 ± 5 mL / min), and the plasma treatment is carried out at 10 Pa to 50 Pa (more preferably 30 ± 5 Pa); and / or, the discharge voltage for plasma treatment is 20 V to 60 V (more preferably 40 V to 50 V), the electrode spacing is 5 mm to 30 mm (more preferably 20 ± 4 mm), and the discharge time is 15 s to 120 s. By using the above-mentioned preferred plasma treatment process parameters, oxygen-containing / nitrogen-containing functional groups can be more effectively introduced onto the carbon powder surface, thereby forming more stable coordination bonds with platinum and nickel ions, reducing the agglomeration and sintering of active components in the obtained catalyst precursor during subsequent calcination heat treatment, and further improving the cycle stability of the catalyst.

[0054] Furthermore, the aforementioned preferred plasma treatment process can significantly improve the pore structure of the carbon support, thereby further reducing the diffusion resistance of the catalytic target (such as oxygen) within the catalyst during subsequent use and improving catalytic efficiency. Simultaneously, plasma treatment of the carbon powder under the aforementioned preferred conditions can further enhance the electron transport efficiency of the resulting activated carbon black and active components, thus significantly optimizing the catalytic activity of the obtained carbon-supported platinum-nickel catalyst.

[0055] Furthermore, the working gas is preferably a mixture of oxygen and nitrogen, with a volume ratio of oxygen to nitrogen of (2~25):(2~25). This preferred working gas can more effectively balance the activation effect on the carbon powder surface, reduce the over-oxidation or nitriding that may occur during single-gas treatment, thereby further improving the interfacial bonding force between the obtained activated carbon powder and the active metal component, and ultimately significantly enhancing the stability of the obtained carbon-supported platinum-nickel catalyst.

[0056] To more effectively reduce adsorbed impurities on the carbon powder surface, improve the cleanliness of plasma treatment, and increase the generation efficiency of active species, thereby obtaining activated carbon black with higher reactivity, the plasma treatment preferably further includes, before starting the discharge, evacuating the plasma reaction chamber to a vacuum level of 10. -2 Pa~10 -3After passing through a pressure of 10 Pa to 50 Pa, working gas is introduced into the plasma reaction chamber to achieve a pressure of 10 Pa to 50 Pa. During the actual plasma treatment process, the reaction boat can be slightly agitated every approximately 15 ± 2 seconds to ensure more uniform carbon powder processing. After treatment, the plasma power supply is turned off, and working gas is continued to be introduced until the reaction chamber cools to room temperature. The carbon powder is then removed, sealed, and stored for later use. In several typical embodiments, the carbon powder is selected from one or more of acetylene black, Vulcan XC-72R, and Ketjen black.

[0057] In step S3, to promote a tighter bond between platinum-nickel metal ions and the carbon support, ultimately forming a catalyst with better dispersibility and higher stability, this step preferably includes: Step S3-1, activating carbon black and solvent undergo a first dispersion to obtain a first suspension; Step S3-2, adding a platinum source to the first suspension and undergoing a second dispersion to obtain a second suspension; Step S3-3, adding a second ammonium salt to the second suspension to obtain a third suspension with a pH of 7-10 (preferably 9-9.5); Step S3-4, adding a nickel source and a complexing agent to the third suspension and undergoing a third dispersion to obtain a fourth suspension; Step S3-5, adding a first reducing agent to the fourth suspension and undergoing a chemical reaction to obtain the precursor product. In particular, the pH control of the third suspension in step S3-3 is crucial, as excessively low pH will cause metal ions to dissolve excessively and fail to adhere effectively; excessively high pH should be avoided to prevent premature precipitation of metal ions, which can easily lead to the formation of agglomerated particles. Therefore, by gradually optimizing the pH value of the third suspension, a more stable precursor structure can be formed, promoting the uniform dispersion of metal ions on the support surface, thereby significantly improving the catalytic activity of the final carbon-supported platinum-nickel catalyst.

[0058] In several more typical embodiments, to promote more uniform contact between activated carbon black and the active metals platinum and nickel, the solid content of activated carbon black in the first suspension is preferably 30 g / L to 100 g / L. To achieve more effective platinum loading and thus better balance catalytic activity and resource cost, the weight ratio of activated carbon black to platinum source is preferably (1~20):1; and / or, the molar ratio of nickel source to platinum source is (1~3):1. The molar ratio of the second ammonium salt to the platinum source is preferably (1~3):1, more preferably (1.8~2.5):1, to more effectively control the pH value of the resulting third suspension and improve the uniformity of the distribution of the active metal on the carbon support.

[0059] To more efficiently regulate the release rate and morphology of active metal ions, more effectively prevent their direct precipitation, and promote a more uniform loading on the carbon support surface, the preferred molar ratio of complexing agent to nickel source is (1~2):1. The preferred ratio of the total molar amount of nickel source and platinum source to the molar amount of the first reducing agent is 1:(2~5) to more effectively achieve preliminary reduction, reduce byproduct formation, further stabilize the precursor structure, and improve the cycle stability of the final carbon-supported platinum-nickel catalyst.

[0060] In practical applications, the platinum source is selected from one or more of chloroplatinic acid, chloroplatinate, [Pt(acac)2], diammonium dinitrite platinum, and [Pt(CH3NH2)4][PtCl4]; and / or, the second ammonium salt is selected from one or more of NH4OH, (NH4)2SO4, and NH4Cl.

[0061] Regarding the type of complexing agent, to promote more uniform deposition of active metal ions (platinum-nickel) on the carbon support surface and reduce metal agglomeration caused by local supersaturation, thereby further improving the dispersibility, stability, and catalytic activity of the resulting catalyst, it is preferably selected from one or more of thiourea, sulfite, phosphoric acid, oxalic acid, arsenoic acid, polyacrylic acid, disodium ethylenediaminetetraacetate, and sodium thiosulfate. Through extensive experimentation, the inventors have preferred one or more of ascorbic acid, sodium ascorbate, sodium citrate, hydrazine hydrate, metal borohydride, ammonium chloride, and oleylamine as the first reducing agent, in order to promote the formation of the platinum-nickel alloy phase and further reduce the formation of byproducts. In particular, ascorbic acid and / or sodium ascorbate not only have better reducing power under mild conditions but also further reduce operational safety risks.

[0062] Furthermore, in order to further improve the uniformity of the reaction system and thus more significantly improve the uniformity of the distribution of active metals on the obtained catalyst, the solvent is preferably a mixed solvent of ethanol and water, and the volume ratio of ethanol to water in the mixed solvent is 1:(1~3).

[0063] Further, in step S3-1, the first dispersion is preferably carried out by ultrasound, with an ultrasound frequency of 5kHz~30kHz and a time of 30min~60min, in order to more effectively break the aggregated state of the activated carbon black and form a more uniform first suspension. In step S3-2, the second dispersion is preferably carried out by stirring, with a stirring speed of 300±50rpm and a time of 1h~2h; in step S3-4, the third dispersion is preferably carried out by stirring, with a stirring time of 1h~2h. The above operations are all aimed at promoting a more uniform dispersion of active metal ions in the first suspension, creating more favorable conditions for subsequent loading. In step S3-5, the first reducing agent is preferably added in the form of a reducing agent solution, with a molar concentration of the first reducing agent in the reducing agent solution of 1.0±0.2mol / L; the reaction temperature is 20℃~50℃, and the time is 1h~3h. The optimized reaction conditions described above can better control the reduction rate of active metal ions and maintain their dispersion at the nanoscale, thereby significantly improving the catalytic activity of the obtained carbon-supported platinum-nickel catalyst.

[0064] In several typical implementations, the reducing agent solution is preferably added to the fourth suspension and reacted at a dropping rate of 5 ± 1 mL / min. A dropping rate that is too slow may lead to uneven distribution of reactants, while a rate that is too fast may cause excessively vigorous local reactions, resulting in agglomeration. (A slow dropping rate may lead to uneven distribution of reactants due to insufficient mixing, resulting in large local concentration differences and affecting the uniformity and rate of the reaction. A fast dropping rate may cause excessively vigorous local reactions, generating a large number of fine crystal nuclei, which are prone to collision and aggregation, affecting the particle size of the product.) By optimizing the dropping rate as described above, a more stable reducing environment can be formed in the reaction system, promoting the gentle and uniform reduction of metal ions to metal atoms, further reducing agglomeration, and providing more uniformly sized and better-dispersed metal particles for the subsequent alloying process, ultimately significantly improving the overall performance of the catalyst.

[0065] In step S4, the second reducing agent is preferably selected from one or more of elemental carbon, CO, and hydrogen to achieve more efficient reduction while reducing impurity formation and further enhancing the catalytic activity of the resulting catalyst. Preferably, the second reducing agent is elemental carbon, and the weight ratio of elemental carbon to the precursor product is (0.1~0.5):1, to facilitate a gentler and more effective reduction of noble metal ions and promote the formation of the platinum-nickel alloy phase. To provide a larger specific surface area and increase the contact area with the metal precursor, thereby more effectively improving the reduction rate, the particle size of the elemental carbon used is more preferably 50 nm~1000 nm. To more effectively reduce agglomeration and obtain a carbon-supported platinum-nickel catalyst with higher catalytic activity, the second reducing agent is preferably hydrogen, and the hydrogen flow rate is 2 mL / min~20 mL / min.

[0066] Furthermore, in practical applications, the preparation method provided by this invention further includes: grinding and refining the calcined product after calcination heat treatment to obtain a carbon-supported platinum-nickel catalyst.

[0067] Furthermore, in step S4, the preferred heating rate for the calcination heat treatment is 5℃ / min to 30℃ / min, the holding temperature is 200℃ to 1000℃, and the holding time is 3h to 10h. This facilitates more effective crystallization, alloying, and stabilization of the metal particles, while further optimizing the pore structure of the catalyst. In practical applications, generally, after the calcination heat treatment is completed, the resulting calcined product is cooled to room temperature in the furnace.

[0068] In several typical embodiments, the preferred calcination heat treatment includes: a first-stage calcination at a first heating rate from 25±2℃ to 300℃~350℃ for 1h~1.5h; a second-stage calcination at a second heating rate from 300℃~350℃ to 600℃~650℃ for 1h~3h; a third-stage calcination at a third heating rate from 600℃~650℃ to 800℃~900℃ for 1.5h~2h; and a fourth-stage calcination at a fourth heating rate from 800℃~900℃ to 950℃~1000℃ for 1.5h~3h.

[0069] By gradually increasing the temperature and maintaining it as described above, the reduction annealing rate of the catalyst precursor can be more effectively controlled, promoting more uniform reduction and alloying of noble metal ions. In particular, the initial annealing at a suitable temperature during the first two stages of calcination heat treatment helps remove organic residues from the precursor, reducing byproducts in subsequent high-temperature processing. The latter two stages of calcination heat treatment are designed to further promote the crystallization of metal particles and the formation of alloy phases, while allowing sufficient time for the metal particles to rearrange, forming an alloy structure of more suitable size and more uniform distribution, thereby significantly improving the catalytic activity and stability of the obtained carbon-supported platinum-nickel catalyst.

[0070] Based on the aforementioned stepped calcination heat treatment, further optimization is achieved: the first heating rate is 5℃ / min to 30℃ / min; and / or, the second, third, and fourth heating rates are each independently 5℃ / min to 10℃ / min. By optimizing the heating rates of each calcination heat treatment stage, the migration and agglomeration of active metal particles can be reduced to a greater extent, while the pore structure and specific surface area of ​​the catalyst can be optimized more effectively, resulting in a carbon-supported platinum-nickel catalyst with higher catalytic activity.

[0071] Furthermore, in practical applications, in order to further reduce impurities, stabilize the structure, and extend the service life of the obtained catalyst, it is preferable to carry out the calcination heat treatment in a protective atmosphere, and the protective atmosphere is selected from one or more of argon, nitrogen, helium and ammonia, with a volumetric flow rate of 1L / min to 10L / min.

[0072] A second aspect of the present invention provides a carbon-supported platinum-nickel catalyst, which is prepared by the above-described method for preparing carbon-supported platinum-nickel catalysts. The carbon-supported platinum-nickel catalyst comprises a carbon black support and an active metal supported on the carbon black support, wherein the total loading of the active metal is 20 wt% to 40 wt%. The carbon-supported platinum-nickel catalyst prepared by the above method exhibits a more uniform distribution of active metal, a higher effective loading, and a stronger interfacial bonding force with the carbon black support, thereby demonstrating particularly superior catalytic activity.

[0073] It should be noted that due to the complex structural formation and compositional changes during the preparation process, and the limitations of the specific materials field and existing testing and characterization methods, it is difficult to comprehensively and quantitatively characterize the complex microstructure of the obtained carbon-supported platinum-nickel catalyst, especially the metal bonding mode. However, performance test results show that the carbon-supported platinum-nickel catalyst obtained in this invention possesses a more stable microstructure and exhibits higher catalytic activity in application. In fact, the carbon-supported platinum-nickel catalyst provided by this invention achieves nano-alloying of the two active metals, platinum and nickel, thus resulting in stronger electronic synergy and correspondingly higher catalytic activity.

[0074] In several preferred embodiments, the carbon-supported platinum-nickel catalyst has a porous structure, and the pore volume of the carbon-supported platinum-nickel catalyst is 1.0 cm³. 3 / g~10.0cm 3 / g, pore size 2nm~50nm, specific surface area 500m² 2 / g~800m 2 / g. In other words, the carbon-supported platinum-nickel catalyst obtained in this invention possesses superior pore structure characteristics, providing more ample diffusion channels for reactants and effectively reducing mass transfer resistance. Simultaneously, the higher specific surface area also significantly exposes more active sites, thereby further enhancing catalytic activity.

[0075] A third aspect of this invention provides the application of the above-described carbon-supported platinum-nickel catalyst as a catalyst in electrochemical reactions, namely, oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), or oxygen evolution reaction (OER). The catalyst obtained by the above-described preparation method of this invention has a superior structure that provides sufficient reactive sites, thereby exhibiting high performance in a variety of electrochemical catalytic reactions.

[0076] Furthermore, because the present invention achieves alloying through designed experimental steps in the catalyst preparation process, it alters the electronic structure of platinum, thereby enhancing its adsorption and activation capabilities for oxygen molecules. Simultaneously, the nickel in the resulting platinum-nickel alloy, the active component, also improves the catalyst's tolerance to oxygen reduction reaction intermediates. In other words, the carbon-supported platinum-nickel catalyst obtained by the present invention is particularly suitable as an ORR catalyst, exhibiting a mass activity of 0.75 A·mg in ORR. Pt - 1 ~0.95A·mg Pt - 1 This is already superior to the 0.25 A·mg of mainstream platinum-carbon catalysts currently on the market. Pt - 1 It has extremely high application value in fields such as fuel cells that rely on oxygen reduction reactions.

[0077] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0078] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0079] Example 1

[0080] A method for preparing a carbon-supported platinum-nickel catalyst: (1) Preparation of (NH4)2Ni(CO3)2, i.e., nickel source:

[0081] Weigh 15g of smelting-grade nickel sulfate (a byproduct of copper smelting, with a nickel content of 17.7wt% in NiSO4·6H2O), dissolve it in 100mL of the first solvent (deionized water, resistivity ≥18.2MΩ·cm), and stir magnetically until completely dissolved to prepare a nickel sulfate solution with a concentration of 0.45mol / L; separately weigh 12g of ammonium sulfate ((NH4)2SO4), dissolve it in 150mL of deionized water, and prepare a first ammonium salt solution with a concentration of 0.83mol / L (mass concentration of 80g / L).

[0082] Impurity removal and metathesis reaction: Add 0.1 mol / L sulfuric acid dropwise to the nickel sulfate solution obtained above to adjust the pH of the system to 2.5, and stir for 30 min to remove Fe. 3+ Al 3+ Impurity ions, etc.

[0083] Subsequently, the first ammonium salt solution prepared above was slowly added dropwise to the nickel sulfate solution at a rate of 10 mL / min, while maintaining the reaction temperature at 50°C and mechanically stirring at 400 rpm for 2 hours. During this process, a double displacement reaction occurs:

[0084] NiSO4+(NH4)2SO4+6H2O=(NH4)2Ni(SO4)2·6H2O

[0085] In the above reaction process, the weight ratio of smelting nickel sulfate, ammonium sulfate (i.e., the first ammonium salt), and water is 3:5.1:20. The actual amount of ammonium sulfate added is twice the theoretical amount of nickel sulfate used, to maintain the weak alkalinity of the system, thereby inhibiting Ni... 2+ hydrolysis.

[0086] After the reaction was completed, the nickel-containing composite salt precipitate was obtained by vacuum filtration using a Buchner funnel. The precipitate was washed four times with deionized water until the pH of the filtrate was 7. The precipitate was placed in a vacuum drying oven and dried at 70°C for 4 hours to obtain (NH4)2Ni(SO4)2·6H2O powder with a purity ≥99.9%, which was used as a nickel source for later use.

[0087] (2) Weigh 8g of Vulcan XC-72R carbon powder and place it in a vacuum drying oven. Dry it at 70℃ for 8h. Spread the dried carbon powder evenly in a quartz reaction boat (1.5mm thick). Then place the reaction boat into the atmospheric pressure dielectric barrier discharge plasma reaction chamber and evacuate it to 5×10⁻⁶. -3 After Pa, the working gas (oxygen to nitrogen volume ratio 1:1) is introduced.

[0088] The gas flow rate was controlled at 35 mL / min, and the pressure inside the chamber was maintained at 30 Pa. The discharge voltage was set to 40 V, the electrode spacing to 20 mm, and the discharge treatment was carried out for 60 s. During this period, the reaction boat was gently shaken every 15 s to ensure uniform treatment. After the treatment was completed, the plasma power supply was turned off, and the working gas was continued to be introduced into the reaction chamber until it cooled to room temperature. The obtained activated carbon black was then taken out and sealed for storage.

[0089] (3-1) The pretreated activated carbon black was placed in 200 mL of the second solvent (deionized water and ethanol volume ratio 2:1) and ultrasonically dispersed at 28 kHz for 45 min to form a uniform suspension with a solid content of 60 g / L, namely the first suspension.

[0090] (3-2) Add 1.2 g of chloroplatinic acid (H2PtCl6·6H2O) to the obtained suspension, that is, the weight ratio of activated carbon black to platinum source is 1:1. Then stir and mix at 300 rpm for 1.5 h to obtain the second suspension.

[0091] (3-3) Add a second ammonium salt NH4OH to the second suspension above, adjust the pH of the suspension system to 9.5, wherein the amount of NH4OH is twice the number of moles of chloroplatinic acid, to obtain a third suspension.

[0092] (3-4) Add 0.9g of (NH4)2Ni(SO4)2·6H2O nickel source powder prepared in step (1) to the third suspension system above (at this time, the molar ratio of nickel source to platinum source is 1:1), and then add 0.8g of disodium ethylenediaminetetraacetate (EDTA-2Na) as a complexing agent (i.e., the molar ratio of complexing agent to nickel source is 1.2:1), and stir the reaction for 1.5h to obtain the fourth suspension.

[0093] (3-5) Subsequently, the first reducing agent NaBH4 solution (molar concentration 0.5 mol / L, total added amount is 3 times the total molar number of platinum salt and nickel salt) was added dropwise at a rate of 5 mL / min, and the reaction temperature was controlled at 35℃, and the reaction was maintained at this temperature for 2 h. After the reaction was completed, the solid product was obtained by filtration and washed 4 times alternately with deionized water and ethanol; the product was placed in a vacuum freeze dryer and dried at -55℃ for 10 h to obtain the carbon-supported platinum-nickel catalyst precursor.

[0094] (4) The obtained precursor and the second reducing agent (elemental carbon powder, average particle size 500 nm) are mixed evenly at a mass ratio of 1:0.3 and loaded into a quartz tube reactor. A protective gas Ar (purity ≥99.99%, volumetric flow rate 5 L / min) is introduced into the quartz tube reactor to purge air. Then, the tube furnace is turned on for gradient heating calcination, including:

[0095] First stage: Increase the temperature from 25℃ to 300℃ at a rate of 20℃ / min, and hold for 1.0h;

[0096] Second stage: Increase the temperature to 650℃ at a rate of 10℃ / min and hold for 2 hours;

[0097] Third stage: Increase the temperature to 850℃ at a rate of 5℃ / min and hold for 2 hours;

[0098] Fourth stage: Increase the temperature to 1000℃ at a rate of 5℃ / min and hold for 3 hours.

[0099] After calcination, the product was cooled to room temperature in the furnace, removed, and ground with an agate mortar until the particle size was uniform to obtain a carbon-supported platinum-nickel catalyst.

[0100] The TEM characterization results of the obtained platinum-nickel supported catalyst are shown in the figure. Figure 1 .

[0101] Example 2

[0102] A method for preparing a carbon-supported platinum-nickel catalyst:

[0103] The nickel source Ni4CO3(OH)6·4H2O was prepared using the same method as in Example 1. Wherein:

[0104] Ammonium carbonate (NH4(CO3)2) was selected as the ammonium salt, and its weight ratio with the nickel source and the first solvent water was controlled to be 3:7.65:10. At the same time, the reaction temperature of the metathesis was changed to 60℃ and the reaction time was changed to 2h.

[0105] After the reaction was completed, the nickel-containing composite salt precipitate was obtained by vacuum filtration using a Buchner funnel. The precipitate was washed four times with deionized water until the pH of the filtrate was 7. The precipitate was then placed in a vacuum drying oven and dried at 80°C for 3 hours to obtain Ni4CO3(OH)6·4H2O powder, which was used as a nickel source.

[0106] (2) Weigh 8g of Ketjen black and place it in a vacuum drying oven. Dry it at 70℃ for 8h. Spread the dried carbon powder evenly in a quartz reaction boat (1.5mm thick). Then place the reaction boat into the atmospheric pressure dielectric barrier discharge plasma reaction chamber and evacuate it to 5×10 -3 After Pa, the working gas (ammonia) is introduced.

[0107] The gas flow rate was controlled at 35 mL / min, and the pressure inside the chamber was maintained at 30 Pa. The discharge voltage was set to 50 V, the electrode spacing to 20 mm, and the discharge treatment was carried out for 45 s. During this period, the reaction boat was gently shaken every 15 s to ensure uniform treatment. After the treatment was completed, the plasma power supply was turned off, and the working gas was continued to be introduced into the reaction chamber until it cooled to room temperature. The obtained activated carbon black was then removed and sealed for storage.

[0108] (3-1) The pretreated activated carbon black was prepared into a uniform suspension with a solid content of 30 g / L, namely the first suspension, according to the method in Example 1.

[0109] (3-2) Controlling the weight ratio of activated carbon black to platinum source to 4:1, diammonium dinitrite platinum (Pt(NH3)2(NO2)2) was added to the resulting suspension. Then, the mixture was stirred at 300 rpm for 1.5 h to obtain a second suspension.

[0110] (3-3) Add a second ammonium salt NH4OH to the second suspension above, adjust the pH of the suspension system to 9.5, wherein the amount of NH4OH is twice the number of moles of chloroplatinic acid, to obtain a third suspension.

[0111] (3-4) Add 0.9g of Ni(HCO3)2·(NH4)HCO3 nickel source powder prepared in step (1) to the third suspension system above (at this time, the molar ratio of nickel source to platinum source is 2:1), then add citric acid as a complexing agent, and control the molar ratio of complexing agent to nickel source to 1.2:1 during the addition process), stir the reaction for 1.5h to obtain the fourth suspension.

[0112] (3-5) Subsequently, ascorbic acid solution (molar concentration 1 mol / L, total added amount 4 times the total molar amount of platinum and nickel salts) was added dropwise at a rate of 5 mL / min, and the reaction temperature was controlled at 45 °C for 1.5 h. After the reaction was completed, the solid product was obtained by filtration and washed 4 times alternately with deionized water and ethanol; the product was placed in a vacuum freeze dryer and dried at -50 °C for 8 h to obtain the carbon-supported platinum-nickel catalyst precursor.

[0113] (4) The obtained precursor is loaded into a quartz tube reactor, and a protective gas Ar (purity ≥99.99%, volumetric flow rate 1 L / min) and a second reducing agent H2 (flow rate 10 mL / min) are introduced into the quartz tube reactor. After purging the air, the tube furnace is turned on for gradient heating calcination, including:

[0114] First stage: Increase the temperature from 25℃ to 300℃ at a rate of 15℃ / min and hold for 1.5 hours;

[0115] Second stage: Increase the temperature to 650℃ at a rate of 10℃ / min and hold for 1.5h;

[0116] Third stage: Increase the temperature to 900℃ at a rate of 10℃ / min and hold for 1.5h;

[0117] Fourth stage: Increase the temperature to 1000℃ at a rate of 10℃ / min and hold for 1.5h.

[0118] After calcination, the product was cooled to room temperature in the furnace, removed, and ground with an agate mortar until the particle size was uniform to obtain a carbon-supported platinum-nickel catalyst.

[0119] Example 3

[0120] A method for preparing a carbon-supported platinum-nickel catalyst:

[0121] The only difference between this embodiment and Embodiment 1 is that in step (1), the weight ratio of smelting nickel sulfate, ammonium carbonate (i.e., the first ammonium salt) and water is changed to 1:0.01:4.

[0122] Example 4

[0123] A method for preparing a carbon-supported platinum-nickel catalyst:

[0124] The only difference between this embodiment and Embodiment 1 is that in step (1), the weight ratio of smelting nickel sulfate, ammonium carbonate (i.e., the first ammonium salt) and water is changed to 30:10:1200.

[0125] Example 5

[0126] A method for preparing a carbon-supported platinum-nickel catalyst:

[0127] The only difference between this embodiment and embodiment 1 is that in step (2), the working gas flow rate during the plasma treatment process is changed to 20 mL / min, the cavity pressure is changed to 10 Pa, the discharge voltage is set to 20 V, and the electrode spacing is set to 5 mm.

[0128] Example 6

[0129] A method for preparing a carbon-supported platinum-nickel catalyst:

[0130] The only difference between this embodiment and embodiment 1 is that in step (2), the working gas flow rate during the plasma treatment process is changed to 50 mL / min, the cavity pressure is changed to 50 Pa, the discharge voltage is set to 60 V, and the electrode spacing is set to 30 mm.

[0131] Example 7

[0132] A method for preparing a carbon-supported platinum-nickel catalyst:

[0133] The only difference between this embodiment and Embodiment 1 is that in step (3-3), the amount of NH4OH is changed to 1.5 times the number of moles of chloroplatinic acid, so that the pH of the resulting third suspension system is changed to 10.

[0134] Example 8

[0135] A method for preparing a carbon-supported platinum-nickel catalyst:

[0136] The only difference between this embodiment and Embodiment 1 is that in step (3-3), the amount of NH4OH is changed to three times the number of moles of chloroplatinic acid, so that the pH of the resulting third suspension system is changed to 7.

[0137] Example 9

[0138] A method for preparing a carbon-supported platinum-nickel catalyst:

[0139] The only difference between this embodiment and Embodiment 1 is that: in step (3-4), the amount of complexing agent is changed so that the molar ratio of complexing agent to nickel source is changed to 3:1, and the total amount of first reducing agent added is changed to 1 times the total molar number of platinum salt and nickel salt; and in step (3-5), the dropping rate of the first reducing agent solution is changed to 1 mL / min.

[0140] Example 10

[0141] A method for preparing a carbon-supported platinum-nickel catalyst:

[0142] The only difference between this embodiment and Embodiment 1 is that: in step (3-4), the amount of complexing agent is changed so that the molar ratio of complexing agent to nickel source is changed to 1:2, and the total amount of first reducing agent added is changed to 6 times the total molar number of platinum salt and nickel salt; and in step (3-5), the dropping rate of the first reducing agent solution is changed to 10 mL / min.

[0143] Example 11

[0144] A method for preparing a carbon-supported platinum-nickel catalyst:

[0145] The only difference between this embodiment and Embodiment 1 is the gradient heating calcination in step (4), specifically:

[0146] First stage: Increase the temperature from 25℃ to 200℃ at a rate of 20℃ / min, and hold for 1.0h;

[0147] Second stage: Increase the temperature to 500℃ at a rate of 10℃ / min and hold for 2 hours;

[0148] Third stage: Heat to 750℃ at a rate of 5℃ / min and hold for 2 hours;

[0149] Fourth stage: Increase the temperature to 1000℃ at a rate of 5℃ / min and hold for 3 hours.

[0150] Example 12

[0151] A method for preparing a carbon-supported platinum-nickel catalyst:

[0152] The only difference between this embodiment and embodiment 1 is that in step (4), the heating rate of the first stage is changed to 3℃ / min, and the heating rates of the second, third and fourth stages are all changed to 15℃ / min.

[0153] Comparative Example 1

[0154] This comparative example uses commercially available Pt / C as the catalyst sample.

[0155] Comparative Example 2

[0156] A method for preparing a carbon-supported platinum-nickel catalyst:

[0157] The only difference between this comparative example and Example 1 is that step (2) was not performed; instead, untreated Vulcan XC-72R carbon powder was used directly as activated carbon black and subsequent steps were performed.

[0158] Comparative Example 3

[0159] A method for preparing a carbon-supported platinum-nickel catalyst:

[0160] The only difference between this comparative example and Example 1 is that step (2) was not performed; instead, 98% concentrated sulfuric acid was used to activate the Vulcan XC-72R carbon powder through a reflux reaction for 12 hours.

[0161] Comparative Example 4

[0162] A method for preparing a carbon-supported platinum-nickel catalyst:

[0163] The only difference between this comparative example and Example 1 is that no complexing agent was added in step (3).

[0164] Comparative Example 5

[0165] A method for preparing a carbon-supported platinum-nickel catalyst:

[0166] The only difference between this comparative example and Example 1 is that the first reducing agent was not added in step (3).

[0167] Test methods for catalyst samples

[0168] Hole volume: Tested according to GB / T 7702.20-2025.

[0169] Aperture: Tested according to GB / T 20042.4-2025.

[0170] Specific surface area: Tested according to GB / T 20042.4-2025.

[0171] For example, the nitrogen adsorption-desorption curves of the catalyst samples obtained in Example 1 and Comparative Example 2 are shown in the figures below. Figure 2 and Figure 3 The pore size distribution diagrams of the catalyst samples obtained in Example 1 and Comparative Example 2 are shown below. Figure 4 and Figure 5 .

[0172] The above tests were performed on each embodiment and comparative example, and the results are shown in Table 1.

[0173] Table 1

[0174]

[0175] Electrochemical catalytic activity test:

[0176] Taking ORR as an example, the test was performed using a rotating ring disk electrode (RRDE, the surface of which is glassy carbon) in accordance with GB / T 20042.4-2025.

[0177] Weigh 5 mg of catalyst sample into a 2 mL centrifuge tube, then add 500 μL of deionized water and 500 μL of ethanol dispersion, followed by 30 μL of 5% (v / v) Nafion solution. Place the centrifuge tube in an ultrasonic cleaner and sonicate at 40 kHz for 30 min to ensure thorough dispersion of the catalyst in the mixed solvent, obtaining catalyst ink. Then, spin-coat 20 μL of the catalyst ink onto the RRDE surface and allow it to air dry to obtain an electrode loaded with the catalyst sample.

[0178] High-purity oxygen was continuously bubbled into a 0.1 mol / L HClO4 electrolyte for 30 min. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) curves were then obtained for each catalyst sample. The half-wave potential (E) of each catalyst sample was obtained from the LSV curves. 1 / 2 The onset potential and mass activity were determined. Then, each sample underwent 5000 cycles of CV testing (scanning voltage range and scan rate 0.6~1.0V and 100mV / s, respectively), and its activity decay rate was calculated.

[0179] For example, the CV curves of the catalyst sample obtained in Example 1 and commercial Pt / C are shown in [reference needed]. Figure 6 The LSV curve is shown below. Figure 7 .

[0180] The electrocatalytic performance of each embodiment and comparative example was tested as described above, and the results are shown in Table 2.

[0181] Table 2

[0182]

[0183] As can be seen from the above description, the embodiments of the present invention, through the organic combination of material design, process innovation, and step optimization, have achieved optimization of the pore structure of the carbon-supported platinum-nickel catalyst and enhancement of its electrochemical catalytic activity. When the obtained catalyst is used in the ORR reaction, it exhibits high catalytic activity and high cycling stability.

[0184] Specifically, comparing Examples 3 and 4 with Example 1, it can be seen that in step S1, by optimizing the weight ratio of smelting nickel sulfate, the first ammonium salt, and water, the generation of by-products can be more effectively avoided during the preparation of nickel sulfate solution. That is, while improving the uniformity of the product, the probability of Ni(OH)2 impurity phase generation is reduced more effectively, and the various properties of the obtained catalyst are further optimized.

[0185] Comparing Examples 5 and 6 with Example 1, it can be seen that in step S2, by optimizing the parameters in the plasma treatment process, oxygen-containing / nitrogen-containing functional groups can be introduced more effectively onto the surface of the carbon powder, thereby forming more stable coordination bonds with platinum and nickel ions, reducing the agglomeration and sintering of the active components in the obtained catalyst precursor during the subsequent calcination heat treatment, and thus further improving the cycle stability of the catalyst.

[0186] Comparing Examples 7 and 8 with Example 1, it can be seen that in step S3-3, by optimizing the amount of the second ammonium salt and thus optimizing the pH value of the third suspension system, a more stable precursor structure can be formed, promoting the uniform dispersion of metal ions on the support surface, thereby significantly improving the catalytic activity of the final carbon-supported platinum-nickel catalyst.

[0187] Comparing Examples 9 and 10 with Example 1, it can be seen that in steps S3-4, by optimizing the amount of complexing agent, the amount of the first reducing agent, and the dropping rate, the release rate and morphology of active metal ions can be adjusted more efficiently, their direct precipitation can be avoided more effectively, and their loading on the carbon support surface can be promoted more uniformly. At the same time, preliminary reduction can be achieved more effectively, reducing the generation of by-products while further stabilizing the precursor structure and improving the cycle stability of the finally obtained carbon-supported platinum-nickel catalyst.

[0188] Comparing Example 11 with Example 1, it can be seen that in step S4, by optimizing the holding temperature and time of the calcination process, the reduction annealing rate of the catalyst precursor can be controlled more effectively, promoting more uniform reduction and alloying of noble metal ions.

[0189] Comparing Example 12 with Example 1, it can be seen that in step S4, by optimizing the heating rate of the calcination process, the agglomeration of active metal particles can be reduced to a greater extent, and the pore structure and specific surface area of ​​the catalyst can be optimized more effectively, resulting in a carbon-supported platinum-nickel catalyst with higher catalytic activity.

[0190] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0191] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a carbon-supported platinum-nickel catalyst, characterized by, include: Step S1: The first ammonium salt reacts with smelting nickel sulfate via a metathesis reaction to obtain a nickel source; Step S2: The carbon powder is subjected to plasma treatment to obtain activated carbon black; The working gas used in the plasma treatment is a mixture of oxygen and nitrogen, and the volume ratio of oxygen to nitrogen in the mixture is (2~25):(2~25). The gas flow rate of the plasma treatment is 20 mL / min to 50 mL / min, and the plasma treatment is carried out at 10 Pa to 50 Pa; the discharge voltage of the plasma treatment is 20 V to 60 V, the electrode spacing is 5 mm to 30 mm, and the discharge time is 15 s to 120 s. In step S3, the nickel source, the activated carbon black, the platinum source, the second ammonium salt, the complexing agent, and the first reducing agent are mixed and contacted to undergo a chemical reaction to obtain the precursor product. Step S3 includes: Step S3-1: The activated carbon black and solvent are first dispersed to obtain a first suspension; Step S3-2: Add the platinum source to the first suspension, and obtain a second suspension through a second dispersion. Step S3-3: Add the second ammonium salt to the second suspension to obtain a third suspension with a pH of 7-10; Steps S3-4: Add the nickel source and the complexing agent to the third suspension, and after third dispersion, obtain the fourth suspension; Step S3-5: Add the first reducing agent to the fourth suspension, and obtain the precursor product through the combination reaction; Step S4: The precursor product and the second reducing agent are calcined to obtain the carbon-supported platinum-nickel catalyst. The first ammonium salt is selected from one or more of ammonium carbonate, ammonium bicarbonate, ammonium sulfate, ammonium oxalate, ammonium acetate, ammonium chloride, and ammonia water; The pyrolysis product of the nickel source is nickel oxide.

2. The method of claim 1, wherein the platinum-nickel on carbon catalyst is prepared by the steps of: Step S1 includes: preparing a nickel sulfate solution by mixing the smelted nickel sulfate with water, adding the first ammonium salt to the nickel sulfate solution, and obtaining the nickel source through the metathesis reaction; The weight ratio of the smelting nickel sulfate, the first ammonium salt, and the water is (1~30):(0.01~10):(4~1200); and / or, The molar concentration of nickel sulfate in the nickel sulfate solution is 0.1 mol / L to 1.5 mol / L; and / or, The smelted nickel sulfate is a byproduct of copper ore smelting, and the nickel content in the smelted nickel sulfate is 15wt%~18wt%.

3. The method of claim 2, wherein the platinum-nickel on carbon catalyst is prepared by the steps of: In step S1 The first ammonium salt is added in the form of a salt solution, and the molar concentration of the first ammonium salt in the salt solution is 0.05 mol / L to 3.0 mol / L; and / or, The salt solution is added to the nickel sulfate solution at a dropping rate of 1 mL / min to 30 mL / min; and / or, The reaction temperature for the metathesis reaction is 50℃~80℃, and the reaction time is 10min~180min.

4. The method of producing a carbon-supported platinum-nickel catalyst according to any one of claims 1 to 3, characterized by, Step S2 includes: laying the carbon powder in a reaction boat with a thickness of 1 mm to 2 mm, and treating it with plasma in a plasma reaction chamber to obtain the activated carbon black.

5. The method of claim 1, wherein, the solid content of the activated carbon black in the first suspension is 30 g / L to 100 g / L; and / or, the weight ratio of the activated carbon black to the platinum source is (1-20): 1; and / or, the molar ratio of the second ammonium salt to the platinum source is (1-3): 1; and / or, the molar ratio of the nickel source to the platinum source is (1-3): 1; and / or, the molar ratio of the complexing agent to the nickel source is (1-2): 1; and / or, the ratio of the total molar amount of the nickel source and the platinum source to the molar amount of the first reducing agent is 1: (2-5).

6. The method of claim 1, wherein, in the step S3-1, the first dispersion is performed by ultrasonic, and the frequency of the ultrasonic is 5 kHz to 30 kHz, and the time is 30 min to 60 min; and / or, in the step S3-2, the second dispersion is performed by stirring, and the stirring speed is 300 ± 50 rpm, and the time is 1 h to 2 h; and / or, in the step S3-4, the third dispersion is performed by stirring, and the stirring time is 1 h to 2 h; and / or, in the step S3-5, the first reducing agent is added in the form of a reducing agent solution, and the molar concentration of the first reducing agent in the reducing agent solution is 1.0 ± 0.2 mol / L; the reaction temperature is 20 °C to 50 °C, and the time is 1 h to 3 h. in the step S4, the second reducing agent is selected from one or more of elemental carbon, CO, and hydrogen. in the step S4, the heating rate of the calcination treatment is 5 °C / min to 30 °C / min, the holding temperature is 200 °C to 1000 °C, and the holding time is 3 h to 10 h. The carbon-supported platinum-nickel catalyst is prepared by the method of any one of claims 1 to 8, and comprises a support carbon black and an active metal supported on the support carbon black, wherein the total loading amount of the active metal is 20 wt% to 40 wt%. The electrochemical reaction is an oxygen reduction reaction, a hydrogen evolution reaction, or an oxygen evolution reaction. ​ ​ ​ ​ ​ ​ 7. The method of producing a carbon-supported platinum-nickel catalyst according to any one of claims 1 to 3, characterized by, ​ ​ 8. The method of claim 1 to 3, wherein the carbon-supported platinum-nickel catalyst is prepared by the steps of: ​ 9. A carbon supported platinum nickel catalyst characterized in that, ​ 10. The carbon supported platinum nickel catalyst of claim 9, wherein, The carbon-supported platinum-nickel catalyst has a porous structure, and a pore volume of 1.0 cm 3 / g~10.0 cm 3 / g, a pore diameter of 2 nm~50 nm, and a specific surface area of 500 m 2 / g~800 m 2 / g.

11. Use of a carbon-supported platinum-nickel catalyst according to claim 9 or 10 as a catalyst in an electrochemical reaction, characterized in that, ​

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