A high-activity and high-stability platinum-nickel alloy catalyst, a preparation method thereof, and application of the catalyst to an electrolysis water hydrogen evolution reaction in an acidic medium
By modifying the carbon black support with nitrogen and phosphorus co-doping and alloying with platinum and nickel, the prepared platinum-nickel alloy catalyst exhibits high activity and stability in acidic media, solving the problem of easy dissolution and agglomeration of platinum-carbon catalysts in acidic media, and achieving cost reduction and performance improvement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CENT SOUTH UNIV
- Filing Date
- 2026-04-14
- Publication Date
- 2026-06-09
AI Technical Summary
Existing platinum-carbon catalysts exhibit easy dissolution and aggregation of platinum nanoparticles in acidic media, leading to a decline in activity and stability. Furthermore, the scarcity and high cost of platinum metal limit its large-scale application.
Using nitrogen and phosphorus co-doped modified carbon black as a support, a highly active and stable platinum-nickel alloy catalyst was prepared by platinum-nickel alloying. The high dispersion of the platinum-nickel alloy on the support was controlled to reduce the platinum loading.
While reducing the amount of platinum used, the activity and stability of the catalyst are significantly improved, production costs are reduced, and catalytic performance is enhanced.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of hydrogen evolution catalyst technology for water electrolysis, specifically relating to a highly active and stable platinum-nickel alloy catalyst, its preparation method, and its application in the hydrogen evolution reaction of water electrolysis in acidic media. Background Technology
[0002] Hydrogen energy, as a clean energy source with zero carbon and high energy density, is the core carrier for building a new energy system and achieving the "dual carbon" goal. Electrolysis of water to produce hydrogen is the mainstream technology for large-scale green hydrogen production. The hydrogen evolution reaction is the core half-reaction of electrolysis of water to produce hydrogen. Among them, the hydrogen evolution reaction in acidic medium has become the core link of the electrolysis of water to produce hydrogen due to its high proton conduction efficiency and fast reaction kinetics. At present, platinum-carbon catalysts are still the most widely used commercial benchmark catalysts in the field of hydrogen evolution reaction. They exhibit far superior catalytic activity in acidic electrolytes compared to alkaline and neutral systems. However, commercial platinum-carbon catalysts have always faced two major bottlenecks: (1) In acidic and highly corrosive environments and long-term electrochemical polarization processes, platinum nanoparticles are prone to dissolution and aggregation, resulting in irreversible loss of electrochemical active sites, which directly leads to the continuous decline of catalytic activity and cycle stability; (2) Platinum metal is scarce in the Earth's crust and the raw material cost is high. Catalysts with high platinum loading significantly increase the core cost of the water electrolysis system, which seriously limits the large-scale engineering application of platinum-based catalysts. Therefore, developing platinum-based catalysts with low platinum loading in acidic media, which can significantly reduce platinum usage and lower catalyst costs while simultaneously improving their catalytic activity and stability in the hydrogen evolution reaction, is a core scientific issue and key requirement for breaking through the technical bottleneck of acidic hydrogen evolution reaction and promoting the industrialization of green hydrogen technology.
[0003] A review of published patents reveals that, to address the aforementioned issues, researchers' modifications to platinum-based catalysts primarily focus on two core directions. The most prevalent modification method is alloying by introducing the transition metal nickel into platinum. Introducing nickel as a modifying element offers significant advantages: First, nickel resources are abundant and inexpensive, effectively reducing platinum usage and drastically lowering catalyst production costs. Second, nickel and platinum have excellent lattice compatibility; their alloy formation allows for electronic control of platinum's d-band centers, optimizing hydrogen adsorption on the catalyst surface. Simultaneously, strain effects alter the surface atomic arrangement of platinum, increasing the exposure of active sites and significantly enhancing catalytic activity. Third, the introduction of nickel can inhibit platinum particle aggregation and dissolution, improving catalyst stability to some extent. Related patents also confirm the feasibility of this modification approach. For example, Chinese patent CN105297107A discloses a method for preparing nano-platinum-nickel / titanium dioxide nanotube electrodes by cyclic voltammetric electrodeposition. By introducing nickel and platinum to form an alloy, it solves the problems of poor particle dispersion and high toxicity of traditional platinum-based catalysts. Chinese patent CN119425723A discloses a platinum-nickel alloy / supported catalyst and its preparation method and application. By utilizing the synergistic effect of nickel and platinum, it achieves uniform dispersion of alloy particles and improves catalytic activity. However, none of the above patents doped and modified the carbon support, resulting in insufficient conductivity and stability of the support, which limits the overall performance of the catalyst.
[0004] Another core modification direction is carbon support modification. As the supporting framework of the catalyst, the performance of the carbon support directly affects the conductivity, number of active sites and stability of the catalyst. Doping modification of the carbon support is a key means to improve its performance. By doping heteroatoms, the electronic structure of the carbon support can be significantly optimized, the specific surface area can be increased, and defect sites can be introduced. At the same time, the interaction between the carbon support and metal particles can be enhanced, thereby inhibiting the aggregation and dissolution of metal particles and improving the activity and stability of the catalyst. Chinese patent CN121748421A discloses a nitrogen-doped carbon-supported platinum catalyst and its preparation method. By modifying the carbon support with nitrogen doping, the conductivity and specific surface area of the support are significantly improved, enhancing the interaction between platinum particles and the support, effectively inhibiting platinum particle agglomeration, and improving the catalyst's hydrogen evolution activity and stability. Chinese patent CN120149437A discloses a phosphorus-doped carbon-supported platinum-based catalyst and its application. By introducing a large number of defect sites into the carbon support through phosphorus doping, the electronic structure of the catalyst surface is optimized, improving hydrogen adsorption kinetics and enhancing the catalyst's resistance to dissolution under acidic conditions. However, this catalyst does not incorporate nickel for alloying modification, resulting in a high platinum content and difficulty in reducing production costs. Chinese patent CN118756199A discloses a nitrogen-phosphorus co-doped carbon-supported catalyst and its preparation method, explicitly including the key step of nitrogen-phosphorus co-doping catalyst preparation. This patent indirectly confirms the importance of single-element doping (nitrogen doping, phosphorus doping) as the basis for co-doping. Its co-doping process compensates for the shortcomings of single doping through the synergistic effect of the two elements, based on single-doping modification.
[0005] In summary, significant progress has been made in the alloying of transition metal nickel and platinum, as well as in the development of platinum catalysts modified with carbon supports. However, to further meet the industrial demand for cost reduction and efficiency improvement, the development of highly active and stable platinum-nickel alloy catalysts still holds immense application potential. Summary of the Invention
[0006] The technical problem to be solved by this invention is to address the problems of excessively high cost, insufficient activity and stability of platinum-carbon catalysts in the current electrolysis of water in acidic media for hydrogen evolution. This invention provides a platinum-nickel alloy catalyst with significantly reduced platinum loading and high activity and stability, as well as its preparation method and application in the electrolysis of water in acidic media for hydrogen evolution, thereby achieving a synergistic improvement in catalyst activity, stability and economic efficiency of preparation.
[0007] To address the aforementioned technical problems, this invention combines nickel-platinum alloying with nitrogen-phosphorus co-doping modification on a carbon support. A novel, highly active, and highly stable platinum-nickel alloy catalyst was designed and prepared, while simultaneously reducing the loading of the precious metal platinum. Using the ethylene glycol method with nitrogen-phosphorus co-doped carbon black as the support, the solution pH, reduction temperature, and stirring speed were strictly controlled during the reduction of platinum and nickel ions to achieve high dispersion of the platinum-nickel alloy on the support. This not only improves the utilization rate of active sites and facilitates synergistic effects between active components but also inhibits the migration and aggregation of active components, thereby enhancing catalyst activity and stability while reducing platinum loading. This fundamentally solves the problem of excessively high costs in existing technologies due to increased platinum loading to maintain catalytic activity.
[0008] The acidic medium water electrolysis hydrogen evolution reaction catalyst of this invention contains platinum, nickel, phosphorus, nitrogen, oxygen, and carbon. It is a powder catalyst with highly dispersed platinum-nickel alloy supported on nitrogen-phosphorus co-doped and modified carbon black. The content of each element is as follows, calculated as 100% by mass:
[0009] 18%~20% platinum, calculated as elemental Pt;
[0010] 2%~8% nickel, based on elemental Ni;
[0011] 2%~6% nitrogen, as N oxides;
[0012] 1%~3% phosphorus, calculated as P oxide;
[0013] 65%~75% carbon, calculated as C oxides;
[0014] 5-7% oxygen, calculated as metal oxides.
[0015] The present invention discloses a method for preparing a highly active and stable platinum-nickel alloy catalyst, which employs the ethylene glycol method, unlike the traditional impregnation method for preparing platinum-carbon catalysts. The steps are as follows:
[0016] 1) Prepare a mixed solution A by thoroughly sonicating ethylene glycol chloroplatinic acid solution, nickel nitrate hexahydrate, modified commercial carbon black, and ethylene glycol;
[0017] 2) Add an appropriate amount of sodium hydroxide solution to the mixed solution A obtained in step 1), adjust the pH to a certain range, and stir thoroughly to obtain mixed solution B;
[0018] 3) Stir the mixed solution B obtained in step 2) at a certain temperature, rotation speed and time to obtain mixed solution C;
[0019] 4) Cool the mixed solution C obtained in step 3) to room temperature, then filter, wash and dry to obtain precursor D;
[0020] 5) The precursor D dried in step 4) is thoroughly ground and calcined to obtain the highly active and stable platinum-nickel alloy catalyst.
[0021] In step 1), the molar ratio of platinum ions to nickel ions is 1:1, 1:2, 2:1, 2:3, or 3:2, preferably 2:1.
[0022] In step 2), the pH value of the mixed solution B is adjusted to a range of 7 to 10, preferably 7.
[0023] In step 3), the stirring temperature is 120~180℃, preferably 140~160℃; the stirring speed is 300~600rpm, preferably 400~500rpm; and the stirring time is 4~8h, preferably 5~7h.
[0024] In step 4), the drying temperature is 50~80℃, preferably 60~70℃.
[0025] In step 5), the calcination temperature is 100~300℃, preferably 150~200℃; the calcination time is 1~4 h, preferably 2~3 h; and the calcination atmosphere is preferably nitrogen.
[0026] The highly active and stable platinum-nickel alloy catalyst of the present invention is prepared by the above method.
[0027] The highly active and stable platinum-nickel alloy catalyst described in this invention can be applied in the hydrogen evolution reaction of water electrolysis in acidic media. While significantly reducing the platinum loading compared to commercial platinum-carbon catalysts, its activity, stability, and corrosion resistance are all simultaneously improved.
[0028] Features and advantages of this invention:
[0029] (1) The catalyst of the present invention uses commercially available carbon black co-doped with nitrogen and phosphorus as a carrier, and is uniformly loaded on it after platinum-nickel alloying. Characterization results (XRD / TEM, etc.) show that the active components are highly dispersed and the utilization rate of active sites is high. Therefore, excellent catalytic performance can be obtained with a low amount of platinum, and the cost is low.
[0030] (2) The catalyst described in this invention does not require the addition of a reducing agent during the preparation process. The reduction of platinum ions and nickel ions can be completed solely through the chemical properties of ethylene glycol itself, thus avoiding the influence of the reducing agent on the preparation of the catalyst, which would cause the reduction of platinum ions and nickel ions to be too fast or too slow.
[0031] (3) The catalyst described in this invention exhibits high activity and stability in the hydrogen evolution reaction of water electrolysis in a strongly acidic medium and can operate stably for a long time. The catalyst support after the reaction is basically not corroded, and has good corrosion resistance. The platinum loading is reduced compared with traditional commercial platinum-carbon catalysts, which has significant advantages in cost reduction and efficiency improvement. Attached Figure Description
[0032] Figure 1 The images show the TEM morphology and particle size distribution of Comparative Example 1, Comparative Example 2, and Example 1.
[0033] Figure 2 The XPS overall spectra of Comparative Example 1, Comparative Example 2 and Example 1 are shown below; the C 1s high-resolution spectrum is shown below; the O 1s high-resolution spectrum and the Pt 4f high-resolution spectrum are shown below; the Ni 2p high-resolution spectrum of Comparative Example 2 and Example 1 are shown below; the P 2p high-resolution spectrum and the N 1s high-resolution spectrum of Example 1 are shown below.
[0034] Figure 3 Polarization curves for Comparative Example 1, Comparative Example 2, and Example 1; 10 mA·cm -2 Et curve; Comparative Example 2 and Example 1 at 25 mA·cm -2 Et curve; Tafel slope curves for Comparative Examples 1, 2 and 1; CV curve; Nyquist curve. Detailed Implementation
[0035] Example 1
[0036] 1) Mixed solution A was obtained by sonicating 100 ml of ethylene glycol, 602 μl of ethylene glycol chloroplatinate solution (32.42 mg Pt / ml), 80 mg of N, P co-doped carbon support, and 15.6 mg of nickel nitrate hexahydrate for 40 min.
[0037] 2) Add an appropriate amount of 1 mol / L sodium hydroxide solution to the mixed solution A obtained in step 1), adjust the pH to about 7, and stir for 30 min to obtain mixed solution B;
[0038] 3) The mixed solution B obtained in step 2) is stirred at a constant temperature of 150℃ and a speed of 450 rpm for 5 h to obtain mixed solution C;
[0039] 4) Cool the mixed solution C obtained in step 3) to room temperature, then filter, wash, and vacuum dry at 60°C to obtain precursor D;
[0040] 5) The precursor D dried in step 4) is thoroughly ground and calcined at 200°C for 2 h under a nitrogen atmosphere to obtain the highly active and stable platinum-nickel alloy catalyst.
[0041] The method for applying the prepared catalyst to the hydrogen evolution reaction of water in acidic medium and its performance analysis is as follows: All electrochemical tests were conducted at 30℃ using a standard three-electrode system on a Chenhua CHI660E electrochemical workstation. A 5mm diameter L-shaped glassy carbon electrode was used as the working electrode substrate. Before use, the electrode was polished with alumina polishing powder, then washed sequentially with ethanol and water, and dried before use.
[0042] The catalyst slurry was prepared as follows: 5.0 mg of catalyst was dispersed in 1.00 ml of a mixed solution (consisting of 950 μl isopropanol and 50 μl 5 wt.% Nafion® solution), and then sonicated in an ice-water bath for 30 min. 8 μl of the slurry was then dropped onto a cleaned glassy carbon electrode and dried at room temperature to obtain the working electrode.
[0043] Carbon rods and Hg|Hg2SO4 electrodes (filled with saturated K2SO4 solution) were used as counter and reference electrodes, respectively. All potentials were converted to values relative to the reversible hydrogen electrode (RHE) according to formula (1). Unless otherwise specified, all potentials in this study are relative to the RHE.
[0044] E(RHE) = E(Hg|Hg2SO4) + 0.059 × pH + 0.656 (1)
[0045] Polarization curves were recorded using linear sweep voltammetry (LSV) at a scan rate of 5.0 mV·s. -1 All polarization curves were corrected for iR compensation. Before recording the polarization curves, they were first heated in 0.5 M H₂SO₄ solution at 50 mV·s⁻¹. -1 The working electrode was cyclically scanned at a scan rate within a potential range of -0.7 V to -1.2 V until a stable voltammetric curve was obtained. The polarization curve was measured at 10 mA·cm⁻¹. -2 The potential corresponding to the current density is the overpotential, denoted as η. 10 The smaller the overpotential, the higher the activity of the catalyst in the hydrogen evolution reaction.
[0046] Potential-time (Et) curves were recorded using chronopotentiometry, with a test current density of 10 mA·cm⁻¹. -2 The test duration was 10 hours. The smaller the fluctuation in the Et curve, the better the stability of the catalyst in HER.
[0047] For the catalyst in Example 1, its performance at 10 mA·cm⁻¹ was measured. -2The overpotential at the current density was 51 mV, the potential change rate during the 10-hour stability test was 1.12%, and the Tafel slope was 35.61 mV·dec. -1 The electrochemically active surface area is 49.44 m². 2 ·g Pt -1 .
[0048] Comparative Example 1
[0049] Compared to Example 1, the difference lies in that no nickel source was added during catalyst preparation, the carbon support remained unchanged, and the Pt loading was controlled to be the same as in Example 1. The resulting catalyst was tested using the method described in Example 1. For the catalyst of Comparative Example 1, its performance at 10 mA·cm⁻¹ was measured. -2 The overpotential at the current density was 64 mV, the potential change rate during the 10-hour stability test was 34.90%, and the Tafel slope was 48.17 mV·dec. -1 The electrochemically active surface area is 12.54 m². 2 ·g Pt -1 .
[0050] Comparative Example 2
[0051] Compared to Example 1, the only difference is that the carbon support was not modified in any way; all other preparation steps were the same as in Example 1. The resulting catalyst was tested using the method described in Example 1. For the catalyst of Comparative Example 1, its performance at 10 mA·cm⁻¹ was measured. -2 The overpotential at the current density was 54 mV, the potential change rate during the 10-hour stability test was 1.90%, and the Tafel slope was 38.80 mV·dec. -1 The electrochemically active surface area is 42.75 m². 2 ·g Pt -1 .
[0052] TEM analysis of the catalysts prepared by Example 1, Comparative Examples 1 and 2 is attached. Figure 1 As shown in Figure (ad), compared to Comparative Example 1, the introduction of the transition metal Ni plays a regulatory role in the growth of metal particles. In Comparative Example 2, the agglomeration of metal particles in the catalyst is effectively suppressed, with the average particle size decreasing from 5.08 nm in Comparative Example 1 to 1.89 nm, while the particle dispersibility is significantly improved. (See attached figure.) Figure 2As shown in (c, e), the catalyst of Example 1 prepared using N and P co-doped carbon support further reduced the average particle size to 1.76 nm, and the particles exhibited a more uniform monodisperse state. This result demonstrates that the synergistic regulation strategy of metal alloying effect and N and P heteroatom doping of the support can effectively suppress the excessive growth, migration, and aggregation of nanoparticles, thus successfully constructing an ultrafine-sized and highly dispersed platinum-nickel alloy catalyst.
[0053] Appendix Figure 2 (d) shows the XPS high-resolution spectra of Pt in the catalysts of Comparative Example 1, Comparative Example 2, and Example 1. It can be observed that Pt in the three catalysts is mainly composed of Pt. 0 and Pt 2+ It exists in the form of Pt. 2+ There are three possible reasons: ① During the catalyst preparation process, Pt 4+ The precursor was not completely reduced to Pt 0 ② The prepared catalyst is partially oxidized by oxygen when exposed to air; ③ Pt forms Pt-OC bonds with oxygen-containing functional groups on the carbon support surface, resulting in charge transfer. Furthermore, the Pt 4f binding energy of catalysts with the addition of transition metal Ni undergoes a positive shift, attributed to the alloying effect of Ni and Pt and the synergistic effect of heteroatom doping on the carbon support. Literature indicates that in the Pt-Ni alloy system, the dominant role of d-orbital hybridization and lattice strain often outweighs the simple electronegativity difference, inducing a net electron transfer from Pt to Ni. This electron transfer leads to an electron-deficient state for Pt atoms, weakening the shielding effect of extranuclear electrons on the nucleus and increasing the effective nuclear charge sensed by the electrons, thus resulting in an increase in the Pt 4f binding energy measured by XPS.
[0054] On the other hand, strong metal-support interaction (SMSI) induced by support doping further exacerbates this phenomenon: First, when Pt nanoparticles are loaded onto N-doped carbon supports, highly electronegative nitrogen species (such as pyridine nitrogen and graphitic nitrogen) extract electrons from the Pt nanoparticles through the carbon framework. Second, oxygen-rich PO species (such as COP bonds) present in the support also act as strong electron acceptors due to the strong electronegativity of oxygen, further reducing the electron density on the Pt surface.
[0055] This change in electronic structure, reflected by the positive shift of the Pt 4f binding energy, leads to an upward shift of the Pt d-band center. According to d-band center theory, this upward shift moderately strengthens the binding affinity between Pt and the hydrogen intermediate (H). ads The binding strength of ) makes the Gibbs free energy of hydrogen adsorption (ΔG) H*The thermodynamic optimization approaches the ideal thermal neutrality value (0 eV). This thermodynamic optimization significantly lowers the energy barrier of the hydrogen evolution reaction, accelerates the reaction kinetics (Tafel and Heyrovsky steps), and thus enhances the intrinsic activity of the catalyst.
[0056] The catalyst of this invention can improve the activity and stability of the catalyst in the hydrogen evolution reaction in a strongly acidic medium while reducing the loading of precious metal platinum, thereby achieving the effect of cost reduction and efficiency improvement.
[0057] Comparing the above embodiments with the comparative examples, it can be seen that the modification strategy of combining transition metal nickel with noble metal platinum and N and P co-doping on a carbon support is the key to obtaining a highly active and stable platinum-nickel alloy catalyst in this invention.
Claims
1. The platinum-nickel alloy catalyst of the present invention is prepared by the ethylene glycol method, and the steps are as follows: 1) Prepare a mixed solution A by thoroughly sonicating ethylene glycol chloroplatinic acid solution, nickel nitrate hexahydrate, modified commercial carbon black, and ethylene glycol; 2) Add an appropriate amount of sodium hydroxide solution to the mixed solution A obtained in step 1), adjust the pH to a certain range, and stir thoroughly to obtain mixed solution B; 3) Stir the mixed solution B obtained in step 2) at a certain temperature, rotation speed and time to obtain mixed solution C; 4) Cool the mixed solution C obtained in step 3) to room temperature, then filter, wash and dry to obtain precursor D; 5) The precursor D dried in step 4) is thoroughly ground and calcined to obtain the highly active and stable platinum-nickel alloy catalyst.
2. As described in claim 1, the molar ratio of platinum ions to nickel ions in step 1) is 1:1, 1:2, 2:1, 2:3, or 3:2, preferably 2:
1.
3. As described in claim 1, in step 3), the stirring temperature is 120~180℃, preferably 140~160℃; the stirring speed is 300~600 rpm, preferably 400~500 rpm; and the stirring time is 4~8h, preferably 5~7h.
4. As described in claim 1, in step 4), the drying temperature is 50~80℃, preferably 60~70℃.
5. The content of each element in the catalyst prepared in step 5) of claim 1 is as follows: 18%~20% platinum, calculated as elemental Pt; 2%~8% nickel, based on elemental Ni; 2%~6% nitrogen, as N oxides; 1%~3% phosphorus, calculated as P oxide; 65%~75% carbon, calculated as C oxides; 5-7% oxygen, calculated as metal oxides.
6. A highly active and stable platinum-nickel alloy catalyst, characterized in that: It is prepared by the preparation method described in any one of claims 1 to 5.
7. The application of the highly active and stable platinum-nickel alloy catalyst according to claim 6 in the hydrogen evolution reaction of water electrolysis in acidic media. Its characteristics are: The platinum loading is significantly reduced compared to commercial platinum-carbon catalysts, resulting in improved corrosion resistance.