XC-72 loaded PtCu composite catalyst as well as preparation method and application thereof

Abstract

The invention discloses an XC-72 loaded PtCu composite catalyst and a preparation method and application thereof, and belongs to the field of electrochemistry, XC-72 carbon black is dissolved in DMF, ultrasonic stirring is performed for 1 min, and a solution A is obtained; taking a precursor platinum salt and a precursor copper salt, putting the precursor platinum salt and the precursor copper salt into a reaction kettle, transferring the solution A into the reaction kettle, and stirring for 20 minutes to obtain a solution B; taking glucose and CTAB (cetyltrimethyl ammonium bromide) into the solution B, stirring for 2-3 hours to obtain a solution C, heating for 32 hours at 160 DEG C, washing for 4 times with ethanol, and performing vacuum drying for 8 hours at 60 DEG C to obtain a target material, and by regulating and controlling the molar ratio of Pt to Cu precursors, taking the glucose as a reducing agent and taking the CTAB as a dispersing agent, inhibiting agglomeration of PtCu nanoparticles on the surface of an XC-72 carbon black carrier, and promoting uniform loading of the PtCu nanoparticles under the interface modification effect of the CTAB, the composite material is prepared. The number of active sites on the surface of the catalyst is increased, a reaction center is provided for catalytic reaction, and catalytic efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical technology, specifically relating to an XC-72 supported PtCu composite catalyst, its preparation method, and its application. Background Technology

[0002] In the field of electrocatalytic materials research, platinum-based catalysts are widely used in clean energy technologies such as fuel cells and water electrolysis due to their unique electronic structure and catalytic performance. However, the scarcity and high price of platinum resources severely restrict its large-scale commercial application. To address this bottleneck, researchers have developed strategies for alloying platinum with transition metals, among which the Pt-Cu alloy system has attracted widespread attention due to its tunable electronic structure and excellent catalytic performance. Different Cu / Pt ratios significantly affect the electronic structure, surface geometry, and catalytic performance of the alloy. By precisely controlling the alloy component ratio, the synergistic regulation of the "strain effect" and "ligand effect" of the catalyst's electronic structure can be achieved, thereby optimizing its catalytic activity and stability.

[0003] Currently, researchers have successfully synthesized a series of nanostructures with varying component ratios, ranging from platinum-rich Pt3Cu to copper-rich PtCu3, using various methods such as hydrothermal / solvothermal synthesis, colloidal synthesis, and template synthesis. Studies have shown that PtCu alloys with different component ratios exhibit significant performance differences in electrocatalytic reactions: copper-rich PtCu3 demonstrates excellent mass activity in the oxygen reduction reaction, while near-equiatomic PtCu alloys show enhanced resistance to CO poisoning in the methanol oxidation reaction. These findings indicate that the performance of catalysts can be directionally optimized by precisely controlling the alloy ratio.

[0004] However, several key scientific questions remain to be addressed in this field. First, the mechanisms of component control during synthesis are not sufficiently well understood; most work focuses on optimizing process parameters, lacking a systematic understanding of fundamental scientific issues such as the reduction kinetics of metal precursors and the phase separation mechanisms during nucleation and growth. Second, the precision and controllability of proportions and sample homogeneity need improvement, particularly in ensuring consistency of components between different batches during large-scale synthesis. Third, existing characterization methods have limited analytical capabilities for component distribution at the nanoscale, making it difficult to monitor component evolution in real time during synthesis. Finally, the stability of PtCu alloys with different proportions is insufficient, especially the dissolution behavior of Cu under electrochemical conditions and its long-term impact on catalyst structure and performance, which has not been systematically evaluated. Summary of the Invention

[0005] Technical problem solved: This invention provides an XC-72 supported PtCu composite catalyst, its preparation method and application, to solve the core technical problems of existing PtCu ammonia oxidation catalysts, which mostly focus on the alloying effect of high Cu ratio.

[0006] Objective of the Invention: This application provides an XC-72 supported PtCu composite catalyst FeC-G@MC&P, its preparation method, and its application. Under the premise of a fixed total molar number of Pt and Cu, by controlling the Cu ratio (Cu molar percentage ≤ 25%), a performance mutation phenomenon of Pt7Cu1 (Cu molar percentage ≈ 12.5%) was discovered for the first time. Furthermore, from three aspects, namely electronic structure regulation, active site reconstruction, and support-metal interface interaction, the enhanced mechanism of precise electronic modification rather than over-alloying under low Cu ratio on the ammonia oxidation activity and stability is revealed, filling the research gap of low Cu-doped Pt-based catalysts in the field of ammonia oxidation.

[0007] To achieve the above objectives, this application provides the following technical solution: A method for preparing an XC-72 supported PtCu composite catalyst, the specific steps of which are as follows: Step 1: Dissolve XC-72 carbon black in DMF and sonicate for 1-3 minutes to obtain solution A with a concentration of 0.5-1.5 mg / mL of XC-72 carbon black; Step 2: Take the precursor platinum salt and precursor copper salt according to the molar ratio of precursor platinum salt: precursor copper salt = 6~9:1, place the precursor platinum salt and precursor copper salt in the reaction vessel, transfer solution A to the reaction vessel, stir at 400-600 rpm for 10-30 min to obtain solution B. Step 3: While stirring solution B, add glucose and CTAB to solution B, control the speed to 400-600 rpm, stir for 2-3 hours to obtain solution C; Step 4: Heat solution C at 150-170℃ for 30-34 hours, then control the rotation speed at 11000-13000 rpm, wash the heated sample with ethanol, and vacuum dry to obtain the target material XC-72 supported PtCu composite catalyst.

[0008] Furthermore, in the first step, the concentration of XC-72 carbon black is 1 mg / mL, and ultrasonic stirring is performed for 1 min. Ultrasonic stirring is to ensure that XC-72 carbon black is uniformly dispersed in DMF.

[0009] Furthermore, in the second step, the molar ratios of Pt:Cu in the precursor platinum salt and precursor copper salt are 6:1, 7:1, and 9:1, respectively.

[0010] Furthermore, in the second step, the precursor platinum salt is platinum acetylacetonate and the precursor copper salt is copper acetylacetonate. The mixture is stirred at 500 rpm for 20 min to obtain solution B.

[0011] Furthermore, in the third step, glucose is used as a reducing agent, and the stirring speed is controlled at 500 rpm for 2-3 hours to reduce the metal ions Pt and Cu in the precursor platinum salt and precursor copper salt into metal nanoparticles, which are then loaded onto XC-72 carbon black. The concentration of glucose in solution C is 12 mg / mL, and the concentration of CTAB is 6.4 mg / mL.

[0012] Furthermore, in the fourth step, the heating temperature is 160℃ and the heating time is 32h, the purpose of which is to enable the Pt and Cu metal nanoparticles to form a more stable structure with XC-72 carbon black.

[0013] Furthermore, the ethanol washing is performed four times, with a centrifugation speed of 12000 r / min and a washing time of 5 min per cycle.

[0014] Furthermore, the vacuum drying temperature is 60°C and the drying time is 8 hours.

[0015] An XC-72 supported PtCu composite catalyst prepared by any of the above preparation methods.

[0016] Application of an XC-72 supported PtCu composite catalyst prepared by any of the above preparation methods in the preparation of ammonia fuel cells.

[0017] This application provides an XC-72 supported PtCu composite catalyst, its preparation method, and its application. Compared with the prior art, it has the following advantages: 1. The preparation process is simple, controllable, and highly operable: This method achieves catalyst preparation through a combination of ultrasonic stirring, mechanical stirring, and hydrothermal reaction, without relying on complex and demanding equipment such as high vacuum and high-temperature calcination. Moreover, the parameters of each step, such as ultrasonic time of 1 min, stirring speed of 500 rpm, reaction temperature of 160℃, and drying temperature of 60℃, are clear and controllable, making it easy to standardize and scale up production. This solves the problems of complex preparation processes, high equipment dependence, and difficulty in mass production of some existing catalysts. 2. The XC-72 supported PtCu composite catalyst prepared in this application exhibits excellent metal component dispersion and sufficient active sites: by adjusting the molar ratio of Pt to Cu precursors to 6:1, 7:1, and 9:1, and using glucose as a reducing agent and CTAB as a dispersant, the aggregation of PtCu nanoparticles on the surface of the XC-72 carbon black support can be effectively inhibited; at the same time, the interfacial modification effect of CTAB can promote the uniform loading of PtCu nanoparticles, significantly increase the number of active sites on the catalyst surface, provide sufficient reaction centers for subsequent catalytic reactions, and improve catalytic efficiency; 3. Stable bonding between the support and active components, resulting in high catalyst stability: During the preparation process, XC-72 carbon black is ultrasonically dispersed in DMF to form a homogeneous solution A. After being fully mixed with the PtCu precursor solution, a strong interaction between the active components and the support can be achieved under hydrothermal conditions. Subsequent high-speed centrifugation at 12,000 rpm and vacuum drying at 60°C further consolidate the bonding effect between the support and PtCu nanoparticles, reduce the loss of active components during the catalytic reaction, extend the catalyst's service life, and solve the problem of poor stability and poor recyclability of some existing catalysts due to unstable component bonding. 4. Low preparation cost and good economic efficiency: The raw materials selected in this method, such as XC-72 carbon black, DMF, glucose, and CTAB, are all industrial-grade conventional chemicals, which are widely available and inexpensive. At the same time, no precious metal additives or expensive special reagents are required in the reaction process, and the energy consumption of each step is low, such as the drying temperature of only 60℃. This significantly reduces the catalyst preparation cost and has good economic efficiency for industrial application. Compared with existing catalyst preparation technologies that rely on expensive raw materials or high-energy-consuming processes, it is more competitive in the market. Attached Figure Description

[0018] Figure 1 The images are scanning electron microscope images of the Pt7Cu1@XC-72 catalyst obtained in Example 1 of this application, where a is the structural morphology of the Pt7Cu1@XC-72 catalyst at high magnification and b is the structural morphology of the Pt7Cu1@XC-72 catalyst at low magnification. Figure 2 The figures show the cyclic voltammetry curves of the Pt7Cu1@XC-72 catalyst obtained in Example 1 of this application and the commercial PtIr / C catalyst in 1.0 M KOH electrolyte solution and 1.0 M KOH + 0.1 M NH3 electrolyte solution. Figure 2 The red line in section 'a' represents the catalytic curve of the Pt7Cu1@XC-72 catalyst in the ammonia oxidation reaction in a 1.0 M KOH + 0.1 M NH3 electrolyte solution, while the black line represents the activation curve of the Pt7Cu1@XC-72 catalyst in a 1.0 M KOH electrolyte solution. Figure 2 The red line in b represents the catalytic curve of the commercial PtIr / C catalyst in the ammonia oxidation reaction in 1.0 M KOH + 0.1 M NH3 electrolyte solution, and the black line represents the activation curve of the commercial PtIr / C catalyst in 1.0 M KOH electrolyte solution. Detailed Implementation

[0019] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0020] Example 1: This example provides a method for preparing a PtCu composite catalyst supported on an XC-72 ammonia fuel cell. The specific steps of the preparation method are as follows: Step 1: Dissolve XC-72 carbon black in DMF and ultrasonically stir for 1 minute. Ultrasonic stirring is to ensure that XC-72 carbon black is evenly dispersed in DMF, resulting in solution A with a concentration of 1 mg / mL of XC-72 carbon black. Step 2: According to the molar ratio of precursor platinum salt to precursor copper salt = 7:1, take precursor platinum salt and precursor copper salt, place precursor platinum salt and precursor copper salt in a reaction vessel, the precursor platinum salt is platinum acetylacetonate, and the precursor copper salt is copper acetylacetonate. Transfer solution A to the reaction vessel and stir at 500 rpm for 20 min to obtain solution B. Step 3: During the stirring process of solution B, glucose and CTAB are added to solution B. Glucose is used as a reducing agent to reduce the metal ions Pt and Cu in the precursor platinum salt and precursor copper salt to metal nanoparticles and load them on XC-72 carbon black. The stirring speed is controlled at 500 rpm and stirred for 2-3 hours to obtain solution C. The concentration of glucose in solution C is 12 mg / mL and the concentration of CTAB is 6.4 mg / mL. Step 4: Solution C was heated at 160℃ for 32 hours to allow the Pt and Cu metal nanoparticles to form a more stable structure with XC-72 carbon black. Then, the rotation speed was controlled at 12000 rpm, and the heated sample was washed with ethanol 4 times, with each wash lasting 5 minutes. The target material, XC-72 supported PtCu composite catalyst, was obtained by vacuum drying at 60℃ for 8 hours.

[0021] In solution C, the concentration of platinum acetylacetone was 10.324 mg / mL and the concentration of copper acetylacetone was 0.9816 mg / mL.

[0022] The obtained Pt7Cu1@XC-72 was observed using a scanning electron microscope (SEM), as shown above. Figure 1 As shown, the morphology of the obtained Pt7Cu1@XC-72 is that of nanoparticles loaded on XC-72 carbon black.

[0023] Ammonia oxidation reaction (AOR) catalytic activity test: Preparation of catalytic electrode: The prepared Pt7Cu1@XC-72 and commercial PtIr / C catalyst, 2 mg each, were dispersed in 480 μL of anhydrous ethanol and 20 μL of Nafion solution, and then sonicated for 30 min to form a homogeneous ink. The Pt loading was maintained at 0.1 mg. 25 μL of the ink was dropped onto a surface with an area of ​​0.196 cm². 2 It is placed on a glassy carbon electrode and then air-dried at room temperature before use.

[0024] AOR test: AOR activation was first tested in 1.0 mol / L KOH at a scan rate of 5 mV / s. Then, the catalytic activity of the prepared sample was determined in a 1.0 mol / L KOH solution containing 0.1 mol / L ammonia at a scan rate of 5 mV / s. The stability of the prepared sample was determined by chronoamperometry. For comparison, commercial PtIr / C (20 wt% Pt nanoparticles supported on Vulcan XC-72 carbon, Aladdin) was prepared using the same steps and testing methods.

[0025] The AOR performance of Pt7Cu1@XC-72 obtained in the implementation example was tested using a KOST workstation in a three-electrode battery system. In the three-electrode system, a saturated calomel electrode and a Pt mesh were used as the reference electrode and counter electrode, respectively.

[0026] Figure 2 Figure 'a' shows the cyclic voltammetry curves of Pt7Cu1@XC-72 in an exemplified embodiment, in a 1.0 mol / L KOH solution containing 1.0 mol / L KOH and 0.1 mol / L ammonia, with a potential range of 0 V to 1.2 V (relative to the reversible hydrogen electrode, RHE) and a scan rate of 5 mV / s. The red line in the figure represents the cyclic voltammetry curve of the catalytic activity of Pt7Cu1@XC-72 in the ammonia oxidation reaction, and the black line represents the activation reaction curve of Pt7Cu1@XC-72. Figure 2 Figure b shows the cyclic voltammetry curves of a commercial PtIr / C catalyst in a 1.0 mol / L KOH solution containing 1.0 mol / L KOH and 0.1 mol / L ammonia, with a potential range of 0 V to 1.2 V (relative to the reversible hydrogen electrode, RHE) and a scan rate of 5 mV / s. The red line in the figure represents the cyclic voltammetry curve of the commercial PtIr / C catalyst composite material for the ammonia oxidation reaction, and the black line represents the activation reaction curve of the commercial PtIr / C catalyst composite material. Figure 2 The AOR activity of Pt7Cu1@XC-72 was found to be 17.91 mA cm⁻¹. -2 In contrast, the activity of commercial PtIr / C is only 1.33 mA cm⁻¹. -2 .

[0027] Example 2, a method for preparing an XC-72 supported PtCu composite catalyst for an ammonia fuel cell, specifically includes the following steps: Step 1: Dissolve XC-72 carbon black in DMF and ultrasonically stir for 1 minute. Ultrasonic stirring is to ensure that XC-72 carbon black is evenly dispersed in DMF, resulting in solution A with a concentration of 1 mg / mL of XC-72 carbon black. Step 2: According to the molar ratio of precursor platinum salt to precursor copper salt = 6:1, take precursor platinum salt and precursor copper salt, place precursor platinum salt and precursor copper salt in a reaction vessel, the precursor platinum salt is platinum acetylacetone and the precursor copper salt is copper acetylacetone, transfer solution A to the reaction vessel, stir at 500 rpm for 20 min to obtain solution B; Step 3: During the stirring process of solution B, glucose and CTAB are added to solution B. Glucose is used as a reducing agent to reduce the metal ions Pt and Cu in the precursor platinum salt and precursor copper salt to metal nanoparticles and load them on XC-72 carbon black. The stirring speed is controlled at 500 rpm and stirred for 2-3 hours to obtain solution C. The concentration of glucose in solution C is 12 mg / mL and the concentration of CTAB is 6.4 mg / mL. Step 4: Solution C was heated at 160℃ for 32 hours to allow the Pt and Cu metal nanoparticles to form a more stable structure with XC-72 carbon black. Then, the rotation speed was controlled at 12000 rpm, and the heated sample was washed with ethanol 4 times, with each wash lasting 5 minutes. The target material, XC-72 supported PtCu composite catalyst, was obtained by vacuum drying at 60℃ for 8 hours.

[0028] Example 3, a method for preparing an XC-72 supported PtCu composite catalyst for an ammonia fuel cell, specifically includes the following steps: Step 1: Dissolve XC-72 carbon black in DMF and ultrasonically stir for 1 minute. Ultrasonic stirring is to ensure that XC-72 carbon black is evenly dispersed in DMF, resulting in solution A with a concentration of 1 mg / mL of XC-72 carbon black. Step 2: Take the precursor platinum salt and precursor copper salt according to the molar ratio of precursor platinum salt: precursor copper salt = 9:1. Place the precursor platinum salt and precursor copper salt in a reaction vessel. The precursor platinum salt is platinum acetylacetonate and the precursor copper salt is copper acetylacetonate. Transfer solution A to the reaction vessel and stir at 500 rpm for 20 min to obtain solution B. Step 3: During the stirring process of solution B, glucose and CTAB are added to solution B. Glucose is used as a reducing agent to reduce the metal ions Pt and Cu in the precursor platinum salt and precursor copper salt to metal nanoparticles and load them on XC-72 carbon black. The stirring speed is controlled at 500 rpm and stirred for 2-3 hours to obtain solution C. The concentration of glucose in solution C is 12 mg / mL and the concentration of CTAB is 6.4 mg / mL. Step 4: Solution C was heated at 160℃ for 32 hours to allow the Pt and Cu metal nanoparticles to form a more stable structure with XC-72 carbon black. Then, the rotation speed was controlled at 12000 rpm, and the heated sample was washed with ethanol 4 times, with each wash lasting 5 minutes. The target material, XC-72 supported PtCu composite catalyst, was obtained by vacuum drying at 60℃ for 8 hours.

[0029] In summary, the PtCu@XC-72 prepared by the method of the present invention has excellent catalytic activity for ammonia oxidation reaction, i.e., good AOR activity, and excellent stability. The preparation process is simple, low-cost, and easy to scale up for industrial production.

[0030] The foregoing description has fully disclosed the specific embodiments of the present invention. It should be noted that any modifications made to the specific embodiments of the present invention by those skilled in the art do not depart from the scope of the claims. Accordingly, the scope of the claims is not limited to the foregoing specific embodiments.

Claims

1. A method for preparing an XC-72 supported PtCu composite catalyst, characterized in that, The specific steps of the preparation method are as follows: Step 1: Dissolve XC-72 carbon black in DMF and sonicate for 1-3 minutes to obtain solution A with a concentration of 0.5-1.5 mg / mL of XC-72 carbon black; Step 2: Take the precursor platinum salt and precursor copper salt according to the molar ratio of precursor platinum salt: precursor copper salt = 6~9:1, place the precursor platinum salt and precursor copper salt in the reaction vessel, transfer solution A to the reaction vessel, stir at 400-600 rpm for 10-30 min to obtain solution B. Step 3: While stirring solution B, add glucose and CTAB to solution B, control the speed to 400-600 rpm, stir for 2-3 hours to obtain solution C; Step 4: Heat solution C at 150-170℃ for 30-34 hours, then control the rotation speed at 11000-13000 rpm, wash the heated sample with ethanol, and vacuum dry to obtain the target material XC-72 supported PtCu composite catalyst.

2. The preparation method of the XC-72 supported PtCu composite catalyst according to claim 1, characterized in that: In the first step, the concentration of XC-72 carbon black is 1 mg / mL, and ultrasonic stirring is performed for 1 min. Ultrasonic stirring is to ensure that XC-72 carbon black is uniformly dispersed in DMF.

3. The preparation method of the XC-72 supported PtCu composite catalyst according to claim 1, characterized in that: In the second step, the molar ratios of the precursor platinum salt and the precursor copper salt are 6:1, 7:1, and 9:1, respectively.

4. The preparation method of the XC-72 supported PtCu composite catalyst according to claim 1, characterized in that: In the second step, the precursor platinum salt is platinum acetylacetonate and the precursor copper salt is copper acetylacetonate. The mixture is stirred at 500 rpm for 20 min to obtain solution B.

5. The method for preparing the XC-72 supported PtCu composite catalyst according to claim 1, characterized in that: In the third step, glucose is used as a reducing agent. The stirring speed is controlled at 500 rpm and the mixture is stirred for 2-3 hours to reduce the metal ions Pt and Cu in the precursor platinum salt and precursor copper salt into metal nanoparticles, which are then loaded onto XC-72 carbon black. The concentration of glucose in solution C is 12 mg / mL and the concentration of CTAB is 6.4 mg / mL.

6. The method for preparing the XC-72 supported PtCu composite catalyst according to claim 5, characterized in that: The heating temperature in the fourth step is 160℃ and the heating time is 32h. The purpose is to make the Pt and Cu metal nanoparticles form a more stable structure with XC-72 carbon black.

7. The method for preparing the XC-72 supported PtCu composite catalyst according to claim 1, characterized in that: The ethanol washing was performed four times, with a centrifugation speed of 12000 r / min and a washing time of 5 min per cycle.

8. The method for preparing the XC-72 supported PtCu composite catalyst according to claim 1, characterized in that: The vacuum drying temperature is 60℃ and the drying time is 8 hours.

9. An XC-72 supported PtCu composite catalyst prepared by any one of the preparation methods of claims 1-8.

10. The application of an XC-72 supported PtCu composite catalyst prepared by any one of the preparation methods of claims 1-8 in the preparation of ammonia fuel cells.

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