A method for preparing and applying a Pt-doped molybdenum carbide catalyst

Abstract

This invention discloses a method for preparing and applying a Pt-doped molybdenum carbide catalyst, belonging to the field of catalytic materials technology. The method comprises the following steps: (1) mixing a molybdenum source, a platinum source, and a carbon source to obtain a mixture; grinding the mixture to obtain product S1; (2) heating product S1 in a Joule heating apparatus under an inert gas atmosphere until fully reacted to obtain product S2; (3) cooling, washing, and drying product S2 to obtain the Pt-doped molybdenum carbide catalyst. This method can synthesize a Pt-doped molybdenum carbide catalyst in a few seconds or even less than one second. This catalyst exhibits good catalytic activity for electrocatalytic hydrogen evolution, chemical hydrogen evolution, and thermochemical hydrogenation reactions, and is widely used in water electrolysis, chlor-alkali industry, organic synthesis, and other fields. The raw materials used in this invention are inexpensive, the process is simple, and the time consumption is short, making it suitable for rapid catalyst production.

Description

Technical Field

[0001] This invention relates to a method for preparing a Pt-doped molybdenum carbide catalyst, belonging to the field of catalytic materials technology. Background Technology

[0002] Molybdenum carbide (MoCb) possesses not only noble metal-like properties but also excellent characteristics such as high melting point, high stability, resistance to sulfur, nitrogen, acid corrosion, and calcination, making it widely used in catalysis fields such as hydrogenation, hydrogen production, and oxygen reduction reactions. However, the catalytic activity of currently developed MoCb catalysts still lags behind that of noble metals. To further improve the catalytic activity of MoCb, researchers have widely adopted the strategy of small-scale noble metal doping. Small-scale noble metal doping not only enhances the catalytic activity of MoCb but also results in low noble metal content, low catalyst cost, and the ability to achieve large-scale production.

[0003] Currently, methods for synthesizing molybdenum carbide (MoCb) with noble metal doping mainly focus on two aspects. The first is to synthesize MoCb first, and then load a small amount of noble metal onto it. Researchers first use strategies such as chemical vapor deposition (CVD), carbothermal hydrogen reduction (CHD), arc discharge (AED), ion melting, and propanol reduction to synthesize MoCb, and then load a certain amount of noble metal using methods such as photodeposition and electrodeposition. This strategy can controllably and uniformly load noble metal onto the MoCb surface; however, the interaction between MoCb and noble metal is weak, and the noble metal is very easy to detach, which is detrimental to subsequent catalytic reactions. The second approach is to directly dope noble metal during the synthesis of MoCb. This strategy can enhance the interaction between MoCb and noble metal, making it less likely for the noble metal to detach. However, since the conventional MoCb synthesis process is generally time-consuming, the noble metal is very prone to agglomeration during synthesis, resulting in uneven distribution of the noble metal on the MoCb, low utilization, and affecting subsequent catalytic reactions. Therefore, there is an urgent need to develop new methods for MoCb doping with noble metal that achieve uniform distribution and strong interaction. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an ultrafast method for preparing Pt-doped molybdenum carbide catalysts, which differs from previously reported methods. This invention can synthesize Pt-doped molybdenum carbide catalysts in seconds or even less than one second. These catalysts exhibit excellent catalytic activity for electrocatalytic hydrogen evolution, chemical hydrogen evolution, and thermochemical hydrogenation reactions, and are widely used in water electrolysis, chlor-alkali industry, organic synthesis, and other fields. To achieve the above objectives, the technical solution of this invention is as follows:

[0005] This invention provides a method for preparing a Pt-doped molybdenum carbide catalyst, comprising the following steps:

[0006] (1) Mix molybdenum source, platinum source and carbon source to obtain a mixture, grind the mixture to obtain product S1;

[0007] (2) Under an inert gas atmosphere, product S1 was heated in a Joule heating apparatus until the reaction was complete, yielding product S2;

[0008] (3) Cool, wash and dry the product S2 to obtain Pt-doped molybdenum carbide catalyst.

[0009] In the above technical solution, further, in step (1), the molybdenum source is one or two of ammonium molybdate, sodium molybdate, zinc molybdate, molybdenum trichloride and molybdenum oxide in any proportion, and the mass percentage of the molybdenum source in product S1 is 30% to 50%.

[0010] In the above technical solution, further, in step (1), the platinum source is one of chloroplatinic acid, sodium chloroplatinate, potassium chloroplatinate and platinum tetrachloride; the mass percentage of the platinum source in product S1 is 0.1% to 5%.

[0011] In the above technical solution, further, in step (1), the carbon source is one or two of activated carbon, conductive carbon black, graphite and glucose mixed in any proportion; the carbon source accounts for 40% to 80% of the mass of product S1.

[0012] In the above technical solution, further, in step (2), the heating temperature is 600–3000℃, the heating time is 0.1–10s, and the heating rate is 10. 3 ~10 4 ℃ / s.

[0013] In the above technical solution, further, in step (2), the inert gas is one or a mixture of two of argon, nitrogen and helium in any proportion.

[0014] Another aspect of the present invention provides the application of the Pt-doped molybdenum carbide catalyst prepared by the above-mentioned method in the fields of water electrolysis, chlor-alkali industry and organic synthesis.

[0015] The beneficial effects of this invention are as follows:

[0016] This invention provides a method for preparing Pt-doped molybdenum carbide catalysts, which can synthesize Pt-doped molybdenum carbide catalysts in a few seconds or even less than one second. Due to the short reaction time, this method effectively avoids the aggregation of the precious Pt metal, improving the utilization rate of Pt during catalysis. The rapid heating rate enhances the interaction between Pt and molybdenum carbide, making them less prone to separation during catalysis and significantly improving catalyst stability. Furthermore, compared with conventional thermal reduction methods, this method does not use hazardous gases such as methane and hydrogen, greatly improving the safety of the synthesis process. This catalyst exhibits excellent catalytic activity for electrocatalytic hydrogen evolution, chemical hydrogen evolution, and thermochemical hydrogenation reactions, and is widely used in water electrolysis, chlor-alkali industry, organic synthesis, and other fields.

[0017] The raw materials used in this invention are inexpensive, the process is simple and quick, and it is suitable for the rapid production of catalysts. Attached Figure Description

[0018] Figure 1 This is a transmission electron microscope (TEM) image of the Pt-doped molybdenum carbide catalyst in Example 1.

[0019] Figure 2 The image shows the XRD pattern of the Pt-doped molybdenum carbide catalyst in Example 1.

[0020] Figure 3 The electrochemical hydrogen evolution performance of the molybdenum carbide and Pt-doped molybdenum carbide catalysts in Example 1 is shown. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the embodiments, but the present invention is not limited to these embodiments.

[0022] Unless otherwise specified, the raw materials used in the embodiments of this invention were all purchased through commercial channels.

[0023] Example 1

[0024] The synthesis of Pt-doped molybdenum carbide catalysts specifically includes the following steps:

[0025] (1) Mix 80mg ammonium molybdate, 180mg activated carbon and 10mg chloroplatinic acid evenly, then put the three into a mortar and grind for 15 minutes. Put the ground mixed powder S1 onto conductive carbon paper.

[0026] (2) The synthesis was carried out by heating using a Joule heater. The synthesis conditions were: heating rate of 2500℃ / s, reaction temperature of 1200℃, reaction time of 2s, and the entire synthesis environment was protected by argon.

[0027] (3) Cool the product obtained in step (2), wash it twice with deionized water, then wash it five times with organic solvent DMF, each time requiring ultrasonication for 5 minutes to thoroughly remove excess carbon-containing substances, and finally wash it twice with ethanol and dry it at 100°C to obtain Pt-doped molybdenum carbide catalyst.

[0028] First, the synthesized materials were characterized using XRD technology, such as... Figure 1 As shown in the XRD pattern, the characteristic peaks of the carbon support and molybdenum carbide are clearly observed. The crystal phase of molybdenum carbide is β phase, indicating that molybdenum carbide was successfully synthesized. No characteristic peaks of Pt were observed, indicating that no aggregated Pt nanoparticles were found in the synthesized material. Next, the composition of the material was analyzed. Inductively coupled plasma microscopy (ICP-MS) results showed that the mass percentage of Pt was 0.5%, indicating that Pt was successfully doped into molybdenum carbide. Finally, the morphology of the material was characterized, as shown in... Figure 2 As shown, scanning electron microscopy reveals that molybdenum carbide particles, approximately 30 nm in size, are uniformly distributed on the carbon support.

[0029] Under acidic conditions, with an overpotential of 35 mV, the hydrogen evolution current density of the Pt-doped molybdenum carbide catalyst can reach 10 mA·cm⁻¹. 2 In comparison, the overpotential of the Pt-free molybdenum carbide catalyst is 110 mV. Figure 3 This indicates that the Pt-doped molybdenum carbide catalyst exhibits good hydrogen evolution catalytic activity.

[0030] Example 2

[0031] The difference from Example 1 is:

[0032] The molybdenum source was 100 mg of molybdenum trichloride, the carbon source was 250 mg of graphite, and the platinum source was 5 mg of platinum tetrachloride. Reaction conditions: heating rate 1000℃ / s, reaction temperature 1000℃, reaction time 1 s, and the entire synthesis environment was under nitrogen protection.

[0033] Molybdenum carbide particles, approximately 50 nm in size, are uniformly distributed on the carbon support. XRD characterization reveals that the molybdenum carbide is in the β phase. ICP-MS analysis of the above material showed that the mass percentage of Pt in the material was 0.1%.

[0034] Example 3

[0035] The difference from Example 1 is:

[0036] The molybdenum source was 100 mg of molybdenum trichloride, the carbon source was 200 mg of glucose, and the platinum source was 15 mg of potassium chloroplatinate. Reaction conditions: heating rate 3000℃ / s, reaction temperature 2000℃, reaction time 0.1 s, and the entire synthesis environment was under argon protection.

[0037] Molybdenum carbide particles, approximately 60 nm in size, are uniformly distributed on the carbon support. XRD characterization reveals that the molybdenum carbide is in the β phase. ICP-MS analysis of the above material showed that the mass percentage of Pt in the material was 1%.

[0038] Example 4

[0039] The difference from Example 1 is:

[0040] The molybdenum source was 200 mg of sodium molybdate, the carbon source was 300 mg of glucose, and the platinum source was 25 mg of potassium chloroplatinate. Reaction conditions: heating rate 3000℃ / s, reaction temperature 600℃, reaction time 10 s, cooling rate 1000℃ / s, and the entire synthesis environment was under argon protection.

[0041] Molybdenum carbide particles, approximately 100 nm in size, are uniformly distributed on the carbon support. XRD characterization reveals that the molybdenum carbide is in the β phase. ICP-MS analysis of the above material showed that the mass percentage of Pt in the material was 1.5%.

[0042] Example 5

[0043] The difference from Example 1 is:

[0044] The molybdenum source was 200 mg of sodium molybdate, the carbon source was 200 mg of glucose, and the platinum source was 10 mg of potassium chloroplatinate. Reaction conditions: heating rate of 10000℃ / s, reaction temperature of 2500℃, reaction time of 0.5 s, cooling rate of 50000℃ / s, and the entire synthesis environment was under argon protection.

[0045] Molybdenum carbide particles, approximately 20 nm in size, are uniformly distributed on the carbon support. XRD characterization reveals that the molybdenum carbide is in the α phase. ICP-MS analysis of the material showed that the mass percentage of Pt in the material was 0.6%.

[0046] As can be seen from Examples 1 to 5 above, Pt-doped molybdenum carbide catalysts can be successfully synthesized. The size of molybdenum carbide nanoparticles can be adjusted according to temperature and reaction time to meet catalytic reactions under different conditions.

[0047] The above description is merely a few embodiments of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any modifications or alterations made by those skilled in the art without departing from the scope of the technical solution of the present invention using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a Pt-doped molybdenum carbide catalyst, characterized in that, Includes the following steps: (1) Mix molybdenum source, platinum source and carbon source to obtain a mixture, grind the mixture to obtain product S1; (2) Under an inert gas atmosphere, product S1 was heated in a Joule heating apparatus and the product S2 was obtained after the reaction was complete. (3) Cool, wash and dry the product S2 to obtain the Pt-doped molybdenum carbide catalyst; In step (1), the platinum source accounts for 0.1% to 5% of the mass of product S1; In step (2), the heating temperature is 600~3000℃, the heating time is 0.1~10 s, and the heating rate is 10. 3 ~10 4 ℃ / s.

2. The method for preparing the Pt-doped molybdenum carbide catalyst according to claim 1, characterized in that: In step (1), the molybdenum source is one or a mixture of two of the following in any proportion: ammonium molybdate, sodium molybdate, zinc molybdate, molybdenum trichloride, and molybdenum oxide. The mass percentage of the molybdenum source in product S1 is 30% to 50%.

3. The method for preparing the Pt-doped molybdenum carbide catalyst according to claim 1, characterized in that: In step (1), the platinum source is one of chloroplatinic acid, sodium chloroplatinate, potassium chloroplatinate, and platinum tetrachloride.

4. The method for preparing the Pt-doped molybdenum carbide catalyst according to claim 1, characterized in that: In step (1), the carbon source is one or two of activated carbon, conductive carbon black, graphite and glucose mixed in any proportion; the carbon source accounts for 40% to 80% of the mass of product S1.

5. The method for preparing the Pt-doped molybdenum carbide catalyst according to claim 1, characterized in that: In step (2), the inert gas is one or a mixture of two of argon, nitrogen and helium in any proportion.

6. The application of a Pt-doped molybdenum carbide catalyst prepared by the method according to any one of claims 1-5 in the fields of water electrolysis, chlor-alkali industry and organic synthesis.

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