An ionic liquid modified metal carbide catalyst and its preparation method and application

Abstract

The present invention discloses an ionic liquid modified metalloid carbide catalyst and its preparation method and application. The catalyst mainly comprises a metalloid carbide and an ionic liquid impregnated and supported on the metalloid carbide, wherein the mass of the ionic liquid is 20-60% of the total mass of the metalloid carbide and the ionic liquid. The ionic liquid is an imidazole ionic liquid, and its structural formula is shown in Formula I: wherein R1, R2, and R3 are the same or different and are independently selected from H, C n H 2n+1 or C m H 2m‑1 , n=1~20, m=2~20; X ‑ The catalyst of the present invention is provided with a new hydrophobic surface by the addition of ionic liquid, which is conducive to the transfer of oxygen to the reaction interface for 2e ‑ Oxygen reduction reaction can produce hydrogen peroxide with high selectivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalytic material preparation, and in particular relates to an ionic liquid modified metal carbide catalyst, a preparation method thereof, and application of the catalyst in hydrogen peroxide production. Background Art

[0002] Hydrogen peroxide, also known as hydrogen peroxide (H2O2), is colorless and transparent. It is an environmentally friendly chemical product that releases only oxygen and water during use, without producing polluting byproducts. It is widely used in industries such as electronics, pharmaceuticals, chemicals, textiles, papermaking, food, and wastewater treatment. Anthraquinone oxidation is currently the primary method for commercial H2O2 production, but this process has drawbacks: first, it can only be produced on a large scale, posing safety risks during storage and transportation; second, it involves waste gas and liquid emissions, high energy consumption, and multiple operational steps.

[0003] In contrast, the synthesis of H2O2 by oxygen reduction reaction in aqueous solution using a simple electrochemical device is considered a green and convenient alternative method. The catalysts commonly used for the electrocatalytic oxygen reduction synthesis of H2O2 are precious metals and transition metal materials. Although they exhibit good electrocatalytic activity, the scarcity of precious metals, metal contamination, and the complex catalyst preparation process limit their practical application. Secondly, during the reaction process, the catalyst surface is gradually wetted, making it difficult to perform electrocatalytic behavior efficiently for a long time, and the stability is poor. Therefore, this technology aims to develop a highly selective, highly stable, low-cost and simple-to-prepare catalyst to achieve efficient electrocatalytic synthesis of H2O2. Summary of the Invention

[0004] To address the shortcomings of the prior art, the present invention provides an ionic liquid-modified metalloid carbide catalyst, its preparation method, and its application in the electrochemical reduction of H2O2. The catalyst uses a metalloid carbide as a support, and an imidazole-based ionic liquid is impregnated onto the metalloid to manipulate the catalyst interface. This catalyst is simple to prepare, exhibits high selectivity and stability in electrochemical oxygen reduction reactions for H2O2 production, and has broad application prospects.

[0005] The main components of the catalyst of the present invention are ionic liquid and metal-like carbide. The addition of ionic liquid gives the catalyst a new hydrophobic surface, which is conducive to the transfer of oxygen to the reaction interface for 2e - Oxygen reduction reaction can produce hydrogen peroxide with high selectivity.

[0006] The technical solution adopted in the present invention is as follows:

[0007] A method for preparing an ionic liquid modified metal carbide catalyst comprises the following steps:

[0008] 1) Dispersing the metalloid carbide and the ionic liquid in an organic solvent, placing the mixture in a centrifuge tube, and crushing it with a cell crusher to fully mix the three substances;

[0009] 2) the mixed solution obtained in step 1) is further stirred and ultrasonically treated in sequence;

[0010] 3) subjecting the mixed solution obtained in step 2) to rotary evaporation to remove the organic solvent, and then placing it in an oven for drying to obtain the ionic liquid modified metalloid carbide catalyst;

[0011] Wherein, the ionic liquid is an imidazole ionic liquid, and its structural formula is shown in Formula I:

[0012]

[0013] In formula I, R1, R2, and R3 are the same or different and are independently selected from H, C n H 2n+1 or C m H 2m-1 , n=1~20, m=2~20; X - It is one or both of hexafluorophosphate and bis(trifluoromethanesulfonyl)imide.

[0014] Furthermore, the metalloid carbide is selected from one or more of boron carbide, silicon carbide, germanium carbide, arsenic carbide, and antimony carbide, preferably boron carbide.

[0015] Furthermore, the mass of the ionic liquid is 20-60%, preferably 30-40%, of the total mass of the metalloid carbide and the ionic liquid.

[0016] Furthermore, the organic solvent is isopropanol solvent, and the ratio of the mass of the metalloid carbide to the volume of the isopropanol solvent is (40-80) mg: (8-12) ml, preferably 60 mg: 10 ml.

[0017] Furthermore, the cell disruption time in step 1) is 15-45 min, preferably 30 min.

[0018] Furthermore, the stirring time in step 2) is 1-3 hours, preferably 1 hour; and the ultrasonic time is 15-45 minutes, preferably 30 minutes.

[0019] Furthermore, in step 3), the rotary evaporation temperature is 60-90° C., preferably 80° C.; the oven temperature is 70-100° C., preferably 85° C.; and the drying time is 8-14 hours, preferably 12 hours.

[0020] The present invention also provides the use of the ionic liquid-modified metal carbide catalyst in the electrocatalytic oxygen reduction preparation of hydrogen peroxide: the catalyst is first dispersed in ethanol and Nafion solution, ultrasonically dispersed to obtain a catalyst slurry, the catalyst slurry is coated on a ring-disk electrode, and dried with an infrared lamp. The ring-disk electrode serves as a working electrode, a mercury / mercuric oxide electrode serves as a reference electrode, a platinum wire serves as a counter electrode, a KOH or Na2SO4 aqueous solution serves as an electrolyte, oxygen is continuously introduced into the electrolyte, and an electrolytic reaction is performed to produce hydrogen peroxide; wherein the concentration of the KOH aqueous solution is 0.05-0.2 mol / L, and the concentration of the Na2SO4 aqueous solution is 0.025-0.1 mol / L.

[0021] Furthermore, the voltage of the electrolysis reaction is 0.2-0.6 V (vs RHE), preferably 0.4 V (vs RHE).

[0022] Compared with existing catalysts, the catalyst prepared by the above technology has the following beneficial effects:

[0023] 1) The ionic liquid-modified metalloid carbide catalyst obtained by the present invention can regulate the properties of the catalyst simply by changing the loading amount of the ionic liquid. The preparation steps are simple, reproducible, and the raw materials are easily available and low in cost.

[0024] 2) The catalyst obtained by the present invention is endowed with a new hydrophobic surface by loading the ionic liquid onto the metal-like carbide. The hydrophobic catalyst surface is conducive to the adsorption of oxygen molecules, and excludes excessive water molecules from occupying the active sites of the catalyst, thereby promoting the 2e - The occurrence of oxygen reduction reaction improves the stability and H2O2 yield; RRDE test shows that its H2O2 selectivity is over 90%, while the electron transfer number is close to 2. After 72h of testing, the current density hardly decreases, proving that the prepared catalyst has good selectivity, excellent cycle stability and good electrochemical activity.

[0025] 3) The catalyst of the present invention contains no precious metals and transition metals, has readily available raw materials, is inexpensive, has a simple preparation process, has low energy consumption, has good electrocatalytic performance for producing hydrogen peroxide and long-term stability, is suitable for industrial production, and has great application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a SEM image of the catalyst prepared in Example 1 of the present invention;

[0027] Figure 2 This is a SEM image of the catalyst prepared in Example 2 of the present invention;

[0028] Figure 3 This is a SEM image of the catalyst prepared in Example 3 of the present invention;

[0029] Figure 4 This is a SEM image of the catalyst prepared in Example 4 of the present invention;

[0030] Figure 5 This is a SEM image of the catalyst prepared in Example 5 of the present invention;

[0031] Figure 6 This is a SEM image of the catalyst prepared in Comparative Example 1 of the present invention;

[0032] Figure 7 The XPS graphs of the catalysts prepared in Example 3 of the present invention and Comparative Example 1 and the 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt ionic liquid are shown;

[0033] Figure 8 A comparison of the relationship between the number of electron transfers and the voltage when the catalysts prepared in Example 3 of the present invention and Comparative Example 1 are used in the electrocatalytic synthesis of H2O2;

[0034] Figure 9 A comparison of the relationship between Faraday efficiency and voltage when the catalysts prepared in Example 3 of the present invention and Comparative Example 1 are used in the electrocatalytic synthesis of H2O2;

[0035] Figure 10 This is a graph of the electrochemical stability of the catalyst prepared in Example 3 of the present invention;

[0036] Table 1 is a selectivity comparison table of Examples 1-14 and Comparative Examples 1-3. DETAILED DESCRIPTION

[0037] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0038] The amount of isopropyl alcohol used in the examples of the present invention and the comparative examples was 10 ml, and the mass of boron carbide (B4C) and silicon carbide (SiC) was 60 mg.

[0039] Example 1 20%-IL@B4C catalyst preparation, comprising the following steps:

[0040] At room temperature, 60 mg of B4C and 15 mg of 1-butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solids were completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was evaporated at 80°C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85°C at a rate of 5°C / min, then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product, 20%-IL@B4C catalyst.

[0041] Example 230%-IL@B4C catalyst preparation, comprising the following steps:

[0042] At room temperature, 60 mg of B4C and 25.7 mg of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solids were completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was rotary evaporated at 80°C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85°C at a rate of 5°C / min, and then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product, 30%-IL@B4C catalyst.

[0043] Example 3 40%-IL@B4C catalyst preparation, comprising the following steps:

[0044] At room temperature, 60 mg of B4C and 40 mg of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solids were completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was evaporated at 80°C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85°C at a rate of 5°C / min, and then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product, 40%-IL@B4C catalyst.

[0045] Example 4 50%-IL@B4C catalyst preparation, comprising the following steps:

[0046] At room temperature, 60 mg of B4C and 60 mg of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solids were completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was rotary evaporated at 80°C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85°C at a rate of 5°C / min, and then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product 50%-IL@B4C catalyst.

[0047] Example 5 60%-IL@B4C catalyst preparation, comprising the following steps:

[0048] At room temperature, 60 mg of B4C and 90 mg of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solids were completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was rotary evaporated at 80°C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85°C at a rate of 5°C / min, then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product, 60%-IL@B4C catalyst.

[0049] Example 6 20%-IL@SiC catalyst preparation, comprising the following steps:

[0050] At room temperature, 60 mg of SiC and 15 mg of 1-butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solids were completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was evaporated at 80°C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85°C at a rate of 5°C / min, and then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product, 20%-IL@SiC catalyst.

[0051] Example 7 30%-IL@SiC catalyst preparation, comprising the following steps:

[0052] At room temperature, 60 mg of SiC and 25.7 mg of 1-butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solid was completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was evaporated at 80°C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85°C at a rate of 5°C / min, and then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product, 30%-IL@SiC catalyst.

[0053] Example 8 40%-IL@SiC catalyst preparation, including the following steps:

[0054] At room temperature, 60 mg of SiC and 40 mg of 1-butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solids were completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was evaporated at 80°C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85°C at a rate of 5°C / min, and then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product, 40%-IL@SiC catalyst.

[0055] Example 9 50%-IL@SiC catalyst preparation, comprising the following steps:

[0056] At room temperature, 60 mg of SiC and 60 mg of 1-butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solid was completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was evaporated at 80°C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85°C at a rate of 5°C / min, and then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product 50%-IL@SiC catalyst.

[0057] Example 10 Preparation of 60%-IL@SiC catalyst, comprising the following steps:

[0058] At room temperature, 60 mg of SiC and 90 mg of 1-butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solids were completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was evaporated at 80°C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85°C at a rate of 5°C / min, and then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product, 60%-IL@SiC catalyst.

[0059] Example 1130%-IL P @B4C catalyst preparation includes the following steps:

[0060] At room temperature, 60 mg of B4C and 25.7 mg of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solid was completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was rotary evaporated at 80°C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser tube. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85°C at a rate of 5°C / min and then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product 30%-IL. P @B4C Catalyst.

[0061] Example 1240%-IL P @B4C catalyst preparation includes the following steps:

[0062] At room temperature, 60 mg of B4C and 40 mg of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solid was completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was rotary evaporated at 80°C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser tube. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85°C at a rate of 5°C / min and then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product 40%-IL. P @B4C Catalyst.

[0063] Example 1330%-IL PThe preparation of SiC catalyst includes the following steps:

[0064] At room temperature, 60 mg of SiC and 25.7 mg of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solid was completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was rotary evaporated at 80 ° C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser tube. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85 ° C at a rate of 5 ° C / min and then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product 30%-IL P @SiC catalyst.

[0065] Example 1440%-IL P The preparation of the @SiC catalyst includes the following steps:

[0066] At room temperature, 60 mg of SiC and 40 mg of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid were weighed and dissolved in 10 ml of isopropanol. The mixture was crushed with a cell crusher for 30 minutes to fully mix the three substances. After stirring for 1 hour, the solid was completely dispersed by ultrasound for 30 minutes. The liquid was taken out and introduced into a chicken heart bottle. The mixture was rotary evaporated at 80°C using a low vacuum rotary evaporator until no isopropanol liquid dripped from the condenser tube. The substance in the chicken heart tube was scraped off with a key and placed in a centrifuge tube. The tube was then placed in an oven and the program was set to heat the temperature from room temperature to 85°C at a rate of 5°C / min and then kept at a constant temperature for 12 hours. After cooling, the tube was taken out and ground with a mortar to obtain the final product 40%-IL P @SiC catalyst.

[0067] Comparative Example 1B4C catalyst preparation includes the following steps:

[0068] Take 60 mg of B4C at room temperature, put it into an oven, set the program to heat it from room temperature to 85°C at a heating rate of 5°C / min, and then keep the temperature constant for 12 hours. After it cools down, take it out and grind it in a mortar to obtain the final product B4C catalyst.

[0069] The SEM images of the catalysts prepared in Examples 1-5 of the present invention and the catalysts of Comparative Examples 1B4C are as follows: Figure 1-6 As shown, from Figure 1-6 From the comparison results, it can be seen that the morphological structures of the catalysts prepared in Examples 1-5 of the present invention after loading with ionic liquids are different, and their surfaces present different morphologies as the amount of ionic liquid changes. It is precisely because of the slight changes in the surface that different electrocatalytic properties are exhibited.

[0070] The XPS graphs of the catalysts prepared in Example 3 and Comparative Example 1 and the 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ionic liquid are as follows: Figure 7 As shown, from Figure 7 It can be seen that the catalyst of Example 3 of the present invention contains characteristic peaks of the ionic liquid, that is, the elements of the ionic liquid are successfully loaded on the boron carbide.

[0071] Comparative Example 2 SiC catalyst preparation, comprising the following steps:

[0072] Take 60 mg of SiC at room temperature, put it into an oven, set the program to heat the temperature from room temperature to 85°C at a heating rate of 5°C / min, and then keep the temperature constant for 12 hours. After it cools down, take it out and grind it in a mortar to obtain the final product SiC catalyst.

[0073] Comparative Example 3 Preparation of acetylene black catalyst, comprising the following steps:

[0074] Take 60 mg of acetylene black at room temperature, put it into an oven, set the program to heat the temperature from room temperature to 85°C at a heating rate of 5°C / min, and then keep the temperature constant for 12 hours. After it cools down, take it out and grind it in a mortar to obtain the final product, acetylene black catalyst.

[0075] Application Example 1:

[0076] The electrocatalytic performance of the catalysts of Examples 1-14 and Comparative Examples 1-3 was verified respectively:

[0077] Catalyst working inks were prepared using the catalysts of Examples 1-14 and Comparative Examples 1-3. 4.0 mg of the catalyst, 100 μL of DuPont 5% Nafion solution, and 900 μL of anhydrous ethanol were uniformly dispersed by ultrasonication for 30 minutes to obtain the corresponding catalyst working inks prepared using the catalysts of Examples 1-14 and Comparative Examples 1-3. 5 μL of the catalyst working ink was applied to the circular glassy carbon area of ​​a rotating ring-disk electrode and dried to form the working electrode.

[0078] An electrochemical workstation (CH760E) was used as the electrochemical generator, with a catalyst-coated rotating ring disk electrode as the working electrode, a platinum wire as the counter electrode, and mercury / mercuric oxide as the reference electrode. The voltage at the platinum ring end, Ering, was 1.3 VRHE. A 0.1 M aqueous KOH solution was used as the electrolyte, and oxygen was continuously introduced (at a flow rate of 30 mL / min). The selective oxygen reduction test voltage range was 0-0.6 VRHE, and the scan rate was 10 mV / s. During the electrochemical test, the disk current and ring current of the rotating ring disk electrode were measured.

[0079] During the test, the results of the H2O2 selectivity at 0.4V (vs RHE) when the catalysts of Examples 1-14 and Comparative Examples 1-3 were used for electrocatalytic reactions are shown in Table 1. As can be seen from Table 1, the introduction of the ionic liquid improved the H2O2 selectivity of the catalyst. When the mass fraction of the ionic liquid was 40%, the selectivity of the catalyst was the highest, approaching 93%. The electron transfer number results of Example 3 and Comparative Example 1 under different voltage conditions are shown in Table 1. Figure 8 As shown, from Figure 8 It can be seen that the electron transfer number of Example 3 is closer to 2. The Faraday efficiency results of Example 3 and Comparative Example 1 under different voltage conditions are as follows: Figure 9 As shown, from Figure 9 It can be seen that the Faraday efficiency of Example 3 is higher.

[0080] Table 1

[0081]

[0082] Conventional non-metallic catalysts for electrocatalytic hydrogen peroxide are carbon materials. Compared with the acetylene black catalyst used in Comparative Example 3, the ionic liquid-modified metal carbide catalyst of the present invention shows significant improvement in catalytic activity.

[0083] Application Example 2 (Service Life of Test Catalyst):

[0084] Using the catalyst from Example 3, a catalyst working ink was prepared: 4.0 mg of the catalyst, 100 μL of DuPont 5% Nafion solution, and 900 μL of anhydrous ethanol were dispersed evenly under ultrasonication for 30 minutes to obtain the catalyst working ink. 5 μL of the catalyst working ink was applied to the circular glassy carbon region of a rotating ring-disk electrode and dried to form the working electrode. The test conditions were the same as those in Example 1, with the test voltage controlled at 0.4 V (vs RHE).

[0085] The present invention is attached Figure 10 This is the electrocatalytic reaction stability diagram of the catalyst at 0.4 V (vs RHE). During the 72-h continuous test, the current density hardly decreased, indicating that the catalyst has good stability.

[0086] The contents described in this specification are merely an enumeration of implementation forms of the inventive concept, and the protection scope of the present invention should not be considered as being limited to the specific forms described in the embodiments.

Claims

1. An ionic liquid modified metal carbide catalyst, characterized in that It is composed of a metal-like carbide and an ionic liquid impregnated and supported on the metal-like carbide, wherein the mass of the ionic liquid is 20-60% of the total mass of the metal-like carbide and the ionic liquid; Wherein, the ionic liquid is an imidazole ionic liquid, and its structural formula is shown in Formula I: ； In formula I, R1, R2, and R3 are the same or different and are independently selected from H, C n H 2n+1 or C m H 2m-1 , n=1~20, m=2~20; X - One or both of hexafluorophosphate and bis(trifluoromethanesulfonyl)imide; The metalloid carbide is selected from one or more of boron carbide and silicon carbide.

2. The ionic liquid modified metal carbide catalyst according to claim 1, characterized in that The metalloid carbide is selected from boron carbide.

3. The ionic liquid modified metal carbide catalyst according to claim 1, characterized in that The mass of the ionic liquid is 30-40% of the total mass of the metalloid carbide and the ionic liquid.

4. The method for preparing an ionic liquid modified metal carbide catalyst according to claim 1, characterized in that The following steps are involved: 1) Disperse the metalloid carbide and ionic liquid in an organic solvent, place the mixture in a centrifuge tube, and crush it with a cell crusher to fully mix the three substances; 2) The mixed solution obtained in step 1) is further stirred and ultrasonically treated in sequence; 3) The mixed solution obtained in step 2) is subjected to rotary evaporation to remove the organic solvent, and then placed in an oven for drying to obtain the ionic liquid modified metalloid carbide catalyst.

5. The method for preparing an ionic liquid modified metal carbide catalyst according to claim 4, characterized in that The organic solvent is isopropanol solvent, and the ratio of the mass of the metalloid carbide to the volume of the isopropanol solvent is (40-80) mg:(8-12) ml.

6. The method for preparing an ionic liquid modified metalloid carbide catalyst according to claim 4, wherein: The cell disruption time in step 1) is 15-45 min.

7. The method for preparing an ionic liquid modified metalloid carbide catalyst according to claim 4, wherein: Step 2) The stirring time is 1-3 h, and the ultrasonic time is 15-45 min; In step 3), the oven temperature is 70-100°C and the drying time is 8-14 hours.

8. Use of the ionic liquid modified metalloid carbide catalyst according to claim 1 in the preparation of hydrogen peroxide by electrocatalytic oxygen reduction.

9. The use according to claim 8, characterized in that: The catalyst is first dispersed in ethanol and Nafion solution, and a catalyst slurry is obtained by ultrasonic dispersion. The catalyst slurry is coated on a ring disk electrode and dried with an infrared lamp. The ring disk electrode serves as a working electrode, a mercury / mercuric oxide electrode serves as a reference electrode, a platinum wire serves as a counter electrode, and a KOH or Na2SO4 aqueous solution serves as an electrolyte. Oxygen is continuously introduced into the electrolyte to produce hydrogen peroxide through an electrolytic reaction. The concentration of the KOH aqueous solution is 0.05-0.2 mol / L, and the concentration of the Na2SO4 aqueous solution is 0.025-0.1 mol / L.

10. The use according to claim 9, characterized in that: The voltage of the electrolysis reaction is 0.2-0.6 V vs RHE.

11. The use according to claim 10, characterized in that: The voltage of the electrolysis reaction is 0.4 V vs RHE.

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