A two-dimensional titanium carbide-polyacrylamide nanocomposite loaded with palladium, and a preparation method and application thereof

Abstract

The application discloses a two-dimensional titanium carbide-polyacrylamide nanocomposite loaded with palladium, which is characterized by the following steps: a two-dimensional titanium carbide material is prepared; a two-dimensional titanium carbide-polyacrylamide nanocomposite is prepared; palladium nanoparticles are prepared; the two-dimensional titanium carbide-polyacrylamide nanocomposite loaded with palladium is prepared; and an electrochemical biosensor is assembled. The two-dimensional titanium carbide-polyacrylamide nanocomposite loaded with palladium can fully disperse and effectively load palladium nanoparticles, and the electrochemical biosensor is constructed by using the two-dimensional titanium carbide-polyacrylamide nanocomposite loaded with palladium, so that the effective detection of dopamine concentration is realized.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, specifically to a palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material, its preparation method, and its application. Background Technology

[0002] Dopamine (DA) is the most abundant catecholamine neurotransmitter in the brain. It is a neurotransmitter that helps cells transmit impulses, excitement, and pleasure, and enhances myocardial contractility and heart rate. However, abnormally variable dopamine concentrations can lead to serious diseases such as sleep and eating disorders, Parkinson's disease, and drug abuse-related addiction. Conversely, excessively low dopamine concentrations can cause brain damage and muscle dysfunction. Therefore, developing electrocatalytically active materials with a wide linear detection range and low detection limit for dopamine concentrations is of significant research importance.

[0003] Palladium nanoparticles, a noble metal, are widely used in catalysis, biolabeling, and other fields due to their high catalytic activity. However, palladium nanoparticles suffer from drawbacks such as easy aggregation and poor stability during use. Therefore, it is of great significance to effectively treat palladium nanoparticles to achieve uniform dispersion and improve their catalytic performance. Summary of the Invention

[0004] The technical objective of this invention is to provide a two-dimensional titanium carbide-polyacrylamide nanocomposite material with a layered porous structure that can fully disperse and effectively load palladium nanoparticles, and to construct it as an electrochemical biosensor to achieve effective detection of dopamine concentration.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is as follows: a two-dimensional titanium carbide-polyacrylamide nanocomposite material loaded with palladium, wherein the composite material uses two-dimensional titanium carbide-polyacrylamide as a carrier, and the carrier is loaded with 10-20% by mass of the active component of metallic palladium. The carrier is composed of titanium carbide and polyacrylamide in a mass ratio of 1:(5-10), and the composite material has a porous layered appearance.

[0006] A method for preparing a palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material includes the following steps:

[0007] Step 1: Preparation of two-dimensional titanium carbide materials

[0008] Titanium aluminum carbide powder was slowly added to hydrofluoric acid solution at a ratio of (0.05-0.2) g / mL over 10-20 min. The reaction was carried out at room temperature with constant stirring for 10-12 h. Afterward, the reaction product was centrifuged, the lower layer precipitate was collected and washed to obtain precipitate I. Then, precipitate I was added to tetramethylammonium hydroxide aqueous solution with a mass concentration of 20-40% at a ratio of (0.1-0.3) g / mL. The reaction was carried out with constant stirring for 10-12 h. Afterward, the reaction product was centrifuged, the lower layer precipitate was collected and washed to obtain precipitate II. Precipitate II was added to deionized water and ultrasonically dispersed for 30-60 min. The resulting dispersion was centrifuged, and the supernatant was vacuum freeze-dried. The resulting solid product was the two-dimensional titanium carbide material, which was then used for later use.

[0009] Step 2: Preparation of two-dimensional titanium carbide-polyacrylamide nanocomposites

[0010] According to the mass ratio of 1:(5-10):(300-500), the two-dimensional titanium carbide material, polyacrylamide and deionized water obtained in step one were weighed and placed in a reaction vessel. After being fully dissolved, the reaction vessel was sealed and vent holes were reserved. The reaction was carried out under nitrogen atmosphere and continuous stirring for 8-12 hours. Afterward, the reaction product was centrifuged, the lower precipitate was taken and washed multiple times to obtain precipitate III. Precipitate III was dispersed in deionized water, the resulting dispersion was centrifuged, and the supernatant was taken and freeze-dried under vacuum. The resulting solid product is the two-dimensional titanium carbide-polyacrylamide nanocomposite material, which is ready for use.

[0011] Step 3: Preparation of palladium nanoparticles

[0012] Palladium dichloride, sodium dodecyl sulfate, and deionized water were weighed out in a mass ratio of 1:(10-20):1667 and placed in a reaction vessel. The reaction was carried out under ultrasonic dispersion for 30-60 min. Afterward, the reaction product was centrifuged, the lower precipitate was taken out, and it was washed several times to obtain precipitate IV. Precipitate IV was placed in a vacuum drying oven and dried at 80-100°C for 1-3 h to obtain palladium nanoparticles for later use.

[0013] Step 4: Preparation of palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposites

[0014] According to a mass ratio of 1:(5-10), palladium nanoparticles obtained in step three and two-dimensional titanium carbide-polyacrylamide nanocomposite materials obtained in step two were weighed separately. Then, the palladium nanoparticles and two-dimensional titanium carbide-polyacrylamide nanocomposite materials were dispersed in deionized water to obtain metal particle dispersion and carrier dispersion, respectively. Then, the metal particle dispersion was slowly added to the carrier dispersion under continuous stirring and the reaction was carried out for 8-12 h under continuous stirring. After that, the reaction product was centrifuged, the lower layer precipitate was taken out and washed multiple times. Then, it was transferred to a vacuum freeze dryer for vacuum freeze drying to obtain the finished palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material.

[0015] Furthermore, in step one, the mass concentration of the hydrofluoric acid solution is 20-40%; and the ratio of precipitate II to deionized water during the ultrasonic dispersion treatment is (0.1-0.5) g / mL.

[0016] Furthermore, in step two, the polyacrylamide has a relative molecular mass of 80,000.

[0017] Furthermore, in steps one and two, the centrifugation speed is 5000–6500 rpm and the processing time is 10–30 min; in step three, the centrifugation speed is 5000–6500 rpm and the processing time is 30–60 min; in step four, the centrifugation speed is 5000–6500 rpm and the processing time is 15–40 min; and in steps one and two, the centrifugation speed for the dispersion is 3000–5000 rpm and the processing time is 30–60 min.

[0018] Furthermore, in step one, the washing process involves sequentially washing with anhydrous ethanol and deionized water; in step two, the multiple washing process involves washing 2-5 times with a mixed solution of anhydrous ethanol and deionized water at a volume ratio of 1:1, with a centrifugation speed of 5000-6500 rpm and a centrifugation time of 10-30 min for each washing; in steps three and four, the multiple washing process involves washing with anhydrous ethanol.

[0019] Furthermore, in steps one, two, and four, the supernatant or precipitate must be frozen into a solid at -20°C before being subjected to vacuum freeze-drying.

[0020] Furthermore, in steps one and three, the ultrasonic dispersion uses an ultrasonic generator with a power of 300W and a frequency of 40kHz.

[0021] A method for constructing an electrochemical biosensor using palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite materials includes the following steps: dispersing the palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite materials in deionized water to prepare a concentration of 1 mg × mL. -1 The composite material dispersion is prepared by uniformly dropping 5-20 μL of the dispersion onto a pre-treated glassy carbon electrode and allowing it to air dry naturally to obtain an electrochemical biosensor.

[0022] Furthermore, the surface pretreatment method of the glassy carbon electrode is as follows: first, the surface of the glassy carbon electrode is polished with 0.05μm alumina polishing powder, then treated with a 1:1 volume ratio of ethanol and distilled water mixed solution under ultrasonic conditions for 60s, and then dried with nitrogen gas flow to obtain the electrode.

[0023] Application of electrochemical biosensors in dopamine concentration detection.

[0024] The beneficial effects of this invention are:

[0025] 1. This invention discloses a palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material. Using metallic palladium as the active particle and two-dimensional titanium carbide-polyacrylamide as the carrier, it effectively improves the dispersion, catalytic activity, and stability of palladium nanoparticles. Synthesized under a nitrogen atmosphere and freeze-dried in a vacuum freeze dryer, the resulting palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material possesses a layered porous structure. When used in the preparation of an electrochemical biosensor, it exhibits high electrocatalytic activity for dopamine, enabling effective detection of dopamine concentration with a wide linear detection range and a low detection limit. The preparation process itself is simple, with mild reaction conditions, easy process control, and strong environmental friendliness.

[0026] 2. In both steps one and two of the preparation process of the present invention, vacuum freeze-drying is used to dry the nano-two-dimensional titanium carbide material and the two-dimensional titanium carbide-polyacrylamide nanocomposite material. Compared with conventional high-temperature vacuum drying technology, vacuum freeze-drying better preserves the original loose porous layered structure of the nano-two-dimensional titanium carbide and nanocomposite material, avoids damage to their structure by the drying process, and provides a favorable environment for the subsequent loading of active metal palladium particles.

[0027] 3. In step two of the preparation process of the present invention, water-soluble polymer polyacrylamide is used to modify two-dimensional titanium carbide, which enhances the structural stability and flexibility of two-dimensional titanium carbide and lays an important foundation for the development of flexible and foldable biosensors.

[0028] 4. The electrochemical biosensor prepared using the nanocomposite material of this invention, as a palladium-loaded titanium carbide-polyacrylamide nanocomposite modified electrode, exhibits higher electrocatalytic activity and better concentration linearity for dopamine compared to the unloaded palladium titanium carbide-polyacrylamide nanocomposite modified electrode. Measurements show that the linear concentration range for dopamine detection by the palladium-loaded titanium carbide-polyacrylamide nanocomposite modified electrode is (0.5-4.5) × 10⁻⁶. -4 mol / L(R 2 =0.997), the detection limit is (2-4)×10 -6 The linear concentration range for dopamine detection by the titanium carbide-polyacrylamide nanocomposite modified electrode without palladium particles was (1.5-4.0) × 10 mol / L, while the linear concentration range for dopamine detection was (1.5-4.0) × 10 mol / L. -4 mol / L(R 2 =0.990), detection limit is 1.0×10 -5 The concentration of mol / L indicates that the nanocomposite material of the present invention has excellent application prospects in the detection of dopamine concentration. Attached Figure Description

[0029] Figure 1 This is a scanning electron microscope image of the palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material prepared in Example 1 of the present invention.

[0030] Figure 2 X-ray powder diffraction patterns comparing the palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material prepared in Example 1 of this invention with palladium nanoparticles and the two-dimensional titanium carbide-polyacrylamide composite material.

[0031] Figure 3 This is a graph showing the detection data of dopamine by the electrochemical biosensor prepared in Example 1 of the present invention. Detailed Implementation

[0032] The present invention will now be described and illustrated in further detail with reference to the accompanying drawings and embodiments. The embodiments described below are provided to better understand the present invention, but do not limit the scope of the invention. Unless otherwise specified, all experimental procedures were conducted at room temperature and pressure.

[0033] A two-dimensional titanium carbide-polyacrylamide nanocomposite material loaded with palladium, wherein the composite material uses two-dimensional titanium carbide-polyacrylamide as a carrier, and the carrier is loaded with 10-20% by mass of the active component of metallic palladium. The carrier is composed of titanium carbide and polyacrylamide in a mass ratio of 1:(5-10), and the composite material has a porous layered appearance.

[0034] The preparation method of the above-mentioned palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material specifically includes the following steps:

[0035] Step 1: Preparation of two-dimensional titanium carbide materials

[0036] Titanium aluminum carbide powder was slowly added to a 20-40% hydrofluoric acid solution at a ratio of (0.05-0.2) g / mL over 10-20 min. The reaction was carried out at room temperature with continuous stirring for 10-12 h. Afterward, the reaction product was centrifuged at 5000-6500 rpm for 10-30 min. The lower precipitate was collected and washed sequentially with anhydrous ethanol and deionized water to obtain precipitate I. Then, precipitate I was added to a 20-40% tetramethylammonium hydroxide aqueous solution at a ratio of (0.1-0.3) g / mL. The reaction was carried out with continuous stirring for 10-12 h. Afterward, the reaction product was centrifuged at 5000-6500 rpm for 10-30 min. After 30 min, the lower precipitate was removed and washed sequentially with anhydrous ethanol and deionized water to obtain precipitate II. Precipitate II was added to deionized water at a ratio of (0.1-0.5) g / mL and ultrasonically dispersed for 30-60 min using an ultrasonic generator with a power of 300W and a frequency of 40kHz. The resulting dispersion was centrifuged at 3000-5000 rpm for 30-60 min. The supernatant was first frozen into a solid at a temperature of -20°C, and then the solid supernatant was subjected to vacuum freeze-drying. The resulting solid product is the two-dimensional titanium carbide material, which is ready for use.

[0037] Step 2: Preparation of two-dimensional titanium carbide-polyacrylamide nanocomposites

[0038] According to a mass ratio of 1:5:333 to 1:10:500, the two-dimensional titanium carbide material obtained in step one, polyacrylamide with a relative molecular mass of approximately 80,000, and deionized water were weighed and placed in a reaction vessel. After complete dissolution, the reaction vessel was sealed, leaving vent holes. The reaction was carried out under a nitrogen atmosphere and continuous stirring for 8–12 h. Then, the resulting reaction product was centrifuged at 5000–6500 rpm for 10–30 min. The lower precipitate was collected and washed 2–5 times with a 1:1 mixture of anhydrous ethanol and deionized water, with each washing performed at a centrifugation speed of 5000–6500 rpm for 10–30 minutes. Precipitate III was obtained by centrifugation at 3000-5000 rpm for 30-60 minutes. The supernatant was then placed in a refrigerator at -20°C and frozen into a solid. The supernatant was then subjected to vacuum freeze-drying. The resulting solid product is the two-dimensional titanium carbide-polyacrylamide nanocomposite material, which is ready for use.

[0039] Step 3: Preparation of palladium nanoparticles

[0040] Palladium dichloride, sodium dodecyl sulfate, and deionized water were weighed and placed in a reaction vessel at a mass ratio of 1:10 to 20:1667. The mixture was ultrasonically dispersed using an ultrasonic generator with a power of 300W and a frequency of 40kHz for 30 to 60 minutes. The reaction product was then centrifuged at 5000 to 6500 rpm for 30 to 60 minutes. The lower precipitate was collected and washed multiple times with anhydrous ethanol to obtain precipitate IV. Precipitate IV was placed in a vacuum drying oven and dried at 80 to 100°C for 1 to 3 hours to obtain palladium nanoparticles for later use.

[0041] Step 4: Preparation of palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposites

[0042] According to a mass ratio of 1:5 to 1:10, palladium nanoparticles obtained in step three and two-dimensional titanium carbide-polyacrylamide nanocomposite materials obtained in step two were weighed separately. Then, the palladium nanoparticles and two-dimensional titanium carbide-polyacrylamide nanocomposite materials were dispersed in deionized water to obtain a metal particle dispersion and a carrier dispersion, respectively. Then, the metal particle dispersion was slowly added to the carrier dispersion under continuous stirring, and the reaction was carried out for 8 to 12 hours under continuous stirring. Afterward, the reaction product was centrifuged at 5000 to 6500 rpm for 15 to 40 minutes, the lower layer precipitate was taken out, and it was washed multiple times with anhydrous ethanol. Then, the precipitate was first frozen into a solid in a refrigerator at -20°C, and then the solid precipitate was transferred to a vacuum freeze dryer for vacuum freeze drying to obtain the finished palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material.

[0043] A method for constructing an electrochemical biosensor using palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite materials includes the following steps:

[0044] 1. First, the surface of the glassy carbon electrode is polished with 0.05μm alumina polishing powder. Then, it is cleaned with a 1:1 volume ratio of ethanol and distilled water under ultrasonic conditions for 60 seconds. After that, it is dried with nitrogen gas to obtain the pretreated glassy carbon electrode for later use.

[0045] 2. Disperse the palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material in deionized water to prepare a concentration of 1 mg × mL. -1 The composite material dispersion was prepared, and then 5-20 μL of the composite material dispersion was uniformly drop-coated onto a pre-treated glassy carbon electrode. After natural drying, an electrochemical biosensor was obtained, which is a palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite modified electrode.

[0046] Application of electrochemical biosensors in dopamine concentration detection.

[0047] Example 1

[0048] The preparation method of palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material in this embodiment mainly includes the following steps:

[0049] Step 1: Preparation of two-dimensional titanium carbide nanomaterials:

[0050] Weigh 6 g of titanium aluminum carbide powder and slowly add it to 60 mL of 25% hydrofluoric acid solution over 10 min. React at room temperature with magnetic stirring for 11 h. Centrifuge the resulting mixture at 5000 rpm for 10 min and collect the precipitate. Wash the precipitate sequentially with anhydrous ethanol and deionized water, and centrifuge to collect the precipitate. Add the precipitate to 30 mL of 25% tetramethylammonium hydroxide aqueous solution and stir for 10 h. Centrifuge the resulting reaction product at 5500 rpm for 20 min and collect the lower layer precipitate. Wash the precipitate sequentially with anhydrous ethanol and deionized water, and then disperse the precipitate in 65 mL of water. In mL of deionized water, the dispersion was ultrasonically dispersed for 40 min using an ultrasonic generator with a power of 300 W and a frequency of 40 kHz. Finally, the dispersion was centrifuged at 3500 rpm for 35 min. The supernatant was then placed in a refrigerator at -20°C to freeze into a solid. The supernatant was then subjected to vacuum freeze-drying. The resulting solid product was the MXene material.

[0051] Step 2: Preparation of two-dimensional titanium carbide-polyacrylamide nanocomposites:

[0052] 0.300 g of titanium carbide MXene powder and 1.5 g of polyacrylamide with a relative molecular mass of approximately 80,000 were weighed into a 250 mL beaker, dissolved in 100 mL of deionized water, sealed with a few pores, and stirred under a nitrogen atmosphere for 10 h. The mixture was then centrifuged at 5000–6500 rpm for 10 min, and the precipitate was collected. The precipitate was washed twice with a 1:1 mixture of anhydrous ethanol and deionized water, with each washing performed at 6000 rpm for 20 min. The precipitate was collected and dispersed in 30 mL of deionized water. The dispersion was centrifuged at 3500 rpm for 30 min. The supernatant was first frozen into a solid at -20°C, and then the supernatant was freeze-dried under vacuum. The resulting solid product was the two-dimensional titanium carbide-polyacrylamide nanocomposite material.

[0053] Step 3: Preparation of palladium nanoparticles:

[0054] Weigh 0.060 g of palladium dichloride and 0.975 g of sodium dodecyl sulfate into a 200 mL beaker, add 100 mL of deionized water, and use an ultrasonic generator with a power of 300 W and a frequency of 40 kHz to ultrasonically disperse them for 60 min. Then, centrifuge the reaction mixture at 6000 rpm for 30 min and collect the precipitate. Wash the precipitate three times with ethanol and place it in a vacuum drying oven to dry at 80°C for 3 h to obtain palladium nanoparticles.

[0055] Step 4: Preparation of palladium-loaded titanium carbide-polyacrylamide nanocomposite materials:

[0056] Weigh 10 mg of titanium carbide-polyacrylamide, dissolve it in 10 mL of deionized water, and ultrasonically disperse it for 10 min. Under stirring, slowly add palladium dispersion (weigh 2 mg of palladium nanoparticles and disperse them in 5 mL of deionized water) to the titanium carbide-polyacrylamide dispersion, and continue stirring for 8 h. Then, centrifuge at 6000 rpm for 15 min and collect the precipitate. Wash the precipitate three times with anhydrous ethanol. Then, freeze the precipitate in a refrigerator at -20°C until it becomes solid. Transfer the solid precipitate to a vacuum freeze dryer for vacuum freeze drying to obtain the finished palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material.

[0057] Step 5: Fabrication of the electrochemical biosensor:

[0058] 1. First, the surface of the glassy carbon electrode is polished with 0.05μm alumina polishing powder. Then, it is cleaned with a 1:1 volume ratio of ethanol and distilled water under ultrasonic conditions for 60 seconds. After that, it is dried with nitrogen gas to obtain the pretreated glassy carbon electrode for later use.

[0059] 2. Disperse the palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material in deionized water to prepare a concentration of 1 mg × mL. -1 The composite material dispersion was prepared, and then 10 μL of the composite material dispersion was uniformly drop-coated onto a pre-treated glassy carbon electrode. After natural drying, an electrochemical biosensor capable of electrochemically testing dopamine activity was obtained. This electrochemical biosensor is a palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite modified electrode.

[0060] Example 2

[0061] The preparation method of palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material in this embodiment mainly includes the following steps:

[0062] Step 1: Preparation of two-dimensional titanium carbide nanomaterials:

[0063] Weigh 12 g of titanium aluminum carbide powder and slowly add it to 60 mL of 40% hydrofluoric acid solution over 20 min. React at room temperature with magnetic stirring for 12 h. Centrifuge the resulting mixture at 6000 rpm for 30 min and collect the precipitate. Wash the precipitate sequentially with anhydrous ethanol and deionized water, and centrifuge to collect the precipitate. Add the precipitate to 40 mL of 20% tetramethylammonium hydroxide aqueous solution and stir for 12 h. Centrifuge the resulting reaction product at 6500 rpm for 10 min and collect the lower layer precipitate. Wash the precipitate sequentially with anhydrous ethanol and deionized water, and then disperse the precipitate on an 80 mL agar. In mL of deionized water, the dispersion was ultrasonically dispersed for 30 min using an ultrasonic generator with a power of 300 W and a frequency of 40 kHz. Finally, the dispersion was centrifuged at 5000 rpm for 30 min. The supernatant was then placed in a refrigerator at -20°C to freeze into a solid. The supernatant was then subjected to vacuum freeze-drying. The resulting solid product was the MXene material.

[0064] Step 2: Preparation of two-dimensional titanium carbide-polyacrylamide nanocomposite material: Weigh 0.2 g of titanium carbide MXene powder and 2.0 g of polyacrylamide with a relative molecular mass of approximately 80,000 into a 250 mL beaker, add 100 mL of deionized water to dissolve, seal the beaker and leave a few pores, stir and react under a nitrogen atmosphere for 12 h, centrifuge at 6000 rpm for 20 min, and collect the precipitate; wash it 5 times with a 1:1 volume ratio of anhydrous ethanol and deionized water, centrifuge at 6500 rpm for 10 min each time, collect the precipitate and disperse it in 30 mL of deionized water, centrifuge the resulting dispersion at 3000 rpm for 60 min, take the supernatant and freeze it into a solid at -20°C, then freeze-dry the solid supernatant under vacuum, and the resulting solid product is the two-dimensional titanium carbide-polyacrylamide nanocomposite material.

[0065] Step 3: Preparation of palladium nanoparticles:

[0066] Weigh 0.060 g of palladium dichloride and 1.2 g of sodium dodecyl sulfate into a 200 mL beaker, add 100 mL of deionized water, and use an ultrasonic generator with a power of 300 W and a frequency of 40 kHz to ultrasonically disperse the mixture for 30 min. Then, centrifuge the reaction mixture at 6500 rpm for 40 min and collect the precipitate. Wash the precipitate three times with ethanol and place it in a vacuum drying oven to dry at 85°C for 2 h to obtain palladium nanoparticles.

[0067] Step 4: Preparation of palladium-loaded titanium carbide-polyacrylamide nanocomposite materials:

[0068] Weigh 20 mg of titanium carbide-polyacrylamide, dissolve it in 10 mL of deionized water, and ultrasonically disperse it for 10 min. Under stirring, slowly add palladium dispersion (weigh 2 mg of palladium nanoparticles, dispersed in 5 mL of deionized water) to the titanium carbide-polyacrylamide dispersion, and continue stirring for 12 h. Then, centrifuge at 6500 rpm for 30 min and collect the precipitate. Wash the precipitate three times with anhydrous ethanol. Then, freeze the precipitate in a refrigerator at -20°C until it becomes solid. Transfer the solid precipitate to a vacuum freeze dryer for vacuum freeze drying to obtain the finished palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material.

[0069] Step 5: Fabrication of the electrochemical biosensor:

[0070] 1. First, the surface of the glassy carbon electrode is polished with 0.05μm alumina polishing powder. Then, it is cleaned with a 1:1 volume ratio of ethanol and distilled water under ultrasonic conditions for 60 seconds. After that, it is dried with nitrogen gas to obtain the pretreated glassy carbon electrode for later use.

[0071] 2. Disperse the palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material in deionized water to prepare a concentration of 1 mg × mL. -1 The composite material dispersion was prepared, and then 20 μL of the composite material dispersion was uniformly drop-coated onto a pre-treated glassy carbon electrode. After natural drying, an electrochemical biosensor capable of electrochemically testing dopamine activity was obtained. This electrochemical biosensor is a palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite modified electrode.

[0072] Example 3

[0073] The preparation method of palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material in this embodiment mainly includes the following steps:

[0074] Step 1: Preparation of two-dimensional titanium carbide nanomaterials:

[0075] 3 g of titanium aluminum carbide powder was slowly added to 60 mL of 20% hydrofluoric acid solution over 10 min. The mixture was reacted at room temperature with magnetic stirring for 12 h. The resulting mixture was centrifuged at 6500 rpm for 15 min, and the precipitate was collected. The precipitate was washed sequentially with anhydrous ethanol and deionized water, and centrifuged to collect the precipitate. The precipitate was added to 30 mL of 40% tetramethylammonium hydroxide aqueous solution, and the mixture was stirred for 11 h. The reaction product was centrifuged at 5000 rpm for 30 min, and the lower precipitate was collected. The precipitate was washed sequentially with anhydrous ethanol and deionized water, and then dispersed in 65 mL of deionized water. The precipitate was ultrasonically dispersed using a 300 W, 40 kHz ultrasonic generator for 60 minutes. The dispersion was centrifuged at 3000 rpm for 60 minutes. The supernatant was then frozen into a solid at -20°C. The supernatant was then subjected to vacuum freeze-drying. The resulting solid product was MXene material.

[0076] Step 2: Preparation of two-dimensional titanium carbide-polyacrylamide nanocomposite material: Weigh 0.3 g of titanium carbide MXene powder and 2.1 g of polyacrylamide with a relative molecular mass of approximately 80,000 into a 250 mL beaker, add 100 mL of deionized water to dissolve, seal the beaker and leave a few pores, stir and react for 8 h under a nitrogen atmosphere, centrifuge at 6500 rpm for 30 min, and collect the precipitate; wash it twice with a 1:1 volume ratio of anhydrous ethanol and deionized water, centrifuging at 5000 rpm for 30 min each time, collect the precipitate and disperse it in 30 mL of deionized water, centrifuge the resulting dispersion at 5000 rpm for 40 min, take the supernatant and freeze it into a solid at -20°C, then freeze-dry the solid supernatant under vacuum, and the resulting solid product is the two-dimensional titanium carbide-polyacrylamide nanocomposite material.

[0077] Step 3: Preparation of palladium nanoparticles:

[0078] Weigh 0.060 g of palladium dichloride and 0.60 g of sodium dodecyl sulfate into a 200 mL beaker, add 100 mL of deionized water, and use an ultrasonic generator with a power of 300 W and a frequency of 40 kHz to ultrasonically disperse the mixture for 40 min. Then, centrifuge the reaction mixture at 5000 rpm for 60 min and collect the precipitate. Wash the precipitate four times with ethanol and place it in a vacuum drying oven to dry at 100°C for 1 h to obtain palladium nanoparticles.

[0079] Step 4: Preparation of palladium-loaded titanium carbide-polyacrylamide nanocomposite materials:

[0080] Weigh 14 mg of titanium carbide-polyacrylamide, dissolve it in 10 mL of deionized water, and ultrasonically disperse it for 10 min. Under stirring, slowly add palladium dispersion (weigh 2 mg of palladium nanoparticles, dispersed in 5 mL of deionized water) to the titanium carbide-polyacrylamide dispersion, and continue stirring for 10 h. Then, centrifuge at 5000 rpm for 40 min and collect the precipitate. Wash the precipitate three times with anhydrous ethanol. Then, freeze the precipitate in a refrigerator at -20°C until it becomes solid. Transfer the solid precipitate to a vacuum freeze dryer for vacuum freeze drying to obtain the finished palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material.

[0081] Step 5: Fabrication of the electrochemical biosensor:

[0082] 1. First, the surface of the glassy carbon electrode is polished with 0.05μm alumina polishing powder. Then, it is cleaned with a 1:1 volume ratio of ethanol and distilled water under ultrasonic conditions for 60 seconds. After that, it is dried with nitrogen gas to obtain the pretreated glassy carbon electrode for later use.

[0083] 2. Disperse the palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material in deionized water to prepare a concentration of 1 mg × mL. -1 The composite material dispersion was prepared, and then 5 μL of the composite material dispersion was uniformly drop-coated onto a pre-treated glassy carbon electrode. After natural drying, an electrochemical biosensor capable of electrochemically testing dopamine activity was obtained. This electrochemical biosensor is a palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite modified electrode.

[0084] Experimental verification

[0085] The morphology, internal structure, and electrocatalytic performance of palladium-supported titanium carbide-polyacrylamide nanocomposites prepared in Examples 1-3 of the present invention were investigated. The specific experimental methods and results are as follows:

[0086] Experimental methods: The morphology of the palladium-loaded titanium carbide-polyacrylamide nanocomposite material prepared in Example 1 of this invention was characterized using scanning electron microscopy (experimental results are shown in...). Figure 1 The internal structure of the palladium-loaded titanium carbide-polyacrylamide nanocomposite material prepared in Example 1 of this invention was analyzed using X-ray diffraction (experimental results are shown in […]). Figure 2 ).

[0087] Dopamine was detected using an electrochemical biosensor constructed based on palladium-loaded titanium carbide-polyacrylamide nanocomposite material in a three-electrode electrochemical system.

[0088] The palladium-loaded titanium carbide-polyacrylamide nanocomposite modified electrode prepared in Example 1 was used as the working electrode, silver-silver chloride as the reference electrode, and platinum wire as the auxiliary electrode. Under a nitrogen atmosphere, the three-electrode system was inserted into an electrolytic cell containing 10 mL of buffer solution with a pH of 7.00. Differential pulse voltammetry was used to test the dopamine solutions of different concentrations. The experimental results are shown below. Figure 3 .

[0089] from Figure 1 As can be clearly seen, the palladium-loaded titanium carbide-polyacrylamide nanocomposite obtained in Example 1 has a loose and porous layered structure, with palladium particles uniformly dispersed on the surface of the titanium carbide-polyacrylamide nanocomposite carrier.

[0090] Figure 2 The images show the X-ray diffraction patterns of the palladium-loaded titanium carbide-polyacrylamide nanocomposite (Pd-MXene-PAM), the palladium-supported titanium carbide-polyacrylamide carrier (MXene-PAM), and a standard card for palladium (Pd). Compared to the titanium carbide-polyacrylamide carrier (Ti3C2MXene-PAM) and the palladium standard card, the palladium-loaded titanium carbide-polyacrylamide nanocomposite (Pd-Ti3C2MXene-PAM) exhibits characteristic peaks of palladium at 40°, 46°, and 49°, indicating that palladium particles were successfully loaded onto the surface of the Ti3C2MXene-PAM composite carrier.

[0091] Figure 3 Differential pulse voltammetry plots of dopamine at different concentrations are presented for an electrochemical biosensor based on palladium-loaded titanium carbide-polyacrylamide nanocomposite materials. The plots show that the oxidation current of dopamine increases continuously with increasing dopamine concentration. A strong linear relationship exists between the oxidation peak current and its concentration, with a linear range of (0.5–4.5) × 10⁻⁶. -4 mol / L(R 2 =0.997), detection limit is 2.0×10 -6 mol / L.

[0092] Testing revealed that the electrochemical biosensor prepared in Example 2 of this invention also exhibits high electrocatalytic activity for dopamine, with a linear concentration range of (1.0-4.5) × 10⁻⁶ for dopamine detection. -4 mol / L(R 2 =0.995), detection limit is 4.0×10 -6 mol / L.

[0093] The electrochemical biosensor prepared in Example 3 of this invention exhibits a linear concentration range of (1.0-4.0) × 10⁻⁶ for dopamine detection. -4 mol / L(R 2 =0.998), detection limit is 3.0×10 -6 mol / L.

Claims

1. A two-dimensional titanium carbide-polyacrylamide nanocomposite material supported on palladium, characterized in that: The composite material uses two-dimensional titanium carbide-polyacrylamide as a carrier, and the carrier is loaded with 10-20% of its active component, palladium metal. The carrier is composed of titanium carbide and polyacrylamide in a mass ratio of 1:(5-10). The composite material has a porous layered appearance. A method for preparing a palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material includes the following steps: Step 1: Preparation of two-dimensional titanium carbide materials Titanium aluminum carbide powder was slowly added to hydrofluoric acid solution at a ratio of (0.05-0.2) g / mL over 10-20 min. The reaction was carried out at room temperature with constant stirring for 10-12 h. Afterward, the reaction product was centrifuged, the lower layer precipitate was collected and washed to obtain precipitate I. Then, precipitate I was added to tetramethylammonium hydroxide aqueous solution with a mass concentration of 20-40% at a ratio of (0.1-0.3) g / mL. The reaction was carried out with constant stirring for 10-12 h. Afterward, the reaction product was centrifuged, the lower layer precipitate was collected and washed to obtain precipitate II. Precipitate II was added to deionized water and ultrasonically dispersed for 30-60 min. The resulting dispersion was centrifuged, and the supernatant was vacuum freeze-dried. The resulting solid product was the two-dimensional titanium carbide material, which was then used for later use. Step 2: Preparation of two-dimensional titanium carbide-polyacrylamide nanocomposites According to a mass ratio of 1:(5-10):(300-500), the two-dimensional titanium carbide material, polyacrylamide, and deionized water obtained in step one were weighed and placed in a reaction vessel. After being fully dissolved, the reaction vessel was sealed with vent holes. The reaction was carried out under a nitrogen atmosphere and continuous stirring for 8-12 hours. Afterward, the reaction product was centrifuged, the lower precipitate was taken, and it was washed multiple times to obtain precipitate III. Precipitate III was dispersed in deionized water, the resulting dispersion was centrifuged, and the supernatant was taken and freeze-dried under vacuum. The resulting solid product is the two-dimensional titanium carbide-polyacrylamide nanocomposite material, which is ready for use. Step 3: Preparation of palladium nanoparticles Palladium dichloride, sodium dodecyl sulfate, and deionized water were weighed out in a mass ratio of 1:(10-20):1667 and placed in a reaction vessel. The reaction was carried out under ultrasonic dispersion for 30-60 min. Afterward, the reaction product was centrifuged, the lower precipitate was taken out, and it was washed several times to obtain precipitate IV. Precipitate IV was placed in a vacuum drying oven and dried at 80-100℃ for 1-3 h to obtain palladium nanoparticles for later use. Step 4: Preparation of palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposites According to a mass ratio of 1:(5-10), palladium nanoparticles obtained in step three and two-dimensional titanium carbide-polyacrylamide nanocomposite materials obtained in step two were weighed separately. Then, the palladium nanoparticles and two-dimensional titanium carbide-polyacrylamide nanocomposite materials were dispersed in deionized water to obtain metal particle dispersion and carrier dispersion, respectively. Then, the metal particle dispersion was slowly added to the carrier dispersion under continuous stirring and the reaction was carried out for 8-12 h under continuous stirring. After that, the reaction product was centrifuged, the lower layer precipitate was taken out and washed multiple times. Then, it was transferred to a vacuum freeze dryer for vacuum freeze drying to obtain the finished palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material.

2. The palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material as described in claim 1, characterized in that: In step one, the mass concentration of the hydrofluoric acid solution is 20-40%; the ratio of precipitate II to deionized water during the ultrasonic dispersion treatment is (0.1-0.5) g / mL.

3. The palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material as described in claim 1, characterized in that: In step two, the polyacrylamide has a relative molecular mass of 80,000.

4. The palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material as described in claim 2, characterized in that: In steps one and two, the centrifugation speed is 5000–6500 rpm and the processing time is 10–30 min; in step three, the centrifugation speed is 5000–6500 rpm and the processing time is 30–60 min; in step four, the centrifugation speed is 5000–6500 rpm and the processing time is 15–40 min; in steps one and two, the centrifugation speed of the dispersion is 3000–5000 rpm and the processing time is 30–60 min.

5. The palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material as described in claim 2, characterized in that: In step one, the washing process involves sequentially washing with anhydrous ethanol and deionized water. In step two, the multiple washing process involves washing 2-5 times with a 1:1 volume ratio of anhydrous ethanol and deionized water, with a centrifugation speed of 5000-6500 rpm and a centrifugation time of 10-30 min for each wash. In steps three and four, the multiple washing process involves washing with anhydrous ethanol.

6. The palladium-supported two-dimensional titanium carbide-polyacrylamide nanocomposite material as described in claim 2, characterized in that: In steps one, two, and four, the supernatant or precipitate must be frozen into a solid at -20°C before being subjected to vacuum freeze-drying.

7. The palladium-supported two-dimensional titanium carbide-polyacrylamide nanocomposite material as described in claim 2, characterized in that: In steps one and three, the ultrasonic dispersion uses an ultrasonic generator with a power of 300W and a frequency of 40kHz.

8. A method for constructing an electrochemical biosensor using a palladium-loaded two-dimensional titanium carbide-polyacrylamide nanocomposite material as described in claim 1, characterized in that, Includes the following steps: Two-dimensional titanium carbide-polyacrylamide nanocomposite material loaded with palladium was dispersed in deionized water to prepare a concentration of 1 mg × mL. -1 The composite material dispersion was uniformly drop-coated onto a pre-treated glassy carbon electrode and allowed to air dry to obtain an electrochemical biosensor.

9. The application of the electrochemical biosensor according to claim 8 in the detection of dopamine concentration.

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