Nano-carbon loaded palladium-cobalt bimetallic nano-material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of catalytic antibiosis of nano-materials, and particularly relates to a nano-carbon-loaded palladium-cobalt bimetallic nano-material and a preparation method and application thereof. The nano-material is prepared through a deposition-precipitation method, palladium and cobalt are dispersed on the surface of nano-diamond and graphene in a bimetallic form, the palladium-cobalt bimetallic nano-material has synergistic oxidase-like catalytic activity, and compared with palladium and iron monometal nano-materials, the palladium-cobalt bimetallic nano-material has obviously improved enzyme-like catalytic activity; the antibacterial performance is excellent. According to the prepared palladium-cobalt bimetallic nano material, the preparation process is green and simple, the reaction process is easy to control, the reaction condition of the prepared palladium-cobalt bimetallic nano material is simple, oxygen can be catalyzed to generate active oxygen only under the acidic condition and the room temperature, and bacteria are efficiently killed. The palladium-cobalt bimetallic nano material shows excellent catalytic antibacterial performance, shows a wide application prospect in the antibacterial field, and is expected to become a new generation of antibacterial material.

Description

Technical Field

[0001] The present invention belongs to the technical field of nano-material catalytic antibacterial, and particularly relates to a nano-carbon supported palladium-cobalt bimetallic nano-material, a preparation method thereof, and an application as an antibacterial agent for catalytic antibacterial. Background Art

[0002] In recent years, the types of bacteria have gradually increased, and the abuse of antibiotics has led to the emergence of bacterial drug resistance, which seriously threatens human health and life. To address this threat, the development of new antibacterial agents is urgent. Due to the unique properties of nanozymes as nano-materials and their catalytic functions similar to natural enzymes, they have attracted extensive attention. Nanozymes can efficiently catalyze the decomposition of oxygen or hydrogen peroxide to generate highly oxidative reactive oxygen species, which cause oxidative stress when acting on bacteria, damage the bacterial structure and internal metabolism, and cause great damage, thereby leading to bacterial death.

[0003] Previously, it has been confirmed that palladium-based nano-materials have peroxidase-like catalytic properties. However, due to the high cost of palladium nano-materials, their large-scale application is limited. Therefore, research on introducing other materials to improve the catalytic performance of nanozymes has been continuously proposed. As a new type of antibacterial agent, bimetallic nano-composites have potential application value in the fields of biomedicine and others. Summary of the Invention

[0004] The object of the present invention is to develop a nano-carbon supported palladium-cobalt bimetallic nano-material with high catalytic antibacterial performance with bimetallic synergistic effect, using nano-diamond@ graphene as a carrier to load palladium-cobalt bimetallic. This nano-material is applied to the field of catalytic antibacterial, has peroxidase-like catalytic activity, can catalyze the decomposition of oxygen to generate highly oxidative reactive oxygen species, and thus efficiently kill bacteria.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A nano-carbon supported palladium-cobalt bimetallic nano-material uses nano-diamond@ graphene as a carrier and palladium-cobalt bimetallic as an active center.

[0007] Preferably, for the above-mentioned nano-carbon supported palladium-cobalt bimetallic nano-material, by mass percentage, the loading amount of palladium is 0.5%, and the loading amount of cobalt is 0.5%.

[0008] The preparation method of the above-mentioned nano-carbon supported palladium-cobalt bimetallic nano-material includes the following steps:

[0009] 1) Disperse the nanodiamond@graphene material in deionized water and ultrasonicate to obtain a suspension. Adjust the pH of the suspension to 10. Under magnetic stirring, slowly drip a mixed solution of palladium salt and cobalt salt with a pH of 4 into the suspension at a constant rate. Stir at 100 °C for 1 hour, then perform suction filtration, washing, and drying to obtain a precursor.

[0010] 2) Reduce the obtained precursor under H 2 conditions at 500 °C for 2 hours to obtain the nanocarbon-supported palladium-cobalt bimetallic nanomaterial.

[0011] Furthermore, in the above preparation method, in step 1), the pH is adjusted using a sodium carbonate solution.

[0012] Furthermore, in the above preparation method, in step 1), the palladium salt is palladium nitrate.

[0013] Furthermore, in the above preparation method, in step 1), the cobalt salt is cobalt nitrate.

[0014] Use of the nanocarbon-supported palladium-cobalt bimetallic nanomaterial as described in any one of the above as an antibacterial agent in antibacterial applications.

[0015] Furthermore, in the above application, the method is as follows: Add the nanocarbon-supported palladium-cobalt bimetallic nanomaterial to the bacterial suspension.

[0016] Furthermore, in the above application, the bacteria are bacteria.

[0017] Even further, in the above application, the bacteria are Escherichia coli.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. In the present invention, nanodiamond@graphene is used as a carrier to load palladium-cobalt bimetals, and this material has excellent peroxidase-like catalytic activity. When used as an antibacterial agent in the antibacterial field, this nanomaterial has excellent antibacterial performance, and the antibacterial rate can reach 99.99%.

[0020] 2. In the present invention, defect-rich nanodiamond@graphene is used as a carrier to load palladium-cobalt bimetals. The defect-rich nanocarbon carrier structure can effectively stabilize the metal through strong metal-carrier interactions, improving the stability of the catalyst.

[0021] 3. In the present invention, nanocarbon is used as a carrier to load palladium-cobalt bimetals as the active center. The palladium-cobalt bimetals have a synergistic catalytic effect, with higher catalytic activity compared to single palladium and cobalt metals, effectively reducing costs.

[0022] 4. The present invention uses nano-carbon as a carrier to load a palladium-cobalt bimetallic nanomaterial, which is prepared by a simple and green deposition-precipitation method and is suitable for large-scale industrial production.

[0023] 5. The present invention uses the nano-carbon supported palladium-cobalt bimetallic nanomaterial as an antibacterial agent. During the antibacterial process, only by catalyzing the decomposition of oxygen to generate strongly oxidizing hydroxyl radicals can bacteria be effectively killed, which is green and efficient.

[0024] 6. The present invention uses nano-carbon as a carrier to load a palladium-cobalt bimetallic nanomaterial, which has great development potential in the fields of biomedicine and antibacterial.

[0025] In summary, for the nano-carbon supported palladium-cobalt bimetallic nanomaterial prepared by the present invention, the synergistic effect of the bimetals significantly improves the enzyme-like catalytic activity of palladium. Compared with palladium and cobalt single-metal nanomaterials, it has higher enzyme-like catalytic activity, which can efficiently catalyze the decomposition of oxygen to generate strongly oxidizing hydroxyl radicals and then completely kill bacteria. The preparation process of the present invention is simple, the reaction is green and efficient, and it has broad application prospects in the field of biomedicine. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the transmission electron microscope characterization diagram (TEM) of the nano-carbon supported palladium-cobalt bimetallic nanomaterial PdCo / ND@G, where A: 20 nm; B: 10 nm.

[0027] Figure 2 It is the related X-ray diffraction diagram (XRD) of Co / ND@G, Pd / ND@G and PdCo / ND@G.

[0028] Figure 3 It is the Raman characterization diagram (Raman) of Co / ND@G, Pd / ND@G and PdCo / ND@G.

[0029] Figure 4 It is the TMB oxidation experiment diagram of Co / ND@G, Pd / ND@G and PdCo / ND@G.

[0030] Figure 5 It is the related antibacterial effect diagram of Co / ND@G, Pd / ND@G and PdCo / ND@G, where A: blank; B: antibacterial effect diagram of Co / ND@G; C: antibacterial effect diagram of Pd / ND@G; D: antibacterial effect diagram of PdCo / ND@G.

[0031] Figure 6 It is the bar chart of the antibacterial rate of Co / ND@G, Pd / ND@G and PdCo / ND@G. DETAILED DESCRIPTION OF THE INVENTION

[0032] To better understand the technical solution of the present invention, specific embodiments are used for further detailed description, but the solution is not limited thereto.

[0033] Example 1 Palladium-cobalt bimetallic nanomaterial supported on nanocarbon (PdCo / ND@G)

[0034] (I) The preparation method includes the following steps:

[0035] 1) Prepare the nanomaterial by the deposition-precipitation method: First, take a round-bottom flask, add 200 mg of nanodiamond@graphene material (ND@G) and 30 mL of deionized water, and ultrasonically disperse the carrier evenly for 30 min. Use 0.25 mol / L sodium carbonate solution to adjust the pH value of the system to 10 to obtain an ND@G suspension. Take appropriate amounts of cobalt nitrate and palladium nitrate solutions (with the loading amounts of palladium and cobalt both being 0.5 wt%) and mix them in a centrifuge tube, add deionized water to 4 mL, and use 0.25 mol / L sodium carbonate to adjust the pH value of the aqueous solution to 4 to obtain a mixed aqueous solution of palladium nitrate and cobalt nitrate. Under magnetic stirring, dropwise add the mixed aqueous solution of palladium nitrate and cobalt nitrate to the ND@G suspension, and keep stirring at 100 °C for 1 hour. Finally, naturally cool the reaction solution to room temperature, filter, wash, and dry it to obtain a precursor. Reduce the precursor in an H 2 atmosphere at 500 °C for 2 hours to obtain the palladium-cobalt bimetallic nanomaterial supported on nanocarbon, denoted as PdCo / ND@G. The mass percentages of palladium and cobalt are both 0.5%.

[0036] 2) Similarly, according to the method in step 1), only add palladium nitrate or cobalt nitrate to separately prepare the cobalt monometallic nanomaterial supported on nanocarbon and the palladium monometallic nanomaterial supported on nanocarbon, denoted as Co / ND@G and Pd / ND@G.

[0037] (II) Detection

[0038] Figure 1 is the TEM image of PdCo / ND@G. It can be seen that the PdCo bimetal is evenly dispersed on the carrier in the form of bimetallic small particles.

[0039] Figure 2 are the XRD characterization diagrams of Co / ND@G, Pd / ND@G, and PdCo / ND@G. By Figure 2 it can be seen that no characteristic diffraction peaks of palladium and cobalt appear in the XRD pattern, indicating that the particle sizes of the palladium-cobalt metals are extremely small.

[0040] Figure 3 are the Raman characterization diagrams of Co / ND@G, Pd / ND@G, and PdCo / ND@G. By Figure 3 it can be seen that the structure of the carrier is not changed after the nanodiamond@graphene is loaded with the palladium-cobalt bimetal, and the material structure is complete.

[0041] Study on the Peroxidase-like Activity of Palladium-Cobalt Bimetallic Nanomaterials PdCo / ND@G Supported on Nanocarbon

[0042] The peroxidase-like activities of monometallic Co / ND@G, Pd / ND@G, and bimetallic PdCo / ND@G nanomaterials were investigated through TMB (3,3',5,5'-tetramethylbenzidine) experiments.

[0043] Method: Add 0.5 mL of the nanomaterial solution, 3 mL of the TMB solution, and 0.5 mL of sodium acetate - acetic acid buffer (100 mM, pH = 4.5) into centrifuge tubes respectively. The catalytic oxidation ability of Co / ND@G, Pd / ND@G, and PdCo / ND@G towards TMB was explored by detecting the change in ultraviolet absorbance at 652 nm of the oxidized oxTMB, and then the peroxidase-like catalytic activities of different nanomaterials were calculated.

[0044] Figure 4 Figure for the TMB experiments of Co / ND@G, Pd / ND@G, and PdCo / ND@G nanomaterials. Through Figure 4 Typical Michaelis-Menten curves of different nanomaterials can be seen, and it can be observed that compared with monometallic Co / ND@G and Pd / ND@G nanomaterials, the bimetallic PdCo / ND@G nanomaterial has the most excellent peroxidase-like activity.

[0045] Example 3 Application of Palladium-Cobalt Bimetallic Nanomaterials PdCo / ND@G Supported on Nanocarbon in Antibacterial

[0046] The antibacterial experiment includes the following steps:

[0047] 1) Preparation of LB medium: Take two 250 mL conical flasks and add appropriate amounts of tryptone, yeast extract powder, and sodium chloride respectively. Add appropriate amount of nutrient agar into another conical flask, pour in deionized water to dissolve it evenly, adjust the pH of the mixture to between 7.2 - 7.4 with 4 mol / L sodium hydroxide, and perform sterilization treatment using an autoclave. After cooling to room temperature, LB liquid medium and LB solid medium are obtained.

[0048] 2) In the workbench sterilized by ultraviolet light, use an inoculation loop burned by an alcohol lamp to streak Escherichia coli (ATCC25922) in three lines on a culture dish, and cultivate the bacteria using a constant temperature biochemical incubator. Take a 10 mL conical flask and add liquid medium, dip a single colony from the third bacterial line on the culture dish into the liquid medium using an inoculation loop, and place the conical flask in a constant temperature shaker and shake and incubate for 10 hours to obtain a bacterial suspension.

[0049] 3) Take 5 mL of the bacterial suspension in a centrifuge tube, wash the bacterial suspension by centrifugation twice with a centrifuge, and then gradually dilute the bacterial solution with a sodium acetate (NaAc-HAc) buffer solution to finally obtain a bacterial solution with a concentration of 10 4 cfu·mL -1 .

[0050] 4) Weigh appropriate amounts of Co / ND@G, Pd / ND@G, and PdCo / ND@G nanomaterials into centrifuge tubes, add 4.5 mL of NaAc-HAc and ultrasonically disperse them evenly to make the concentration of the nanomaterials 0.05 mg / mL. Then, add 0.5 mL of the bacterial suspension with a concentration of 10 4 cfu·mL -1 to each tube, shake well, react in a constant temperature oscillator for 20 min, take 100 μL of the material solution and spread it on a culture dish, place the culture dish in a constant temperature incubator at 37 °C for 12 h, observe the colony growth, and at the same time count and calculate the antibacterial rate.

[0051] Figure 5 Figure [Figure number] is the antibacterial effect diagram of Co / ND@G, Pd / ND@G, and PdCo / ND@G nanomaterials. In the figure, A is the blank control; B is the antibacterial effect diagram of Co / ND@G; C is the antibacterial effect diagram of Pd / ND@G; D is the antibacterial effect diagram of PdCo / ND@G. It can be observed that compared with the single-metal Co / ND@G and Pd / ND@G nanomaterials, the bimetallic PdCo / ND@G nanomaterial has the best antibacterial performance, and its antibacterial rate is as high as 99.8%. This fully demonstrates that the synthesized palladium-cobalt bimetallic nanomaterial PdCo / ND@G supported on nanocarbon of the present invention has excellent antibacterial performance and great application potential in the field of catalytic antibacterial. Figure 6 ​

Claims

1. A nanocarbon-supported palladium-cobalt bimetallic nanomaterial, characterized in that: The nano-carbon-supported palladium-cobalt bimetallic nanomaterial uses nano-diamond@graphene as a carrier and palladium-cobalt bimetallic as an active center.

2. A nanocarbon-supported palladium-cobalt bimetallic nanomaterial according to claim 1, characterized in that: In terms of mass percentage, the loading amount of palladium is 0.5%, and the loading amount of cobalt is 0.5%.

3. The method for preparing a nanocarbon-supported palladium-cobalt bimetallic nanomaterial according to claim 1 or 2, characterized in that: The steps include: 1) dispersing the nanodiamond@graphene material in deionized water and ultrasonically obtaining a suspension, adjusting the pH of the suspension to 10, and dripping a mixed solution of palladium salt and cobalt salt with a pH of 4 into the suspension at a uniform rate under magnetic stirring, stirring at 100° C. for 1 hour, filtering, washing, and drying to obtain a precursor; 2) The obtained precursor is reduced at 500° C. and H 2 for 2 hours to obtain nanocarbon-supported palladium-cobalt bimetallic nanomaterials.

4. The preparation method according to claim 3, characterized in that: In step 1), the pH is adjusted using sodium carbonate solution.

5. The preparation method according to claim 3, characterized in that: In step 1), the palladium salt is palladium nitrate.

6. The preparation method according to claim 3, characterized in that: In step 1), the cobalt salt is cobalt nitrate.

7. Use of the nanocarbon-supported palladium-cobalt bimetallic nanomaterial according to claim 1 or 2 as an antibacterial agent in antibacterial applications.

8. The use according to claim 7, characterized in that: The method is as follows: adding nanocarbon-loaded palladium-cobalt bimetallic nanomaterials into a bacterial suspension.

9. The use according to claim 7, characterized in that: The bacteria are bacteria.

10. The use according to claim 9, characterized in that: The bacteria is Escherichia coli.

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