Preparation method and photo-thermal conversion, photocatalysis and antibacterial application of copper nanowire / ZnCdS nanosheet material

Abstract

The invention belongs to the technical field of nano functional materials, and particularly discloses a preparation method of a copper nanowire / ZnCdS nanosheet material and photo-thermal conversion, photocatalysis and antibacterial application of the copper nanowire / ZnCdS nanosheet material. According to the preparation method, copper nanowires with defects are prepared through tannic acid, defect sites capture Zn < 2 + > and Cd < 2 + > through electrostatic attraction or coordination, ZnCdS nanosheets are loaded on the surfaces of the copper nanowires, the copper nanowire / ZnCdS nanosheet material is prepared, the high-conductivity copper nanowires and the ZnCds form a large number of interface structures, and the conductivity of the copper nanowires is improved. The photocatalyst has efficient photothermal conversion performance, wide-spectrum photocatalytic activity and a synergistic antibacterial effect, and has the advantages of being simple in preparation process, low in cost, environmentally friendly and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nanofunctional materials, and specifically discloses a preparation method of copper nanowire / ZnCdS nanosheet material and photo-thermal conversion, photocatalysis and antibacterial application. BACKGROUND

[0002] Metal sulfides show high photocatalytic activity in hydrogen production and pollutant degradation due to their low cost, suitable energy band structure and easy preparation process. More and more researchers pay attention to bimetallic sulfides such as ZnCdS because of more active sites, diverse chemical structures, adjustable band gap and edge position, and higher chemical and light stability compared with single metal sulfides, and the bimetallic sulfides show good application potential in photocatalysis. However, the photocatalytic activity of the bimetallic sulfides is hindered by the rapid recombination of photo-generated carriers and slow migration rate. Meanwhile, ZnCdS has poor dispersibility, resulting in buried active sites.

[0003] Highly conductive carriers can help separate photo-generated electrons and holes, and are expected to improve the photocatalytic activity of bimetallic sulfides such as ZnCdS. However, it is a challenge to prepare carrier-loaded ZnCdS, improve the dispersibility of ZnCdS and enhance the interface electron transfer. SUMMARY

[0004] The application prepares copper nanowire / ZnCdS nanosheet material, and prepares copper nanowires with defects by tannic acid. The defect sites capture Zn 2+ , Cd 2+ by electrostatic attraction or coordination, provide initial nucleation centers for ZnCdS, avoid buried adsorption sites caused by ZnCdS agglomeration, and simultaneously have excellent conductivity, which can act as an "electron channel" to accelerate the separation and transfer of photo-generated carriers in ZnCdS and improve the photocatalytic performance of ZnCdS.

[0005] The preparation method of the copper nanowire / ZnCdS nanosheet material comprises the following steps: (1) At room temperature, dissolve tannic acid in deionized water, add appropriate NaOH, and stir for 10 minutes to adjust the pH to 8-10.

[0006] (2) Add CuCl2·2H2O and continuously stir for 20 minutes to form a blue solution.

[0007] (3) Add ascorbic acid, stir for 5 minutes to uniformly disperse the reducing agent, transfer the mixed solution to a three-necked flask, and place it in an oil bath at 60-70℃ for 2-4 hours of heat preservation reaction.

[0008] (4) Centrifugal collection of the precipitate and resuspension in an ethanol solution of 0.1 wt% tannic acid to obtain a copper nanowire dispersion.

[0009] (5) Mixing of the copper nanowire dispersion with deionized water, addition of Zn(Ac)2 and Cd(Ac)2 (molar ratio nZn:nCd = 1:1) and stirring for 30 minutes.

[0010] (6) Addition of thiourea (molar ratio nZn:nS = 1:6), stirring for 1 hour and then transferring the mixture to a reaction kettle for hydrothermal reaction at 180°C for 18 hours.

[0011] (7) Centrifugal collection of the precipitate and freeze-drying at -70°C to obtain a copper nanowire / ZnCdS nanosheet material.

[0012] Preferably, the amounts of tannic acid, CuCl2·2H2O and ascorbic acid are 50-200 mg: 0.1 mmol: 35 mg.

[0013] Preferably, the amounts of the copper nanowire dispersion, Zn(Ac)2, Cd(Ac)2 and thiourea are 10 mL: 0.1-0.3 mmol: 0.1-0.3 mmol: 0.3-1.8 mmol.

[0014] Preferably, the concentration of copper nanowires in the copper nanowire dispersion is 1 wt% and the concentration of tannic acid is 0.1 wt%.

[0015] Preferably, the molar ratio nZn:nCd of Zn(Ac)2 and Cd(Ac)2 is 1:1.

[0016] Preferably, the molar ratio nZn:nS of Zn(Ac)2 and thiourea is 1:2-6.

[0017] Preferably, the amounts of the copper nanowire dispersion and deionized water in step (5) are 1:2.

[0018] The copper nanowire / ZnCdS nanosheet material prepared by the above method has applications in photothermal conversion, photocatalysis and antibacterial materials.

[0019] Further, the application of the copper nanowire / ZnCdS nanosheet material in photocatalysis is photocatalytic degradation of organic matter.

[0020] Further, the pollutant is formaldehyde.

[0021] The present application has the following advantages: The copper nanowire / ZnCdS nanosheet material prepared by the application is a defective copper nanowire prepared by tannic acid. The macromolecular structure of tannic acid can act as a selective end-capping agent to promote the formation of a nanowire structure. Meanwhile, the tannic acid molecules are rich in phenolic hydroxyl groups and amino groups, which can form stable chelates with Cu , slow down the reduction rate of Cu , generate irregular polyhedral seed crystals, and easily develop into defects such as stacking faults and dislocations in subsequent growth. These defects capture Zn 2+ , Cd 2+ through electrostatic attraction or coordination to provide initial nucleation centers for ZnCdS and avoid ZnCdS agglomeration. The copper nanowire with high conductivity forms a large number of interface structures with ZnCds, which improves the carrier separation efficiency and enhances the photocatalytic effect. The Cu-based material has low cost and abundance, as well as surface plasmon resonance photothermal effect, which forms a synergistic enhancement effect with photocatalysis. The material has high-efficiency photothermal conversion performance, wide-spectrum photocatalytic activity, and synergistic antibacterial effect, and has the advantages of simple preparation process, low cost, and environmental friendliness. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is an SEM image of the copper nanowire of Comparative Example 1; Figure 2 is an SEM image of the ZnCdS nanosheet of Comparative Example 2; Figure 3 is an SEM image of the copper nanowire / ZnCdS nanosheet material of Example 1; Figure 4 is an SEM image of the copper nanowire / ZnCdS nanosheet material of Example 2; Figure 5 is an SEM image of the copper nanowire / ZnCdS nanosheet material of Example 3; Figure 6 is an SEM image of the copper nanowire / ZnCdS nanosheet material of Example 4; Figure 7 is an SEM image of the copper nanowire / ZnCdS nanosheet material of Example 5; Figure 8 is an SEM image of the copper nanowire / ZnCdS nanosheet material of Example 6; Figure 9 is the photoluminescence intensity of the materials of Examples 1-6 and Comparative Examples 1-2; Figure 10 is the light-induced temperature rise graph of the materials of Examples 1-6 and Comparative Examples 1-2; Figure 11 is the inhibition of bacterial survival rate under light of the materials of Examples 1-6 and Comparative Examples 1-2; Figure 12SEM of the E. coli solution after treatment of the material of Example 6; Figure 13 Photolysis formaldehyde removal efficiency for the materials of Examples 1-6, Comparative Examples 1-2. DETAILED DESCRIPTION

[0023] Experimental Example 1

[0024] (1) At room temperature, 50 mg of tannic acid was dissolved in 25 mL of deionized water, and an appropriate amount of NaOH was added, and stirred for 10 minutes to adjust the pH to 8.

[0025] (2) 0.1 mmol of CuCl2 2H2O was added, and stirring was continued for 20 minutes to form a blue solution.

[0026] (3) 35 mg of ascorbic acid was added, and stirring was continued for 5 minutes to uniformly disperse the reducing agent, and the mixed solution was transferred to a 50 mL three-necked flask and placed in a 60°C oil bath for 4 hours of reaction.

[0027] (4) The precipitate was collected by centrifugation and resuspended in an ethanol solution of 0.1 wt% tannic acid to obtain a 1 wt% copper nanowire dispersion.

[0028] (5) 10 mL of the copper nanowire dispersion was mixed with 20 mL of deionized water, and 0.1 mmol of Zn(Ac)2 and 0.1 mmol of Cd(Ac)2 were added, and stirring was continued for 30 minutes.

[0029] (6) 0.6 mmol of thiourea was added, and after stirring for 1 hour, the mixture was transferred to a 50 mL reaction kettle and hydrothermally reacted at 180°C for 18 hours.

[0030] (7) The precipitate was collected by centrifugation and freeze-dried at -70°C to obtain a copper nanowire / ZnCdS nanosheet material.

[0031] Experimental Example 2

[0032] (1) The same as Example 1.

[0033] (2) The same as Example 1.

[0034] (3) The same as Example 1.

[0035] (4) Same Example 1.

[0036] (5) 10 mL of the copper nanowire dispersion was mixed with 20 mL of deionized water, and 0.2 mmol of Zn(Ac)2 and 0.2 mmol of Cd(Ac)2 were added, and stirring was continued for 30 minutes.

[0037] (6) 1.2 mmol of thiourea was added, and after stirring for 1 hour, the mixture was transferred to a 50 mL reaction kettle for hydrothermal reaction at 180°C for 18 hours.

[0038] (7) The precipitate was collected by centrifugation and freeze-dried at -70°C to obtain the copper nanowire / ZnCdS nanosheet material.

[0039] Experimental Example 3

[0040] (1) The same as in Example 1.

[0041] (2) The same as in Example 1.

[0042] (3) The same as in Example 1.

[0043] (4) The same as in Example 1.

[0044] (5) 10 mL of the copper nanowire dispersion liquid was mixed with 20 mL of deionized water, and 0.3 mmol of Zn(Ac)2 and 0.3 mmol of Cd(Ac)2 were added, and stirred for 30 minutes.

[0045] (6) 1.8 mmol of thiourea was added, and after stirring for 1 hour, the mixture was transferred to a 50 mL reaction kettle for hydrothermal reaction at 180°C for 18 hours.

[0046] (7) The precipitate was collected by centrifugation and freeze-dried at -70°C to obtain the copper nanowire / ZnCdS nanosheet material.

[0047] Experimental Example 4

[0048] (1) At room temperature, 50 mg of tannic acid was dissolved in 25 mL of deionized water, and an appropriate amount of NaOH was added, and stirred for 10 minutes to adjust the pH to 9.

[0049] (2) 0.1 mmol of CuCl2·2H2O was added, and stirring was continued for 20 minutes to form a blue solution.

[0050] (3) 35 mg of ascorbic acid was added, and stirred for 5 minutes to uniformly disperse the reducing agent, and the mixed solution was transferred to a 50 mL three-necked flask and placed in a 60°C oil bath for 3 hours.

[0051] (4) The precipitate was collected by centrifugation and resuspended in an ethanol solution of 0.1 wt% tannic acid to obtain a 1 wt% copper nanowire dispersion liquid.

[0052] (5) The same as in Example 1.

[0053] (6) The same as in Example 1.

[0054] (7) The precipitate was collected by centrifugation and freeze-dried at -70°C to obtain the copper nanowire / ZnCdS nanosheet material.

[0055] Experimental Example 5

[0056] (1) At room temperature, 100 mg of tannic acid was dissolved in 25 mL of deionized water, and an appropriate amount of NaOH was added. After stirring for 10 minutes, the pH was adjusted to 9.

[0057] (2) 0.1 mmol of CuCl2·2H2O was added, and stirring was continued for 20 minutes to form a blue solution.

[0058] (3) 35 mg of ascorbic acid was added, and stirring was continued for 5 minutes to uniformly disperse the reducing agent. The mixed solution was transferred to a 50 mL three-necked flask and placed in a 60°C oil bath for 2 hours of reaction.

[0059] (4) The precipitate was collected by centrifugation and resuspended in an ethanol solution of 0.1 wt% tannic acid to obtain a 1 wt% copper nanowire dispersion.

[0060] (5) 10 mL of the copper nanowire dispersion was mixed with 20 mL of deionized water, and 0.1 mmol of Zn(Ac)2 and 0.1 mmol of Cd(Ac)2 were added. Stirring was continued for 30 minutes.

[0061] (6) 0.3 mmol of thiourea was added, and after stirring for 1 hour, the mixed solution was transferred to a 50 mL reaction kettle for 180°C hydrothermal reaction for 18 hours.

[0062] (7) The precipitate was collected by centrifugation and freeze-dried at -70°C to obtain the copper nanowire / ZnCdS nanosheet material.

[0063] Experimental Example 6

[0064] (1) At room temperature, 200 mg of tannic acid was dissolved in 25 mL of deionized water, and an appropriate amount of NaOH was added. After stirring for 10 minutes, the pH was adjusted to 10.

[0065] (2) 0.1 mmol of CuCl2·2H2O was added, and stirring was continued for 20 minutes to form a blue solution.

[0066] (3) 35 mg of ascorbic acid was added, and stirring was continued for 5 minutes to uniformly disperse the reducing agent. The mixed solution was transferred to a 50 mL three-necked flask and placed in a 60°C oil bath for 2 hours of reaction.

[0067] (4) The precipitate was collected by centrifugation and resuspended in an ethanol solution of 0.1 wt% tannic acid to obtain a 1 wt% copper nanowire dispersion.

[0068] (5) 10 mL of copper nanowire dispersion was mixed with 20 mL of deionized water, 0.1 mmol of Zn(Ac)2 and 0.1 mmol of Cd(Ac)2 were added, and stirred for 30 minutes.

[0069] (6) 0.3 mmol of thiourea was added, and after stirring for 1 hour, the mixture was transferred to a 50 mL reaction kettle, and hydrothermal reaction was carried out at 180°C for 18 hours.

[0070] (7) The precipitate was collected by centrifugation, and copper nanowire / ZnCdS nanosheet material was obtained by freeze-drying at -70°C.

[0071] Comparative Example 1

[0072] (1) 50 mg of tannic acid was dissolved in 25 mL of deionized water at room temperature, and an appropriate amount of NaOH was added, and stirred for 10 minutes to adjust the pH to 8.

[0073] (2) 0.1 mmol of CuCl2·2H2O was added, and stirring was continued for 20 minutes to form a blue solution.

[0074] (3) 35 mg of ascorbic acid was added, and stirring was continued for 5 minutes to uniformly disperse the reducing agent, and the mixed solution was transferred to a 50 mL three-necked flask and placed in a 60°C oil bath for 4 hours.

[0075] (4) The precipitate was collected by centrifugation, and resuspended in an ethanol solution of 0.1 wt% tannic acid to obtain a 1 wt% copper nanowire dispersion.

[0076] Comparative Example 2

[0077] (1) 0.1 mmol of Zn(Ac)2 and 0.1 mmol of Cd(Ac)2 were weighed and added to 30 mL of deionized water, and stirred for 30 minutes.

[0078] (2) 0.3 mmol of thiourea was added, and after stirring for 1 hour, the mixture was transferred to a 50 mL reaction kettle, and hydrothermal reaction was carried out at 180°C for 18 hours.

[0079] (3) The precipitate was collected by centrifugation, and ZnCdS nanosheet material was obtained by freeze-drying at -70°C.

[0080] Figures 1-8 SEM images of the materials of Examples 1-6 and Comparative Examples 1-2 are shown. As can be seen from the figures, the surface of the copper nanowires in Comparative Example 1 is smooth ( Figure 1 ), and the agglomerated ZnCdS nanosheets in Comparative Example 2 are Figure 2 ​). The surface of the copper nanowires of Examples 1-6 was obviously rough, i.e. in-situ grown ZnCdS, which improved the dispersibility of the ZnCdS Figures 3-8 ).

[0081] Figure 9 The photoluminescence intensity of the materials of Examples 1-6 and Comparative Examples 1-2 (the solid material powder was placed on a fluorescence solid support and fixed on the instrument of F-4500, the excitation wavelength was 365 nm, and the luminescence intensity was recorded from 400 nm to 700 nm) is shown in the figure. It can be seen from the figure that the fluorescence intensity of the Cu nanowires prepared in Comparative Example 1 is low, the fluorescence intensity of the ZnCdS prepared in Comparative Example 2, and the fluorescence intensity of Examples 1-6 is obviously reduced. This is because the carrier separation efficiency is improved in Examples 1-6.

[0082] Figure 10 The photothermal test results of the materials of Examples 1-6 and Comparative Examples 1-2 are shown: 200 μg mL -1 of the material aqueous solution was exposed to a 300 W xenon lamp, and the real-time solution temperature was recorded at an interval of 50 s. The photothermal effect of Comparative Example 2 is not obvious, the Cu nanowires prepared in Comparative Example 1 are heated to a maximum of 44.7°C, and the ZnCdS / copper nanowire materials of Examples 1-6 are obviously heated under light, and most of them are higher than the Cu nanowires, and the highest can be heated to 56°C.

[0083] Figure 11 The bactericidal test of the materials of Examples 1-6 and Comparative Examples 1-2 is shown: Staphylococcus aureus and Escherichia coli were cultured overnight, then diluted with PBS buffer to 10 7 C FU mL -1 , 100 μg mL -1 of the material was added, and a 300 W xenon lamp was irradiated for 10 minutes. Subsequently, the bacterial suspensions of different treatment groups were appropriately diluted and incubated on solid plate medium for 12 h. The colonies produced were quantitatively counted. The blank group was not added with any material, as 100% bacterial survival rate. The Cu nanowires prepared in Comparative Example 1 were treated for 10 minutes, and the bacterial survival rates were 53.5 and 59.2%, respectively, the ZnCdS nanosheet prepared in Comparative Example 2 was treated for 10 minutes, and the bacterial survival rates were 96.1 and 95.4%, respectively, and the ZnCdS / copper nanowire materials of Examples 1-6 were treated for 10 minutes, and the bacterial survival rates were as low as 4.3 and 5.2%.

[0084] Figure 12 The SEM image of Escherichia coli after light treatment of Example 6 is shown. It can be observed that the Escherichia coli bacterial morphology is not complete, and damage occurs.

[0085] Figure 13The test results of photocatalytic degradation of gaseous formaldehyde of the materials of Examples 1-6 and Comparative Examples 1-2 are shown: the temperature and humidity in a 200L closed cabin are controlled at 27°C and 30%, a heating table in the cabin is preheated to 80°C, 150ul of formaldehyde solution is dropped into a glass culture dish and placed on the heating table to heat for 2min to make formaldehyde completely volatilize. A certain amount of photocatalyst is uniformly dispersed in 10mL of deionized water, quickly put into the cabin, stirred in the dark for 30min to reach adsorption-desorption equilibrium, then the reaction solution is irradiated by a 300W xenon lamp to start the light reaction test, every 30min 10mL is taken out for concentration detection using a formaldehyde detector. Comparative Examples 1-2 are difficult to remove formaldehyde under light, Examples 1-6 quickly degrade formaldehyde under light, and the highest removal rate of Example 6 reaches 99% in 3h.

[0086] The above ideal embodiments according to the present application are for inspiration, through the above description, relevant personnel can make various changes and modifications without deviating from the scope of the technical idea of the present application. The technical scope of the present application is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. A method for preparing a copper nanowire / ZnCdS nanosheet material, characterized in that, The method comprises the following steps: (1) at room temperature, dissolve tannic acid in deionized water, adjust pH to 8-10; (2) add CuCl2·2H2O, stir to form a blue solution; (3) add ascorbic acid, stir until uniform, and place the mixed solution in a 60-70℃ water bath for 2-4 hours; (4) centrifuge to collect the precipitate, and resuspend it in an ethanol solution of tannic acid to obtain a copper nanowire dispersion; (5) mix the copper nanowire dispersion with deionized water, add Zn(Ac)2 and Cd(Ac)2, and stir for 30 minutes; (6) add thiourea, stir for 1 hour, then transfer the mixture to a reaction kettle, and perform hydrothermal reaction at 180℃ for 18 hours; (7) centrifuge to collect the precipitate, and freeze-dry to obtain a copper nanowire / ZnCdS nanosheet material.

2. The method of claim 1, wherein the copper nanowire / ZnCdS nanoplatelet material is prepared by the steps of: (a) preparing a ZnCdS nanoplatelet material; (b) preparing a copper nanowire material; and (c) mixing the ZnCdS nanoplatelet material and the copper nanowire material. In step (1), the pH is adjusted using NaOH.

3. The method of claim 1, wherein the copper nanowire / ZnCdS nanoplatelet material is prepared by the steps of: (a) preparing a ZnCdS nanoplatelet material; (b) preparing a copper nanowire material; and (c) mixing the ZnCdS nanoplatelet material and the copper nanowire material. The amounts of tannic acid, CuCl2·2H2O, and ascorbic acid are 50-200 mg, 0.1 mmol, and 35 mg, respectively.

4. The method of claim 1, wherein the copper nanowire / ZnCdS nanoplatelet material is prepared by the steps of: In the copper nanowire dispersion, the concentration of copper nanowires is 1 wt%, and the concentration of tannic acid is 0.1 wt%.

5. The method of claim 1, wherein the copper nanowire / ZnCdS nanoplatelet material is prepared by the steps of: (a) preparing a ZnCdS nanoplatelet material; (b) preparing a copper nanowire material; and (c) mixing the ZnCdS nanoplatelet material and the copper nanowire material. The amounts of the copper nanowire dispersion, Zn(Ac)2, Cd(Ac)2, and thiourea are 10 mL, 0.1-0.3 mmol, 0.1-0.3 mmol, and 0.6-1.8 mmol, respectively; the molar ratio of Zn(Ac)2 to Cd(Ac)2 is 1:1; and the molar ratio of Zn(Ac)2 to thiourea is 1:

6.

6. The method of claim 1, wherein the copper nanowire / ZnCdS nanoplatelet material is prepared by the steps of: In step (5), the amounts of the copper nanowire dispersion and deionized water are 1:

2.

7. A copper nanowire / ZnCdS nanosheet material prepared by the method of any one of claims 1-6.

8. Use of the copper nanowire / ZnCdS nanosheet material of claim 7 in photothermal conversion, photocatalysis, and antibacterial materials.

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