CN113130885A

CN113130885A - Preparation method and application of titanium dioxide @ silver spherical composite material

Info

Publication number: CN113130885A
Application number: CN202110373385.6A
Authority: CN
Inventors: 高翠玲; 吴恩凯; 赵阳; 李智; 官杰; 范红梅
Original assignee: Shandong Institute for Product Quality Inspection
Current assignee: Shandong Institute for Product Quality Inspection
Priority date: 2021-04-07
Filing date: 2021-04-07
Publication date: 2021-07-16
Anticipated expiration: 2041-04-07
Also published as: CN113130885B

Abstract

The invention belongs to the technical field of composite materials, and particularly relates to a preparation method and application of a titanium dioxide @ silver spherical composite material. The preparation method is realized by the following steps: dissolving tetrabutyl Titanate (TG) in deionized water to obtain a TG aqueous solution, stirring, dripping mercaptoethanol-arginine-aqueous solution, and continuously stirring to obtain a precursor solution for later use; adding silver nitrate and ammonia water into the precursor solution, stirring at room temperature, centrifuging the precipitate, dissolving the precipitate in deionized water with the same volume, adding glucose, stirring, centrifuging, washing, drying, putting the dried intermediate in a tubular furnace, and calcining to obtain the TiO2@ Ag composite material. The size of the composite material prepared by the invention is controllable, and the Ag nano particles are uniformly coated on the surface of the TiO2 sphere, so that the composite material has excellent electrochemical performance and excellent antibacterial performance; the preparation method provided by the invention is simple and effective, and can realize large-scale industrial production.

Description

Preparation method and application of titanium dioxide @ silver spherical composite material

Technical Field

The invention belongs to the technical field of composite materials, and particularly relates to a preparation method and application of a titanium dioxide @ silver spherical composite material.

Background

Rechargeable batteries are increasingly in demand due to large-scale applications such as stationary electrical storage and electric vehicles. Lithium ion batteries have the advantages of long cycle life and high energy density, and are considered as the most promising candidates. However, if mass production of LIBs is achieved in the near future, globally limited lithium reserves may be exhausted, and therefore, sodium ion batteries have attracted increasing attention as a substitute for lithium ion batteries due to the low cost of sodium sources and high natural abundance. However, because the radius of sodium ions is large, the redox potential is higher than that of lithium, and when large sodium ions are considered, the large interstitial spaces within the crystal structure of the electrode material require sufficient electrochemical capacity and cyclability. Based on the research on the negative electrode material of lithium ion batteries, one of the effective methods to solve these problems has been explored is high-conductivity material coating. Ag has high conductivity, so that coating Ag particles is an effective way for improving the electrochemical performance of TiO 2.

Guo Li Xue et al disclose that Ag @ TiO2 nano-particle plasmon effect enhances perovskite solar thin film battery performance, and its nano-silver particle is used as a core layer, and TiO2 is used as a shell layer to cover the surface of the silver particle, and the prepared material has irregular morphology, and the performance needs to be further improved.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a preparation method of a titanium dioxide @ silver spherical composite material, wherein titanium dioxide is used as an inner core of the composite material, and Ag nano particles are uniformly coated on the surface of a TiO2 sphere.

The invention also provides an application of the titanium dioxide @ silver spherical composite material.

The technical scheme adopted by the invention for realizing the purpose is as follows:

the invention provides a preparation method of a titanium dioxide @ silver spherical composite material, which comprises the following steps:

(1) dissolving tetrabutyl Titanate (TG) in deionized water to obtain a TG aqueous solution, stirring, dripping mercaptoethanol-arginine-aqueous solution, and continuously stirring to obtain a precursor solution for later use;

(2) adding silver nitrate and ammonia water into the precursor solution, stirring at room temperature, centrifuging the precipitate, dissolving the precipitate in deionized water with the same volume, adding glucose, stirring, centrifuging, washing and drying to obtain a TG @ Ag intermediate;

(3) and (3) calcining the dried TG @ Ag intermediate in a tubular furnace to obtain the TiO2@ Ag composite material.

Further, in the step (1), the mass ratio of the mercaptoethanol-arginine-water solution is 0.2: 1: 40; the volume ratio of the TG aqueous solution to the mercaptoethanol-arginine-aqueous solution is 1: 0.6-0.8; the time for continuing stirring is 20-30 min.

Further, the concentration of the aqueous TG solution is 3 mg/mL; the mass ratio of TG to silver nitrate is 3: 1; the mass volume ratio of the silver nitrate to the ammonia water is 0.05 g: 1 mL; the mass ratio of the silver nitrate to the glucose is 1: 1.

in the preparation process, in the step (2), the stirring time is 2 hours.

Further, the calcination is carried out for 2 hours at 450 ℃ under an Ar atmosphere.

The invention also provides application of the TiO2@ Ag composite material prepared by the preparation method in high-conductivity materials and antibacterial materials.

The invention has the beneficial effects that:

(1) the TiO2@ Ag composite material prepared by the invention has controllable size, and Ag nanoparticles are uniformly coated on the surface of a TiO2 sphere, so that the composite material has excellent electrochemical performance and excellent antibacterial performance;

(2) the preparation method provided by the invention is simple and effective, and can realize large-scale industrial production.

Drawings

FIG. 1 is a flow chart of the preparation of TiO2@ Ag composite material.

FIG. 2 is a transmission electron microscope image of the TiO2@ Ag composite prepared in example 1.

FIG. 3 is a cyclic voltammogram of the TiO2@ Ag composite prepared in example 1.

FIG. 4 is a graph of the charge-discharge curves of the TiO2@ Ag composite (A) and pure TiO2 (B) prepared in example 1 at a current density of 200 mA g-1.

FIG. 5 is a graph of the cycling performance of the TiO2@ Ag composite prepared in example 1 and pure TiO2 at a current density of 200 mA g-1 (A); long cycle performance plots (B) of TiO2@ Ag composite and pure TiO2 at 1000 and 2000 mA g-1 current densities.

FIG. 6 is a graph of the AC impedance of the TiO2@ Ag composite prepared in example 1 and pure TiO 2.

FIG. 7 is a scanning electron micrograph of the TiO2@ Ag composite prepared in comparative example 1.

Detailed Description

The technical solution of the present invention is further explained and illustrated by the following specific examples.

The preparation flow chart of the TiO2@ Ag composite material is shown in figure 1.

Example 1

(1) Dissolving 0.15g of tetrabutyl titanate TG in 50mL of deionized water to obtain a TG aqueous solution, stirring, simultaneously dropwise adding 30mL of mercaptoethanol-arginine-aqueous solution (the mass ratio is 0.2: 1: 40), and continuously stirring for 30min to obtain a precursor solution for later use;

(2) adding 0.05g of silver nitrate and 1mL of ammonia water into the precursor solution, stirring for 2h at room temperature, centrifuging the precipitate, dissolving the precipitate into 50mL of deionized water, adding 0.05g of glucose, stirring for 2h, centrifuging, washing, and drying to obtain a TG @ Ag intermediate;

(3) and calcining the dried TG @ Ag in a tube furnace at 450 ℃ for 2h in Ar atmosphere to obtain the TiO2@ Ag composite material.

Comparative example 1

(1) Dissolving 0.15g of tetrabutyl titanate TG in 50mL of deionized water to obtain a TG aqueous solution, stirring, simultaneously dropwise adding 30mL of arginine-aqueous solution (the mass ratio is 1: 40), and continuously stirring for 30min to obtain a precursor solution for later use;

Comparative example 2

(1) Dissolving 0.15g of tetrabutyl titanate TG in 50mL of deionized water to obtain a TG aqueous solution, stirring, adding 0.05g of silver nitrate and 1mL of ammonia water into the precursor solution, stirring for 2 hours at room temperature, centrifuging the precipitate, dissolving in 50mL of deionized water, adding 0.05g of glucose, stirring for 2 hours, centrifuging, washing, and drying to obtain a TG @ Ag intermediate;

(2) and calcining the dried TG @ Ag in a tube furnace at 450 ℃ for 2h in Ar atmosphere to obtain the TiO2@ Ag composite material.

(one) results and discussion

1. Transmission electron microscope test analysis

FIG. 2 is a transmission electron micrograph of the TiO2@ Ag composite prepared in example 1. As can be seen from the figure, the TiO2@ Ag composite material has good dispersibility, no agglomeration state is seen, the diameter of the microsphere is about 500 nm, and a large number of nano Ag particles with the size of about 3 nm are uniformly adhered to the surface of the microsphere, meanwhile, the microspheres prepared in comparative examples 1 and 2 have poor dispersibility, and as shown in FIG. 7, the agglomeration phenomenon occurs, and the diameter is basically the same as that of example 1.

The growth mechanism of the composite material prepared by the invention is as follows: a certain amount of pores exist in the TG precursor when the TG precursor is formed, a certain amount of silver ammonia ions enter the TG through the pores due to diffusion in the stirring process, after centrifugation, the silver ammonia ions in the TG precursor and the silver ammonia ions adsorbed to the surface of the TG by electrostatic force are retained, and when the centrifuged TG particles are soaked into a solution containing a reducing agent again, the silver ammonia ions in the microspheres are timely reduced when being diffused to the surfaces of the microspheres, so that Ag particles are formed on the surfaces of the microspheres. So that the Ag particles can be uniformly attached to the surface of the microsphere.

2. Electrochemical characterization of materials

The composite material prepared in example 1 was subjected to electrochemical performance characterization.

(1) Cyclic voltammetric assay

FIG. 3 is a CV curve of TiO2@ Ag composite tested at a scan rate of 0.1 mVs-1 over a potential range of 0.01-3.0V (vs Na/Na +). In the first cycle, a significant cathodic peak was observed at about 1.0V, and was not observed in the later cycles, which was associated with electrolyte decomposition and SEI film formation. Meanwhile, a pair of redox peaks at 0.5/0.7V was observed on the CV curve, which is related to the reaction between Ti3+ and Ti4+ during the deintercalation of sodium ions.

(2) Charge-discharge test analysis

FIG. 4 is a graph showing charge-discharge tests of 1, 10, 50, 100 and 200 cycles of TiO2@ Ag composite (A) and pure TiO2 (B) at a current density of 200 mA g-1 and a voltage range of 0.01-3.0V (vs Na/Na +). The TiO2@ Ag composite material in FIG. 4 (A) has a first discharge capacity of 467.8 mAh g-1, and reversible capacities of 194.9, 146.8, 157.1 and 150.8 mAh g-1 after 10, 50, 100 and 200 cycles, respectively. Except for the 1 st cycle and the 10 th cycle, the charge and discharge curves of the composite material almost completely coincide, which shows that the capacity stability is better under the condition of low current density. And for pure TiO2, the first discharge capacity of the material is only 248.3 mAh g < -1 >, and the reversible capacity of the material is only maintained between 95 and 99 mAh g < -1 > in the subsequent circulation.

(3) Cycle performance test analysis

FIG. 5 (A) is a graph of the cycling performance and coulombic efficiency of a TiO2@ Ag composite and pure TiO2 at a current density of 200 mA g-1. At a current density of 200 mA g < -1 >, the initial coulombic efficiency of the TiO2@ Ag composite material is 34.2%, and the irreversible capacity loss is caused by the formation of an SEI film. In the subsequent circulation, the coulombic efficiency of the material is gradually increased, after 10 cycles of circulation, the coulombic efficiency of the composite material is increased to 95%, after 37 cycles, the coulombic efficiency of the composite material is basically maintained to be more than 99%, and after 200 cycles, the reversible capacity of the composite material is 150.8 mAh g < -1 >, which is far higher than that of pure TiO2 (99.7 mAh g < -1 >). This demonstrates that the diffusion of electrons and Na + ions is facilitated by the coating of Ag particles, resulting in a TiO2@ Ag composite with a much higher reversible capacity than pure TiO 2. FIG. 5 (B) is a long cycle test plot of TiO2@ Ag composite and pure TiO2 at high current densities of 1000 and 2000 mA g-1. After the TiO2@ Ag composite material is circulated 1800 times under the current density of 1000 mA g < -1 > and through an activation process, the reversible capacity is still maintained at 121 mAh g < -1 >, and the pure phase is only 62.5 mAh g < -1 >. Under the high current density of 2000 mA g < -1 >, the TiO2@ Ag composite material still shows excellent long-cycle stability, and after 1800 cycles, the reversible capacity of the composite material can still reach 84.4 mA g < -1 >, and is even better than that of pure TiO2 under the current density of 1000 mA g < -1 >. The excellent electrochemical properties benefit from the Ag particle conductivity and the buffering effect on the material during charging and discharging.

(4) AC impedance test analysis

FIG. 6 shows EIS patterns of TiO2@ Ag composite and pure TiO 2. The semi-circle radius of the high frequency region represents the charge transfer resistance of the material and the slope of the low frequency region represents the ion diffusion resistance. From the figure, the semi-circle diameter of the NTiO2@ NC electrode material is obviously smaller than that of pure TiO2, which shows that the charge transfer resistance of the TiO2@ Ag composite material is lower. Furthermore, the steeper slope of TiO2@ Ag means faster Li + diffusion due to the Ag particles of the coating layer significantly improving the conductivity of the material.

3. Report of bacteriostasis experiment

3.1 experimental materials, instruments and strains:

tryptone (Oxoid), agar (Beijing Dingguo), yeast extract (Oxoid), sodium chloride (Shanghai medicine), sterile petri dish (Labserv), sterile 6mm diameter disc filter paper (Xinhua brand filter paper), sterile water, 0.22 μm filter membrane (Millipore). Type a2 secondary biosafety cabinet (shanghai bokings); constant temperature incubator (Shanghai Jingcheng).

Strain: staphylococcus aureus 8325-4, escherichia coli, pseudomonas aeruginosa 14, enterococcus faecalis MMH594, bacillus subtilis and bacillus cereus.

3.2 antibacterial experiments

(1) Preparing a bacterial suspension: taking the strain to culture in LB liquid culture medium at 37 ℃ overnight with shaking for recovery. The culture solution is coated on an LB solid medium plate and cultured for 16 h at 37 ℃. Single colonies were picked up and grown in logarithmic phase in LB liquid medium at 37 ℃ with shaking, and diluted to about 10 with sterilized LB liquid medium⁶cfu/mL。

(2) Preparation of a test sample: 1.50 mg of each of the samples of example 1, comparative example 1 and comparative example 2 was precisely weighed, and suspended in 3 mL and 7.5 mL of sterile water to prepare sample solutions having concentrations of 500. mu.g/m and 200. mu.g/mL, respectively.

(3) Bacteriostatic experiment by a filter paper sheet method: sterile LB solid medium was poured onto a plate, and the plate was streaked and divided into 6 zones. And (3) coating a flat plate with 200 mu L of a bacterial liquid coater, then air-drying, respectively dripping 20 mu L of different sample test liquids with different concentrations onto a sterilized filter paper sheet with the diameter of 6mm, and placing the sterilized filter paper sheet in the center of a streaking area of the flat plate with the bacterial culture medium after air-drying. At 37^oAnd C, culturing for 20-26 h in an incubator, observing whether the bacteriostatic circle around the filter paper disc exists or not, and measuring the diameter of the bacteriostatic circle. The experiment was repeated 3 times.

The experimental results are as follows:

bacteriostatic screening experiments on 6 common pathogenic bacteria show that the composite material prepared by the invention has bacteriostatic effects of different degrees, wherein the bacteriostatic effect on gram-negative bacteria escherichia coli, pseudomonas aeruginosa, gram-positive bacteria staphylococcus aureus, bacillus subtilis and bacillus cereus is better; has poorer bacteriostatic effect on enterococcus faecalis than other bacteria. Specifically, the results are shown in Table 1.

TABLE 1

The TiO2@ Ag composite material is successfully prepared by a simple method. In the experimental process, redundant silver ammonia ions are removed through centrifugation, so that the coating layer Ag particles are uniformly distributed on the surface of the TiO2 microsphere. The Ag particles on the surface of the TiO2 microsphere are beneficial to the transmission kinetics of electrons and sodium ions, so that the TiO2@ Ag composite material has excellent long-cycle stability, and after 1800 cycles of high current density of 2000 mA g < -1 >, the reversible capacity of the composite material can still reach 84.4 mA g < -1 >, even higher than the reversible capacity (62.5 mAh g < -1 >) of pure TiO2 at 1000 mA g < -1 > current density. And the prepared composite material has excellent antibacterial performance.

Claims

1. A preparation method of a titanium dioxide @ silver spherical composite material is characterized by comprising the following steps:

(2) adding silver nitrate and ammonia water into the precursor solution, stirring at room temperature, centrifuging the precipitate, dissolving the precipitate into deionized water with the same volume as that in the step (1), adding glucose, stirring, centrifuging, washing and drying to obtain a TG @ Ag intermediate;

2. The method according to claim 1, wherein in the step (1), the ratio by mass of the mercaptoethanol-arginine-water solution is 0.2: 1: 40; the volume ratio of the TG aqueous solution to the mercaptoethanol-arginine-aqueous solution is 1: 0.6-0.8; the time for continuing stirring is 30-40 min.

3. The production method according to claim 1, wherein the concentration of the aqueous TG solution is 3 mg/mL; the mass ratio of TG to silver nitrate is 3: 1; the mass volume ratio of the silver nitrate to the ammonia water is 0.05 g: 1 mL; the mass ratio of the silver nitrate to the glucose is 1: 1.

4. the method according to claim 3, wherein the stirring time in step (2) is 2 hours.

5. The method according to any one of claims 1 to 4, wherein the calcination is carried out at 450 ℃ under Ar atmosphere for 2 hours.

6. The application of the TiO2@ Ag composite material prepared by the preparation method of any one of claims 1-5 in high-conductivity materials and antibacterial materials.