WO2017219608A1

WO2017219608A1 - Platinum nanoparticle/titanium dioxide nanotube array manufacturing method, electrode, non-enzymatic glucose sensor, and composite material

Info

Publication number: WO2017219608A1
Application number: PCT/CN2016/108310
Authority: WO
Inventors: 赖跃坤; 刘慧�; 李飞洋; 孙青梅; 张生; 李煜伟; 王涛; 何志成; 黄剑莹; 张克勤
Original assignee: 苏州蓝锐纳米科技有限公司
Priority date: 2016-06-23
Filing date: 2016-12-02
Publication date: 2017-12-28
Also published as: CN106167912A; CN106167912B

Abstract

The present invention discloses a platinum nanoparticle/titanium dioxide (TiO₂) nanotube array manufacturing method, electrode, non-enzymatic glucose sensor, and composite material. The method comprises: S1. pre-treating a titanium plate; S2. using an anode oxidation process to manufacture a TiO₂ nanotube array; S3. using an electropolymerization process to construct a biomimetic polydopamine coating on the TiO₂ nanotube; S4. using an inherent reducing property of the dopamine coating to load a platinum nanoparticle on the surface of the TiO₂ nanotube; and S5. using a pre-manufactured working electrode to perform non-enzymatic glucose sensor performance testing. The platinum nanoparticle/TiO₂ nanotube array uses electropolymerization of polydopamine and reduction process to obtain a platinum nanoparticle and TiO₂ nanotube composite material. The composite material can be used for manufacturing a non-enzymatic glucose sensor. The electropolymerization method for loading a platinum nanoparticle onto a biomimetic polydopamine addresses the issues of long processing time and poor uniformity of a conventional dopamine immersion and self-polymerization method.

Description

Method for preparing platinum nanoparticle/titanium dioxide nanotube array, electrode, non-enzymatic glucose sensor and composite material

Technical field

The invention relates to the field of materials, in particular to a method for preparing a platinum nanoparticle/titanium dioxide nanotube array, an electrode, a non-enzymatic glucose sensor and a composite material.

Background technique

As a new type of n-type semiconductor material, titanium dioxide (TiO ₂ ) has outstanding chemical stability, photoelectric properties, biocompatibility and corrosion resistance. It has been widely used in photocatalytic degradation of pollutants and fuel-sensitized solar energy. Batteries, biomedical materials, gas sensors, and photolysis of water to produce hydrogen. In addition to the same surface effect, low size effect, quantum size effect and macroscopic quantum tunneling effect as nano-materials, nano-TiO ₂ has its special properties, especially catalytic properties.

Compared with TiO ₂ nanoparticles, TiO ₂ nanotube arrays have the advantages of large specific surface area, high surface energy, easy recycling and low loading rate of electrons and holes, which have attracted more attention and research. However, TiO ₂ nanotube arrays still have some disadvantages, which limits its application in many aspects. For example, (1) TiO _{2 has} a wide band gap (3.2 eV for anatase and 3.0 eV for rutile), and can only absorb 3 to 5% of solar energy (λ < 387 nm), and has low utilization rate; (2) The recombination rate of photogenerated electron-hole pairs of TiO ₂ nanotubes is still high and the photocatalytic activity is low.

Aiming at the above problems, it is a hot research topic to improve the photoelectrocatalytic performance of TiO ₂ nanotube arrays by doping metal, non-metal and semiconductor nanoparticles with TiO ₂ nanotube arrays by various means. On the one hand, the dispersion of noble metal nanoparticles on the surface of TiO ₂ nanotubes can assist in the capture of photogenerated electrons, accelerate the separation of electron holes, and thus inhibit the photocomposite electron and hole recombination. On the other hand, the noble metal particles can enhance the visible light absorbing ability of the TiO ₂ nanotubes by the surface resonance effect. Compared with other noble metals such as Ag and Cu, Pt is used in the detection of glucose, hydrogen peroxide, degradation of methanol, formic acid, methyl ester, etc., and has superior catalytic performance, making Pt-loaded TiO ₂ nanotubes widely used in non- Enzyme glucose detection electrode, photodegradation of pollutants, hydrogen production by photolysis, fuel cells, etc. In addition, Pt nanoparticles have an ionic surface resonance effect, and they can also be applied to TiO ₂ nanotubes to enhance the Raman signal of organic matter by Raman enhancement to detect contaminants.

In recent years, polydopamine (PDA) has been widely used for surface modification of biological materials due to its good adhesion to various substrates (such as metals, glass, organics, etc.) and good biocompatibility; The PDA can achieve electroless metallization of the surface of the material by its own reductive properties. Dissolving an appropriate amount of dopamine in a buffer, under aerobic conditions, dopamine oxidation is self-polymerized and deposited on the surface of various substrates from inorganic (metal, metal oxide) to organic (polymer) to form on the surface of the substrate. A layer of PDA coating with permanent adhesion. In-depth studies have shown that the catechol groups and amino functional groups of dopamine play a major role in the adhesion process of polydopamine. The use of catechol groups can exhibit reducing power for precious metal salts such as gold, silver and platinum, and valuable metal particles can be derived from polydopamine layers; can be hydrophilic with thiol or amino groups. Hydrophobic organic molecules or polymers undergo Michael addition reaction and Schiff base reaction, and functional organic substances are introduced onto the surface of the material to make the surface of the material have special properties such as corrosion resistance, abrasion resistance, biological activity and biological phase. Capacitive and other features. Compared with other surface modification methods, the method of modifying the substrate by PDA is simple and convenient, independent of the geometry of the substrate to be modified, and the surface after modification has good chemical reactivity. However, the reaction process of polydopamine obtained by self-polymerization of dopamine by conventional impregnation method takes a long time, the dosage is large, and the uniformity of the modified film layer is poor. Therefore, it is particularly important to find a faster, simpler and more economical way to achieve surface modification of biomimetic polydopamine coatings.

Therefore, in order to solve the above problems, it is necessary to propose a further solution.

Summary of the invention

The technical problem solved by the present invention is to provide a method for preparing a platinum nanoparticle/titanium dioxide nanotube array to overcome the problems in the prior art.

The technical solution adopted by the present invention to solve the technical problem thereof is:

A method for preparing a platinum nanoparticle/titanium dioxide nanotube array, comprising:

Preparing an array of TiO ₂ nanotubes on the substrate by anodization, and then calcining the substrate;

Preparing a dopamine solution as an electrolyte, using the above substrate as a working electrode, a platinum electrode as a counter electrode, a silver electrode or a silver chloride electrode as a reference electrode, and placing the working electrode, the counter electrode and the reference electrode into the dopamine solution a TiO ₂ nanotube array loaded with a biomimetic polydopamine coating on the substrate by cyclic voltammetry on an electrochemical workstation;

A chloroplatinic acid solution was prepared, and the TiO ₂ nanotube array loaded with the biomimetic polydopamine coating on the above substrate was immersed in the chloroplatinic acid solution for a certain period of time to obtain a platinum nanoparticle/titanium dioxide nanotube array.

Further, the concentration of dopamine solution is 0.2-0.8 mg/ml, the pH of dopamine solution is 6.5-8.0, the voltage range of cyclic voltammetry is -1V to 1V, the number of scanning cycles is 15-35 laps, and the scanning rate is 50. -200mV/S.

Further, the concentration of the chloroplatinic acid solution is 0.1-0.8 mg/ml, and the immersion time of the titanium dioxide nanotube array loaded with the biomimetic polydopamine in the chloroplatinic acid is 1-5 h, and the platinum is induced by the dopamine during the impregnation process. The above reaction conditions: 60-100 ° C water bath shaking.

The present invention also provides an electrode provided with a platinum nanoparticle/titanium dioxide nanotube array prepared by the above preparation method.

The present invention also provides a non-enzymatic glucose sensor provided with a platinum nanoparticle/titanium dioxide nanotube array prepared by the above preparation method.

The present invention also provides a composite material provided with a platinum nanoparticle/titanium dioxide nanotube array prepared by the above preparation method.

The invention has the beneficial effects that the method for reducing platinum by electropolymerization loading biomimetic polydopamine solves the problems of long time and poor uniformity of the process in the self-polymerization of the dopamine conventional impregnation method. The invention has the advantages of simple and easy operation, controllable polydopamine film layer, and control of dispersion and size of platinum nanoparticles. The platinum nanoparticle-modified titanium dioxide nanotube array can improve the photoelectric effect of the titanium dioxide nanotube array on the one hand; on the other hand, improve the catalytic ability of the titanium dioxide nanotube array to achieve electrochemical degradation of methanol, formic acid, mercaptan and for fabrication Non-enzymatic glucose sensor. Compared with pure TiO ₂ , the photoelectric properties of platinum-loaded TiO ₂ nanotube arrays are significantly improved, and have good chemical stability and recyclability. Platinum nanoparticles/titanium dioxide nanotube arrays can be applied to photocatalytic degradation. Objects, non-enzymatic glucose sensors, fuel cells, Raman enhancement, etc., have the advantages of high precision, simple process, fast and economical.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a few embodiments described in the present invention, and other drawings can be obtained from those skilled in the art without any inventive effort.

1 is a schematic flow chart of a method for preparing a platinum nanoparticle/titanium dioxide nanotube array of the present invention.

2 is a cyclic voltammogram of the modification of a polydopamine coating onto a titania nanotube by electropolymerization in a platinum nanoparticle/titanium dioxide nanotube array prepared in Example 1. FIG.

3 is an SEM image of a platinum/titanium dioxide nanotube array prepared according to the present invention, the top four are front views, and the lower four are beveled views. Among them, (a), (b), (c), (d) are platinum nanoparticle-loaded titanium dioxide impregnated with chloroplatinic acid concentrations of 0.1 mg/ml, 0.2 mg/ml, 0.4 mg/ml, and 0.8 mg/ml, respectively. SEM image of the nanotube array.

4 is an SEM image of a conventional doped self-polymerization method and an electrochemical polymerization method for preparing platinum nanoparticles loaded on a titanium dioxide nanotube array by polydopamine. In the diagram (a), the platinum/titanium dioxide nanotube array is prepared by conventional self-polymerization polymerization. Dopamine, in (b), the platinum/titania nanotube array is prepared by electrochemical polymerization.

5 is an EDS and elemental distribution map of a platinum nanoparticle/titanium dioxide nanotube array prepared in Example 1;

6 is an XRD pattern of an unmodified TiO ₂ nanotube array and a platinum nanoparticle modified TiO ₂ nanotube array of a platinum nanoparticle/titanium dioxide nanotube array prepared in Example 1.

7 is a TEM, HRTEM, and selected area electron diffraction pattern of a platinum nanoparticle/titanium dioxide nanotube array prepared in Example 1. Views (a), (b) are TEMs of platinum nanoparticle/titanium dioxide nanotube arrays, view (c) is HRTEM of platinum nanoparticles/titanium dioxide nanotube arrays, and view (d) is a selected area electron diffraction pattern of view (c) (SAED).

8 is an XPS diagram of an unmodified TiO ₂ nanotube array and a platinum nanoparticle-modified TiO ₂ nanotube array of a silver nanoparticle/titanium dioxide nanotube array prepared in Example 2, wherein (a) is a full spectrum Figure (b) is a narrow spectrum of platinum.

9 embodiment is an ultraviolet absorption spectrum of FIG. 3 in the unmodified TiO ₂ nanotube array and different concentrations of platinum nanoparticles TiO ₂ modified embodiment nanotube array.

Example 4 FIG. 10 is a modified embodiment of the non-nanotube array TiO ₂ and varying concentrations of platinum nanoparticles modified TiO ₂ nano-tube array photocurrent of FIG.

11 is an impedance spectrum of an unmodified TiO ₂ nanotube array and a platinum nanoparticle-modified TiO ₂ nanotube array in the presence or absence of illumination in Example 1. FIG.

12 is an oxidation curve of a platinum-modified TiO ₂ nanotube array of Example 2 for different concentrations of glucose solution. The embedded map is a partial enlarged view of the glucose oxidation curve.

13 is a graph showing the response of an unmodified TiO ₂ nanotube array and a platinum-modified TiO ₂ nanotube array in Example 2 to a glucose solution. The embedded graph is a fitted curve of current density as a function of glucose concentration.

Fig. 14 is a graph showing the influence of the interference effect of platinum-modified TiO ₂ nanotube arrays on ascorbic acid, uric acid and the like in the non-enzymatic glucose sensor of Example 2.

detailed description

In order to make those skilled in the art better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. The embodiments are only a part of the embodiments of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of the present invention.

FIG. 1 is a schematic flow chart of a method for preparing a platinum nanoparticle/titanium dioxide nanotube array of the present invention.

S1. The base body can be selected from titanium sheets, and the titanium sheets are pretreated first.

Specifically, the titanium sheet is cleaned. Wherein, the titanium sheet is pure titanium or titanium alloy, and its size is 1.5 cm×3.0 cm. The titanium sheet was ultrasonically cleaned by dilute nitric acid, acetone, ethanol and deionized water for 20-40 min.

S2. Preparation of TiO ₂ nanotube array by anodization.

Specifically, the cleaned titanium sheet is used as an anode, the platinum sheet is used as a cathode, ammonium fluoride and water in an ethylene glycol solution are used as an electrolyte, a certain voltage is applied, anodization is performed twice, and anodization is performed to obtain TiO ₂ nanotubes. The array was recalcined to obtain a better crystalline anatase TiO ₂ nanotube array.

Among them, in the ethylene glycol solution, the mass percentage concentration of ammonium fluoride is 0.2-0.8 wt%, and the volume percentage concentration of water is 2.0-4.0 v%. The voltage for the first anodization is 40-60 V for 1-3 h, and the voltage for the second anodization is 40-60 V for 3-10 min. The prepared TiO2 nanotube array was calcined in air at a calcination temperature of 400-500 ° C, a calcination time of 1-3 h, and a calcination temperature rise and a temperature drop rate of 3-8 ° C/min. By calcination, a more crystalline anatase-type TiO ₂ nanotube array is obtained.

S3. A biomimetic polydopamine coating was constructed on TiO ₂ nanotubes by electropolymerization.

Specifically, the dopamine solution is prepared as an electrolyte, the TiO ₂ nanotube array obtained in step S2 is used as a working electrode, the platinum plate is used as a counter electrode, and silver/silver chloride is used as a reference electrode, and the cyclic voltammetry curve is scanned by an electrochemical workstation to obtain a load. A titanium dioxide nanotube array with a biomimetic polydopamine coating.

Specifically, the dopamine solubility is 0.2-0.8 mg/ml, and the solution pH is 6.5-8.0 (weak acid). Cyclic voltammetry has a voltage range of -1V to 1V, a scanning lap of 15-35 laps, and a scan rate of 50-200 mV/s. When the TiO ₂ nanotube array was cleaned, it was washed with deionized water at a drying condition of 80 ° C for 6 h.

S4. Based on the polydopamine coating, the platinum nanoparticles are supported on the surface of the titanium dioxide nanotubes by their own reducing properties.

Specifically, the concentration of the chloroplatinic acid solution is 0.1-0.8 mM, and the immersion time of the titanium dioxide nanotube array loaded with the biomimetic polydopamine in the chloroplatinic acid is 1-5 h, and the reaction conditions are: temperature (60-100 ° C), low speed oscillation.

The prepared substrate can be used as an electrode and can be widely used in the field of non-enzymatic glucose sensors.

The performance test of the non-enzymatic glucose sensor was performed using the prepared working electrode.

Specifically, the cycle voltage is -1V-0.8V, the number of scanning turns is 5-15 turns, and the scan rate is 20-100 mV/s. In the oxidation curve, the glucose concentration was 0-0.05 M, and in the interference curve, the glucose drop concentration was 0-10 mM, and the ascorbic acid and uric acid drop concentrations were 2 mM.

Further, it is defined that the TiO ₂ nanotube array in step S4 is immersed in a chloroplatinic acid solution, and the concentration of the precursor chloroplatinic acid solution is 0.1-0.8 mg/ml, and 0.1 Pt/TiO ₂ NTs in the figure indicates the precursor chloroplatinum. The acid concentration was 0.1 mg/ml, 0.2 Pt/TiO ₂ NTs indicates that the concentration of the precursor chloroplatinic acid was 0.2 mg/ml, and 0.4 Pt/TiO ₂ NTs indicates that the concentration of the precursor chloroplatinic acid was 0.4 mg/ml, 0.8. Pt/TiO ₂ NTs indicates that the concentration of the precursor chloroplatinic acid was 0.8 mg/ml.

As shown in Figures 3-1 and 3-2, an SEM image of a platinum nanoparticle/titanium dioxide nanotube array prepared in accordance with the present invention is shown. As can be seen from the figure, the length of the nanotubes in the platinum nanoparticle/titanium dioxide nanotube array is 2-4 μm, the diameter of the nanotubes is 80-100 nm, and the thickness of the tube wall is 10-20 nm.

The above described objects, features and advantages of the present invention will become more apparent from the aspects of the appended claims. However, the invention is not limited to the embodiments shown, but also includes any other known changes within the scope of the claims.

First, "an embodiment" or "an embodiment" as used herein refers to a particular feature, structure, or characteristic that can be included in at least one implementation of the invention. The appearances of the "in one embodiment", "a" or "an"

The present invention will be described in detail with reference to the accompanying drawings and the like. The scope.

In addition, the abbreviations of the letters mentioned in the present invention are fixed abbreviations in the field, and some of the letters are explained as follows: SEM image: electronic scanning image; TEM image: transmission electron scanning image; HRTEM image: high resolution Rate transmission electron scanning imaging; SAED: selected area electron diffraction pattern; EDS diagram: energy spectrum; XRD pattern: X-ray diffraction pattern; XPS spectrum: X-ray photoelectron spectroscopy spectrum.

Example 1

(1) Preparation of TiO ₂ nanotube array by pretreatment of titanium sheet and secondary anodization. The pure titanium substrate was ultrasonically washed with dilute nitric acid, acetone, absolute ethanol and deionized water for 15 min. The platinum plate electrode was used as the cathode, and an electrolyte solution containing 98 v% ethylene glycol (0.30 wt% ammonium fluoride) and 2 v% water was simultaneously inserted, and anodized at a voltage of 40 V for 1.5 h. After the ultrasonic layer was peeled off, 40 V was continuously applied. After anodizing for 8 min, a TiO ₂ nanotube array was prepared and calcined at 450 ° C for 2 h to transform it from an amorphous state to anatase.

(2) A platinum nanoparticle-composited titanium oxide nanotube array was prepared by electropolymerization of polydopamine-induced reduction. Prepare 50ml of 1.5mg/ml Tris, adjust the pH to 7.0, make buffer, add 0.1g of dopamine hydrochloride to obtain dopamine solution. After the solution is evenly dispersed, the TiO ₂ nanotube array in step S2 is used as the working electrode, platinum. sheet as a counter electrode, Ag / AgCl as a reference electrode, using an electrochemical workstation as a cyclic voltammetry curves, the scan voltage range -1V-1V, the rate of 80mV / S, the number of turns of the scanning circle 15, of the TiO ₂ nano The tube array is cleaned and dried to obtain a titanium dioxide nanotube array loaded with biomimetic polydopamine.

(3) Reducing precious metal platinum nanoparticles by dopamine, and setting different concentrations of chloroplatinic acid solution, 0.1mg/ml, 0.2mg/ml, 0.3mg/ml and 0.4mg/ml, respectively, to prepare the prepared polydopamine The titanium dioxide nanotubes were respectively immersed in different concentrations of chloroplatinic acid under the condition of 60 ° C water bath shaking, the immersion time was 2 h, and then taken out and washed with water to obtain a platinum nanoparticle/titanium dioxide nanotube array.

(5) Application of non-enzymatic glucose sensor to prepared platinum nanoparticle/titanium dioxide nanotube array: 0.1M sodium hydroxide solution is used as supporting electrolyte, platinum nanoparticle/titanium dioxide nanotube array is used as working electrode, platinum plate is used as pair The electrode, silver/silver chloride was used as the reference electrode, and the glucose was detected by the cyclic voltammetry curve of the electrochemical workstation. The glucose was sequentially added with a concentration of 5 mM, and further, the electrode performance interference detection was performed to test the interference of the prepared electrode against ascorbic acid and uric acid. Wherein the glucose addition concentration is 2-10 mM, and the concentration of uric acid and ascorbic acid is 2 mM.

As shown in Fig. 2, Fig. 2 is a cyclic voltammogram of the polydopamine coating modified onto the titanium dioxide nanotube by electropolymerization. The curve gradually stabilizes from the second scan.

As shown in FIGS. 3-1 and 3-2, FIGS. 3-1 and 3-2 are SEM topographies of the platinum nanoparticle/titanium dioxide nanotube array prepared in Example 1, and it can be seen that the platinum nanoparticles of 10-30 nm are known. It is deposited evenly on the surface and inside of the nanotube.

As shown in Figure 4, Figures (a) and (b) show polydopamine coatings by conventional self-polymerization and electrochemical polymerization, respectively. An SEM image of a platinum/titanium dioxide nanotube array was obtained. Among them, the two methods adopt the concentration of dopamine hydrochloride listed in Example 1, and are all immersed in the same concentration of chloroplatinic acid solution, the reaction conditions are the same, wherein the self-polymerization time by the conventional impregnation method is 24h, The time of the electrochemical polymerization method is about 6 minutes. From the SEM topography, the loading of platinum nanoparticles in the platinum/titanium dioxide nanotube array prepared by electrochemical impregnation method is significantly larger than that of the platinum/titanium dioxide nanotube array prepared by the traditional impregnation self-polymerization method. At the same time, the platinum nanoparticles have better dispersibility, which in turn indicates a more uniform polydopamine coating. Therefore, it can be concluded that the method of reducing platinum nanoparticles by electropolymerization loading biomimetic polydopamine solves the problems of long time and poor uniformity in the process of self-polymerization by the traditional impregnation method.

5 is a selected EDS and elemental distribution diagram of the platinum nanoparticle/titanium dioxide nanotube array prepared in Example 1, indicating that the platinum nanoparticle/titanium dioxide nanotube array mainly contains C, Ti, O, and Pt elements.

It can be seen from Fig. 6 that the unmodified TiO ₂ nanotubes are mainly composed of anatase and Ti substrates, and the peaks appearing at 25.3°, 37.9°, 48.0° and 53.9° correspond to anatase (101), (004), respectively. 200) and (105) crystal faces (JCPDS no. 21-1272). After depositing Pt nanoparticles in the TiO ₂ nanotube array, a peak appeared at 39.8°, corresponding to the (111) crystal plane of Pt (JCPDS no. 04-0802), and thus, consistent with the TEM results in FIG.

It can be seen from Fig. 7 that the TEM results further indicate that the platinum nanoparticles are uniformly distributed on the surface and inside of the TiO ₂ nanotubes, and the particle size is about 10 nm; the HRTEM and SAED images show that the lattice spacing of the TiO ₂ anatase (101) crystal face is 0.352. The interplanar spacing of nm and Pt(111) planes is 0.217 nm, which is consistent with the XRD test results of FIG.

Figure 8 is a full spectrum and a narrow spectrum of unmodified TiO ₂ nanotubes and platinum modified TiO ₂ nanotubes, except for O 1s (532.4 eV), Ti 2p (458.9 eV) and C 1s (284.5 eV) peaks, Pt 4f ( The presence of a 72.6 eV) peak demonstrates a Pt modified TiO ₂ nanotube array. It can be seen from the Pt 4f high-resolution XPS spectrum (b) that the peak spacing of Pt 4f7/2 (71.0 eV) and Pt 4f5/2 (74.4 eV) is 3.4 eV, which proves the existence of Pt ⁰

Further, as shown in FIGS. 9, 10 and 11, FIG. 9 is an ultraviolet absorption spectrum of an unmodified TiO ₂ nanotube array and a platinum/titania nanotube array of different concentrations; FIG. 10 is an unmodified TiO ₂ nanometer. Photocurrent profiles of tube arrays and platinum/titania nanotube arrays with different concentrations of modification; Figure 11 shows the AC impedance curves of unmodified TiO ₂ nanotube arrays and platinum/titania nanotube arrays in the presence or absence of light.

It can be seen from FIG. 9 that the absorption peak of the unmodified TiO ₂ nanotube is lower than 390 nm, and after the Pt nanoparticle is modified, the absorption intensity increases and the light absorption rate increases at 400-700 nm.

In Fig. 10, using 0.1M anhydrous sodium sulfate as an electrolyte, a xenon lamp (filtering a wavelength below 400 nm with a filter) simulates visible light, the distance from the light source to the beaker is 15 cm, and the light intensity is 60 mW/cm ² . The photocurrent test was carried out under the three-electrode system of the CHI660D electrochemical workstation. The photocurrent curves of unmodified TiO ₂ nanotubes and platinum nanoparticles/titanium dioxide nanotubes with different deposition concentrations in the visible range are shown. The photocurrent of the Pt/TiO ₂ nanotube array of 0.1-0.8 mg/ml was 0.050 mA/cm ² , 0.056 mA/cm ² , 0.072 mA/cm ² , and 0.042 mA/cm ² were unmodified TiO ₂ nanotubes, respectively. The photocurrent (0.004 mA/cm ² ) is 13 times, 14 times, 18 times, and 11 times, which means that the TiO2 nanotube array improves the separation efficiency of electron hole pairs after modifying the Pt nanoparticles.

In Fig. 11, with 0.1M anhydrous sodium sulfate as the electrolyte, a xenon lamp (filtering out the wavelength below 400 nm with a filter) simulates visible light, the distance from the light source to the beaker is 15 cm, and the light intensity is 60 mW/cm ² . The photocurrent test was carried out under the three-electrode system of the CHI660D electrochemical workstation. The graph shows the AC impedance spectra of unmodified TiO ₂ nanotube arrays and platinum/titanium dioxide nanotube arrays in the presence or absence of visible light, respectively. The arc diameter of the high frequency region characterizes the electron transfer process, and the smaller the diameter, The smaller the resistance. The impedance value of the platinum/titanium dioxide nanotube array is significantly smaller than that of the unmodified titanium dioxide nanotube array; under visible light irradiation, the array of platinum/titanium dioxide nanotubes is significantly smaller, showing superior photoelectric performance.

In Fig. 12, a 0.1 M sodium hydroxide solution is used as a supporting electrolyte, and an oxidation curve of a platinum/titanium dioxide nanotube array in a sodium hydroxide solution of different concentrations of glucose, wherein a peak of about -0.8 V is a glucose adsorption surface on the electrode surface. Electrochemical oxidation, a peak of about -0.4 V is the further oxidation of the intermediate produced by the electrochemical oxidation of glucose on the surface of the electrode. A peak of about 0.2 V is caused by the direct oxidation of glucose in the solution phase to the electrode. As the glucose concentration continues to increase, the peak value also increases.

Figure 13 is a glucose response step curve. The embedded graph is a linear fit curve of current density as a function of glucose concentration. The equation is y = 0.01518x + 0.7326 and R ² = 0.9765.

Figure 14 shows the interference of ascorbic acid and uric acid in the process of detecting glucose. The influence rate of glucose on current density is 100%, the influence rate of ascorbic acid on current density is about 4%, and the influence rate of uric acid on current density. It is about 0.3%.

Example 2

(1) Preparation of TiO ₂ nanotube array by pretreatment of titanium sheet and secondary anodization. The pure titanium substrate was ultrasonically washed with dilute nitric acid, acetone, absolute ethanol and deionized water for 10 min. Taking the platinum plate electrode as the cathode, inserting an electrolyte solution containing 97v% ethylene glycol (ammonium fluoride 0.4wt%) and 3v% water, anodizing with a voltage of 50V for 2h, after ultrasonically peeling off the film layer, continue to apply a voltage of 50V anode. After oxidation for 6 min, an array of TiO ₂ nanotubes was prepared and calcined at 450 ° C for 1.5 h to convert it from an amorphous state to anatase.

(2) A platinum nanoparticle-composited titanium oxide nanotube array was prepared by electropolymerization of polydopamine-induced reduction. Prepare 50ml of 1.2mg/ml Tris, adjust the pH to 7.5, make buffer, add 0.2g of dopamine hydrochloride to obtain dopamine solution. After the solution is evenly dispersed, the TiO ₂ nanotube array in step S2 is used as the working electrode, platinum. sheet as a counter electrode, Ag / AgCl as a reference electrode, using an electrochemical workstation as a cyclic voltammetry curve, a scanning voltage range of -1 ~ 1V, 100mV / S, a scanning rate of 20 turns the number of turns of TiO ₂ nano The tube array is cleaned and dried to obtain a titanium dioxide nanotube array loaded with biomimetic polydopamine.

(3) using dopamine to reduce the precious metal platinum, and arranging different concentrations of chloroplatinic acid solution, respectively, 0.05mg/ml, 0.1mg/ml, 0.2mg/ml and 0.4mg/ml, the prepared polydopamine-loaded titanium dioxide The nanotubes were immersed in different concentrations of chloroplatinic acid under the conditions of 70 ° C water bath shaking, immersion time was 3 h, then taken out of water and dried to obtain a platinum nanoparticle/titanium dioxide nanotube array.

(5) Application of non-enzymatic glucose sensor to prepared platinum nanoparticle/titanium dioxide nanotube array: 0.1M sodium hydroxide solution is used as supporting electrolyte, platinum nanoparticle/titanium dioxide nanotube array is used as working electrode, platinum plate is used as pair The electrode, silver/silver chloride was used as the reference electrode, and the glucose was detected by the cyclic voltammetry curve of the electrochemical workstation. The glucose was sequentially added with a concentration of 10 mM, and further, the electrode performance interference detection was performed to test the interference of the prepared electrode against ascorbic acid and uric acid. Wherein the glucose addition concentration is 5-10 mM, and the concentration of uric acid and ascorbic acid is 5 mM.

Example 3

(1) Preparation of TiO ₂ nanotube array by pretreatment of titanium sheet and secondary anodization. The pure titanium substrate was ultrasonically washed with dilute nitric acid, acetone, absolute ethanol and deionized water for 25 min. Taking the platinum plate electrode as the cathode, inserting an electrolyte solution containing 99v% ethylene glycol (0.15% by weight of ammonium fluoride) and 1v% water, anodizing with a voltage of 60V for 1 hour, and after ultrasonically peeling off the film layer, continue to apply a voltage of 60V anode. After oxidation for 5 min, a TiO ₂ nanotube array was prepared and calcined at 450 ° C for 1 h to convert it from an amorphous state to anatase.

(2) A platinum nanoparticle-composited titanium oxide nanotube array was prepared by electropolymerization of polydopamine-induced reduction. Prepare 50ml of 1.0mg/ml Tris, adjust the pH to 7.5, make buffer, add 0.3g of dopamine hydrochloride to obtain dopamine solution. After the solution is evenly dispersed, the TiO ₂ nanotube array in step S2 is used as the working electrode, platinum. sheet as a counter electrode, Ag / AgCl as a reference electrode, using an electrochemical workstation as cyclic voltammetry curve, the scanning voltage range of -1 ~ 1V, 150mV / S, scanning rate of 25 turns the number of turns of TiO ₂ nano The tube array is cleaned and dried to obtain a titanium dioxide nanotube array loaded with biomimetic polydopamine.

(3) using dopamine to induce the reduction of precious metal platinum, and arranging different concentrations of chloroplatinic acid solution, respectively 0.1mg/ml, 0.2mg/ml, 0.4mg/ml and 0.8mg/ml, the prepared polydopamine-loaded titanium dioxide The nanotubes were immersed in different concentrations of chloroplatinic acid under the conditions of 80 ° C water bath shaking, immersion time was 2.5 h, then taken out of water and dried to obtain a platinum nanoparticle/titanium dioxide nanotube array.

(5) Application of non-enzymatic glucose sensor to prepared platinum nanoparticle/titanium dioxide nanotube array: 0.1M sodium hydroxide solution is used as supporting electrolyte, platinum nanoparticle/titanium dioxide nanotube array is used as working electrode, platinum plate is used as pair The electrode, silver/silver chloride was used as the reference electrode, and the glucose was detected by the cyclic voltammetry curve of the electrochemical workstation. The glucose was sequentially added with a concentration of 3 mM. Further, the electrode performance interference detection was used to test the interference of the prepared electrode against ascorbic acid and uric acid. Wherein the glucose addition concentration is 1-5 mM, and the concentration of uric acid and ascorbic acid is 1 mM.

Example 4

(1) Preparation of TiO ₂ nanotube array by pretreatment of titanium sheet and secondary anodization. The pure titanium substrate was ultrasonically washed with dilute nitric acid, acetone, absolute ethanol and deionized water for 15 min. The platinum plate electrode was used as the cathode, and an electrolyte solution containing 98 v% ethylene glycol (0.30 wt% ammonium fluoride) and 2 v% water was inserted, and anodized with a voltage of 50 V for 2.5 h. After the ultrasonic layer was peeled off, 50 V was continuously applied. After anodizing for 10 min, an array of TiO ₂ nanotubes was prepared and calcined at 450 ° C for 2 h to convert it from an amorphous state to anatase.

(2) A platinum nanoparticle-composited titanium oxide nanotube array was prepared by electropolymerization of polydopamine-induced reduction. Prepare 50ml of 1.2mg/ml Tris, adjust the pH to 7.0, make buffer, add 0.4g of dopamine hydrochloride to obtain dopamine solution. After the solution is evenly dispersed, the TiO ₂ nanotube array in step S2 is used as the working electrode, platinum. sheet as a counter electrode, Ag / AgCl as a reference electrode, using an electrochemical workstation as a cyclic voltammetry curves, the scan voltage range -1V-1V, the rate of 50mV / S, the number of turns of the scanning circle 20, of the TiO ₂ nano The tube array is cleaned and dried to obtain a titanium dioxide nanotube array loaded with biomimetic polydopamine.

(3) using dopamine to induce the reduction of precious metal platinum, and arranging different concentrations of chloroplatinic acid solution, respectively 0.1mg/ml, 0.2mg/ml, 0.3mg/ml and 0.4mg/ml, the prepared polydopamine-loaded titanium dioxide The nanotubes were immersed in different concentrations of chloroplatinic acid under the conditions of 90 ° C water bath shaking, the immersion time was 2 h, then taken out of water and dried to obtain a platinum nanoparticle/titanium dioxide nanotube array.

(5) Application of non-enzymatic glucose sensor to prepared platinum nanoparticle/titanium dioxide nanotube array: 0.1M sodium hydroxide solution is used as supporting electrolyte, platinum nanoparticle/titanium dioxide nanotube array is used as working electrode, platinum plate is used as pair The electrode, silver/silver chloride was used as the reference electrode, and the glucose was detected by the cyclic voltammetry curve of the electrochemical workstation. The glucose was sequentially added with a concentration of 4 mM, and further, the electrode performance interference detection was performed to test the interference of the prepared electrode against ascorbic acid and uric acid. Wherein the glucose addition concentration is 2-10 mM, and the concentration of uric acid and ascorbic acid is 2 mM.

Compared with the prior art, the beneficial effects of the invention are: the platinum nanoparticle/titanium dioxide nanotube array of the invention adopts the method of electropolymerization loading biomimetic polydopamine to realize the reduction of platinum nanoparticles, and solves the self-polymerization process of the traditional dopamine impregnation method. The problem of long time consumption and poor uniformity is that the process is simple and easy to operate, the polydopamine film layer can be controlled, and the dispersion and size of the platinum nanoparticles are controlled at the same time. Platinum nanoparticles modified TiO ₂ nanotube arrays aspect TiO ₂ can improve the photoelectric effect of the nanotube array; on the other hand to improve the catalytic performance of TiO ₂ nanotube arrays, to achieve the electrochemical degradation of methanol, formic acid, and thiol Used to make non-enzymatic glucose sensors. Compared with pure TiO ₂ , the photoelectric properties of platinum-loaded TiO ₂ nanotube arrays are significantly improved, and have good chemical stability and recyclability. Platinum nanoparticles/titanium dioxide nanotube arrays can be applied to photocatalytic degradation. Objects, non-enzymatic glucose sensors, fuel cells, Raman enhancement, etc., have the advantages of high precision, simple process, fast and economical.

It will be apparent to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and The invention may be embodied in other specific forms without departing from the spirit and scope of the invention. Therefore, the present embodiments are to be considered as illustrative and not restrictive, and the scope of the invention is defined by the appended claims instead All changes in the meaning and scope of equivalent elements are included in the present invention. Any reference signs in the claims should not be construed as limiting the claim.

In addition, it should be understood that although the description is described in terms of embodiments, not every embodiment includes only one independent technical solution. The description of the specification is merely for the sake of clarity, and those skilled in the art should regard the specification as a whole. The technical solutions in the respective embodiments may also be combined as appropriate to form other embodiments that can be understood by those skilled in the art.

Claims

A method for preparing a platinum nanoparticle/titanium dioxide nanotube array, comprising:

Preparing an array of TiO 2 nanotubes on the substrate by anodization, and then calcining the substrate;

Preparing a dopamine solution as an electrolyte, using the above substrate as a working electrode, a platinum electrode as a counter electrode, a silver electrode or a silver chloride electrode as a reference electrode, and placing the working electrode, the counter electrode and the reference electrode into the dopamine solution a TiO 2 nanotube array loaded with a biomimetic polydopamine coating on the substrate by cyclic voltammetry on an electrochemical workstation;

A chloroplatinic acid solution was prepared, and the TiO 2 nanotube array loaded with the biomimetic polydopamine coating on the above substrate was immersed in the chloroplatinic acid solution for a certain period of time to obtain a platinum nanoparticle/titanium dioxide nanotube array.
The method for preparing a platinum nanoparticle/titanium dioxide nanotube array according to claim 1, wherein:

Dopamine solution concentration is 0.2-0.8mg/ml, dopamine solution pH is 6.5-8.0, cyclic voltammetry voltage range is -1V to 1V, scanning lap is 15-35 laps, scanning rate is 50-200mV/S .
The method for preparing a platinum nanoparticle/titanium dioxide nanotube array according to claim 1, wherein:

The concentration of the chloroplatinic acid solution is 0.1-0.8 mg/ml, and the immersion time of the titanium dioxide nanotube array loaded with the biomimetic polydopamine in the chloroplatinic acid is 1-5 hours, and the platinum is induced by the dopamine in the impregnation process. Conditions: 60-100 ° C water bath shaking.
An electrode characterized in that the electrode is provided with a platinum nanoparticle/titanium dioxide nanotube array produced by the production method of claim 1, 2 or 3.
A non-enzymatic glucose sensor characterized in that the non-enzymatic glucose sensor is provided with a platinum nanoparticle/titanium dioxide nanotube array prepared by the preparation method of claim 1, 2 or 3.
A composite material characterized in that the composite material is provided with a platinum nanoparticle/titanium dioxide nanotube array prepared by the production method of claim 1, 2 or 3.