阅读说明：本技术 一种AgBiS2敏化TiO2复合膜材料的应用 (AgBiS2Sensitized TiO2Application of composite membrane material ) 是由 王宁 王静 刘梦楠 段继周 侯保荣 戈成岳 张冉 舒向泉 贺永鹏 林建康 乔泽 于 2020-12-24 设计创作，主要内容包括：本发明涉及一种复合膜光阳极材料,尤其是涉及一种AgBiS-2敏化TiO-2复合膜材料(AgBiS-2/TiO-2纳米管阵列复合薄膜材料)及其制备和应用。本发明的复合膜结构为AgBiS-2纳米颗粒沉积于TiO-2纳米管阵列薄膜表面上。AgBiS-2纳米颗粒复合后,TiO-2对可见光的响应显著增强,光电化学性能明显提高,且半导体复合后匹配的能带位置能够驱动光生载流子对的快速分离,降低复合率。本发明的AgBiS-2敏化TiO-2纳米管阵列复合薄膜,作为光阳极材料进行阴极保护时,相比TiO-2材料而言,显著提高了可见光的利用率和光生载流子对的分离率,降低了304不锈钢的电极电位,降低腐蚀速率,极大地提升了光电化学阴极保护性能。(The invention relates to a composite film photo-anode material, in particular to AgBiS 2 Sensitized TiO 2 Composite film material (AgBiS) 2 /TiO 2 Nanotube array composite film material), and preparation and application thereof. The composite membrane structure of the invention is AgBiS 2 Deposition of nanoparticles on TiO 2 The nanotube array film surface. AgBiS 2 After the nanoparticles are compounded, TiO 2 The response to visible light is obviously enhanced, the photoelectrochemical performance is obviously improved, and the matched energy band position after the semiconductor is compounded can drive the photo-generated carrier pair to be quickly separated, so that the compounding rate is reduced. AgBiS of the invention 2 Sensitized TiO 2 The nanotube array composite film is used as a photoanode material for cathodic protection, compared with TiO 2 In terms of materials, the utilization rate of visible light and the separation rate of photo-generated carrier pairs are obviously improved, the electrode potential of 304 stainless steel is reduced, the corrosion rate is reduced, and the photoelectrochemistry cathodic protection performance is greatly improved.)

1. AgBiS₂Sensitized TiO₂The application of the composite membrane material is characterized in that: AgBiS₂Sensitized TiO₂The composite film material is applied to photoelectrochemical cathodic protection of metal.

2. The AgBiS of claim 1₂Sensitized TiO₂The application of the composite membrane material is characterized in that: the composite film is madeIs used as photo-anode material in photoelectrochemical cathodic protection.

3. The AgBiS of claim 1₂Sensitized TiO₂The application of the composite membrane material is characterized in that: the composite film material is applied to the photoelectrochemistry cathode protection of metal as an anti-corrosion protective film.

4. The AgBiS of claim 1₂Sensitized TiO₂The application of the composite membrane material is characterized in that: the composite film material loads TiO on the surface₂Dipping the matrix of the nanotube array film into a solution containing Ag, S and Bi ions to perform a continuous ion layer deposition reaction on the TiO₂Formation of Ag on the surface of nanotube array film₂S and Bi₂S₃The nano particles are calcined to obtain AgBiS₂Nanoparticle sensitized TiO₂Nanotube array composite membranes.

5. The AgBiS according to claim 4₂Sensitized TiO₂The application of the composite membrane material is characterized in that: the surface is loaded with TiO₂Soaking the substrate of the nanotube array film into a solution containing Ag, S and Bi ions to perform continuous ion layer deposition reaction to load TiO on the surface₂Sequentially carrying out Ag on the substrate of the nanotube array film₂S deposition cycle and Bi₂S₃Deposition cycle of TiO₂Formation of Ag on the surface of nanotube array film₂S and Bi₂S₃Nanoparticles, wherein each cycle is performed at least once.

6. The AgBiS of claim 5₂Sensitized TiO₂The application of the composite membrane material is characterized in that: the Ag is₂S deposition cycle is to load TiO on the surface₂Firstly, immersing a substrate of the nanotube array film into AgNO containing 0.05-0.1M₃Soaking in ethanol solution for 10-20 s, washing with anhydrous ethanol, and immediately soaking in 0.05-0.1M Na₂Soaking in S methanol solution for 10-20S, and cleaning with absolute ethyl alcohol to obtain the finished productFormed into one time Ag₂S, deposition circulation; repeatedly performing the deposition cycle for several times to obtain Ag₂S deposition cycle, so that in TiO₂Formation of Ag on the surface of nanotube array film₂And (3) S nanoparticles.

7. The AgBiS of claim 5₂Sensitized TiO₂The application of the composite membrane material is characterized in that: the Bi₂S₃The deposition cycle is to form Ag on the surface₂TiO of S nanoparticles₂The matrix of the nanotube array film is first immersed in a solution containing 0.05-0.1M Bi (NO)₃)₃Soaking in acetone solution for 10-20 s, washing with anhydrous ethanol, and immediately soaking in 0.05-0.1M Na₂S methanol solution is dipped for 10 to 20S, washed by absolute ethyl alcohol and then dipped into 0.05 to 0.1M Bi (NO)₃)₃Soaking in acetone solution for 10-20 s, washing with anhydrous ethanol, and immediately soaking in 0.05-0.1M Na₂S, soaking in methanol solution for 10-20S, and cleaning with absolute ethyl alcohol to obtain Bi for one time₂S₃Deposition circulation; repeatedly performing the deposition cycle for a plurality of times to realize the repeated deposition of Bi₂S₃Deposition cycle of TiO₂Ag is formed on the surface of the nanotube₂S and Bi₂S₃And (3) nanoparticles.

8. The AgBiS of claim 5₂Sensitized TiO₂The application of the composite membrane material is characterized in that: the calcination is to form Ag on the surface₂S、Bi₂S₃TiO nanoparticles₂Placing the substrate of the nanotube array film in a muffle furnace, setting the temperature to be 100-150 ℃, calcining for 1-1.5 h under the condition of nitrogen flow, and obtaining AgBiS on the surface of the substrate₂Sensitized TiO₂A composite membrane material.

Technical Field

The invention relates to a composite film photo-anode material, in particular to AgBiS₂Sensitized TiO₂Application of composite membrane material.

Background

The photoelectrochemistry cathodic protection technology is a corrosion protection technology for converting solar energy into electrochemical energy required by metal corrosion, can coat a semiconductor on the surface of protected metal, and can be used as a photoanode to be connected with the metal through a lead, thereby generating cathodic protection effect on the metal. Under the condition of illumination, after the energy of light radiation on the semiconductor is higher than the band gap, electrons in the valence band are activated and transited to the conduction band to become freely moving photo-generated electrons, if the potential of the conduction band of the semiconductor is more negative than the self-corrosion potential of metal, a large number of photo-generated electrons are transferred to the metal substrate, the metal is in an electron-rich state, the potential of the metal substrate becomes more negative than the self-corrosion potential of the metal, and the metal is in an oxidation resistant state, so that the effect of cathodic protection is achieved.

TiO₂The semiconductor material has the advantages of excellent photoelectric performance, stable physical and chemical properties, low toxicity, abundant resources and low manufacturing cost, and can be widely applied to the field of photoelectrochemical cathode protection. The application of semiconductor materials in the field of photoelectrochemical cathode protection needs to meet certain conditions. First, the conduction band potential of the semiconductor must be lower than that of the semiconductor in the same solventSelf-corrosion potential in the liquid; secondly, the forbidden bandwidth of the semiconductor material cannot be too wide; third, the photocarrier pairs of the semiconductor are easy to separate and have low recombination rates. However, TiO₂The band gap is wider (3.2eV), only ultraviolet light with the wavelength less than 378nm can be absorbed, and the utilization rate of visible light is low; and the photo-excited electron-hole pairs are easy to recombine, the light quantum efficiency is low, and TiO is in the dark condition₂The photoelectrochemical cathodic protection effect cannot be exerted. Therefore, finding a material with narrow band gap to be compounded with and improve the separation rate of photo-generated carrier pairs is to improve TiO₂The important research direction of photoelectric conversion performance.

AgBiS₂Is a nontoxic I-V-VI group ternary chalcogenide semiconductor material, has the advantages of wide intrinsic absorption spectrum, high extinction coefficient, good conductivity and the like, has the forbidden bandwidth of 1.2eV, is a narrow band gap material with excellent performance, and is compounded to TiO₂The nano-wire surface can widen the absorption range of light and increase the utilization rate of light. AgBiS₂Crystal used as narrow forbidden band semiconductor to modify TiO₂The application of (2) has also progressed. Pen-Chi Huang, Wei-Chih Yang and Ming-Way Lee et al use continuous ion-shell adsorption on TiO₂Deposition of AgBiS on thin films₂Crystals of such that TiO₂The light absorption property of the composition is greatly improved, the composition is extended from an ultraviolet spectrum region to a visible spectrum region, and AgBiS is used₂/TiO₂The photocurrent density of the solar cell prepared from the composite material is 7.61mA/cm²The open circuit potential was 0.18V, and the light energy conversion efficiency was improved to 0.53%. Electrochemical atomic layer deposition method on TiO by Shuqin Zhou, Junyou Yang and Xin Li et al₂Depositing quantum dots AgBiS on surface of nanorod₂The compound has excellent effect when being applied to a dye-sensitized solar cell, the conversion efficiency is 0.95 percent, and the photocurrent density can reach 4.22mA/cm²The open circuit potential value was 0.53V. But AgBiS₂TiO modified as narrow-forbidden band photoelectric semiconductor material₂The research of the nanotube array film in photoproduction cathode protection metal has not been found yet.

Disclosure of Invention

The invention aims toProviding an AgBiS₂Sensitized TiO₂Application of composite membrane material.

In order to achieve the purpose, the invention adopts the technical scheme that:

AgBiS₂Sensitized TiO₂Use of composite film material, AgBiS₂Sensitized TiO₂The composite film material is applied to photoelectrochemical cathodic protection of metal.

The composite film is used as a photo-anode material and is applied to photoelectrochemical cathode protection.

The composite film material is applied to the photoelectrochemistry cathode protection of metal as an anti-corrosion protective film.

The composite film material loads TiO on the surface₂Dipping the matrix of the nanotube array film into a solution containing Ag, S and Bi ions to perform a continuous ion layer deposition reaction on the TiO₂Formation of Ag on the surface of nanotube array film₂S and Bi₂S₃The nano particles are calcined to obtain AgBiS₂Nanoparticle sensitized TiO₂Nanotube array composite membranes.

The surface is loaded with TiO₂Soaking the substrate of the nanotube array film into a solution containing Ag, S and Bi ions to perform continuous ion layer deposition reaction to load TiO on the surface₂Sequentially carrying out Ag on the substrate of the nanotube array film₂S deposition cycle and Bi₂S₃Deposition cycle of TiO₂Formation of Ag on the surface of nanotube array film₂S and Bi₂S₃Nanoparticles, wherein each cycle is performed at least once.

The Ag is₂S deposition cycle is to load TiO on the surface₂Firstly, immersing a substrate of the nanotube array film into AgNO containing 0.05-0.1M₃Soaking in ethanol solution for 10-20 s, washing with anhydrous ethanol, and immediately soaking in 0.05-0.1M Na₂Soaking in S methanol solution for 10-20S, and cleaning with absolute ethyl alcohol to obtain the primary Ag₂S, deposition circulation; repeatedly performing the deposition cycle for several times to obtain Ag₂S deposition cycle, so that in TiO₂Formation of Ag on the surface of nanotube array film₂And (3) S nanoparticles.

The Bi₂S₃The deposition cycle is to form Ag on the surface₂TiO of S nanoparticles₂The matrix of the nanotube array film is first immersed in a solution containing 0.05-0.1M Bi (NO)₃)₃Soaking in acetone solution for 10-20 s, washing with anhydrous ethanol, and immediately soaking in 0.05-0.1M Na₂S methanol solution is dipped for 10 to 20S, washed by absolute ethyl alcohol and then dipped into 0.05 to 0.1M Bi (NO)₃)₃Soaking in acetone solution for 10-20 s, washing with anhydrous ethanol, and immediately soaking in 0.05-0.1M Na₂S, soaking in methanol solution for 10-20S, and cleaning with absolute ethyl alcohol to obtain Bi for one time₂S₃Deposition circulation; repeatedly performing the deposition cycle for a plurality of times to realize the repeated deposition of Bi₂S₃Deposition cycle of TiO₂Ag is formed on the surface of the nanotube₂S and Bi₂S₃And (3) nanoparticles.

The calcination is to form Ag on the surface₂S、Bi₂S₃TiO nanoparticles₂Placing the substrate of the nanotube array film in a muffle furnace, setting the temperature to be 100-150 ℃, calcining for 1-1.5 h under the condition of nitrogen flow, and obtaining AgBiS on the surface of the substrate₂Sensitized TiO₂A composite membrane material.

The above-mentioned surface-supported TiO₂The matrix of the nanotube array film is TiO obtained on the surface of a titanium matrix by an anodic oxidation method₂A nanotube array film.

The anodic oxidation method is characterized in that a titanium metal plate with a certain size is cut, cleaned and polished to serve as a photo-anode, a platinum sheet is used as a cathode, the photo-anode and the platinum sheet are placed in electrolyte together, and a constant potential of 10-20V is applied for anodic oxidation for 1-1.5 hours. And (3) washing the obtained material with deionized water, placing the washed material in a muffle furnace at 400-450 ℃ for calcining for 1.5-2 h, taking out the calcined material and placing the calcined material in a dust-free dryer for later use.

The electrolyte is glycol and NH₄F and deionized water, wherein the alcohol is ethylene glycol and NH₄The volume ratio of the F solution is 10-20, NH₄The mass fraction of the solution F is3～7wt％。

Further, the Ag₂S deposition cycle refers to loading TiO on the surface₂Firstly, immersing a substrate of the nanotube array film into AgNO containing 0.05-0.1M₃Soaking in an ethanol solution for 10-20 s, cleaning with absolute ethanol, and drying with air flow; then immediately immersing in Na containing 0.05-0.1M₂Soaking in S methanol solution for 10-20S, washing with absolute ethyl alcohol, and drying with air flow to obtain the primary Ag₂And S, deposition circulation.

The AgNO₃The ethanol solution is 0.6-1.2 g AgNO₃Dissolving in 70mL of ethanol to obtain 0.05-0.1M AgNO₃Ethanol solution. The Na is₂The S methanol solution is 0.8-1.7 g of Na₂S·9H₂Dissolving O in 70mL of methanol to obtain 0.05-0.1M of Na₂S methanol solution.

The Bi₂S₃The deposition cycle is to form Ag on the surface₂TiO of S nanoparticles₂The matrix of the nanotube array film is first immersed in a solution containing 0.05-0.1M Bi (NO)₃)₃Soaking in acetone solution for 10-20 s, washing with anhydrous ethanol, drying with air flow, and immediately soaking in Na containing 0.05-0.1M₂S, soaking in a methanol solution for 10-20S, cleaning with absolute ethyl alcohol, and drying with air flow; then, the substrate is immersed in Bi (NO) of 0.05 to 0.1M₃)₃Soaking in acetone solution for 10-20 s, washing with anhydrous ethanol, drying with air flow, and immediately soaking in Na containing 0.05-0.1M₂S, soaking in methanol solution for 10-20S, washing with absolute ethyl alcohol, and drying with air flow to obtain primary Bi₂S₃And (5) deposition circulation.

The Bi (NO)₃)₃The acetone solution is prepared by weighing 1.4-2.8 g of Bi (NO)₃)₃Dissolving in 70mL acetone to obtain 0.05-0.1M Bi (NO)₃)₃Acetone solution. The Na is₂The S methanol solution is 0.8-1.7 g of Na₂S·9H₂Dissolving O in 70mL of methanol to obtain 0.05-0.1M of Na₂S methanol solution.

The reaction mainly occurs in the process, and the chemical reaction equation is as follows:

2AgNO₃+Na₂S＝Ag₂S+2NaNO₃ (1)

2Bi(NO₃)₃+3Na₂S＝Bi₂S₃+6NaNO₃ (2)

Ag₂S+Bi2S₃＝2AgBiS₂ (3)

the AgBiS₂/TiO₂The photoelectrochemical cathode protection test method of the nanotube array composite membrane comprises the following steps: the device for characterizing the photoelectric properties is filled with 0.1M Na₂S solution single system of photoelectrolysis cell; the electrochemical workstation is CHI660E, the photoanode is connected with the working electrode, the counter electrode is a platinum electrode, and the counter electrode is in short circuit with the counter reference electrode and is connected with the grounding terminal. The device for testing the protection performance of the photoelectrochemical cathode comprises an etching pool filled with 3.5 wt% NaCl solution and a sample tank filled with 0.1M Na₂And the two electrolytic cells are connected by a nafion membrane. Electrochemical measurements electrochemical work stations with a three-electrode system (P4000+, USA): AgBiS₂/TiO₂The nanotube array composite membrane is used as a photo-anode, a platinum sheet is used as a counter electrode, a saturated calomel electrode is used as a reference electrode, a 304 stainless steel electrode and the photo-anode are connected by a copper wire to be used as a working electrode, and an open-circuit potential time curve and a photocurrent density time curve are tested. The light source is a 300W high-pressure xenon lamp, and the wavelength of the irradiation light source is visible light with the wavelength of more than 400 nm. Simulating visible light by using a xenon lamp, and directly irradiating AgBiS₂/TiO₂The surface of the nanotube array composite membrane. Open circuit potential diagram coupling composite membrane and 304 stainless steel with TiO₂The open circuit potential diagrams of the membrane and the 304 stainless steel coupling are compared to obtain the difference of the protection effects of the two.

The basic principle of the invention is as follows:

semiconductors have a unique energy band structure, and upon irradiation of light, the semiconductor absorbs photons of light of a sufficiently high frequency, and electrons are excited to transition from the valence band to the conduction band. In the same solution, when the potential of the conduction band of the semiconductor is negative to that of the metal, electrons can migrate from the semiconductor to the metal with lower potential, and cathodic protection of the metal material is realized. TiO 2₂Is aThe wide band gap semiconductor has band gap of 3.2eV, and only ultraviolet light with wavelength less than 378nm and high energy can excite TiO₂The wavelength range of visible light of electrons in a semiconductor valence band is about 400-800 nm, and the energy of ultraviolet light only accounts for 4% of solar illumination, so that TiO₂The utilization rate of visible light is low. In addition to this, photo-excited TiO₂The generated photo-generated carriers are easy to compound, the photon quantum efficiency is low, the photoelectric conversion efficiency is low, and the electrochemical cathodic protection effect on metal can not be exerted under the dark condition. AgBiS₂The optical waveguide has the advantages of narrow forbidden band width, high utilization rate of light, wide intrinsic absorption spectrum, high extinction coefficient, good conductivity and the like. Thus, compared to TiO₂In other words, AgBiS₂/TiO₂The composite film not only can be used for dissolving TiO₂The light absorption range of the solar cell widens to a visible light area, so that the solar energy utilization rate is improved, the matching energy band structure also reduces the recombination rate of photon-generated carriers, the separation rate is improved, more electrons migrate to a metal surface with high potential, and the corrosion protection effect on metal is effectively improved.

The invention has the advantages that:

AgBiS is prepared by the invention₂Nanoparticles and TiO₂The nanotube is compounded, so that not only TiO is obviously enhanced₂The response to light improves the utilization rate of sunlight, effectively reduces the recombination rate of photo-generated carrier pairs, further reduces the electrode potential of metal, and obviously improves TiO₂The cathodic protection effect of (1). The method specifically comprises the following steps:

1. the photo-anode AgBiS of the invention₂/TiO₂The nanotube array composite membrane has uniform tube diameter and narrow forbidden band width of AgBiS₂The modification of (3) can greatly improve the separation rate of photo-generated carrier pairs, enhance the photoelectric conversion capability and effectively improve the utilization rate of sunlight.

2. The photo anode AgBiS₂/TiO₂The nanotube array composite membrane is placed in an electrolyte solution and coupled with 304 stainless steel for a photoelectrochemical cathodic protection test. 304 stainless steel coupled with composite material under irradiation of visible lightThe open-circuit potential of the steel can be reduced to about-900 mV, which is far lower than the self-corrosion potential, indicating AgBiS under illumination₂/TiO₂The nanotube array composite membrane has good cathodic protection effect on 304 stainless steel; under dark conditions, the electrode potential of the stainless steel was maintained at-700 mV vs. AgSbS₂/TiO₂The nanotube array composite membrane has lower corrosion potential, which indicates that the composite membrane in a dark state can play a more effective photoelectrochemical cathode protection role on 304 stainless steel.

In conclusion, the AgBiS prepared by the anodic oxidation method and the continuous ion layer deposition method is adopted in the invention₂/TiO₂When the nanotube array composite film is used as a photo-anode, the cathode protection effect on 304 stainless steel is greatly improved, and the nanotube array composite film is an excellent anti-corrosion protection material.

Drawings

FIG. 1 shows pure TiO provided in the examples of the present invention₂Nanotube film and AgBiS₂/TiO₂Schematic diagram of a photocurrent density testing device of the nano composite film.

FIG. 2 shows pure TiO provided in the examples of the present invention₂Nanotube film and AgBiS₂/TiO₂Electrochemical testing device diagram of the nano composite film.

FIG. 3 shows pure TiO provided in the examples of the present invention₂Nanotube film (a) and AgBiS₂/TiO₂XRD pattern of nanocomposite film (b).

FIG. 4 shows TiO provided in an embodiment of the present invention₂Nanotubes (a) and AgBiS₂AgBiS with different deposition cycle times₂/TiO₂SEM images of nanotube array composite membranes (b-d).

FIG. 5 shows AgBiS according to an embodiment of the present invention₂/TiO₂XPS full spectrum (a), Bi4f (b), Ag3d (c), S2S (d) and Ti2p (e) of the nanotube array composite membrane are high-resolution XPS spectrums.

FIG. 6 shows pure TiO provided in the examples of the present invention₂Nanotube array film (a) and AgBiS₂/TiO₂Ultraviolet-visible absorption spectrum of nanocomposite film (b).

FIG. 7 shows a graph T according to an embodiment of the present inventioniO₂Nanotube array film and AgBiS₂AgBiS prepared under different deposition cycle times₂/TiO₂The composite film as a photoanode under intermittent visible light and 0.1M Na₂SO₄The photocurrent density time curve was measured in solution. Wherein light on indicates turning on the light source, light off indicates turning off the light source, and the abscissa is time(s) and the ordinate is photocurrent density (μ A · cm)^-2)。

FIG. 8 shows a 304 stainless steel electrode and pure TiO provided in accordance with an embodiment of the present invention₂Nanotube array film and AgBiS₂AgBiS prepared under different deposition cycle times₂/TiO₂Open circuit potential time profiles under intermittent visible light and in 3.5 wt% NaCl electrolyte when the nanocomposite films were connected as photoanodes. Wherein light on means to turn on the light source and light off means to turn off the light source. Time(s) on the abscissa and voltage (V vs. sce) on the ordinate.

Detailed Description

The invention is further explained below with reference to examples and figures.

The composite membrane structure of the invention is AgBiS₂Deposition of nanoparticles on TiO₂On the surface of the nanotubes. AgBiS₂After sensitization of the nanoparticles, TiO₂The response to a visible light region is obviously enhanced, and the matching energy band position after the semiconductor is compounded can improve the separation rate of photon-generated carriers. AgBiS of the invention₂Sensitized TiO₂The nanotube array composite film is used as a photoanode material for cathodic protection, compared with TiO₂As for the material, the utilization rate of visible light and the separation rate of photon-generated carriers are greatly improved, the electrode potential of 304 stainless steel is obviously reduced, the corrosion rate is reduced, and the photoelectrochemistry cathode protection effect is enhanced.

Further, the invention uses AgBiS₂Narrow band gap and photogenerated carrier in TiO₂The characteristic of fast transmission in the nanotube is combined, and the TiO is enhanced₂The utilization rate of visible light is increased, and the separation rate of photon-generated carriers is increased, so that more photon-generated electrons are transferred to protected metal, and photoelectricity is enhancedThe chemical cathode protection effect can be used in the field of cathode protection of metal materials.

Example 1

The preparation of the photo-anode comprises the following steps:

pretreatment of a titanium substrate: cutting an industrial titanium metal plate (20mm multiplied by 10mm multiplied by 0.3mm) with the purity of more than 99.6 percent as a growth substrate of the composite membrane, sequentially carrying out ultrasonic cleaning by acetone, absolute ethyl alcohol and ultrapure water for 10min, 10min and 30min respectively, and blow-drying for later use. 0.9g of NH are weighed₄F, dissolved in 4mL deionized water and concentrated HNO metered in a fume hood₃And 30% H₂O₂Each 12mL of the solution is placed in a beaker to be mixed, and the solution is mixed uniformly by ultrasonic treatment for 5min to prepare the polishing solution. And (3) selecting a flat and scratch-free titanium sheet, soaking the titanium sheet in a small amount of polishing solution for 15s, taking out the titanium sheet, and ultrasonically cleaning the titanium sheet for 30min by using deionized water. Placing the polished titanium sheet into a container containing absolute ethyl alcohol in volume ratio: deionized water 1: 1, and storing for use.

TiO₂Preparing a nanotube array film: weighing 0.44gNH₄And F, dissolving in 8mL of deionized water, and uniformly stirring. 80mL of ethylene glycol and NH are measured₄And mixing the solutions F, and uniformly stirring to prepare the anodic oxidation electrolyte. And pouring 80mL of electrolyte into a 100mL beaker, taking the polished titanium sheet as an anode and the polished platinum sheet as a counter electrode, clamping the titanium sheet and the platinum electrode by using a clamp, placing the titanium sheet and the platinum electrode into the electrolyte, and respectively connecting the anode and the cathode of a direct current power supply. Setting the voltage of a direct current power supply to be 20V, after anodizing for 1h, cleaning a titanium sheet by using ethanol and deionized water, drying the titanium sheet, sintering the titanium sheet in a muffle furnace at the set temperature of 450 ℃ for 2h, cooling the titanium sheet to room temperature along with the furnace, taking the titanium sheet out, placing the titanium sheet in a dust-free drier for later use, and obtaining TiO on the surface of the titanium sheet₂A nanotube array film.

AgBiS₂/TiO₂Preparing a nanotube array composite membrane: weighing 1.19g AgNO₃Dissolving in 70mL ethanol solution, stirring at room temperature for 60min to obtain 0.1M AgNO at 25 deg.C₃Ethanol solution; weighing 1.68g Na₂S·9H₂Dissolving O in 70mL of methanol, and stirring at room temperature for 20min to obtain 0.1M Na at 25 ℃₂S methanol solution. Balance2.765g of Bi (NO) are taken₃)₃Dissolving in 70mL acetone, heating and stirring for 20min to obtain 0.1M Bi (NO) at 40 deg.C₃)₃Acetone solution; weighing 1.68g Na₂S·9H₂Dissolving O in 70mL methanol, heating and stirring for 20min to obtain 0.1M Na at 40 deg.C₂S methanol solution. After the solution is completely dissolved and configured, loading TiO on the surface₂The titanium sheet of the nanotube array film is immersed in the 0.1MAGNO film at 25 ℃ prepared in the above way₃Soaking in ethanol solution for 10s, immediately washing with anhydrous ethanol for 3s, and drying with air flow; then, the titanium plate was immersed in 0.1M Na at 25 ℃ in the above-mentioned configuration₂Soaking in S-methanol solution for 20S, immediately washing with anhydrous ethanol for 3S, and drying with air flow to obtain Ag solution₂S deposition circulation to obtain Ag₂S-sensitized TiO₂A nanotube array film. Then the titanium sheet after the above treatment is immersed in the above prepared 0.1M Bi (NO) at 40 DEG C₃)₃Soaking in acetone solution for 10s, immediately washing with anhydrous ethanol for 3s, drying with air flow, and soaking the titanium sheet in 0.1M Na at 40 deg.C₂Soaking in S methanol solution for 20S, immediately washing with anhydrous ethanol for 3S, and drying with air flow; then immersed in 0.1M Bi (NO) at 40 ℃ in the above configuration₃)₃After immersing in acetone solution for 10s, it was immediately washed with absolute ethanol for 3s and dried with air flow, and then immersed in 0.1M Na at 40 deg.C₂Soaking in S methanol solution for 20S, immediately washing with absolute ethyl alcohol for 3S, and drying with air flow to finish the steps for one time₂S₃Depositing and circulating to obtain Ag on the titanium-based surface₂S and Bi₂S₃Sensitized TiO₂A nanotube array film. The processed titanium sheet leans against the crucible wall, is placed in a muffle furnace, is heated to 150 ℃ at the speed of 5 ℃/min, and is calcined for 1h under the condition of nitrogen flow, and the AgBiS can be obtained₂/TiO₂A nanocomposite film. The number of deposition cycles was set to 2, 4 and 7 times, and respectively designated as 2c-AgBiS₂/TiO₂(2-ABS)，4c-AgBiS₂/TiO₂(4-ABS)，7c-AgBiS₂/TiO₂(7-ABS) to obtain AgBiS₂AgBiS with different deposition cycle times₂/TiO₂A nano-composite film material, a nano-composite film,

AgBiS for different deposition times₂/TiO₂The performance of the nano composite film material is characterized, and the result shows that the material is AgBiS₂When the number of cyclic deposition times is 4, AgBiS₂/TiO₂The nano composite film material has the best performance.

To AgBiS₂/TiO₂Carrying out photoelectrochemistry and photoproduction cathode protection performance tests on the nanotube array composite membrane: the device for characterizing the photoelectric properties is filled with 0.1M Na₂S solution single system of photoelectrolysis cell; the electrochemical workstation is CHI660E, the photoanode is connected with the working electrode, the counter electrode is a platinum electrode, and the counter electrode is in short circuit with the counter reference electrode and is connected with the grounding terminal. The device for testing the photoproduction cathodic protection performance comprises a corrosion tank filled with 3.5 wt% of NaCl solution and a device filled with 0.1M Na₂And the two electrolytic cells are communicated through a nafion membrane. Electrochemical measurements electrochemical work stations with a three-electrode system (P4000+, USA): AgBiS₂/TiO₂The nanotube array composite membrane is used as a photo-anode, a platinum sheet is used as a counter electrode, a saturated calomel electrode is used as a reference electrode, 304 stainless steel and the photo-anode are coupled through a copper wire to be used as working electrodes, and an open-circuit potential time curve and a photocurrent density time curve are tested. The light source is a 300W high-pressure xenon lamp, and the wavelength of the irradiation light source is visible light with the wavelength of more than 400 nm. Simulating visible light by using a xenon lamp, and directly irradiating AgBiS₂/TiO₂Nanotube array composite membrane surface (see fig. 1 and 2).

FIG. 3 is pure TiO₂And AgBiS₂/TiO₂XRD pattern of the nanocomposite. In the figure, the curve (a) shows diffraction peaks at positions with 2 theta of 25.3 degrees, 37.0 degrees, 37.9 degrees, 48.1 degrees, 53.7 degrees and 55.0 degrees, and the diffraction peaks are attributed to TiO of anatase phase₂(JCPDS, 21-1272) corresponding to crystal planes 101, 004, 200, 105, 211, respectively; in the figure, except the diffraction peak of the curve a, the diffraction peak of the curve (b) shows cubic AgBiS at 27.5 degrees, 31.6 degrees, 45.8 degrees and 54.2 degrees₂The characteristic diffraction peaks of (JCPDS, 04-0699) correspond to crystal planes 111, 200, 220, 311, respectively, and no other peaks are found in the figure. Results preliminaryShows that: AgBiS₂Successfully deposit on TiO₂Forming AgBiS₂/TiO₂And (c) a complex.

FIG. 4 is TiO₂Nanotubes and AgBiS₂AgBiS of different deposition cycle numbers₂/TiO₂SEM of nanotube array composite membrane. In FIG. A, TiO can be seen₂The diameter of the nanotube is about 80nm, the wall thickness is about 10nm, and the length is about 100 nm; FIG. (b) is 2c-AgBiS₂/TiO₂Surface morphology of nanocomposite, small amount of AgBiS₂Nanoparticles have been successfully loaded onto TiO₂Surface and mouth edge of nanotube, AgBiS₂Growth direction of nanoparticles and TiO₂The opening directions of the nanotubes are consistent; FIG. (c) is 4c-AgBiS₂/TiO₂The surface appearance of the nano composite can show more AgBiS₂Nanoparticles in TiO₂Nanotube nozzle deposition and aggregation, but TiO₂The nanotubes still maintain a tubular structure; FIG. (d) is 7c-AgBiS₂/TiO₂Surface topography of nanocomposites, Mass AgBiS₂Nanoparticles in TiO₂The nanotubes are aggregated and stacked in bulk to form clusters, and TiO is added₂The nanotube orifice is blocked. The results show that: the number of deposition cycles affects the surface morphology of the composite, and AgBiS is obtained when the number of deposition cycles is 4₂/TiO₂The nanotube composite film has an optimal sunlight absorption morphology.

FIG. 5 is AgBiS₂/TiO₂The XPS full spectrum (a), Bi4f (b), Ag3d (c), S2S (d) and Ti2p (e) of (A) are high resolution XPS spectra. FIG. (a) shows that only characteristic peaks of Ti, O, Ag, Bi, S and C elements appear in the composite, wherein C1S is an impurity peak for instrument calibration; FIG. (b) illustrates that the valence of Bi element is + 3; panel (c) illustrates that Ag is +1 valent in the composite; FIG. (d) shows the characteristic peak to which the binding energy belongs at 225.4eV and AgBiS₂The characteristics of the two are similar; panel (e) illustrates the presence of TiO in the nanocomposite₂. The results show that: the chemical composition of the nanocomposite film is AgBiS₂And TiO₂。

FIG. 6 shows pure TiO₂Nanotube array film and AgBiS₂/TiO₂Ultraviolet-visible absorption spectrum of the nano-composite film. Curve (a) shows pure TiO₂The light absorption range of the nanotube array film is mainly distributed in an ultraviolet region with the wavelength less than 380nm, and the absorption edge is 387nm, which is similar to anatase phase TiO₂The forbidden band width of the crystal is consistent with 3.2 eV; curve (b) shows that the sample AgBiS₂/TiO₂The light absorption range of the nanocomposite film is significantly red-shifted. The results show that: compared with pure TiO₂In other words, AgBiS₂/TiO₂The light absorption intensity of the nanotube array composite in the visible light region is greatly increased.

FIG. 7 is TiO₂Nanotube array film and AgBiS₂AgBiS of different deposition cycle numbers₂/TiO₂The composite film as a photoanode under intermittent visible light and 0.1M Na₂SO₄The photocurrent density time curve was measured in solution. The photocurrent density characterizes the photoelectric conversion performance. As can be seen from the figure, TiO₂The photocurrent density generated by the nanotube array is 8uA/cm^-2(ii) a When AgBiS₂AgBiS prepared with deposition times of 2, 4 and 7₂/TiO₂The current density generated by the nanotube array composite film is 24uA/cm respectively^-2，40uA/cm^-2，48uA/cm^-2. The results show that: in contrast to TiO₂Nanotubes, AgBiS₂/TiO₂The photocurrent generated by the nanotube array composite film is large, which shows that the separation capability of electron-hole pairs in the film is strong, the recombination probability is low, and the light utilization rate and the conversion efficiency are greatly improved, so the AgBiS₂/TiO₂The nanotube array composite membrane has excellent cathode protection effect; through multiple on-off light experiments, AgBiS₂/TiO₂The nanocomposite films also have very high stability. Wherein, AgBiS₂4 times of deposition of AgBiS is prepared_2/TiO₂The nanocomposite film 4-ABS has more excellent photoelectric conversion capability.

FIG. 8 shows a 304 stainless steel electrode and pure TiO₂Nanotube array film and AgBiS₂AgBiS prepared under different deposition cycle times₂/TiO₂Nanometer compositeOpen circuit potential time profiles under intermittent visible light and in 3.5 wt% NaCl electrolyte when the compound films were attached as photoanodes. The open circuit potential reflects the corrosion state of the stainless steel electrode. As can be seen, under light conditions, and TiO₂The potential of the 304 stainless steel electrode coupled with the photo-anode is reduced from-210 mV to-480 mV, and the potentials of the nanocomposite films connected with the 2-ABS, the 4-ABS and the 7-ABS prepared under different deposition cycle times are respectively reduced to-630 mV, -950mV and-795 mV, which indicates that TiO₂Nanotubes and AgBiS₂/TiO₂The nanotube array composite film has protective effect on 304 stainless steel, and AgBiS₂Nanoparticle to TiO₂The photoelectrochemistry cathode protection effect is obviously enhanced after modification, and the 4-ABS nano composite film has the optimal modification effect; when the light source is turned off, and TiO₂The potential of the 304 stainless steel coupled with the photoanode is basically recovered, while the electrode potential of the sample 4-ABS to stainless steel can still be maintained at about-820 mV for more than 12 hours, which indicates that pure TiO is in the dark₂Has no cathode protection effect on a stainless steel electrode, and is AgBiS₂AgBiS prepared with 4 deposition cycles₂/TiO₂The nano composite film 4-ABS still has photoelectrochemical cathode protection effect on 304 stainless steel.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.