阅读说明：本技术 一种环保型锌银铟硒量子点敏化的掺杂光阳极及其制备方法与光电化学电池 (Environment-friendly doped photo-anode sensitized by zinc-silver-indium-selenium quantum dots, preparation method thereof and photoelectrochemical cell ) 是由 童鑫 龙治行 王志明 刘程 王瑞 于 2021-06-29 设计创作，主要内容包括：本发明公开了一种环保型锌银铟硒量子点敏化的掺杂光阳极及其制备方法与光电化学电池,该方法包括以下步骤：(1)制备二氧化钛阻挡层；(2)制备氧化石墨烯掺杂的二氧化钛复合光阳极；(3)合成环保型锌银铟硒量子点；(4)制备量子点敏化光阳极；(5)光阳极表面钝化。通过本发明提供的制备方法,将环保型锌银铟硒量子点用于敏化光阳极,可以显著提高其对光的吸收范围。并且在二氧化钛电极中掺杂氧化石墨烯,可以提升电子在电极中传递的速率,同时抑制了光生电子与空穴在电极中的复合,显著提高了光电化学电池的性能,使其在一个标准模拟太阳光照射下,饱和光电流密度高达6.5mA/cm～(2)。(The invention discloses an environment-friendly doped photo-anode sensitized by zinc, silver, indium and selenium quantum dots, a preparation method thereof and a photoelectrochemical cell, wherein the method comprises the following steps: (1) preparing a titanium dioxide barrier layer; (2) preparing a titanium dioxide composite photo-anode doped with graphene oxide; (3) synthesizing environment-friendly zinc-silver-indium-selenium quantum dots; (4) preparing a quantum dot sensitized photoanode; (5) and passivating the surface of the photoanode. By adopting the preparation method provided by the invention, the environment-friendly zinc-silver-indium-selenium quantum dots are used for sensitizing the photo-anode, and the absorption range of the quantum dots on light can be remarkably improved. And the titanium dioxide electrode is doped with the graphene oxide, so that the transfer rate of electrons in the electrode can be improved, the recombination of photo-generated electrons and holes in the electrode is inhibited, the performance of the photoelectrochemical cell is obviously improved, and the saturated photocurrent density of the photoelectrochemical cell is up to 6.5mA/cm under the irradiation of standard simulated sunlight 2 。)

1. A preparation method of an environment-friendly doped photo-anode sensitized by zinc, silver, indium and selenium quantum dots is characterized by comprising the following steps:

(1) preparation of titanium dioxide Barrier layer

Cleaning and blow-drying a substrate, spin-coating a titanium-nano oxide solution on the substrate, and then calcining to prepare a titanium dioxide barrier layer;

(2) preparation of graphene oxide doped titanium dioxide photoanode

Mixing ethanol dispersion liquid of graphene oxide, titanium dioxide slurry and a dispersing agent, performing ultrasonic treatment, and pumping to 1/5 of the volume of the original mixture under a vacuum condition to obtain slurry; coating the slurry on the titanium dioxide barrier layer prepared in the step (1), and preparing a graphene oxide doped titanium dioxide photo-anode through molding, sizing, heating and heat preservation;

(3) synthetic environment-friendly zinc-silver-indium-selenium quantum dot

Dissolving zinc acetate, silver nitrate and indium acetate in a mixed organic solvent to obtain a reaction solution, then adding a selenium precursor solution into the reaction solution, heating and preserving heat until quantum dots completely grow to obtain a zinc-silver-indium-selenium quantum dot solution;

(4) preparation of quantum dot sensitized photoanode

Mixing the zinc-silver-indium-selenium quantum dot solution with an organic solvent, shaking and centrifuging to obtain a supernatant, adding ethanol into the supernatant, centrifuging to obtain a precipitate, and dissolving the precipitate in toluene to obtain a deposition solution; constructing an electrophoresis device by using the graphene oxide doped titanium dioxide anode and the deposition solution for electrophoretic deposition to obtain an environment-friendly zinc-silver-indium-selenium quantum dot sensitized graphene oxide doped titanium dioxide photoanode;

(5) photoanode surface passivation

And (4) sequentially placing the photoanode prepared in the step (4) in a zinc source and a sulfur source for soaking for 45-75s, then washing and drying, and repeating the steps of soaking, washing and drying for 1-2 times.

2. The method for preparing an environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photoanode as claimed in claim 1, wherein the substrate is FTO conductive glass, and the cleaning comprises sequentially placing the substrate in acetone, ethanol and deionized water, ultrasonically cleaning for 20-40min, and drying by nitrogen.

3. The method for preparing the environment-friendly doped photoanode sensitized by the zinc-silver-indium-selenium quantum dots as claimed in claim 1, wherein the mixing ratio of the ethanol dispersion liquid of the graphene oxide, the dispersing agent and the titanium dioxide slurry is 1-3 mL: 1-2 mL: 1-2g, wherein the concentration of the ethanol dispersion liquid of the graphene oxide is 0.1mg/mL, and the ultrasonic time is 20-40 min.

4. The method for preparing an environment-friendly doped photo-anode sensitized by zinc, silver, indium and selenium quantum dots as claimed in claim 1, wherein the method comprises the following steps: the thickness of the film coated on the titanium dioxide barrier layer by the slurry is 10-15 μm, the forming-shaping-heating-heat preservation process comprises the steps of standing for 10-15min at normal temperature for tape casting and shaping, then heating for 5-7min at the temperature of 140 ℃ for shaping, and finally heating to the temperature of 550 ℃ at the temperature rising rate of 4-6 ℃/min and keeping for 20-40 min.

5. The method for preparing an environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photo-anode according to claim 1, wherein the concentrations of zinc acetate, silver nitrate and indium acetate added into a solvent are respectively as follows: 0.025mol/L, 0.01mol/L and 0.025mol/L, wherein the mixed organic solvent is a mixture of octadecene and a ligand, and the volume ratio of the octadecene solvent to the ligand is 8:1.0-1.2, wherein the ligand is a mixture of dodecyl mercaptan and oleic acid in a volume ratio of 1: 0.1-0.2; the selenium precursor solution is prepared by the following method: dissolving 0.05-0.06mmol selenium powder in a mixed solution of 0.4mL of dodecyl mercaptan and 1.0mL of oleylamine, and performing ultrasonic dispersion.

6. The method for preparing an environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photo-anode according to claim 1, wherein the step (3) specifically comprises the following steps: adding a mixed organic solvent into zinc acetate, silver nitrate and indium acetate, degassing for 5-15min at 55-65 ℃ in vacuum, heating to 100-.

7. The method for preparing an environment-friendly doped photoanode sensitized by zinc-silver-indium-selenium quantum dots according to claim 1, wherein the organic solvent in the step (4) comprises toluene or cyclohexane, the volume ratio of the zinc-silver-indium-selenium quantum dot solution to the organic solvent to ethanol is 1-3:1-3:6-8, and the electrophoretic deposition method comprises the following steps: two graphene oxide doped titanium dioxide photoanodes are taken as a working electrode and a counter electrode of the electrophoresis device respectively, the electrode distance is 1cm, the electrode area is 0.5cm x 1.0cm, the voltage is 200V, and the deposition time is 1-3 h.

8. The method for preparing an environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photo-anode according to claim 1, wherein the zinc source is a methanol solution of zinc acetate, and the concentration of the zinc source is 0.1 mol/L; the sulfur source is a solution with the concentration of 0.1mol/L obtained by dissolving sodium sulfide in a mixed solvent, the mixed solvent is obtained by equal-volume mixing of methanol and deionized water, and the rinsing process is rinsing by using a corresponding solvent.

9. The environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photo-anode prepared by the preparation method of the environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photo-anode according to any one of claims 1 to 8.

10. A photoelectrochemical cell comprising a photoanode, a platinum counter electrode, a 3mol/L silver/silver chloride reference electrode of potassium chloride and an electrolyte of a mixed solution of 0.25mol/L sodium sulphide and 0.35mol/L sodium sulphite (pH 13); wherein the photo-anode is the environment-friendly doped photo-anode sensitized by the zinc-silver-indium-selenium quantum dots as claimed in claim 9.

Technical Field

The invention belongs to the technical field of photochemical batteries, and particularly relates to an environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photo-anode, a preparation method thereof and a photoelectrochemical battery.

Background

Photoelectrochemical cells are cells made using semiconductor-liquid junctions that can directly use light energy and convert it into a clean renewable hydrogen energy source, alleviating the energy crisis. The photoelectrochemical cell is composed of a photoelectrode with optical activity, electrolyte and an external circuit, is simple in structure, and has lower device cost compared with a technology of producing hydrogen by photovoltaic power generation and water electrolysis. Among them, semiconductor titanium dioxide is often used as an anode material of a photoelectrochemical cell because of its good stability and appropriate energy band position. However, the large band gap (-3.2 eV) of titanium dioxide causes that only part of the ultraviolet light in the sunlight can be utilized, the conversion efficiency of light energy to hydrogen energy is seriously influenced, and the problem can be overcome well by introducing quantum dots with wide absorption spectrum range to sensitize the titanium dioxide photoanode. In addition, the hydrogen production technology of the quantum dot sensitized photoelectrochemical cell cannot be put into practical application in a large scale at present and is limited to the following aspects: firstly, the traditional quantum dot sensitized doped photo-anode material contains toxic metal elements such as lead and cadmium, and is not beneficial to the development of the technology from the aspects of environmental protection and commercialization; secondly, the activity and stability of the environment-friendly photoelectrode material which is researched are low; thirdly, the photoelectrode material has a limited absorption range of sunlight, and the near infrared part cannot be effectively utilized; fourth, the conventional photoelectrode is formed by stacking titanium dioxide nanoparticles, and photo-generated electrons are easily recombined with holes when being transferred at a titanium dioxide interface, which finally results in the reduction of the photoelectrochemical conversion efficiency.

Disclosure of Invention

The invention aims to provide an environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photo-anode, a preparation method thereof and a photoelectrochemical cell, which can solve a series of problems of high toxicity, narrow absorption spectrum range and low activity of a quantum dot photoelectrochemical cell in the prior art.

In order to achieve the aim, the invention provides a preparation method of an environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photo-anode, which comprises the following steps:

(1) preparation of titanium dioxide Barrier layer

Cleaning and blow-drying a substrate, spin-coating a titanium-nano oxide solution on the substrate, and then calcining to prepare a titanium dioxide barrier layer;

(2) preparation of graphene oxide doped titanium dioxide photoanode

Mixing ethanol dispersion liquid of graphene oxide, titanium dioxide slurry and a dispersing agent, performing ultrasonic treatment, and pumping to 1/5 of the volume of the original mixture under a vacuum condition to obtain slurry; coating the slurry on the titanium dioxide barrier layer prepared in the step (1), and preparing a graphene oxide doped titanium dioxide photo-anode through molding, sizing, heating and heat preservation;

(3) synthetic environment-friendly zinc-silver-indium-selenium quantum dot

Dissolving zinc acetate, silver nitrate and indium acetate in a mixed organic solvent to obtain a reaction solution, then adding a selenium precursor solution into the reaction solution, heating and preserving heat until quantum dots completely grow to obtain a zinc-silver-indium-selenium quantum dot solution;

(4) preparation of quantum dot sensitized photoanode

Mixing the zinc-silver-indium-selenium quantum dot solution with an organic solvent, shaking and centrifuging to obtain a supernatant, adding ethanol into the supernatant, centrifuging to obtain a precipitate, and dissolving the precipitate in toluene to obtain a deposition solution; constructing an electrophoresis device by using the graphene oxide doped titanium dioxide anode and the deposition solution for electrophoretic deposition to obtain an environment-friendly zinc-silver-indium-selenium quantum dot sensitized graphene oxide doped titanium dioxide photoanode;

(5) photoanode surface passivation

And (4) sequentially placing the photoanode prepared in the step (4) in a zinc source and a sulfur source for soaking for 45-75s, then washing and drying, and repeating the steps of soaking, washing and drying for 1-2 times.

Further, the substrate is FTO conductive glass, and the cleaning comprises the steps of respectively placing the substrate in acetone, ethanol and deionized water, ultrasonically cleaning for 20-40min, and drying by using nitrogen.

Further, the coating of the step (1) is spin coating at the rotating speed of 4000-.

Further, the mixing ratio of the ethanol dispersion liquid of graphene oxide, the dispersing agent and the titanium dioxide slurry is 1-3 mL: 1-2 mL: 1-2g, the concentration of the ethanol dispersion liquid of the graphene oxide is 0.1mg/mL, and the ultrasonic time is 20-40 min.

Further, the thickness of the film coated on the titanium dioxide barrier layer by the slurry is 10-15 μm, the process of molding, shaping, heating and heat preservation is that the slurry is firstly stood for 10-15min for tape casting molding at normal temperature, then heated for 5-7min for shaping at the temperature of 140 ℃ for 100-.

Further, the concentrations of zinc acetate, silver nitrate and indium acetate added into the solvent are respectively as follows: 0.025mol/L, 0.01mol/L and 0.025mol/L, wherein the mixed organic solvent is a mixture of octadecene and a ligand, the volume ratio of the octadecene to the ligand is 8:1.0-1.2, and the ligand is a mixture of dodecyl mercaptan and oleic acid in a volume ratio of 1: 0.1-0.2; the selenium precursor solution is prepared by the following method: dissolving 0.05-0.06mmol selenium powder in a mixed solution of 0.4mL of dodecyl mercaptan and 1.0mL of oleylamine, and performing ultrasonic dispersion.

Further, the step (3) specifically includes the following processes: adding a solvent and a ligand into zinc acetate, silver nitrate and indium acetate, degassing for 5-15min at 55-65 ℃ in vacuum, heating to 100-.

Further, the organic solvent in the step (4) comprises toluene or cyclohexane, the volume ratio of the zinc-silver-indium-selenium quantum dot solution to the organic solvent to the ethanol is 1-3:1-3:6-8, and the electrophoretic deposition method comprises the following steps: two graphene oxide-doped titanium dioxide anodes are taken as a working electrode and a counter electrode of the electrophoresis device respectively, the electrode distance is 1cm, the electrode area is 0.5cm x 1.0cm, the voltage is 200V, and the deposition time is 1-3 h.

Further, the zinc source is methanol solution of zinc acetate, and the concentration of the zinc source is 0.1 mol/L; the sulfur source is a solution with the concentration of 0.1mol/L obtained by dissolving sodium sulfide in a mixed solvent, the mixed solvent is obtained by equal-volume mixing of methanol and deionized water, and the rinsing process is rinsing by using a corresponding solvent.

The environment-friendly doped photo-anode sensitized by the zinc-silver-indium-selenium quantum dots is prepared by adopting the preparation method of the environment-friendly doped photo-anode sensitized by the zinc-silver-indium-selenium quantum dots.

A photoelectrochemical cell comprises an environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photoanode, a platinum counter electrode, a silver/silver chloride reference electrode of 3mol/L potassium chloride and an electrolyte of a mixed solution (pH is 13) of 0.25mol/L sodium sulfide and 0.35mol/L sodium sulfite.

In summary, the invention has the following advantages:

1. the quantum dots prepared by the method do not contain any toxic heavy metal elements (such as lead, cadmium and the like);

2. the absorption spectrum range of the photo-anode prepared by the invention can reach near-infrared wave band, and solar energy can be more effectively utilized;

3. according to the invention, the titanium dioxide electrode is doped with the graphene oxide, so that the resistance of electrons in the electrode is reduced, and the recombination of electrons and holes on the titanium dioxide interface is inhibited;

4. the performance of a photoelectrochemical cell equipped with the environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photoanode prepared by the method is obviously improved, and the saturated photocurrent density is up to 6.5mA/cm under the irradiation of simulated sunlight²(the performance of the titanium dioxide photo-anode is close to the highest value of the photo-anode of the similar near-infrared light electrochemical cell), compared with the performance of the titanium dioxide photo-anode sensitized by the zinc-silver-indium-selenium quantum dots without doped graphene oxide, is improved by 23%;

5. the photoelectrochemical cell equipped with the environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photoanode prepared by the method has the hydrogen yield of 5.2 mu mol in 1 hour, and the hydrogen yield is improved by 79 percent compared with the electrode yield of undoped graphene oxide;

6. the photoelectrochemical cell equipped with the environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photo-anode prepared by the method can keep 70% of stability of the photo-anode under 1-hour light-dark alternate irradiation, and is greatly improved compared with a titanium dioxide electrode which does not participate in graphene oxide.

Drawings

Fig. 1 is a photo-anode of oxidized graphene doped titanium dioxide sensitized by the environment-friendly zinc-silver-indium-selenium quantum dots prepared in example 1;

fig. 2 is a schematic structural diagram of an environment-friendly zinc-silver-indium-selenium quantum dot sensitized oxidized graphene doped titanium dioxide photoanode prepared in example 1;

fig. 3 is a current density-voltage curve of the environment-friendly zinc-silver-indium-selenium quantum dot sensitized oxidized graphene doped titanium dioxide photoanode prepared in example 1 under a standard simulated sunlight illumination condition.

Detailed Description

The principles and features of this invention are described below in conjunction with embodiments, which are included to explain the invention and not to limit the scope of the invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Example 1

The embodiment provides a preparation method of an environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photo-anode, which comprises the following steps:

(1) preparation of titanium dioxide Barrier layer

Cleaning the FTO conductive glass in acetone, ethanol and deionized water in sequence by ultrasonic waves for 30min respectively, and drying by using nitrogen; spin-coating a titanium-nano oxide (Ti-hydroxide BL/SC, the same below) solution on an FTO conductive glass substrate at a rotation speed of 5000r/min, and then putting the FTO conductive glass substrate into a muffle furnace to heat to 500 ℃ for calcination and keeping the temperature for 30min to prepare a titanium dioxide barrier layer;

(2) preparation of graphene oxide doped titanium dioxide photoanode

Firstly, preparing 0.1mg/mL of graphene oxide ethanol dispersion liquid, adding 1.5mL of the dispersion liquid into 1g of titanium dioxide slurry (18NR-AO), then adding 2mL of ethanol serving as a dispersing agent, and placing the mixture in ultrasonic waves for dispersing for 30 min; pumping the dispersed slurry mixed solution in vacuum to 1/5, and then coating the prepared graphene oxide doped titanium dioxide slurry on a calcined FTO glass substrate by a blade coating thickness of 14 μm; standing at normal temperature for 13min for tape casting, heating on a heating plate at 120 deg.C for 6min for shaping, and heating in a muffle furnace at a heating rate of 5 deg.C/min to 500 deg.C for 30 min.

(3) Synthetic environment-friendly zinc-silver-indium-selenium quantum dot

Firstly, preparing a precursor solution of selenium, and dissolving 0.54mmol of selenium powder in a mixed solution of 0.4mL of dodecyl mercaptan and 1.0mL of oleylamine for ultrasonic dispersion for later use; then putting 0.2mmol of zinc acetate, 0.08mmol of silver nitrate and 0.2mmol of indium acetate in a 50mL three-neck flask, adding 8mL of octadecene, 1mL of dodecanethiol and 100 mu L of oleic acid solution, degassing at 60 ℃ for 10min in vacuum, then heating to 120 ℃ for dehydration for 20min, and ensuring that the raw materials are completely dissolved and are clear and transparent; heating the solution to 175 ℃ at the heating rate of 2 ℃/min, preserving the temperature for 10min, then quickly injecting the precursor solution of selenium into the reaction solution, and keeping the reaction temperature at 175 ℃ for 40min to ensure that the quantum dots completely grow; finally placing the three-neck flask in cold water to quench the reaction, transferring the reaction liquid into a centrifuge tube to be collected, and refrigerating in a refrigerator at 4 ℃;

(4) preparation of quantum dot sensitized photoanode

Preparing a deposition solution, taking 2mL of zinc-silver-indium-selenium quantum dot solution, adding 2mL of toluene to fully dissolve quantum dots containing organic ligands into the solution, centrifuging at the rotating speed of 3500r/min for 3min to obtain supernatant, adding 7mL of ethanol into the supernatant to change the solution into suspension, fully oscillating, centrifuging at the rotating speed of 12000r/min for 3min to obtain precipitate, and re-dispersing in 8mL of toluene to obtain the deposition solution; taking two obtained graphene oxide-doped titanium dioxide electrodes as a working electrode and a counter electrode of an electrophoresis device respectively, wherein the electrode distance is 1cm, the electrode area is about 0.5cm x 1.0cm, applying a voltage of 200V, and depositing for 2h to obtain an environment-friendly zinc-silver-indium-selenium quantum dot sensitized graphene oxide-doped titanium dioxide photoanode;

(5) photoanode surface passivation

Preparing 0.1mol/L zinc acetate solution (the solvent is methanol) and 0.1mol/L sodium sulfide solution (the solvent is mixed solution of methanol and deionized water with equal volume) as a zinc source and a sulfur source, sequentially immersing the photoanode into the zinc source and the sulfur source for 1min respectively, then rinsing with the corresponding solvents and drying with nitrogen, recording the operation as one cycle, and carrying out two cycle operations in total in the whole passivation process.

The environmental-friendly doped photoanode sensitized based on the zinc-silver-indium-selenium quantum dots prepared in example 1 (shown in fig. 1-3) was used as an anode, silver/silver chloride of 3mol/L potassium chloride was used as a reference electrode, a mixed solution of 0.25mol/L sodium sulfide and 0.35mol/L sodium sulfite (pH 13) was used as an electrolyte, and a platinum counter electrode were used to form a photoelectrochemical cell, and a standard solar simulator of am1.5g was used as a light source to perform performance tests, and the results are shown in table 1.

Example 2

The embodiment provides a preparation method of an environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photo-anode, which comprises the following steps:

(1) preparation of titanium dioxide Barrier layer

Cleaning the FTO conductive glass in acetone, ethanol and deionized water in sequence by ultrasonic waves for 30min respectively, and drying by using nitrogen; spin-coating a titanium-nano oxide solution on an FTO conductive glass substrate at a rotating speed of 5500r/min, then putting the FTO conductive glass substrate into a muffle furnace, heating to 550 ℃, calcining and keeping for 40min to prepare a titanium dioxide barrier layer;

(2) preparation of graphene oxide doped titanium dioxide photoanode

Firstly, preparing 0.1mg/mL of graphene oxide ethanol dispersion liquid, adding 2mL of the dispersion liquid into 2g of titanium dioxide slurry (18NR-AO), then adding 2mL of ethanol serving as a dispersing agent, and placing the mixture in ultrasonic waves for dispersing for 30 min; pumping the dispersed slurry mixed solution in vacuum to 1/5, and then coating the prepared graphene oxide doped titanium dioxide slurry on a calcined FTO glass substrate by a blade with the thickness of 12.2 mu m; standing at normal temperature for 15min for tape casting, heating on a heating plate at 120 deg.C for 6min for shaping, and heating in a muffle furnace at a heating rate of 5 deg.C/min to 500 deg.C for 30 min.

(3) Synthetic environment-friendly zinc-silver-indium-selenium quantum dot

Firstly, preparing a precursor solution of selenium, and dissolving 0.54mmol of selenium powder in a mixed solution of 0.4mL of dodecyl mercaptan and 1.0mL of oleylamine for ultrasonic dispersion for later use; then putting 0.2mmol of zinc acetate, 0.08mmol of silver nitrate and 0.2mmol of indium acetate in a 50mL three-neck flask, adding 8mL of octadecene, 1mL of dodecyl mercaptan and 200 mu L of oleic acid solution, degassing at 60 ℃ in vacuum for 10min, then heating to 120 ℃ for dehydration for 20min, and ensuring that the raw materials are completely dissolved and are clear and transparent; heating the solution to 175 ℃ at the heating rate of 2 ℃/min, preserving the temperature for 10min, then quickly injecting the precursor solution of selenium into the reaction solution, and maintaining the reaction temperature of 175 ℃ for 40min to ensure that the quantum dots completely grow; finally placing the three-neck flask in cold water to quench the reaction, transferring the reaction liquid into a centrifuge tube to be collected, and refrigerating in a refrigerator at 4 ℃;

(4) preparation of quantum dot sensitized photoanode

Firstly, preparing a deposition solution, taking 2mL of zinc-silver-indium-selenium quantum dot solution, adding 2mL of toluene to fully dissolve an organic ligand in the solution, adding 7mL of ethanol solution to obtain a suspension, fully oscillating, centrifuging to obtain a precipitate, and re-dispersing in 8mL of toluene to serve as the deposition solution; taking two obtained graphene oxide-doped titanium dioxide electrodes as a working electrode and a counter electrode of an electrophoresis device respectively, applying a voltage of 200V to deposit for 2h, wherein the electrode distance is 1cm, the electrode area is 0.5cm x 1.0cm, and finally obtaining an environment-friendly zinc-silver-indium-selenium quantum dot sensitized graphene oxide-doped titanium dioxide photoanode;

(5) photoanode surface passivation

Preparing 0.1mol/L zinc acetate solution (the solvent is methanol) and 0.1mol/L sodium sulfide solution (the solvent is mixed solution of methanol and deionized water with equal volume) as a zinc source and a sulfur source, sequentially immersing the photoanode into the zinc source and the sulfur source for 1min respectively, then rinsing with the corresponding solvents and drying with nitrogen, recording the operation as one cycle, and carrying out two cycle operations in total in the whole passivation process.

Example 3

The embodiment provides a preparation method of an environment-friendly zinc-silver-indium-selenium quantum dot sensitized doped photo-anode, which comprises the following steps:

(1) preparation of titanium dioxide Barrier layer

Cleaning the FTO conductive glass in acetone, ethanol and deionized water in sequence by ultrasonic waves for 30min respectively, and drying by using nitrogen; spin-coating a titanium-nano oxide solution on an FTO conductive glass substrate at the rotating speed of 5000r/min, then putting the FTO conductive glass substrate into a muffle furnace, heating to 600 ℃, calcining and keeping for 25min to prepare a titanium dioxide barrier layer;

(2) preparation of graphene oxide doped titanium dioxide photoanode

Firstly, preparing 0.1mg/mL of graphene oxide ethanol dispersion liquid, adding 2mL of the dispersion liquid into 1g of titanium dioxide slurry (18NR-AO), then adding 2mL of ethanol serving as a dispersing agent, and placing the mixture in ultrasonic waves for dispersing for 30 min; pumping the dispersed slurry mixed solution in vacuum to 1/5, and then coating the prepared graphene oxide doped titanium dioxide slurry on a calcined FTO glass substrate by a blade with the thickness of 10.5 mu m; standing at normal temperature for 13min for tape casting, heating on a heating plate at 120 deg.C for 6min for shaping, and heating in a muffle furnace at a heating rate of 5 deg.C/min to 500 deg.C for 30 min.

(3) Synthetic environment-friendly zinc-silver-indium-selenium quantum dot

Firstly, preparing a precursor solution of selenium, and dissolving 0.54mmol of selenium powder in a mixed solution of 0.4mL of dodecyl mercaptan and 1.0mL of oleylamine for ultrasonic dispersion for later use; then putting 0.2mmol of zinc acetate, 0.08mmol of silver nitrate and 0.2mmol of indium acetate in a 50mL three-neck flask, adding 8mL of octadecene, 1mL of dodecanethiol and 100 mu L of oleic acid solution, degassing at 60 ℃ for 10min in vacuum, then heating to 120 ℃ for dehydration for 20min, and ensuring that the raw materials are completely dissolved and are clear and transparent; heating the solution to 175 ℃ at the heating rate of 2 ℃/min, preserving the temperature for 10min, then quickly injecting the precursor solution of selenium into the reaction solution, and maintaining the reaction temperature of 175 ℃ for 40min to ensure that the quantum dots completely grow; finally placing the three-neck flask in cold water to quench the reaction, transferring the reaction liquid into a centrifuge tube to be collected, and refrigerating in a refrigerator at 4 ℃;

(4) preparation of quantum dot sensitized photoanode

Preparing a deposition solution, taking 2mL of zinc-silver-indium-selenium quantum dot solution, adding 2mL of toluene to fully dissolve quantum dots containing organic ligands into the solution, centrifuging at the rotating speed of 3500r/min for 3min to obtain supernatant, adding 7mL of ethanol into the supernatant to change the solution into suspension, fully oscillating, centrifuging at the rotating speed of 12000r/min for 3min to obtain precipitate, and re-dispersing in 8mL of toluene to obtain the deposition solution; taking two obtained graphene oxide-doped titanium dioxide electrodes as a working electrode and a counter electrode of an electrophoresis device respectively, wherein the electrode distance is 1cm, the electrode area is about 0.5cm x 1.0cm, applying a voltage of 200V, and depositing for 2h to obtain an environment-friendly zinc-silver-indium-selenium quantum dot sensitized graphene oxide-doped titanium dioxide photoanode;

(5) photoanode surface passivation

Preparing 0.1mol/L zinc acetate solution (the solvent is methanol) and 0.1mol/L sodium sulfide solution (the solvent is mixed solution of methanol and deionized water with equal volume) as a zinc source and a sulfur source, sequentially immersing the photoanode into the zinc source and the sulfur source for 1min respectively, then rinsing with the corresponding solvents and drying with nitrogen, recording the operation as one cycle, and carrying out two cycle operations in total in the whole passivation process.

Comparative example 1

The comparative example provides another preparation method of an environment-friendly zinc-silver-indium-selenium quantum dot sensitized pure titanium dioxide photo-anode, which comprises the following steps:

(1) preparation of titanium dioxide Barrier layer

Cleaning the FTO conductive glass in acetone, ethanol and deionized water in sequence by ultrasonic waves for 30min respectively, and drying by using nitrogen; spin-coating a titanium-nano oxide solution on an FTO conductive glass substrate at the rotating speed of 5000r/min, then putting the FTO conductive glass substrate into a muffle furnace, heating to 500 ℃, calcining and keeping for 30min to prepare a titanium dioxide barrier layer;

(2) preparation of pure titanium dioxide photoanode

Firstly, 1g of titanium dioxide slurry (18NR-AO) is blade-coated on a calcined FTO glass substrate to a blade coating thickness of 14 μm; standing at normal temperature for 13min for tape casting, heating on a heating plate at 120 deg.C for 6min for shaping, and heating in a muffle furnace at a heating rate of 5 deg.C/min to 500 deg.C for 30 min.

(3) Synthetic environment-friendly zinc-silver-indium-selenium quantum dot

Firstly, preparing a precursor solution of selenium, and dissolving 0.54mmol of selenium powder in a mixed solution of 0.4mL of dodecyl mercaptan and 1.0mL of oleylamine for ultrasonic dispersion for later use; then putting 0.2mmol of zinc acetate, 0.08mmol of silver nitrate and 0.2mmol of indium acetate in a 50mL three-neck flask, adding 8mL of octadecene, 1mL of dodecanethiol and 100 mu L of oleic acid solution, degassing at 60 ℃ for 10min in vacuum, then heating to 120 ℃ for dehydration for 20min, and ensuring that the raw materials are completely dissolved and are clear and transparent; heating the solution to 175 ℃ at the heating rate of 2 ℃/min, preserving the temperature for 10min, then quickly injecting the precursor solution of selenium into the reaction solution, and maintaining the reaction temperature of 175 ℃ for 40min to ensure that the quantum dots completely grow; finally placing the three-neck flask in cold water to quench the reaction, transferring the reaction liquid into a centrifuge tube to be collected, and refrigerating in a refrigerator at 4 ℃;

(4) preparation of quantum dot sensitized photoanode

Preparing a deposition solution, taking 2mL of zinc-silver-indium-selenium quantum dot solution, adding 2mL of toluene to fully dissolve quantum dots containing organic ligands into the solution, centrifuging at the rotating speed of 3500r/min for 3min to obtain supernatant, adding 7mL of ethanol into the supernatant to change the solution into suspension, fully oscillating, centrifuging at the rotating speed of 12000r/min for 3min to obtain precipitate, and re-dispersing in 8mL of toluene to obtain the deposition solution; taking two obtained pure titanium dioxide electrodes as a working electrode and a counter electrode of an electrophoresis device respectively, wherein the electrode distance is 1cm, the electrode area is about 0.5cm x 1.0cm, applying a voltage of 200V, and depositing for 2h to obtain an environment-friendly pure titanium dioxide photo-anode sensitized by zinc, silver, indium and selenium quantum dots;

(5) photoanode surface passivation

Preparing 0.1mol/L zinc acetate solution (the solvent is methanol) and 0.1mol/L sodium sulfide solution (the solvent is mixed solution of methanol and deionized water with equal volume) as a zinc source and a sulfur source, sequentially immersing the photoanode into the zinc source and the sulfur source for 1min respectively, then rinsing with the corresponding solvents and drying with nitrogen, recording the operation as one cycle, and carrying out two cycle operations in total in the whole passivation process.

The environment-friendly zinc-silver-indium-selenium quantum dot sensitized pure titanium dioxide photoanode prepared in comparative example 1 is used as a photoanode, silver/silver chloride of 3mol/L potassium chloride is used as a reference electrode, a mixed solution of 0.25mol/L sodium sulfide and 0.35mol/L sodium sulfite (pH 13) is used as an electrolyte and a platinum counter electrode to jointly form a photoelectrochemical cell, and a standard AM1.5G solar simulator is used as a light source to perform photoelectrochemical performance tests. The results are shown in Table 1.

Table 1 photoelectrochemical cell performance test data

As can be seen from Table 1, the environment-friendly quantum dot sensitized graphene oxide doped titanium dioxide photo-anode prepared by the method has excellent photoelectrochemical properties and excellent stability, wherein the saturation photocurrent density is up to 6.5mA/cm under the irradiation of simulated sunlight²The performance of the titanium dioxide photo-anode sensitized by the zinc-silver-indium-selenium quantum dots which are similar to those of the titanium dioxide photo-anode not doped with the graphene oxide is improved by 23 percent; the hydrogen yield is 5.2 mu mol in 1 hour, which is improved by 79 percent compared with the electrode yield of the undoped graphene oxide; under the alternate irradiation of light and dark for 1 hour, the light anode can keep 70% of stability, and is greatly improved compared with a titanium dioxide electrode which is not doped with graphene oxide.

While the present invention has been described in detail with reference to the illustrated embodiments, it should not be construed as limited to the scope of the present patent. Various modifications and changes may be made by those skilled in the art without inventive step within the scope of the appended claims.