Preparation Method and Application of a Cadmium Sulfide Nanotube Array Catalyst

Abstract

The present invention discloses a preparation method and application of a cadmium sulfide nanotube array catalyst. First, a cadmium sulfide nanorod array is prepared on a conductive glass by a hydrothermal method; then, a cadmium sulfide nanotube array catalyst is prepared by etching the cadmium sulfide nanorod array using a photolithography method. The cadmium sulfide nanotube array catalyst prepared by the present invention utilizes the excellent visible light absorption characteristics of cadmium sulfide to improve the light energy utilization rate, and uses a tubular nanostructure with a large specific surface area to increase the active area of the photoelectrocatalytic water splitting reaction, effectively promoting the separation and transmission of photogenerated carriers, inhibiting the recombination of photogenerated carriers, and showing excellent photoelectrocatalytic water splitting hydrogen production performance. The process of the present invention is simple, the synthesized substance has high purity, the size is at the nanometer level, and the raw materials used are cheap, which is suitable for the field of photoelectrocatalytic water splitting hydrogen production.

Description

Technical Field

[0001] The present invention belongs to the technical field of inorganic optoelectronic materials, and particularly relates to a preparation method of a cadmium sulfide nanotube array catalyst and its photoelectrocatalytic application. Background Art

[0002] In recent years, with the rapid development of social economy and the increasing energy demand, energy and environmental issues have become two major hot issues of widespread concern in the world. Therefore, the development and utilization of efficient clean energy are imminent. For example, the photoelectrocatalytic water splitting technology for hydrogen production driven by solar energy using semiconductor photoanode materials has received extensive attention.

[0003] The key to the photoelectrocatalytic water splitting technology is the construction of the photoanode material, which is usually composed of a semiconductor photocatalytic material as the photocatalyst for the photoelectrocatalytic water splitting technology. However, current photocatalysts still have problems such as wide bandgap, low solar energy utilization rate, and high carrier recombination rate. Cadmium sulfide (CdS) semiconductor material has a relatively narrow bandgap and is an important visible light-responsive photocatalytic material. Given these unique advantages of cadmium sulfide, it has currently been used to construct semiconductor photoanodes and applied to photoelectrocatalysis and photocatalytic water splitting for hydrogen production. However, the high recombination rate of photo-generated carriers limits its efficiency of photocatalytic water splitting for hydrogen production.

[0004] Photolithography is a common method for surface treatment of semiconductor catalysts. To a certain extent, this method can improve the photocatalytic performance. In the prior art, the technology of photolithography often uses a single-wavelength laser etching, and such methods cannot make good use of the auxiliary effect of photo-generated electrons and holes on surface etching. Currently, there has not yet appeared a new method for realizing photolithography of nanoarray catalysts and achieving better technical effects.

[0005] Aiming at the above problems, the present invention regulates the morphology of cadmium sulfide by a new method of photolithography of nanoarrays, prepares a cadmium sulfide nanotube array catalyst with a large specific surface area, increases the active area of the photoelectrocatalytic reaction, effectively inhibits the recombination of photo-generated carriers, and thus improves the efficiency of photoelectrocatalytic water splitting for hydrogen production. Therefore, exploring a cadmium sulfide morphology with a high specific surface area and its corresponding preparation method is an important way to improve the efficiency of cadmium sulfide photoelectrocatalytic water splitting for hydrogen production. Summary of the Invention

[0006] Aiming at the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a preparation method of a cadmium sulfide nanotube array catalyst. The nanotube array catalyst prepared by the preparation method provided by the present invention can increase the specific surface area of the photoelectrocatalytic reaction excited by visible light, quickly separate and transport photo-generated electron-hole pairs, effectively inhibit the recombination of photo-generated carriers, and finally achieve the purpose of improving its efficiency of photoelectrocatalytic water splitting for hydrogen production.

[0007] To achieve the above-mentioned invention objectives, the present invention provides the following technical solutions:

[0008] A preparation method of a cadmium sulfide nanotube array catalyst, comprising the following steps:

[0009] Step 1: Prepare a cadmium sulfide nanorod array by using a simple one-step hydrothermal method

[0010] (1) Disperse cadmium nitrate, thiourea, and glutathione in deionized water according to a molar ratio of (1 - 1.5):(1 - 1.5):(0.5 - 1), and stir at room temperature to obtain a precursor mixture;

[0011] (2) Wash the conductive glass and remove the oil stain, and perform ultrasonic treatment in anhydrous ethanol, acetone, isopropanol, and deionized water in sequence, and then dry it;

[0012] (3) Add the conductive glass treated in step (2) to the precursor mixture obtained in step (1), place it in a reaction kettle, and perform a hydrothermal reaction. The reaction temperature is 180 - 220 °C, and the reaction time is 5 - 10 h;

[0013] (4) After the reaction is complete, cool the conductive glass obtained in step (3) to room temperature, wash it clean with deionized water, transfer it to a vacuum oven at 60 - 90 °C and dry it for 2 - 5 hours to obtain the cadmium sulfide nanorod array;

[0014] Step 2: Prepare a cadmium sulfide nanotube array by using a photolithography method

[0015] First, add the cadmium sulfide nanorod array obtained in step 1 to an etching solution, where the etching solution is a mixed aqueous solution of sodium hydroxide and sodium carbonate; subsequently, irradiate the cadmium sulfide nanorod array sample immersed in the etching solution with visible light for 2 - 5 h; finally, take out the sample, wash and dry it to obtain the cadmium sulfide nanotube array catalyst.

[0016] Preferably, in step 1, the molar ratio of cadmium nitrate, thiourea, and glutathione is (1.1 - 1.4):(1.1 - 1.4):(0.6 - 0.8);

[0017] More preferably, in step 1, the molar ratio of cadmium nitrate, thiourea, and glutathione is 1.2:1.2:0.72.

[0018] Preferably, in the hydrothermal reaction of step 1 (3), the reaction temperature is 190 - 210 °C, and the reaction time is 8 - 10 h;

[0019] More preferably, in the hydrothermal reaction of step 1 (3), the reaction temperature is 200 °C, and the reaction time is 8 h.

[0020] Preferably, the molar ratio of sodium hydroxide to sodium carbonate in step two is (0.1 - 0.2):(0.2 - 0.5).

[0021] More preferably, the molar ratio of sodium hydroxide to sodium carbonate in step two is 0.15:0.4.

[0022] Preferably, the light power of visible light incident on the sample surface in step two is 120 - 200 mW / cm2.

[0023] More preferably, the light power of visible light incident on the sample surface in step two is 150 mW / cm2.

[0024] Preferably, the visible light irradiation time in step two is 2 - 4 h, and more preferably 3 h.

[0025] A cadmium sulfide nanotube array catalyst is prepared according to the above preparation method.

[0026] According to the above cadmium sulfide nanotube array catalyst is used as a photoelectrocatalytic material for photoelectrocatalytic water splitting to produce hydrogen.

[0027] Characterization Instruments

[0028] The crystal structure of the prepared sample is tested by an Ultima U type X-ray diffractometer (XRD) from Rigaku Corporation of Japan. The elemental distribution and valence state of the prepared sample are analyzed by an ESCALAB 250XI type X-ray photoelectron spectrometer (XPS) from Thermo Fisher Scientific of the United States, with the signal of carbon at a binding energy of 284.8 eV as a reference. The morphology of the prepared sample is characterized by an S-4800 type field emission scanning electron microscope (SEM) from Hitachi Corporation of Japan and a JEM-2100Plus type transmission electron microscope (TEM) from JEOL Ltd. of Japan. The light absorption characteristics of the prepared sample are analyzed by a LAMBDA-950 type ultraviolet-visible-near-infrared spectrophotometer from PerkinElmer of the United States.

[0029] Photoelectric Response Test

[0030] The photoelectric response characteristics of the prepared sample are tested by a CHI760e type electrochemical workstation from Shanghai Chenhua. In an unbiased three-electrode system, the prepared sample is used as the working electrode, a platinum wire is used as the counter electrode, and a silver / silver chloride electrode is used as the reference electrode. The electrolyte used is a mixed solution of 0.25 M Na2SO3 and 0.35 M Na2S. Before the test, argon gas is introduced into the electrolyte for 20 min to remove the dissolved oxygen in the electrolyte.

[0031] Photoelectrocatalytic Hydrogen Production Test

[0032] The photocatalytic hydrogen production activity of the prepared sample was tested in a side-radiation sealed reaction cell equipped with a graduated hydrogen collection tube. During a typical photocatalytic hydrogen production process, 200 ml of deionized water containing sacrificial agents (0.25 M Na2SO3 and 0.35 M Na2S) was added to the reaction cell, where S2- / SO32- ions served as hole scavengers. The sample with a size of 1.5 - 2.0 cm2 was used as the working electrode, a platinum wire as the counter electrode, and a silver / silver chloride electrode as the reference electrode. The above three electrodes were connected to the reaction cell, and the reaction cell was connected to a three-electrode system without bias voltage. A 300 W xenon lamp was selected as the light source, and an ultraviolet cut-off filter (λ≥400 nm) was used to generate visible light irradiation. The light emitted by the xenon lamp was vertically irradiated onto the sample electrode through the quartz window on the side of the reaction cell. At room temperature, the hydrogen gas generated in the sealed reaction cell was collected into the graduated hydrogen collection tube by the water displacement method, and the volume of hydrogen gas generated in the reaction cell was measured through the scale on the hydrogen collection tube.

[0033] Preparation principle: Under visible light irradiation, electrons in the valence band of cadmium sulfide nanorods absorb photon energy and transition to the conduction band, forming electron-hole pairs. After the electron-hole pairs migrate to the surface of the photoanode, they will undergo an oxidation-reduction reaction with the mixed solution of sodium carbonate and sodium hydroxide, resulting in a photoetching phenomenon. Since the core part of the cadmium sulfide nanorods is less stable than the sidewalls, the photoetching rate of the core part is faster than that of the sidewalls. By controlling the illumination time, cadmium sulfide nanotubes are formed.

[0034] Compared with the prior art, the advantages of the present invention are as follows:

[0035] (1) The present invention ingeniously adopts the photoetching method, combines the process of generating electron-hole pairs by photoexciting semiconductors with the reaction of alkaline etching, regulates the morphology of the cadmium sulfide nanorod array, and prepares a cadmium sulfide nanotube array catalyst. There is currently no relevant report on the photocatalytic water splitting for hydrogen production using a cadmium sulfide nanotube array.

[0036] (2) The present invention utilizes the excellent visible light absorption characteristics of cadmium sulfide to improve the light energy utilization rate, uses the tubular nanostructure with a large specific surface area to increase the active area of the visible light photocatalytic reaction, effectively promotes the separation and transport of photo-generated carriers, and inhibits the recombination of photo-generated carriers.

[0037] (3) The process of the present invention is simple, the synthesized substance has a high purity, the size is at the nanometer level, and the raw materials used are cheap, which is suitable for the field of photocatalytic water splitting for hydrogen production. Description of the Drawings

[0038] Figure 1 It is a schematic diagram of the preparation process of the cadmium sulfide nanorods and nanotube array catalyst prepared in Example 1 of the present invention.

[0039] Figure 2 X-ray diffraction pattern of the cadmium sulfide nanorod and nanotube array catalysts prepared in Example 1 of the present invention.

[0040] Figure 3 X-ray photoelectron spectroscopy of the cadmium sulfide nanotube array catalyst prepared in Example 1 of the present invention. (a) is the full spectrum, (b) is the fine spectrum of Cd, and (c) is the fine spectrum of S.

[0041] Figure 4 Transmission electron microscope and high-resolution images of the cadmium sulfide nanotube array catalyst prepared in Example 1 of the present invention. (a) is the transmission electron microscope image, and (b, c) are the high-resolution transmission electron microscope images.

[0042] Figure 5 Scanning electron microscope images of the cadmium sulfide nanorod and nanotube array catalysts prepared in Example 1 of the present invention. (a, b) are the scanning electron microscope images of the cadmium sulfide nanorod array, and (c, d) are the scanning electron microscope images of the cadmium sulfide nanotube array catalyst.

[0043] Figure 6 Optical absorption spectrum and bandgap diagram of the cadmium sulfide nanorod and nanotube array catalysts prepared in Example 1 of the present invention. (a) is the optical absorption spectrum, and (b) is the bandgap diagram.

[0044] Figure 7 Transient photocurrent density curve and linear sweep voltammogram of the cadmium sulfide nanorod and nanotube array catalysts prepared in Example 1 of the present invention. (a) is the transient photocurrent density curve, and (b) is the linear sweep voltammogram.

[0045] Figure 8 Hydrogen production amount and hydrogen production rate curves of the cadmium sulfide nanorod and nanotube array catalysts prepared in Example 1 of the present invention. (a) is the hydrogen production amount diagram, and (b) is the hydrogen production rate curve diagram.

[0046] Figure 9 X-ray diffraction pattern of the corresponding CdS-1 and CdS-2 samples in Comparative Example 1-2 of the present invention.

[0047] Figure 10 Scanning electron microscope images of the corresponding CdS-1 and CdS-2 samples in Comparative Example 1-2. (a, b) are the scanning electron microscope images of the CdS-1 sample, and (c, d) are the scanning electron microscope images of the CdS-2 sample.

[0048] Figure 11Transient photocurrent density and linear sweep voltammetry curves of the corresponding CdS-1 and CdS-2 samples for Comparative Examples 1-2. (a) is the transient photocurrent density curve graph, and (b) is the linear sweep voltammetry curve graph. Detailed implementation manners

[0049] To make the content of the present invention easier to understand, the technical solutions of the present invention will be further described below in conjunction with specific implementation manners. However, the embodiments are intended to explain the present invention and should not be construed as limiting the present invention.

[0050] A preparation method of a cadmium sulfide nanotube array catalyst includes the following steps:

[0051] Step 1: Prepare a cadmium sulfide nanorod array by using a simple one-step hydrothermal method

[0052] (1) Cadmium nitrate, thiourea, and glutathione are dispersed in deionized water according to a molar ratio of (1-1.5):(1-1.5):(0.5-1), and stirred at room temperature to obtain a precursor mixture solution;

[0053] (2) Wash the conductive glass and remove the oil stain, and perform ultrasonic treatment in anhydrous ethanol, acetone, isopropanol, and deionized water in sequence, and then dry it;

[0054] (3) Add the conductive glass treated in step (2) to the precursor mixture solution obtained in step (1), place it in a reaction kettle, and perform a hydrothermal reaction. The reaction temperature is 180-220 °C, and the reaction time is 5-10 h;

[0055] (4) After the reaction is complete, cool the conductive glass obtained in step (3) to room temperature, wash it clean with deionized water, and transfer it to a vacuum oven at 60-90 °C to dry for 2-5 hours to obtain the cadmium sulfide nanorod array;

[0056] Step 2: Prepare a cadmium sulfide nanotube array by using a photolithography method

[0057] First, add the cadmium sulfide nanorod array obtained in step 1 to an etching solution, where the etching solution is a mixed aqueous solution of sodium hydroxide and sodium carbonate; subsequently, irradiate the cadmium sulfide nanorod array sample containing the etching solution with visible light for 2-5 h; finally, take out the sample, wash and dry it to obtain a cadmium sulfide nanotube array catalyst.

[0058] Example 1

[0059] Step 1: Prepare a cadmium sulfide nanorod array by using a simple one-step hydrothermal method

[0060] (1) Preheat the constant temperature drying oven and set the temperature to 200 °C;

[0061] (2) Measure 40 ml of deionized water with a graduated cylinder and pour it into a beaker.

[0062] (3) Weigh 1.2 mmol of cadmium nitrate tetrahydrate (0.3701 g) and pour it into the beaker. Place the beaker on a magnetic stirrer and stir for 10 minutes.

[0063] (4) Weigh 1.2 mmol of thiourea (0.0913 g), pour it into the beaker, and place the beaker on a magnetic stirrer and stir for 10 minutes.

[0064] (5) Weigh 0.72 mmol of glutathione (0.2212 g) and pour it into the beaker. Place the beaker on a magnetic stirrer and stir for 30 minutes.

[0065] (6) Incline two FTO conductive glasses and place them into the inner liner of the reaction kettle with the conductive surface facing down.

[0066] (7) Pour 40 ml of the reaction precursor solution into the inner liner and seal the reaction kettle.

[0067] (8) Place the reaction kettle in a constant temperature drying oven for 8 hours.

[0068] (9) After the reaction is completed, take out the reaction kettle. Cool the reaction kettle to room temperature and take out the pale yellow sample. Rinse it thoroughly with deionized water, and then place it in a constant temperature drying oven at 60 °C for 2 hours to obtain a cadmium sulfide nanorod array sample.

[0069] Step 2: Preparation of cadmium sulfide nanotube arrays using photolithography

[0070] First, prepare the etching solution: Measure 300 ml of deionized water with a graduated cylinder and pour it into a beaker. Pour 0.15 M (1.8 g) of sodium hydroxide and 0.4 M (12.72 g) of sodium carbonate into the beaker in sequence. After stirring for 30 minutes, let it stand for 24 hours. Secondly, the photolithography operation on the conductive glass grown with cadmium sulfide nanorod arrays is as follows:

[0071] (1) Pour 200 ml of the etching solution into the reaction cell.

[0072] (2) Vertically place the cadmium sulfide nanorod array sample grown on the FTO conductive glass into the solution.

[0073] (3) Use a xenon lamp with a power of 300 W as the light source and use an ultraviolet cut-off filter to process it, only using visible light. The incident light intensity needs to be measured and calibrated with a power meter to ensure that the light power incident on the sample surface is 150 mW / cm2.

[0074] (4) Irradiate the cadmium sulfide nanorod array for 3 hours.

[0075] After the irradiation is completed, take out the sample, rinse it thoroughly with deionized water, and then place it in a constant temperature drying oven at 60 °C for 2 hours to obtain the cadmium sulfide nanotube array catalyst.

[0076] The following are the composition, morphology characterization, and photocatalytic water splitting hydrogen production performance test results of the cadmium sulfide nanotube array catalyst prepared in the experimental example:

[0077] Figure 1 This is the preparation flow chart of the cadmium sulfide nanotube array catalyst prepared in the embodiment of the present invention. It shows the process of preparing the cadmium sulfide nanotube array catalyst by using a new photolithography method to control the morphology of the cadmium sulfide nanoarray on the basis of preparing the cadmium sulfide nanorod array by the hydrothermal method.

[0078] Figure 2 This is the X-ray diffraction pattern. As can be seen from the figure, the diffraction peaks of the prepared CdS nanorod array and CdS nanotube array match the hexagonal phase CdS phase of the standard card JCPDS (41-1049), and there are no impurity peaks in the sample, indicating that the prepared CdS has high purity.

[0079] Figure 3 This is the X-ray photoelectron spectroscopy diagram. As can be seen from the figure, there are two elements, Cd and S, in the CdS nanotube array structure, which proves the successful preparation of the CdS nanotube array structure.

[0080] Figure 4 This is the transmission electron microscope and high-resolution image. As can be seen from Figure 4 in (a), the axis of the CdS nanorod is etched to form a depression. Figure 4 In the high-resolution transmission electron microscope images shown in (b) and (c), clear lattice fringes appear, corresponding to the (002) crystal plane of CdS.

[0081] Figure 5 This is the scanning electron microscope image. As can be seen from the figure, the scanning electron microscope images (a, b) of the CdS nanorods show a hexagonal columnar nanostructure; the scanning electron microscope images (c, d) of the CdS nanotubes show that after photolithography, the axis of the nanorod is etched to form a tubular nanostructure.

[0082] Figure 6 This is the optical absorption spectrum and band gap diagram. As can be seen from the figure, after the CdS nanorods are etched into CdS nanotubes, the optical absorption intensity at a wavelength of 300-500 nm increases, the absorption edge is still 540 nm, and the band gap is still 2.34 eV.

[0083] Figure 7 This is the transient photocurrent density curve graph and linear sweep voltammogram graph. As can be seen from Figure 7As can be seen from the transient photocurrent density curves shown in (a), all the tested samples have very sensitive light response characteristics. Among them, the photocurrent density of the CdS nanorod array is 1.0 mA·cm-2; after photoetching for 3 hours, the photocurrent density of the prepared CdS nanotube array increases significantly, reaching 2.5 mA·cm-2, which is 2.5 times that of the CdS nanorod array; from Figure 7 As can be seen from the linear sweep voltammetry curves shown in (b), the photocurrent density of all samples increases with the increase of the applied bias voltage, and the increase of the photocurrent density of the CdS nanotube array after photoetching for 3 hours is more significant.

[0084] Figure 8 They are the hydrogen production amount and hydrogen production rate curves. From Figure 8 As can be seen from the hydrogen production amount vs. time curve shown in (a), under continuous visible light irradiation for 2 h, the hydrogen production amount per unit area of the CdS nanorod array and CdS nanotube array photoanodes is linearly correlated with the irradiation time, indicating that all the prepared sample electrodes have stable hydrogen production ability. From Figure 8 As can be seen from the hydrogen production rate curves of the CdS nanorod array and CdS nanotube array photoanodes shown in (b), the CdS nanotube array photoanode has a higher hydrogen production rate than the CdS nanorod array, which can reach 21.4 μmol·cm-2·h-1, 3.19 times that of the nanorod array (6.7 μmol·cm-2·h-1).

[0085] In addition, for comparison, the effects of the etching solution selection and light irradiation conditions were investigated.

[0086] Comparative Example 1: The same conditions and parameters as in Example 1 were used, and the difference from Example 1 was that under the same time and the same etching solution conditions, a cadmium sulfide sample was obtained without light irradiation, and this sample was denoted as CdS-1.

[0087] Comparative Example 2: The same conditions and parameters as in Example 1 were used, and the difference from Example 1 was that under the same time and the same light irradiation conditions, the etching solution was changed to 0.15 M sodium hydroxide solution to obtain a cadmium sulfide sample, and this sample was denoted as CdS-2.

[0088] Based on Comparative Examples 1-2, they were studied by X-ray diffraction patterns, scanning electron microscope images, and transient photocurrent density and linear sweep voltammetry curves, and it can be seen that:

[0089] Figure 9 They are the X-ray diffraction patterns of the corresponding CdS-1 and CdS-2 samples in Comparative Examples 1-2. As can be seen from the figure, the diffraction peaks of the prepared CdS-1 and CdS-2 samples match the hexagonal CdS phase of the standard card JCPDS (41-1049).

[0090] Figure 10 Scanning electron microscope images of the CdS-1 and CdS-2 samples corresponding to Comparative Examples 1-2. As can be seen from the figure, the scanning electron microscope images (a, b) of the CdS-1 sample show that the center of the cadmium sulfide nanorods is not etched without illumination. The scanning electron microscope images (c, d) of the CdS-2 sample show that after changing the etching solution to sodium hydroxide, the nanorods are etched, but the damage is relatively severe, and large-sized blocky structures appear.

[0091] Figure 11 Transient photocurrent density and linear sweep voltammetry curves of the CdS-1 and CdS-2 samples corresponding to Comparative Examples 1-2. From Figure 11 As can be seen from the transient photocurrent density curve shown in (a) therein, all the tested samples have very sensitive light response characteristics. The photocurrent density of the CdS-1 sample without illumination is not much different from that of the CdS nanorods; after changing the etching solution to sodium hydroxide solution and photolithographically etching for 3 hours, the photocurrent density of the prepared CdS-2 sample increases to 1.7 mA·cm-2. From Figure 11 As can be seen from the linear sweep voltammetry curve shown in (b) therein, the photocurrent density of all samples increases with the increase of the applied bias voltage.

[0092] Combined with Comparative Examples 1-2, the present invention shows that the center of the cadmium sulfide nanorod catalyst rods prepared without illumination is not etched and nanotubes cannot be formed, while using a single sodium hydroxide as the etching solution will result in severe damage to the nanorods, and the photoelectrocatalytic reaction effect is not as good as that in the case of using a mixed solution of sodium hydroxide and sodium carbonate as the etching solution and assisted etching under illumination conditions.

[0093] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for preparing a cadmium sulfide nanotube array catalyst, characterized in that: The steps include: Step 1: Preparation of CdS nanorod arrays using a simple one-step hydrothermal method (1) dispersing cadmium nitrate, thiourea and glutathione in deionized water at a molar ratio of (1-1.5):(1-1.5):(0.5-1), and stirring at room temperature to prepare a precursor mixture; (2) Clean and degrease the conductive glass, and perform ultrasonic treatment in anhydrous ethanol, acetone, isopropanol, and deionized water in sequence, and dry the glass; (3) adding the conductive glass treated in step (2) to the precursor mixture obtained in step (1), placing the mixture in a reaction kettle, and performing a hydrothermal reaction at a reaction temperature of 180-220° C. for a reaction time of 5-10 h; (4) After the reaction is complete, the conductive glass obtained in step (3) is cooled to room temperature, washed with deionized water, and transferred to a vacuum oven at 60-90° C. for drying for 2-5 hours to obtain the cadmium sulfide nanorod array; Step 2: Preparation of CdS nanotube arrays using photolithography First, the cadmium sulfide nanorod array obtained in step 1 is added into an etching solution, wherein the etching solution is a mixed aqueous solution of sodium hydroxide and sodium carbonate; Subsequently, the cadmium sulfide nanorod array sample immersed in the etching solution is irradiated with visible light for 2-5 hours; finally, the sample is taken out, washed, and dried to obtain a cadmium sulfide nanotube array catalyst; In step 2, the molar ratio of sodium hydroxide to sodium carbonate is (0.1-0.2): (0.2-0.5); Use a 300 W xenon lamp as the light source and use a UV cutoff filter to process it. Only use visible light. The incident light intensity needs to be measured and calibrated with an optical power meter. In step 2, the optical power of visible light incident on the sample surface is 120-200 mW / cm 2 .

2. The method for preparing a cadmium sulfide nanotube array catalyst according to claim 1, characterized in that: In step 1, the molar ratio of cadmium nitrate, thiourea and glutathione is (1.1-1.4): (1.1-1.4): (0.6-0.8).

3. The method for preparing a cadmium sulfide nanotube array catalyst according to claim 1, characterized in that: In step 1 (3), the reaction temperature of the hydrothermal reaction is 190-210° C. and the reaction time is 8-10 h.

4. The method for preparing a cadmium sulfide nanotube array catalyst according to claim 1, characterized in that: The visible light irradiation time in step 2 is 2-4h.

5. The cadmium sulfide nanotube array catalyst prepared according to the method for preparing a cadmium sulfide nanotube array catalyst according to any one of claims 1 to 4.

6. Use of the cadmium sulfide nanotube array catalyst according to claim 5 as a photoelectrocatalytic material for photoelectrocatalytic decomposition of water to produce hydrogen.

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