MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of photocatalysis, and relates to an MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material and a preparation method and application thereof, and the preparation method comprises the following steps: S1, pretreatment; s2, MgCl2. 6H2O, CoCl2. 6H2O, urea, dehydrated ATP (adenosine triphosphate) and water are adopted, and MgCo-LDH / ATP is obtained; s3, synthesizing a BiVO4 electrode plate; s4, Mg (NO3) 2.6 H2O, isopropanol and MgCo-LDH / ATP are taken and subjected to ultrasonic mixing; and constructing an electro-deposition system by using a BiVO4 electrode plate, and carrying out electrophoretic deposition to obtain the composite photo-anode material. The prepared ternary composite photocatalytic material has excellent catalytic activity, the rate of photoelectrocatalytic water decomposition is greatly increased, and the catalytic effect is improved; in addition, the preparation process is simple to operate, and the synthesis period is short.

Description

Technical Field

[0001] The invention belongs to the field of photocatalysis technology and relates to a MgCo-LDH / ATP / BiVO 4 Ternary composite photocatalytic material and preparation method and application thereof. Background Art

[0002] Fossil energy is the main energy source at present, but the combustion of traditional fossil fuels will continuously release harmful pollutants into the atmosphere. The accumulation of harmful pollutants will damage the living environment and endanger human health. Therefore, the development of new fuels and the catalytic conversion of pollutants such as carbon dioxide that have been emitted into the air are urgent issues that need to be faced in environmental purification. Hydrogen energy, as a feasible technical route to promote global energy transformation, has gradually become a hot topic in the energy field. This is because hydrogen energy is an ideal clean secondary energy source. Using renewable energy to produce hydrogen, using hydrogen storage materials to store hydrogen, and using hydrogen fuel cells to generate electricity will constitute a "net zero emission" sustainable hydrogen energy system, becoming an important path to achieve "deep decarbonization" in addition to renewable energy.

[0003] There are many methods for producing hydrogen at present. Among them, catalytic hydrogen production is a method that uses catalysts to accelerate the hydrogen production reaction. It is a sustainable hydrogen production technology that can produce hydrogen from a variety of raw materials such as natural gas, biomass, water, etc. The selection of catalytic hydrogen production catalyst is a very important link. At this stage, BiVO 4 BiVO has the ability to photocatalyze water oxidation. 4 Among the three crystal structures of tetragonal scheelite, tetragonal zircon and monoclinic scheelite, monoclinic scheelite was shown to be the most photoactive; BiVO 4 It also has a high charge separation rate (1.23V RHE ≥90%) and slow photocorrosion rate. The synergistic effect of these characteristics makes BiVO 4 It becomes a special water oxidation photoanode. In previous studies, BiVO was successfully prepared using the metal organic decomposition (MOD) process. 4 The film was used as a photoanode to catalyze hydrogen production.

[0004] Although BiVO 4 is a promising solar water oxidation photoanode, but pure BiVO 4 The PEC activity is significantly lower than its theoretical photocurrent value of 7.5 mA / cm 2 , especially at low bias applications, due to the partial visible light response, high electron-hole recombination rate in the bulk phase, poor conductivity, high surface electron-hole recombination rate, and slow surface hole transfer kinetics, resulting in the low conductivity of pure BiVO 4 The photoanode performance is low, which reduces the catalytic efficiency. In order to improve the BiVO 4The efficient catalytic performance of the photoanode is improved by various modifications to improve the shortcomings of charge recombination, poor electronic conductivity and slow water oxidation. However, the existing methods of element doping, semiconductor composite, defect engineering and crystal surface process for BiVO 4 However, in the modification method, the catalyst still has technical problems of poor catalytic effect and low catalytic activity. In addition, the existing modification process is complicated to prepare, and requires high temperature and high pressure, harsh conditions, and is dangerous. Summary of the invention

[0005] In view of the technical problems of poor catalytic effect, low catalytic activity and complex preparation of existing photoelectrocatalysts, the present invention provides a MgCo-LDH / ATP / BiVO 4 The ternary composite photocatalytic material and its preparation method and application, the prepared ternary composite photocatalytic material has excellent catalytic activity, greatly improves the rate of photoelectrocatalytic water decomposition, and improves the catalytic effect; in addition, the preparation process is simple to operate and the synthesis cycle is short.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] MgCo-LDH / ATP / BiVO 4 The preparation method of the ternary composite photocatalytic material comprises the following steps:

[0008] S1. Preprocessing

[0009] The attapulgite is pretreated by filtering, washing and calcining to obtain dehydrated ATP;

[0010] S2, MgCo-LDH / ATP synthesis

[0011] S2.1, MgCl 2 6H 2 O、CoCl 2 6H 2 O, urea, and the dehydrated ATP in step S1 are dissolved in water and stirred to obtain a mixed solution A; the MgCl 2 6H 2 O、CoCl 2 6H 2 The mass ratio of O, urea, dehydrated ATP and water is (0.8132-0.9):(1.903-2.0):(0.72-0.9):(0.03-0.07):(50-60);

[0012] S2.2, placing the mixed solution A in a polytetrafluoroethylene liner, and sequentially reacting, washing, drying and grinding to obtain MgCo-LDH / ATP;

[0013] S3. Synthesis of BiVO 4

[0014] S3.1, preparing BiOI precursor solution;

[0015] S3.2, using a three-electrode system, depositing the BiOI precursor solution on a glass sheet to obtain a glass sheet with a BiOI film deposited thereon;

[0016] S3.3, adding vanadium acetylacetonate to dimethyl sulfoxide solvent, wherein the mass volume ratio of vanadium acetylacetonate to dimethyl sulfoxide solvent is 0.133 g: 2.5 mL, dissolving by ultrasonication to obtain a mixed solution; and taking 100 μL of the mixed solution and uniformly drop-casting it on a glass sheet with a BiOI film deposited thereon, and annealing, calcining, washing, and drying to obtain BiVO 4 Electrode sheet;

[0017] S4, MgCo-LDH / ATP / BiVO 4 Synthesis of ternary composite photocatalytic materials

[0018] Take Mg(NO 3 ) 2 6H 2 O, isopropanol and MgCo-LDH / ATP were ultrasonically mixed in a mass volume ratio of 0.01 g:50 ml:0.04 g to 0.06 g; and the BiVO 4 The electrode sheet was used to construct an electrodeposition system for electrophoretic deposition to obtain MgCo-LDH / ATP / BiVO 4 Ternary composite photocatalytic material.

[0019] It is further defined that in step S1, the calcination temperature is 300-400°C and the calcination time is 2-4h.

[0020] It is further defined that in step S2.1, the stirring time is 30-60 min.

[0021] It is further defined that in step S3.1, the specific process of preparing the BiOI precursor solution is:

[0022] Add KI to water and fully dissolve it, and adjust the pH to 1.60-1.63; then add Bi(NO 3 ) 3 ·5H 2 O is stirred until completely dissolved to obtain a mixed solution;

[0023] dissolving p-benzoquinone in anhydrous ethanol to obtain a p-benzoquinone ethanol solution; and dropping the p-benzoquinone ethanol solution into the mixed solution to form a BiOI precursor solution;

[0024] The KI, water, Bi(NO3 ) 3 ·5H 2 The mass volume ratio of O, p-benzoquinone and anhydrous ethanol is 3.32g:50ml:0.97g:(0.498-0.5)g:20ml.

[0025] It is further defined that in step S3.2, the preparation process of the glass sheet deposited with the BiOI film is specifically as follows:

[0026] The glass slide is placed in a mixed solvent for ultrasonic cleaning for 30 minutes. The mixed solvent is a mixture of anhydrous ethanol, acetone and water, and then rinsed and dried for later use.

[0027] A three-electrode system with conductive glass as a working electrode, a platinum electrode as a counter electrode and Ag / AgCl as a reference electrode was used to carry out deposition by cyclic voltammetry to obtain a glass sheet with a BiOI film deposited thereon.

[0028] It is further defined that in the cyclic voltammetry method, the scan rate is 5 mV / s and the potential range is -0.13 V to 0 V.

[0029] It is further defined that in step S3.3, the calcination reaction temperature is 450-500° C. and the time is 2-4 hours.

[0030] Further defined, in step S4, the three-electrode system is: using two iron electrodes, FTO glass as an anode, BiVO 4 The electrode sheet is the cathode and the suspension is the electrolyte.

[0031] Using the MgCo-LDH / ATP / BiVO 4 MgCo-LDH / ATP / BiVO prepared by the preparation method of ternary composite photocatalytic material 4 Ternary composite photocatalytic material.

[0032] As described in MgCo-LDH / ATP / BiVO 4 Ternary composite photocatalytic materials are used as photoanode materials in photoelectrocatalytic water decomposition.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The present invention uses the photocatalyst BiVO 4 The ternary composite photocatalytic material BiVO was obtained by combining MgCo-LDH and attapulgite (ATP). 4It is cheap, easy to obtain, green, non-toxic, has a suitable band gap (about 2.4eV), and has stable chemical properties and strong photoresponsiveness. MgCo-LDH has strong oxidizing ability and good photogenerated charge mobility. When MgCo-LDH is irradiated with visible light, the photogenerated holes in the valence band of MgCo-LDH have strong oxidizing properties, which is beneficial to photoelectrocatalytic water decomposition. Due to the strong oxidizing ability of MgCo-LDH and BiVO in the ternary composite photocatalytic material, the photogenerated holes in the valence band of MgCo-LDH have strong oxidizing properties, which is beneficial to photoelectrocatalytic water decomposition. 4 A hole transport channel is inserted between the MgCo-LDH / ATP / BiVO 4 The ternary composite photocatalytic material has high photoelectrochemical stability in a simulated seawater environment with a pH of 7-9.5, which has strong application prospects for utilizing seawater to produce hydrogen.

[0035] 2. The composite material of the present invention is composed of visible light responsive BiVO 4 The photocatalyst was constructed by combining it with ultraviolet light-responsive MgCo-LDH, and attapulgite was inserted between the interfaces of the two as a transmission channel for holes and electrons to accelerate the photoelectrocatalytic reaction.

[0036] 3. MgCo-LDH / ATP / BiVO prepared by the present invention 4 When the ternary composite photocatalytic material is used as a catalyst for photoelectrocatalytic water decomposition, it can preferentially adsorb water molecules on the catalyst surface, react with the photogenerated electrons and holes induced by semiconductor light, and effectively improve the hydrogen production efficiency. No waste gas is generated during the decomposition process, and the catalytic process is clean and environmentally friendly, thus overcoming the problems of slow charge and mass transfer in traditional water electrolysis processes.

[0037] 4. The preparation method of the catalyst of the present invention can be achieved by mixing, hydrothermal and calcination. The preparation process is simple to operate and only takes 10 hours to complete the preparation of the catalyst, and the synthesis cycle is short. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The X-ray diffraction (XRD) analysis results of different photoanode materials;

[0039] Figure 2 Photoluminescence spectra (PL spectra) of different photoanode materials;

[0040] Figure 3 is the absorption capacity of different photoanode materials to sunlight;

[0041] Figure 4 Linear cyclic voltammetry curves and transient photocurrent density curves of different photoanode materials;

[0042] Figure 5 EIS curves and surface photovoltage test diagrams of different photoanode materials;

[0043] Figure 6 The specific surface area and open circuit photovoltage (OCP) versus time curves of different photoanode materials;

[0044] Figure 7 is the UV absorption curve of different photoanode materials;

[0045] Figure 8 This is the XPS analysis result of the ternary composite photocatalytic material of the present invention;

[0046] Fig. 9 The contact angle results of different photoanode materials;

[0047] Fig.10 SEM morphologies of different photoanode materials. DETAILED DESCRIPTION

[0048] The technical solution of the present invention is now described in detail with reference to the accompanying drawings and embodiments.

[0049] The present invention provides a MgCo-LDH / ATP / BiVO 4 The preparation method of the ternary composite photocatalytic material comprises the following steps:

[0050] S1. Preprocessing

[0051] The attapulgite (ATP for short) is pre-treated by filtering, washing and calcining to obtain dehydrated ATP.

[0052] In this step, the attapulgite is filtered and washed in advance to remove insoluble impurities.

[0053] S2, MgCo-LDH / ATP synthesis

[0054] S2.1, MgCl 2 6H 2 O、CoCl 2 6H 2 O, urea, and the dehydrated ATP in step S1 are dissolved in water and stirred evenly to obtain a mixed solution A.

[0055] MgCl 2 6H 2 O、CoCl 2 6H 2 The mass ratio of O, urea, dehydrated ATP and water is (0.8132-0.9):(1.903-2.0):(0.72-0.9):(0.03-0.07):(50-60);

[0056] S2.2. Place the mixed solution A in a polytetrafluoroethylene liner for reaction, washing, drying, and grinding to obtain MgCo-LDH / ATP.

[0057] In step S2.1, the stirring time is 30-60 min. The stirring allows the MgCo-LDH to be uniformly loaded on the needle-shaped ATP.

[0058] S3. Synthesis of BiVO 4 Electrode sheet

[0059] S3.1. Prepare BiOI precursor solution.

[0060] In this step, the specific process of preparing the BiOI precursor solution is:

[0061] Add KI to water and fully dissolve it, and adjust the pH to 1.60-1.63; then add Bi(NO 3 ) 3 ·5H 2 O is stirred until completely dissolved to obtain a mixed solution; p-benzoquinone is dissolved in anhydrous ethanol to obtain a p-benzoquinone ethanol solution; and the p-benzoquinone ethanol solution is added dropwise to the mixed solution to form a BiOI precursor solution.

[0062] Using 1 mol / L HNO 3 Adjusting the pH value can prepare BiVO with uniform nanoflower-like bismuth vanadate on the surface. 4 Base.

[0063] KI, water, Bi(NO 3 ) 3 ·5H 2 The mass dosage ratio of O, p-benzoquinone and anhydrous ethanol is 3.32g:50ml:0.97g:(0.498-0.5)g:20ml.

[0064] S3.2, using a three-electrode system, deposit the BiOI precursor solution on a glass sheet to obtain a glass sheet with a BiOI film deposited thereon. Preferably, the glass sheet is a FTO glass sheet.

[0065] The preparation process of step S3.2 of the present invention is specifically:

[0066] The glass sheet was ultrasonically cleaned in a mixed solvent for 30-60 minutes. The mixed solvent was mixed with anhydrous ethanol, acetone and water in a volume ratio of 1:1:1, and then rinsed and dried for use. A three-electrode system (FTO conductive glass as a working electrode, a platinum electrode as a counter electrode, and Ag / AgCl as a reference electrode) was used to deposit by cyclic voltammetry to obtain a glass sheet with a BiOI film deposited thereon.

[0067] In the present invention, the cyclic voltammetry method has a scanning rate of 5 mV / s and a potential range of -0.13 V to 0 V. In this step, the electrochemical deposition of the three-electrode system is adopted, and BiOI can be uniformly and tightly loaded on the FTO glass sheet in the form of a film.

[0068] S3.3, adding vanadium acetylacetonate to dimethyl sulfoxide solvent, wherein the mass volume ratio of vanadium acetylacetonate to dimethyl sulfoxide solvent is 0.133 g: 2.5 mL, dissolving by ultrasonication to obtain a mixed solution; and taking 100 μL of the mixed solution and uniformly drop-casting it on a glass sheet with a BiOI film deposited thereon, and annealing, calcining, washing, and drying to obtain BiVO 4 Electrode sheet.

[0069] In step S3.3 of the present invention, the calcination temperature is 450-500° C. and the time is 2-4 hours.

[0070] S4, MgCo-LDH / ATP / BiVO 4 Synthesis of ternary composite photocatalytic materials

[0071] Take Mg(NO 3 ) 2 6H 2 O, isopropanol and MgCo-LDH / ATP were ultrasonically mixed in a mass volume ratio of 0.01 g:50 ml:0.04 g to 0.06 g; and the BiVO 4 The electrode sheet was used to construct an electrodeposition system for electrophoretic deposition to obtain MgCo-LDH / ATP / BiVO 4 Ternary composite photoanode materials.

[0072] In step S4 of the present invention, two iron electrodes are used, FTO glass is used as an anode, and BiVO 4 The electrode sheet is the cathode and the suspension is the electrolyte.

[0073] In step S4 of the present invention, Mg(NO 3 ) 2 6H 2 O and isopropanol were used as the dispersion solution for electrophoretic deposition, which made MgCo-LDH / ATP charged and able to move to BiVO in a directional manner under the action of an applied voltage. 4 Above, MgCo-LDH / ATP / BiVO 4 Ternary composite photocatalytic material.

[0074] In the present invention, the ultrasonic time is 30-60 min.

[0075] Using the above MgCo-LDH / ATP / BiVO 4MgCo-LDH / ATP / BiVO prepared by the preparation method of ternary composite photocatalytic material 4 The ternary composite photocatalytic material has excellent light absorption and response capabilities. It will rapidly generate a large number of photogenerated electrons and holes under light conditions, and an intermediate layer is inserted in the middle to transmit charges, making it difficult for the electrons and holes generated by light excitation to recombine. They can participate in redox reactions separately, greatly improving the rate of photoelectrocatalytic water decomposition. It can be used as a photoanode material in the photoelectrocatalytic decomposition of water to produce hydrogen and oxygen.

[0076] The preparation and performance of the ternary composite photocatalytic material provided by the present invention are described below through several groups of specific implementation methods.

[0077] It should be noted that, unless otherwise specified, the drugs and reagents used in the following examples are all conventional commercially available products in the art.

[0078] It should be noted that, unless otherwise specified, the chemical operations used in the following examples are all routine operations in the art.

[0079] Example 1

[0080] The MgCo-LDH / ATP / BiVO provided in this embodiment 4 The preparation method of the ternary composite photocatalytic material comprises the following steps:

[0081] S1. Preprocessing

[0082] The attapulgite is filtered and washed; then placed in a muffle furnace and calcined at 300° C. for 3 h to obtain dehydrated ATP.

[0083] S2. Preparation of MgCo-LDH / ATP

[0084] Take 0.8132g MgCl 2 6H 2 O, 1.903gCoCl 2 6H 2 O, 0.72g urea and 0.03g dehydrated ATP were added into 50ml distilled water and stirred for 1h to obtain a pink-purple suspension, which was recorded as mixed solution A; the mixed solution A suspension was reacted in an oven at 200℃ for 8h, and the obtained product was washed by alternating centrifugation with water and ethanol, dried and ground to obtain the product MgCo-LDH / ATP.

[0085] S3. Preparation of BiVO 4 Electrode sheet

[0086] S3.1, weigh 3.32g KI and dissolve it in 50ml distilled water, then use 1mol / L HNO 3After adjusting the solution pH to 1.60-1.63, 0.970 g Bi(NO 3 ) 3 ·5H 2 O and stirred until the solution turned bright orange, marking the solution as solution A. Then weigh 0.5 g of p-benzoquinone and dissolve it in 20 ml of anhydrous ethanol and stir until it is completely dissolved, marking this solution as solution B; solution B was added dropwise into solution A to obtain a BiOI precursor solution.

[0087] S3.2, electrochemical deposition of BiOI precursor solution was performed using a three-electrode system, with a Pt sheet electrode as a counter electrode, an Ag / AgCl electrode as a reference electrode, an iron electrode as a working electrode, and a FTO blank glass sheet sandwiched between the iron electrode to carry BiOI. Deposition was performed by cyclic voltammetry (CV) at a scan rate of 5 mV / s in a potential range of -0.13 to 0 V to obtain a glass sheet with a BiOI film deposited thereon.

[0088] Take multiple pieces with an area of ​​1×2cm 2 The FTO glass sheet was placed in a mixed solution of ethanol, acetone and distilled water (volume ratio of anhydrous ethanol: acetone: distilled water = 1:1:1) and ultrasonically cleaned for 60 minutes. After cleaning, it was rinsed with distilled water and placed in an oven for drying.

[0089] S3.3, weigh 0.133g of vanadium acetylacetonate and dissolve it in 2.5ml of dimethyl sulfoxide and ultrasonicate it for 60min to obtain solution C; finally, add 100μL of solution C to each glass sheet with BiOI film deposited on it, place it in a muffle furnace and calcine it at 500℃ for 2h to obtain BiVO 4 Electrode sheet.

[0090] S4. Preparation of ternary composite materials

[0091] Weigh 0.04 g of the prepared MgCo-LDH / ATP and 0.01 g of Mg(NO 3 ) 2 6H 2 O, respectively, were added to 50 ml of isopropanol and ultrasonicated for 60 min to obtain a lavender suspension; two iron electrodes were used, FTO glass was used as the anode, and BiVO 4 The electrode sheet was used as the cathode, and MgCo-LDH / ATP was electrophoretically deposited on the prepared BiVO 4 On the electrode sheet, MgCo-LDH / ATP / BiVO 4 Ternary composite photocatalytic material.

[0092] Example 2

[0093] The MgCo-LDH / ATP / BiVO provided in this embodiment 4The preparation method of the ternary composite photocatalytic material comprises the following steps:

[0094] S1. Preprocessing

[0095] The attapulgite is filtered and washed; then placed in a muffle furnace and calcined at 400° C. for 2 h to obtain dehydrated ATP.

[0096] S2. Synthesis of MgCo-LDH / ATP

[0097] Take 0.8132g MgCl 2 6H 2 O, 1.903 g CoCl 2 6H 2 O, 0.72g urea and 0.05g dehydrated ATP were added into 50ml distilled water in sequence and stirred for 1h to obtain a pink-purple suspension, which was marked as mixed solution A; the mixed solution A suspension was reacted in an oven at 150°C for 10h, and the obtained product was washed by alternating centrifugation with water and ethanol, dried and ground to obtain the product MgCo-LDH / ATP.

[0098] S3. Preparation of BiVO 4 Electrode sheet

[0099] S3.1, weigh 3.32g KI and dissolve it in 50ml distilled water, then use 1mol / L HNO 3 After adjusting the solution pH to 1.60, 0.970 g Bi(NO 3 ) 3 ·5H 2 O and stirred until the solution turned bright orange, marking the solution as solution A. Then weigh 0.498 g of p-benzoquinone and dissolve it in 20 ml of anhydrous ethanol and stir until it is completely dissolved, marking this solution as solution B. Solution B was added dropwise into solution A to obtain a BiOI precursor solution.

[0100] S3.2. Finally, a three-electrode system was used to electrochemically deposit the BiOI precursor solution. The Pt sheet electrode was used as the counter electrode, the Ag / AgCl electrode was used as the reference electrode, and the iron electrode was used as the working electrode. The FTO blank glass sheet was sandwiched between the iron electrode to carry BiOI. The deposition was performed by cyclic voltammetry (CV) at a scanning rate of 5 mV / s in a potential range of -0.13 to 0 V to obtain a glass sheet with a BiOI film deposited thereon.

[0101] Take multiple pieces with an area of ​​1×2cm 2 The FTO glass sheet was placed in a mixed solution of ethanol, acetone and distilled water (volume ratio of anhydrous ethanol: acetone: distilled water = 1:1:1) and ultrasonically cleaned for 30 minutes. After cleaning, it was rinsed with distilled water and placed in an oven for drying.

[0102] S3.3, weigh 0.133g of vanadium acetylacetonate and dissolve it in 2.5ml of dimethyl sulfoxide and ultrasonicate it for 30min to obtain solution C; finally, add 100μL of solution C to each glass sheet with BiOI deposited on it and place it in a muffle furnace and calcine it at 450℃ for 4h to obtain BiVO 4 Electrode material.

[0103] S4. Preparation of ternary composite materials

[0104] Weigh 0.04 g of the prepared MgCo-LDH / ATP and 0.01 g of Mg(NO 3 ) 2 6H 2 O were added to 50 ml of isopropanol and ultrasonicated for 30 min to obtain a lavender suspension. Two iron electrodes were used, FTO glass was used as the anode, and BiVO 4 The electrode sheet was used as the cathode, and MgCo-LDH / ATP was electrophoretically deposited on the prepared BiVO 4 On the electrode sheet, MgCo-LDH / ATP / BiVO 4 Ternary composite photocatalytic material.

[0105] Example 3

[0106] The MgCo-LDH / ATP / BiVO provided in this embodiment 4 The preparation method of the ternary composite photocatalytic material comprises the following steps:

[0107] S1. Preprocessing

[0108] The attapulgite is filtered and washed; then placed in a muffle furnace and calcined at 350° C. for 2 h to obtain dehydrated ATP.

[0109] S2. Synthesis of MgCo-LDH / ATP

[0110] Take 0.8132g MgCl 2 6H 2 O, 1.903gCoCl 2 6H 2 O, 0.72g urea and 0.07g dehydrated ATP were added into 50ml distilled water and stirred for 1.5h to obtain a pink-purple suspension, which was marked as mixed solution A; the mixed solution A suspension was reacted in an oven at 160°C for 9h, and the obtained product was washed by alternating centrifugation with water and ethanol, dried and ground to obtain the product MgCo-LDH / ATP.

[0111] S3. Preparation of BiVO 4 Electrode sheet

[0112] S3.1. Weigh 3.32 g of KI and dissolve it in 50 ml of distilled water. Then, use 1 M HNO 3 to adjust the pH of the solution to 1.60 - 1.63. After that, weigh 0.970 g of Bi(NO 3 ) 3 ·5H 2 O and stir until the solution turns bright orange. Mark this solution as Solution A. Weigh 0.5 g of p-benzoquinone and dissolve it in 20 ml of absolute ethanol by stirring until completely dissolved. Mark this solution as Solution B. Drop Solution B into Solution A drop by drop to obtain the BiOI precursor solution.

[0113] S3.2. Use a three-electrode system to electrochemically deposit the BiOI precursor solution. The Pt plate electrode is the counter electrode, the Ag / AgCl electrode is the reference electrode, and the iron electrode is the working electrode. The FTO blank glass sheet is clamped on the iron electrode to carry BiOI. Through cyclic voltammetry (CV) at a scanning rate of 5 mV / s, deposit in the potential range of -0.13 to 0 V to obtain a glass sheet deposited with a BiOI film.

[0114] Take multiple FTO glass sheets with an area of 1×2 cm 2 and place them in a mixed solution of ethanol, acetone, and distilled water (volume ratio of absolute ethanol:acetone:distilled water = 1:1:1) for ultrasonic cleaning for 40 min. After that, rinse with distilled water and place them in an oven to dry for later use.

[0115] S3.3. Weigh 0.133 g of vanadyl acetylacetonate and dissolve it in 2.5 ml of dimethyl sulfoxide, and ultrasonicate for 45 min to obtain Solution C. Finally, drop 100 μL of Solution C onto the glass sheet deposited with the BiOI thin film and then place it in a muffle furnace and calcine at 480 °C for 3 h to obtain the BiVO 4 electrode sheet.

[0116] S4. Preparation of ternary composite material

[0117] Weigh 0.04 g of the prepared MgCo-LDH / ATP and 0.01 g of Mg(NO 3 ) 2 ·6H 2 O and add them to 50 ml of isopropanol respectively, and ultrasonicate for 50 min to obtain a light purple suspension. Use two iron electrodes, with the FTO glass as the anode and the BiVO 4 electrode sheet as the cathode, and electrophoretically deposit MgCo-LDH / ATP on the prepared BiVO 4 electrode sheet to obtain the MgCo-LDH / ATP / BiVO 4 ternary composite photocatalytic material.

[0118] Example 4

[0119] The MgCo-LDH / ATP / BiVO provided in this embodiment 4 The preparation method of the ternary composite photocatalytic material comprises the following steps:

[0120] S1. Preprocessing

[0121] The attapulgite is filtered and washed; then placed in a muffle furnace and calcined at 380° C. for 2 h to obtain dehydrated ATP.

[0122] S2. Synthesis of MgCo-LDH / ATP

[0123] Take 0.8132g MgCl 2 6H 2 O, 1.903 g CoCl 2 6H 2 O, 0.72g urea and 0.1g dehydrated ATP were added into 50ml distilled water and stirred for 1h to obtain a pink-purple suspension, which was marked as mixed solution A; the mixed solution A suspension was reacted in an oven at 180°C for 8h, and the obtained product was washed by alternating centrifugation with water and ethanol, dried and ground to obtain the product MgCo-LDH / ATP.

[0124] S3. Preparation of BiVO 4 Electrode sheet

[0125] Weigh 3.32 g KI and dissolve it in 50 ml distilled water. Then use 1 M HNO 3 After adjusting the solution pH to 1.60-1.63, 0.970 g Bi(NO 3 ) 3 ·5H 2 O and stirred until the solution turned bright orange, marking the solution as solution A. Then weigh 0.498 g of p-benzoquinone and dissolve it in 20 ml of anhydrous ethanol and stir until it is completely dissolved, marking this solution as solution B. Solution B was added dropwise into solution A to obtain a BiOI precursor solution.

[0126] S3.2. The BiOI precursor solution was electrochemically deposited using a three-electrode system, with a Pt sheet electrode as the counter electrode, an Ag / AgCl electrode as the reference electrode, and an iron electrode as the working electrode. A FTO blank glass sheet was sandwiched between the iron electrode to carry BiOI. Cyclic voltammetry (CV) was used to perform deposition at a scan rate of 5 mV / s in a potential range of -0.13 to 0 V to obtain a glass sheet with a BiOI film deposited thereon.

[0127] Take multiple pieces with an area of ​​1×2cm 2The FTO glass sheet was placed in a mixed solution of ethanol, acetone and distilled water (anhydrous ethanol: acetone: distilled water volume ratio = 1:1:1) and ultrasonically cleaned for 45 minutes. After cleaning, it was rinsed with distilled water and placed in an oven for drying.

[0128] S3.3, weigh 0.133g of vanadium acetylacetonate and dissolve it in 2.5ml of dimethyl sulfoxide and ultrasonicate for 30min to obtain solution C. Finally, 100μL of solution C was added dropwise to each glass sheet with BiOI deposited on it and then placed in a muffle furnace and calcined at 480℃ for 3h to obtain BiVO 4 Electrode sheet.

[0129] S4. Preparation of ternary composite materials

[0130] Weigh 0.04 g of the prepared MgCo-LDH / ATP and 0.01 g of Mg(NO 3 ) 2 6H 2 O, respectively, were added to 50 ml of isopropanol and ultrasonicated for 45 min to obtain a lavender suspension; two iron electrodes were used, FTO glass was used as the anode, and BiVO 4 The electrode sheet was used as the cathode, and MgCo-LDH / ATP was electrophoretically deposited on the prepared BiVO 4 On the electrode sheet, MgCo-LDH / ATP / BiVO 4 Ternary composite photocatalytic material.

[0131] Furthermore, the MgCo-LDH / ATP / BiVO prepared in Example 4 4 The ternary composite photocatalytic material was used as a sample, and the photocatalytic performance of the ternary composite photocatalytic material prepared by the present invention was studied.

[0132] In the study of photocatalytic performance, the following control samples were also set up: BiVO 4 Electrode sheet, ATP / BiVO 4 Binary composite photocatalytic materials and MgCo-LDH / BiVO 4 Binary composite photocatalytic materials.

[0133] Specifically, BiVO 4 The electrode sheet was prepared in step S3 of Example 4; ATP / BiVO 4 Preparation method of binary composite photocatalytic material and MgCo-LDH / BiVO 4 The preparation method of the binary composite photocatalytic material refers to Example 4, which is as follows.

[0134] 1. ATP / BiVO 4 The method for preparing a binary composite photocatalytic material comprises the following steps:

[0135] S1. Preprocessing

[0136] The attapulgite is filtered and washed; then placed in a muffle furnace and calcined at 380° C. for 2 h to obtain dehydrated ATP.

[0137] S2. Preparation of BiVO 4 Electrode sheet

[0138] S2.1, weigh 3.32g KI and dissolve it in 50ml distilled water, then use 1M HNO 3 After adjusting the solution pH to 1.60-1.63, 0.970 g Bi(NO 3 ) 3 ·5H 2 O and stirred until the solution turned bright orange, marking the solution as solution A. Then weigh 0.498 g of p-benzoquinone and dissolve it in 20 ml of anhydrous ethanol and stir until it is completely dissolved, marking this solution as solution B. Solution B was added dropwise into solution A to obtain a BiOI precursor solution.

[0139] S2.2. The BiOI precursor solution was electrochemically deposited using a three-electrode system, with a Pt sheet electrode as the counter electrode, an Ag / AgCl electrode as the reference electrode, and an iron electrode as the working electrode. A FTO blank glass sheet was sandwiched between the iron electrode to carry BiOI. Cyclic voltammetry (CV) was used to perform deposition at a scan rate of 5 mV / s in a potential range of -0.13 to 0 V to obtain a glass sheet with a BiOI film deposited thereon.

[0140] Take multiple pieces with an area of ​​1×2cm 2 The FTO glass sheet was placed in a mixed solution of ethanol, acetone and distilled water (anhydrous ethanol: acetone: distilled water volume ratio = 1:1:1) and ultrasonically cleaned for 45 minutes. After cleaning, it was rinsed with distilled water and placed in an oven for drying.

[0141] S2.3, weigh 0.133g of vanadium acetylacetonate and dissolve it in 2.5ml of dimethyl sulfoxide and ultrasonicate it for 30min to obtain solution C. Finally, 100μL of solution C was added dropwise to each glass sheet with BiOI deposited on it and then placed in a muffle furnace and calcined at 480℃ for 3h to obtain BiVO 4 Electrode sheet.

[0142] S3. Preparation of binary composite materials

[0143] Weigh 0.04 g of the prepared ATP and add it to 50 ml of isopropanol. Ultrasonicate for 45 min to obtain a lavender suspension. Use two iron electrodes, FTO glass as the anode, and BiVO 4 The electrode sheet is used as the cathode, and ATP is electrophoretically deposited on the prepared BiVO 4 On the electrode sheet, ATP / BiVO4 Binary composite photocatalytic materials.

[0144] 2. MgCo-LDH / BiVO 4 The method for preparing a binary composite photocatalytic material comprises the following steps:

[0145] S1. Synthesis of MgCo-LDH

[0146] Take 0.8132g MgCl 2 , 1.903 g CoCl 2 6H 2 O, 0.72g urea were added successively into 50ml distilled water and stirred for 1h to obtain a pink-purple suspension, marked as mixed solution A; the mixed solution A suspension was reacted in an oven at 180°C for 8h, and the obtained product was washed by alternating centrifugation with water and ethanol, dried and ground to obtain the product MgCo-LDH.

[0147] S2. Preparation of BiVO 4 Electrode sheet

[0148] S2.1, weigh 3.32g KI and dissolve it in 50ml distilled water, then use 1M HNO 3 After adjusting the solution pH to 1.60-1.63, 0.970 g Bi(NO 3 ) 3 ·5H 2 O and stirred until the solution turned bright orange, marking the solution as solution A. Then weigh 0.498 g of p-benzoquinone and dissolve it in 20 ml of anhydrous ethanol and stir until it is completely dissolved, marking this solution as solution B. Solution B was added dropwise into solution A to obtain a BiOI precursor solution.

[0149] S2.2. The BiOI precursor solution was electrochemically deposited using a three-electrode system, with a Pt sheet electrode as the counter electrode, an Ag / AgCl electrode as the reference electrode, and an iron electrode as the working electrode. A FTO blank glass sheet was sandwiched between the iron electrode to carry BiOI. Cyclic voltammetry (CV) was used to perform deposition at a scan rate of 5 mV / s in a potential range of -0.13 to 0 V to obtain a glass sheet with a BiOI film deposited thereon.

[0150] Take multiple pieces with an area of ​​1×2cm 2 The FTO glass sheet was placed in a mixed solution of ethanol, acetone and distilled water (anhydrous ethanol: acetone: distilled water volume ratio = 1:1:1) and ultrasonically cleaned for 45 minutes. After cleaning, it was rinsed with distilled water and placed in an oven for drying.

[0151] S2.3, weigh 0.133g of vanadium acetylacetonate and dissolve it in 2.5ml of dimethyl sulfoxide and ultrasonicate it for 30min to obtain solution C. Finally, 100μl of solution C was added dropwise to each glass sheet with BiOI deposited on it and then placed in a muffle furnace and calcined at 480℃ for 3h to obtain BiVO 4 Electrode sheet.

[0152] S3. Preparation of binary composite materials

[0153] Weigh 0.04 g of the prepared MgCo-LDH and 0.01 g of Mg(NO 3 ) 2 6H 2 O, respectively, were added to 50 ml of isopropanol and ultrasonicated for 45 min to obtain a lavender suspension; two iron electrodes were used, FTO glass was used as the anode, and BiVO 4 The electrode sheet was used as the cathode, and MgCo-LDH was electrophoretically deposited on the prepared BiVO 4 On the electrode sheet, MgCo-LDH / BiVO 4 Ternary composite photocatalytic material.

[0154] Test 1

[0155] X-ray diffraction (XRD) analysis was performed on the prepared ternary composite photocatalytic material in order to clearly understand the crystal structure of the ternary composite photocatalytic material.

[0156] Sample: BiVO 4 Electrode sheet, ATP / BiVO 4 Binary composite photocatalytic material, MgCo-LDH / BiVO 4 Binary composite photocatalytic material and MgCo-LDH / ATP / BiVO prepared in Example 4 4 Ternary composite photocatalytic material.

[0157] Experimental process: Using an X-ray diffraction instrument, under the conditions of current of 20mA, voltage of 40Kv, scanning speed of 5° / min and scanning range of 5°-80°, the XRD pattern corresponding to the above samples was obtained; the XRD pattern is shown in Figure 1 shown.

[0158] Figure 1 BiVO 4 The diffraction peak positions correspond to those in JCPDS.No.14-0688, indicating that the experimentally synthesized BiVO 4 It is a monoclinic scheelite structure. The 2θ values ​​of 11.8°, 23.0°, 34.4°, and 45.3° correspond to the crystal planes of MgCo-LDH, indicating that MgCo-LDH / ATP / BiVO 4 The ternary composite photocatalytic material was successfully prepared.

[0159] Test 2

[0160] Sample: BiVO 4 Electrode sheet, MgCo-LDH / BiVO 4 Binary composite photocatalytic material, MgCo-LDH / ATP / BiVO prepared in Example 4 4 Ternary composite photocatalytic material.

[0161] Experimental process: Using a PE LS-55DE photoluminescence spectrometer, with an excitation wavelength of 200nm and a scanning wavelength range of 200-700nm, the photoluminescence spectra (PL) corresponding to the above samples were obtained. The results are as follows: Figure 2 shown.

[0162] from Figure 2 It can be seen that the composite material has the lowest PL peak intensity, which indicates the effective separation ability of photogenerated carriers. Electrons and holes can participate in the redox reaction respectively, accelerating the production of oxygen on the surface of the photoanode catalyst and the rapid production of hydrogen on the cathode, reflecting the excellent photoelectrocatalytic water decomposition oxygen and hydrogen production activity.

[0163] Verification 3

[0164] The ability of photoanode catalytic materials to absorb sunlight was studied by analyzing the UV-Vis of the photoanode.

[0165] Sample: BiVO 4 Electrode sheet, ATP / BiVO 4 Binary composite photocatalytic material, MgCo-LDH / BiVO 4 Binary composite photocatalytic material and MgCo-LDH / ATP / BiVO prepared in Example 4 4 Ternary composite photocatalytic material.

[0166] Experimental process: Using UV-3600Plus UV-visible diffuse reflectance absorption spectrometer, the MgCo-LDH / ATP / BiVO with different ATP contents were measured in the wavelength range of 200-800nm. 4 Composite photoelectrocatalytic materials, pure MgCo-LDH powder prepared in the embodiment and BiVO 4 The UV absorption capacity of the photoanode is shown in Figure 2. Figure 3 shown.

[0167] See also Figure 3 It can be seen that MgCo-LDH / ATP / BiVO 4 The ternary composite photocatalytic material has the highest light absorption capacity, BiVO 4After loading MgCo-LDH co-catalyst and hole transport channel ATP, the light absorption range of the electrode is broadened, and a wider range of light energy can be utilized. Under the conditions of photoelectrocatalysis, more photogenerated electrons and holes will be generated, which is equivalent to increasing the reaction active sites in disguise, and the performance of water decomposition to produce hydrogen and oxygen is greatly improved.

[0168] Verification 4

[0169] Sample: BiVO 4 Electrode sheet, ATP / BiVO 4 Binary composite photocatalytic material, MgCo-LDH / BiVO 4 Binary composite photocatalytic material and MgCo-LDH / ATP / BiVO prepared in Example 4 4 Ternary composite photocatalytic material.

[0170] Experimental process: A three-electrode system was used at 0.5 MK 3 BO 3 Photoelectric performance test in solution, see Figure 4 , where (a) is the linear cyclic voltammetry curve and (b) is the transient photocurrent density curve.

[0171] Figure 4 (a) shows that MgCo-LDH / ATP / BiVO 4 The ternary composite photocatalyst has the highest photocurrent density. MgCo-LDH / BiVO 4 Binary composite photocatalytic materials and ATP / BiVO 4 Binary composite photocatalytic materials compared to BiVO 4 The photocurrent density was improved, indicating that MgCo-LDH and ATP acted as hole-electron pair transmission channels or co-catalysts. Figure 4 (b) shows the composite MgCo-LDH / ATP / BiVO 4 The ternary composite photocatalytic material has the highest photocurrent density and the smallest peak, indicating that the recombination of its photogenerated electrons and holes is the slowest, and more holes and electrons are involved in the redox reaction to produce the target product.

[0172] Verification 5

[0173] Sample: BiVO 4 Electrode sheet, ATP / BiVO 4 Binary composite photocatalytic material, MgCo-LDH / BiVO 4 Binary composite photocatalytic material and MgCo-LDH / ATP / BiVO prepared in Example 4 4 Ternary composite photocatalytic material.

[0174] Experimental process: A three-electrode system was used at 0.5 MK 3 BO 3 The photoelectric performance test was carried out in a simulated seawater environment with a solution pH of 7-9.5. The results are as follows Figure 5 As shown, (a) is the EIS curve and (b) is the surface photovoltage test diagram.

[0175] from Figure 5 (a) EIS shows that: MgCo-LDH / ATP / BiVO 4 The ternary composite photocatalytic material has the smallest arc radius, proving that it has the smallest interfacial charge transfer resistance, which is also consistent with its highest photocurrent density. Figure 5 As can be seen in (b), the final composite sample has the highest electron lifetime, with more electrons and holes that can participate in the redox reaction respectively, which helps to decompose water to produce hydrogen and oxygen. The kinetics of water oxidation reaction is reduced, and it has high photoelectrochemical stability, which has strong application prospects for utilizing seawater to produce hydrogen.

[0176] Verification 6

[0177] Sample: BiVO 4 Electrode sheet, ATP / BiVO 4 Binary composite photocatalytic material, MgCo-LDH / BiVO 4 Binary composite photocatalytic material and MgCo-LDH / ATP / BiVO prepared in Example 4 4 Ternary composite photocatalytic material.

[0178] Experimental process: A three-electrode system was used at 0.5 mol / LK 3 BO 3 The photoelectric performance test was carried out in the solution, and the results were as follows Figure 6 As shown, (a) is the material specific surface area data calculated from the linear voltammetric scanning curve under no light conditions; (b) is the open circuit photovoltage (OCP) and time curve measured under AM1.5G lighting and dark conditions.

[0179] from Figure 6 (a) shows: MgCo-LDH / ATP / BiVO 4 The ternary composite photocatalytic material has the highest active area, which matches its highest photoelectrocatalytic activity. Figure 6 (b) It can be seen that the open circuit voltage (OCP) is caused by the splitting of the quasi-Fermi level of electrons and holes under light. Its value is the OCP under light-irradiated photoanode minus the OCP in the dark. OCP is an important means to evaluate the degree of band bending. The larger the value, the more conducive to charge separation. The results show that: in MgCo-LDH / BiVO 4The introduction of an ATP intermediate layer can effectively improve the energy band curvature, which is consistent with the corresponding photoelectrocatalysis (PEC) performance results and has excellent performance in water decomposition to produce oxygen and hydrogen.

[0180] Verification 7

[0181] By analyzing the UV-Vis of the photoanode, we can understand the material's ability to absorb sunlight.

[0182] Sample: BiVO 4 Electrode sheet, ATP / BiVO 4 Binary composite photocatalytic material, MgCo-LDH / BiVO 4 Binary composite photocatalytic material and MgCo-LDH / ATP / BiVO prepared in Example 4 4 Ternary composite photocatalytic material.

[0183] Experimental process: The above samples were used as photoanode materials, and tested by UV-Vis diffuse reflectance absorption spectrometer (UV-Vis), and BaSO 4 Perform a blank experiment and then add a load of 1×1 cm 2 The photoanode material is placed on BaSO 4 The test was carried out on a test board with the optical background as the background, and its optical performance was analyzed. The test wavelength range was: 200nm-800nm.

[0184] See also Figure 7 MgCo-LDH loading broadens the UV absorption range of the electrode, BiVO 4 The absorption edge of MgCo-LDH / ATP / BiVO was extended from 508nm to 520nm. After adding ATP interlayer, 4 The absorption edge of the ternary composite photocatalytic material has basically not changed, but the ultraviolet absorption intensity has increased, indicating that the ATP intermediate layer has improved the MgCo-LDH / BiVO 4 Light absorption capacity of ternary composite photocatalytic materials.

[0185] Verification 8

[0186] Sample: MgCo-LDH / ATP / BiVO prepared in Example 4 4 Ternary composite photocatalytic material.

[0187] Experimental process: X-ray photoelectron spectrometer (XPS) was used with a monochromatic Al Kα X-ray source, C1s as the energy reference (284.8 eV), and operating conditions of 14.9 mA and 16 Kv to understand the chemical composition and elemental valence state of the prepared photoanode. The chemical composition and elemental state of the material were analyzed. The results are as follows Figure 8 shown.

[0188] from Figure 8 The peaks of Bi, O, V, Mg, and Co can be found, and no other impurity peaks appear. This indicates that MgCo-LDH / ATP / BiVO 4 The ternary composite photocatalytic material was successfully prepared.

[0189] Verification 9

[0190] Sample: BiVO 4 Electrode sheet, ATP / BiVO 4 Binary composite photocatalytic material, MgCo-LDH / BiVO 4 Binary composite photocatalytic material and MgCo-LDH / ATP / BiVO prepared in Example 4 4 Ternary composite photocatalytic material.

[0191] Experimental process: The test was conducted using a contact angle tester. The above samples were used as photoanode materials, and the photoanode materials were loaded on FTO. Then the FTO loaded with photoanode materials was directly placed flat on the test bench, 1 μmL of water was dripped, and the phenomenon was recorded and the contact angle was measured. The results are as follows: Fig. 9 (a), (b), (c), and (d) are BiVO 4 , ATP / BiVO 4 、MgCo-LDH / BiVO 4 and MgCo-LDH / ATP / BiVO 4 The corresponding contact angle.

[0192] from Fig. 9 The contact angle data show that: MgCo-LDH / ATP / BiVO 4 The ternary composite photocatalytic material has an almost zero contact angle, proving that it has the greatest hydrophilicity, which is of great benefit to photoelectrocatalytic water decomposition. Water molecules are easily adsorbed on the surface of the photoanode material and react with the photogenerated electrons and holes generated by the light-induced action of the semiconductor material at the fastest speed, accelerating the rate of hydrogen and oxygen production from water decomposition.

[0193] Verification 10

[0194] Sample: BiVO 4 Electrode sheet and MgCo-LDH / ATP / BiVO prepared in Example 4 4 Ternary composite photocatalytic material.

[0195] Experimental process: Using a scanning electron microscope (SEM), stick the cut small pieces of electrode material on the test bench, spray gold 1-2 times, and then take SEM photos. The working voltage is 0.5kV~30kV, and the range is generally between 2μm-500nm to observe the morphology of the sample. The results are as follows Fig.10 As shown; (a) is BiVO 4 SEM images of MgCo-LDH / ATP / BiVO at 1 μm. (b) 4 SEM image of MgCo-LDH / ATP / BiVO at 1 μm and 3000 times magnification. 4 Scanning electron microscope image of .

[0196] from Fig.10 As can be seen in (a), there is uniform nanostructured bismuth vanadate on the worm-like bismuth vanadate substrate. Fig.10 (b) It can be seen that BiVO 4 It was completely covered, and the granular MgCo-LDH hydrotalcite grew evenly on the surface of ATP. Fig.10 (c) It can be seen more clearly that the granular MgCo-LDH hydrotalcite grows evenly on the surface of ATP, increasing the number of chemical reaction sites. This shows that ATP is indeed 4 It acts as a bridge for charge transfer between the photoanode and the co-catalyst MgCo-LDH, facilitating the separation and transfer of electrons and holes. The hydrogen and oxygen production capacity of the anode and cathode in water decomposition is greatly improved. The photoanode material has a large photocurrent density and good stability in a simulated environment of PH = 7-9.5, which has great application prospects for hydrogen production from seawater.

[0197] From the above catalytic performance studies, it can be seen that MgCo-LDH, ATP and BiVO 4 In the ternary composite material system formed together, attapulgite ATP serves as a transmission channel for holes and electrons, making it difficult for holes and electrons to recombine. They can participate in redox reactions separately, greatly improving the rate of photoelectrocatalytic water decomposition, and can be used as a photoanode material in the photoelectrocatalytic decomposition of water to produce hydrogen and oxygen.

[0198] The catalytic performance study of the present invention is based on the MgCo-LDH / ATP / BiVO prepared in Example 4. 4 The ternary composite photocatalytic material was used. When the MgCo-LDH / ATP / BiVO prepared in Examples 1 to 3 was used, 4 The ternary composite photocatalytic material was used as a sample, and the above test was used to study and find that it was different from the MgCo-LDH / ATP / BiVO 4The ternary composite photocatalytic materials have the same or similar catalytic properties and can all be used as photoanode materials in the photoelectrocatalytic decomposition of water to produce hydrogen and oxygen.

[0199] It should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material, characterized in that: The following steps are involved: S1. Preprocessing The attapulgite is pretreated by filtering, washing and calcining to obtain dehydrated ATP; S2, MgCo-LDH / ATP synthesis S2.1, dissolving MgCl2·6H2O, CoCl2·6H2O, urea, and the dehydrated ATP of step S1 in water, and stirring evenly to obtain a mixed solution A; the mass ratio of MgCl2·6H2O, CoCl2·6H2O, urea, dehydrated ATP and water is (0.8132-0.9):(1.903-2.0):(0.72-0.9):(0.03-0.07):(50-60); S2.2, placing the mixed solution A in a polytetrafluoroethylene liner, and sequentially reacting, washing, drying and grinding to obtain MgCo-LDH / ATP; S3, Synthesized BiVO4 electrode sheet S3.1, preparing BiOI precursor solution; S3.2, using a three-electrode system, depositing the BiOI precursor solution on a glass sheet to obtain a glass sheet with a BiOI film deposited thereon; S3.3, adding vanadium acetylacetonate to dimethyl sulfoxide solvent, wherein the mass volume ratio of vanadium acetylacetonate to dimethyl sulfoxide solvent is 0.133 g: 2.5 mL, dissolving by ultrasonication to obtain a mixed solution; and taking 100 μL of the mixed solution and uniformly drop-casting it on a glass sheet deposited with a BiOI film, and sequentially annealing, calcining, washing and drying to obtain a BiVO4 electrode sheet; Synthesis of S4, MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic materials Mg(NO3)2·6H2O, isopropanol and MgCo-LDH / ATP were ultrasonically mixed in a mass volume ratio of 0.01 g:50 ml:0.04 g-0.06 g to obtain a suspension; and an electrodeposition system was constructed using the BiVO4 electrode sheet of step S3 for electrophoretic deposition to obtain a MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material.

2. The method for preparing the MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material according to claim 1, characterized in that: In the step S1, the calcination temperature is 300-400° C. and the calcination time is 2-3 hours.

3. The method for preparing the MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material according to claim 1, characterized in that: In the step S2.1, the stirring time is 30-60 min.

4. The method for preparing the MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material according to claim 1, characterized in that: In step S3.1, the specific process of preparing the BiOI precursor solution is: Add KI into water to fully dissolve it, and adjust the pH to 1.60-1.63; then add Bi(NO3)3·5H2O and stir until it is completely dissolved to obtain a mixed solution; Dissolving p-benzoquinone in anhydrous ethanol to obtain a p-benzoquinone ethanol solution; and dropping the p-benzoquinone ethanol solution into the mixed solution to form a BiOI precursor solution; The mass volume ratio of KI, water, Bi(NO3)3·5H2O, p-benzoquinone and anhydrous ethanol is 3.32g:50ml:0.97g:(0.498-0.5)g:20ml.

5. The method for preparing the MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material according to claim 1, characterized in that: In step S3.2, the preparation process of the glass sheet deposited with the BiOI film is specifically as follows: The glass slide is placed in a mixed solvent for ultrasonic cleaning for 30 minutes. The mixed solvent is a mixture of anhydrous ethanol, acetone and water, and then rinsed and dried for later use. A three-electrode system with conductive glass as a working electrode, a platinum electrode as a counter electrode and Ag / AgCl as a reference electrode was used to carry out deposition by cyclic voltammetry to obtain a glass sheet with a BiOI film deposited thereon.

6. The method for preparing the MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material according to claim 5, characterized in that: In the cyclic voltammetry, the scan rate is 5 mV / s and the potential range is from -0.13 V to 0 V.

7. The method for preparing the MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material according to claim 1, characterized in that: In the step S3.3, the calcination temperature is 450-500° C. and the calcination time is 2-4 hours.

8. The method for preparing the MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material according to claim 1, characterized in that: In the step S4, two iron electrodes are used, FTO glass is used as an anode, a BiVO4 electrode sheet is used as a cathode, and the suspension is used as an electrolyte.

9. MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material prepared by the preparation method of MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material according to claim 1.

10. The MgCo-LDH / ATP / BiVO4 ternary composite photocatalytic material as claimed in claim 9 is used as a photoanode material in photoelectrocatalytic water decomposition.

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