BiOI(010) / Cs3Bi2I9(006) Photothermal Catalyst for Hydrogen Production by Water Splitting and Its Preparation Method and Application

Abstract

The present invention discloses a BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting cathode for hydrogen production, its preparation method and application, belonging to the technical fields of catalysts and hydrogen energy. The present invention first synthesizes BiOI(010) exposing special crystal planes, and then composes the N-type perovskite semiconductor Cs3Bi2I9 with the P-type semiconductor BiOI to construct a Z-type heterojunction, obtaining the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalyst. The present invention applies the perovskite system to photo-thermal catalytic water splitting for hydrogen production, and 2‑ the [Bi2O2] 3‑ unit of BiOI exposing special crystal planes is connected in series with the [Bi2I9] double octahedron unit of Cs3Bi2I9 to form a unique electron transport channel, improving the carrier mobility, suppressing the easy recombination of photo-generated electrons and holes, and achieving an excellent hydrogen production rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst hydrogen energy, and particularly relates to a BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel, and a preparation method and application thereof. Background Art

[0002] With the development of the industrial society, it is urgent to develop new renewable clean energy. Among them, hydrogen energy has rich reserves, high specific heat, is renewable, and is pollution-free, making it a very ideal clean energy. There are many ways to obtain hydrogen energy, such as hydrogen production from fossil fuels, electrolytic water hydrogen production, and decomposition of organic substances (methanol, ethanol, etc.) to produce hydrogen. However, these methods ultimately still require the consumption of fossil energy or electrical energy or organic substances (methanol, ethanol) that can be directly used as fuels, which is not worth the loss. Scientists have found that using solar energy to decompose water to produce hydrogen is the most ideal way to obtain hydrogen energy because solar energy is inexhaustible and the end product of hydrogen combustion is water, realizing circular utilization. The process of photocatalytic water splitting hydrogen production is as follows: (1) When irradiated with light having an energy equal to or greater than the band gap (Eg), electrons in the valence band of the semiconductor are photoexcited and jump to the conduction band to form free electrons, leaving an equal amount of positively charged holes in the valence band; (2) The photo-generated electrons and holes migrate in opposite directions under the action of an electric field, but part of them recombine due to the Coulomb force; (4) The electrons and holes migrating to the surface of the catalyst undergo redox reactions with the adsorbed substances on the surface. Among them, semiconductor photocatalysts are important media for converting solar energy into chemical energy. The selection criteria for highly efficient hydrogen production catalysts are mainly: (1) having strong light absorption ability and a wide spectral response range, so as to fully absorb solar energy; (2) having a suitable band gap and conduction band potential; (3) having a high separation efficiency of photo-generated electrons and holes; (4) Since the photocatalytic reaction mainly occurs at the surface active sites of the catalyst, it is necessary to have highly active surface reaction sites.

[0003] Therefore, it is very important to develop semiconductor photocatalysts with suitable energy band structures and excellent optoelectronic properties. It has been found that in recent years, halide perovskite semiconductors developed have excellent optoelectronic properties, such as a wide adjustable band gap, long carrier lifetime, long diffusion distance, large absorption coefficient, high charge mobility, etc., making them highly favored in the fields of solar cells and optoelectronics.

[0004] The general formula of halide perovskite is ABX3, where A is a monovalent cation, such as MA, FA, Cs + or Rb + ; B is a divalent metal ion, which can be Pb 2+ or Sn 2+ ; X is a halogen ion (Cl, Br, and I).

[0005] Among numerous halide perovskites, Cs3Bi2I9 (CBI) has a relatively narrow bandgap and the ability to respond to the entire visible light spectrum. It exhibits excellent optoelectronic properties such as light absorption and carrier mobility, and has good application prospects in solar cells, LEDs, lasers, and photodetectors. Theoretically, these excellent optoelectronic properties of halide perovskites are also applicable to photocatalytic water splitting for hydrogen production.

[0006] However, at present, there are few studies on halide perovskites in the field of photocatalytic water splitting for hydrogen production. Some studies have applied them to hydrogen production by decomposing ethanol, decomposing saturated HI / HBr, degrading nitrogen oxides, reducing CO2, etc. However, ethanol itself is a clean fuel with a high calorific value, and saturated HI / HBr is very costly, so these two methods have no industrial application value.

[0007] For example, CN112108162A discloses a composite photocatalyst of Bi2WO6 and Cs3Bi2I9 for photocatalytic CO2 reduction. CN113275026A discloses a heterojunction visible-light photocatalyst of metal oxide SnO2 and halide perovskite quantum dots Cs3Bi2I9 for degrading nitric oxide. CN111790408B discloses a bismuth / antimony-based perovskite photocatalytic material with the chemical formula Cs3Bi 2x Sb 2-2x I9 (x is 0 - 1) for photocatalytic decomposition of saturated HI. In the literature Yali Ji, Jianli Li, et al., Adv. Funct. Mater. 2022, 32, 2201721., the photocatalytic decomposition of ethanol for hydrogen production by Cs3Bi2I9 was studied. Without the need to load noble metals, the rate reached 2157.8 μmol / h / g. However, in the above studies, even in the fields of photocatalytic decomposition of ethanol and degradation of organic substances, single Cs3Bi2I9 also has problems such as easy recombination of electron-hole pairs and poor stability.

[0008] Due to its insufficient water stability, there are almost no successful precedents for its use in photocatalytic water splitting at present. The investigation found that the following main problems still exist: (1) Cs3Bi2I9 is easily decomposed under aqueous environment or polar solvent conditions, and the metal ions therein will undergo hydrolysis. Therefore, most studies are carried out in ethanol or saturated acid solutions; (2) The electron-hole pairs generated by Cs3Bi2I9 under light excitation are very easy to recombine under the action of Coulomb force, so the quantum conversion efficiency is low; (3) Cs3Bi2I9 exhibits a distorted and defect-modulated hexagonal perovskite structure, in which a pair of [BiI6] 3- octahedra share faces to form [Bi2I9] 3- double octahedra, with separated [Bi2I9] 3-The double octahedral structure results in a low carrier mobility, thus leading to poor charge transport kinetics performance; (4) There are many intermediate energy levels in Cs3Bi2I9 perovskite, which form intrinsic defects and act as recombination centers, causing the recombination of photo-generated electrons and holes, and being unfavorable for the separation of photo-generated electrons and holes in the photocatalyst; (5) Although the conduction band potential of Cs3Bi2I9 is relatively negative and can meet the theoretical requirements for hydrogen production by water reduction, the valence band potential is relatively low and insufficient to overcome the overpotential. Therefore, it is necessary to compound it with other semiconductors to increase the valence band potential. Summary of the Invention

[0009] Based on the problems of the prior art, the technical problems to be solved by the present invention are: (1) attempting to screen out halide perovskite materials that meet the band gap width and conduction band potential for photocatalytic water splitting to produce hydrogen and have excellent optical properties; (2) applying the screened halide perovskite with a suitable energy band structure to the research of photocatalytic water splitting to produce hydrogen and further modifying it to improve its activity and stability; (3) solving the problem that most halide perovskites are unstable in an aqueous environment so that they can be used in the research of photocatalytic water splitting to produce hydrogen; (4) optimizing the design of a single halide perovskite, such as constructing a heterojunction, etc., to improve its stability and the ability of electron-hole separation; (5) constructing a special electron transport channel by compounding a halide perovskite with other semiconductors to solve problems such as the easy recombination of photo-generated electrons and holes in a single catalyst, resulting in a low photo-quantum conversion efficiency.

[0010] To solve the above technical problems, the present invention first provides a preparation method of a BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting to produce hydrogen catalyst with a special electron transport channel, which includes the following steps:

[0011] A. Drop an iodine source solution into a bismuth source solution and continuously stir to obtain solution X;

[0012] B. Adjust the pH of solution X obtained in step A to 5-7 and stir to obtain solution Y;

[0013] C. Heat the solution Y obtained in step B to 160-200 °C for reaction;

[0014] D. After the reaction in step C is completed, the obtained product is subjected to solid-liquid separation, washing and drying to obtain BiOI(010) with exposed special crystal planes;

[0015] E. Disperse the BiOI(010) obtained in step D in organic solvent A and stir to obtain solution A;

[0016] F. Dissolve CsI, BiI3 and a surfactant in organic solvent B to obtain solution B;

[0017] G. Add the solution B obtained in step F dropwise into the solution A obtained in step E, and stir to obtain solution Z;

[0018] H. Heat the solution Z obtained in step G to 90 - 110 °C for reaction. After the reaction is completed, the obtained product is subjected to solid-liquid separation, washing, and drying to obtain the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalyst.

[0019] Among them, in the above preparation method, in step A, the iodine source is at least one of potassium iodide or sodium iodide.

[0020] Preferably, in the above preparation method, in step A, the iodine source is potassium iodide.

[0021] Among them, in the above preparation method, in step A, the concentration of I in the iodine source solution is 0.4 - 0.6 mol / L.

[0022] Among them, in the above preparation method, in step A, the solvent of the iodine source solution is at least one of water, ethanol, and ethylene glycol.

[0023] Preferably, in the above preparation method, in step A, the solvent of the iodine source solution is water.

[0024] Among them, in the above preparation method, in step A, the bismuth source is at least one of bismuth nitrate, bismuth chloride, bismuth bromide, bismuth acetate, and bismuth sulfate.

[0025] Preferably, in the above preparation method, in step A, the bismuth source is bismuth nitrate.

[0026] Among them, in the above preparation method, in step A, the concentration of Bi in the bismuth source solution is 0.4 - 0.6 mol / L.

[0027] Among them, in the above preparation method, in step A, the solvent of the bismuth source solution is at least one of water, ethanol, and ethylene glycol.

[0028] Preferably, in the above preparation method, in step A, the solvent of the bismuth source solution is ethanol.

[0029] Among them, in the above preparation method, in step A, the volume ratio of the iodine source solution to the bismuth source solution is 3 - 5:3 - 5.

[0030] Among them, in the above preparation method, in step B, 0.5 - 1.5 mol / L NaOH aqueous solution is used to adjust the pH.

[0031] Among them, in the above preparation method, in step B, the stirring time is 1 - 3 h.

[0032] Among them, in the above preparation method, in step C, the reaction time is 5 - 7 h.

[0033] Among them, in the above preparation method, in step D, the washing is carried out by washing with water and ethanol 2 to 4 times.

[0034] Among them, in the above preparation method, in step D, the drying temperature is 70 to 90 °C.

[0035] Among them, in the above preparation method, in step D, the drying time is 7 to 9 h.

[0036] Among them, in the above preparation method, in step E, the dispersion is ultrasonic dispersion.

[0037] Among them, in the above preparation method, in step E, the stirring time is 1 to 3 h.

[0038] Among them, in the above preparation method, in step E, the organic solvent A is at least one of isopropanol and toluene.

[0039] Preferably, in the above preparation method, in step E, the organic solvent A is isopropanol.

[0040] Among them, in the above preparation method, in step E, the dosage of the solution A is controlled so that the mass percentage of BiOI(010) in the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalyst is 5 to 15%.

[0041] Among them, in the above preparation method, in step E, the volume ratio of the organic solvent A used in step E to the organic solvent B used in step F is 45 to 50:3 to 5.

[0042] Among them, in the above preparation method, in step F, the molar ratio of CsI, BiI3 and the additive is 0.15 to 0.20:0.10 to 0.15:0.05 to 0.15.

[0043] Among them, in the above preparation method, in step F, the surfactant is at least one of cetyltrimethylammonium bromide, polyvinylpyrrolidone, and sodium dodecylbenzenesulfonate.

[0044] Preferably, in the above preparation method, in step F, the surfactant is cetyltrimethylammonium bromide.

[0045] Among them, in the above preparation method, in step F, the organic solvent B is at least one of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, ethanol, and acetonitrile.

[0046] Preferably, in the above preparation method, in step F, the organic solvent B is dimethyl sulfoxide.

[0047] Among them, in the above preparation method, in step F, the dosage of the organic solvent B is 3-5 mL / 0.15-0.20 mmol of CsI.

[0048] Among them, in the above preparation method, in step G, the stirring time is 1-3 h.

[0049] Among them, in the above preparation method, in step H, the reaction time is 1-3 h.

[0050] Among them, in the above preparation method, in step H, the washing is carried out with isopropanol 2-4 times.

[0051] Among them, in the above preparation method, in step H, the drying temperature is 50-70 °C.

[0052] Among them, in the above preparation method, in step H, the drying time is 10-14 h.

[0053] Based on the above preparation method, the present invention also provides a BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel prepared by the above preparation method.

[0054] The present invention screens out Cs3Bi2I9 perovskite and composes the N-type perovskite semiconductor Cs3Bi2I9 with the P-type semiconductor BiOI, greatly improving the catalytic performance, stability, etc. of the catalyst. Therefore, the present invention also provides the above BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel for use in photocatalytic water splitting hydrogen production, photocatalytic decomposition of organic matter for hydrogen production, photocatalytic reduction of CO2, photocatalytic degradation of organic pollutants, photo-thermal catalytic water splitting hydrogen production, photo-thermal catalytic decomposition of organic matter for hydrogen production, photo-thermal catalytic reduction of CO2, photo-thermal catalytic degradation of organic pollutants, photoelectrochemical catalytic water splitting hydrogen production, photoelectrochemical catalytic decomposition of organic matter for hydrogen production, photoelectrochemical catalytic reduction of CO2 or photoelectrochemical catalytic degradation of organic pollutants.

[0055] In particular, the present invention breaks the current situation that halide perovskite can only be used for decomposing ethanol and saturated acids to produce hydrogen, enabling the BiOI(010) / Cs3Bi2I9(006) halide perovskite to have an excellent hydrogen production rate. Therefore, preferably, the present invention provides its application in photocatalytic water splitting hydrogen production, photo-thermal catalytic water splitting hydrogen production or photoelectrochemical catalytic water splitting hydrogen production.

[0056] The beneficial effects of the present invention:

[0057] 1. The present invention realizes the screening of halide perovskite materials that meet the band gap and conduction band potential for photocatalytic water splitting for hydrogen production and have excellent optical properties, and innovatively applies the Cs3Bi2I9 perovskite system to photo-thermal catalytic water splitting for hydrogen production;

[0058] 2. BiOI(010) is difficult to synthesize due to its high surface energy, so there is less research on it. The present invention synthesizes BiOI(010) with exposed special crystal planes by regulating reaction conditions such as solution pH value and temperature. Compared with conventional BiOI(001), it has an open channel structure, shortens the electron transport distance, and is conducive to the migration of photo-generated electrons to surface active sites within the effective lifetime;

[0059] 3. The present invention composes an N-type perovskite semiconductor Cs3Bi2I9 and a P-type semiconductor BiOI to construct a Z-type heterojunction. Since the valence band potential of Cs3Bi2I9 is relatively close to the conduction band potential of BiOI, electrons on the conduction band of BiOI directly react with holes on the valence band of Cs3Bi2I9, thereby inhibiting the recombination of photo-generated electrons and holes in Cs3Bi2I9. At the same time, compared with conventional PN heterojunctions, it does not reduce the reduction ability of photo-generated electrons;

[0060] 4. BiOI is composed of alternating I - layers and [Bi2O2] 2- layers. In Cs3Bi2I9, a pair of [BiI6] 3- octahedra share a face to form [Bi2I9] 3- double octahedra. The present invention connects the [Bi2O2] 2- unit of BiOI in series with the [Bi2I9] 3- double octahedron unit of Cs3Bi2I9. BiOI and Cs3Bi2I9 have common elements Bi and I, forming a stronger force. The structural units [Bi2O2] 2- and [Bi2I9] 3- are connected to each other to form a unique electron transport channel, solving the problems of low carrier mobility and easy recombination of photo-generated electrons and holes;

[0061] 5. The present invention successfully applies BiOI(010) / Cs3Bi2I9(006) halide perovskite to water splitting for hydrogen production and achieves an excellent hydrogen production rate of 15.5 mmol / h / g, breaking the current situation that halide perovskite can only be used for hydrogen production from ethanol and saturated acids. Description of the Drawings

[0062] Figure 1Schematic diagram of the preparation route for the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel.

[0063] Figure 2 XRD patterns of BiOI, Cs3Bi2I9, and BiOI / Cs3Bi2I9.

[0064] Figure 3 SEM images of Cs3Bi2I9, BiOI, and BiOI / Cs3Bi2I9; where (a)-(b) are Cs3Bi2I9, (c) is BiOI, and (d) is BiOI / Cs3Bi2I9.

[0065] Figure 4 Atomic structure simulation diagram of the special electron transport channel [Bi2O2]-[Bi2I9] formed in BiOI(010) / Cs3Bi2I9(006).

[0066] Figure 5 Calculated energy band structure diagram of Cs3Bi2I9.

[0067] Figure 6 Time-resolved fluorescence spectra and carrier lifetime simulation diagrams of Cs3Bi2I9 and BiOI / Cs3Bi2I9.

[0068] Figure 7 Physical diagram of the photo-thermal catalytic water splitting hydrogen production device built in the present invention.

[0069] Figure 8 Photo-thermal catalytic water splitting hydrogen production activity diagrams of BiOI, Cs3Bi2I9, and BiOI / Cs3Bi2I9.

[0070] Figure 9 Energy band and photocatalytic reaction mechanism diagram of the Z-scheme heterojunction BiOI(010) / Cs3Bi2I9(006) of the present invention. Detailed implementation manners

[0071] Specifically, a preparation method for the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel includes the following steps:

[0072] A. Drop the iodine source solution into the bismuth source solution and continuously stir to obtain solution X;

[0073] B. Adjust the pH of solution X obtained in step A to 5-7, stir to obtain solution Y;

[0074] C. Heat the solution Y obtained in step B to 160 - 200 °C for reaction (generally transfer the solution Y to a hydrothermal reactor for reaction);

[0075] D. After the reaction in step C is completed, the obtained product is subjected to solid - liquid separation, washing and drying to obtain BiOI(010) with exposed special crystal planes;

[0076] E. Disperse the BiOI(010) obtained in step D in organic solvent A and stir to obtain solution A;

[0077] F. Dissolve CsI, BiI3 and a surfactant in organic solvent B to obtain solution B;

[0078] G. Drop the solution B obtained in step F into the solution A obtained in step E and stir to obtain solution Z;

[0079] H. Heat the solution Z obtained in step G to 90 - 110 °C for reaction (generally transfer the solution Z to a hydrothermal reactor for reaction). After the reaction is completed, the obtained product is subjected to solid - liquid separation, washing and drying to obtain the BiOI(010) / Cs3Bi2I9(006) photo - thermal catalyst.

[0080] In the present invention, by judging whether the band gap, conduction band and valence band energy levels of the perovskite meet the thermodynamic requirements for water splitting to produce hydrogen, as well as stability, environmental friendliness, etc., it is first screened and found that the N - type semiconductor Cs3Bi2I9 can meet the band gap and conduction band potential for photocatalytic water splitting to produce hydrogen, and has excellent optical properties, making it possible to apply halide perovskite to water splitting to produce hydrogen. Therefore, the present invention is committed to solving problems such as the stability problem, charge transfer kinetics problem and application range limitation of Cs3Bi2I9.

[0081] The present invention also screens and finds that the P - type semiconductor BiOI, which has the same elements Bi and I as Cs3Bi2I9, may form a special PN junction - Z - type heterojunction with it. It is found that BiOI with exposed special (010) crystal planes has an open [Bi2O2] 2- electron transport channel and has more excellent electron transport kinetic performance compared with traditional BiOI(001). Since BiOI is composed of alternating I - layers and [Bi2O2] 2- layers, but BiOI is particularly prone to exposing the (001) crystal plane, which limits the electron transport. When the reaction conditions are regulated to selectively expose the (010) crystal plane, an open electron transport channel will be formed, which is conducive to the rapid migration of electrons to the surface active sites. Cs3Bi2I9 exhibits a distorted and defect - modulated hexagonal perovskite structure, in which a pair of [BiI6] 3- octahedra share faces to form [Bi2I9]3- Double octahedra, due to the common elements Bi and I they contain, are composed of the structural units [Bi2O2] 2- and [Bi2I9] 3- which are interconnected to form a unique electron transport channel, potentially constructing an efficient photocatalytic and thermocatalytic water splitting hydrogen production catalyst.

[0082] In the present invention, by controlling the synthesis conditions, the BiOI nanosheets expose the special (010) crystal plane, thus forming an open [Bi2O2] 2- electron transport channel, which has more excellent electron transport kinetic performance compared with the traditional BiOI(001), and interacts with [Bi2I9] in Cs3Bi2I9(006). 3- Due to the sharing of the [Bi-I] unit between the two, they have stronger electron migration ability. Tests have found that this catalyst has excellent photoelectrochemical performance.

[0083] In the present invention, Cs3Bi2I9 is combined with the P-type semiconductor BiOI whose energy band structure can form a Z-scheme heterojunction. Tests show that the energy band structure of Cs3Bi2I9 is E g = 2.06V, CB = -0.64V, VB = 1.42V, and the energy band structure of BiOI is E g = 1.80V, CB = 0.75V, VB = 2.55V; Since Cs3Bi2I9 and BiOI contain the common elements Bi and I, and in the present invention we synthesized BiOI(010) with exposed special crystal planes, which has an open channel structure compared with the conventional BiOI(001), shortening the electron transport distance and being more conducive to the migration of photo-generated electrons to the catalyst surface within the effective lifetime; the structural units [Bi2O2] 2- and [Bi2I9] 3- are interconnected to form a unique electron transport channel, solving the problems of low carrier mobility and easy recombination of photo-generated electron-hole pairs.

[0084] In step A of the present invention, the iodine source is controlled to be at least one of potassium iodide and sodium iodide, preferably potassium iodide; the concentration of I in the iodine source solution is controlled to be 0.4 - 0.6 mol / L; the bismuth source is controlled to be at least one of bismuth nitrate, bismuth chloride, bismuth bromide, bismuth acetate, and bismuth sulfate, preferably bismuth nitrate; the concentration of Bi in the bismuth source solution is controlled to be 0.4 - 0.6 mol / L; the volume ratio of the iodine source solution to the bismuth source solution is controlled to be 3 - 5:3 - 5 (generally, it is necessary to control the molar ratio of Bi:I in the system to be 1:1). In step A, actually, the iodine source solution and the bismuth source solution can also be directly mixed, or the bismuth source solution can be dropped into the iodine source solution, but such operations may affect the dispersibility and are not conducive to complete dissolution. Therefore, in step A of the present invention, it is preferred to drop the iodine source solution into the bismuth source solution, and at the same time, dissolve the iodine source and the bismuth source separately first and then drop them, which can reduce the reaction rate, make the reaction more sufficient, and the particle size smaller and more uniform. In the present invention, each specific bismuth source can use anhydrous bismuth salt or hydrated bismuth salt, which does not affect the target product. However, since the price of anhydrous compounds is generally more expensive, hydrated salts are generally used, such as bismuth nitrate pentahydrate, etc.

[0085] In step A, the solvent of the iodine source solution is at least one of water (generally deionized water), ethanol, and ethylene glycol, preferably water; the solvent of the bismuth source solution is at least one of water (generally deionized water), ethanol, and ethylene glycol, preferably ethanol.

[0086] In step A, after the dropping is completed, the solid will not dissolve immediately. Therefore, in the present invention, continuous stirring is required until the solid is fully dissolved.

[0087] In step B of the present invention, an inorganic or organic base common in the art can be used to adjust the pH of the system, as long as the base does not affect the reaction. For example, 0.5 - 1.5 mol / L NaOH aqueous solution is used to adjust the pH. In step B, after adjusting the pH, stir for 1 - 3 h to make them fully contact, which is conducive to a full reaction.

[0088] In step C of the present invention, the reaction time is controlled to be 5 - 7 h.

[0089] In steps A - C of the present invention, by controlling reaction conditions such as the solution pH value and temperature, the crystal orientation growth is controlled, and BiOI nanosheets are formed, thereby synthesizing BiOI(010) with exposed special crystal planes. Compared with conventional BiOI(001), it has an open channel structure, which is more conducive to compounding with Cs3Bi2I9, shortens the electron transport distance, and is beneficial for the migration of photo-generated electrons to surface active sites within the effective lifetime.

[0090] In step D of the present invention, the washing is carried out 2 - 4 times with water and ethanol; the drying temperature is 70 - 90 °C; the drying time is 7 - 9 h.

[0091] In step E of the present invention, ultrasonic dispersion is adopted, and stirring is carried out for 1 to 3 hours after dispersion to facilitate sufficient reaction. In step E, the organic solvent A is at least one of isopropanol and toluene, preferably isopropanol.

[0092] The present invention has found through research that the mass fraction of BiOI has an important influence on the performance of the catalyst. When the content of BiOI is low, it cannot fully play the role of promoting electron-hole separation in the Z-scheme heterojunction. When the content is too high, agglomeration occurs, blocking the light absorption of Cs3Bi2I9 and being unfavorable for performance improvement. Therefore, in step E of the present invention, the dosage of solution A is controlled so that the mass percentage of BiOI(010) in the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalyst is 5 to 15%; the volume ratio of the organic solvent A used in step E to the organic solvent B used in step F is 45 to 50:3 to 5; in step F, the molar ratio of CsI, BiI3, and the additive is 0.15 to 0.20:0.10 to 0.15:0.05 to 0.15, so as to achieve a better composite ratio of BiOI(001) and Cs3Bi2I9.

[0093] In step F of the present invention, the surfactant is at least one of cetyltrimethylammonium bromide, polyvinylpyrrolidone, and sodium dodecylbenzenesulfonate, preferably cetyltrimethylammonium bromide; the organic solvent B is at least one of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, ethanol, and acetonitrile, preferably dimethyl sulfoxide; and the dosage of the organic solvent B is controlled to be 3 to 5 mL / 0.15 to 0.20 mmol of CsI.

[0094] In step G of the present invention, the purpose of dropping is to enable slow and sufficient reaction and reduce agglomeration. Although direct mixing is also possible, it may not be as sufficient as dropping reaction, and problems may also occur; in addition, since there is more solution A and less solution B, solution B is dropped into solution A. On the one hand, it is more convenient, and on the other hand, it is conducive to sufficient diffusion. In step G, the stirring time is 1 to 3 hours to facilitate sufficient reaction.

[0095] In step H of the present invention, the reaction time is 1 to 3 hours; the washing is carried out with isopropanol 2 to 4 times; the drying temperature is 50 to 70 °C; the drying time is 10 to 14 hours.

[0096] The present invention also provides a BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel prepared by the above preparation method. The catalyst of the present invention is a material that can be used for reduction reactions, that is, it is a cathode. For example, in a photo-thermal catalytic reaction, the catalyst of the present invention can be called a photo-cathode.

[0097] The present invention obtains Cs3Bi2I9 perovskite through screening, and constructs a Z-scheme heterojunction by combining the N-type perovskite semiconductor Cs3Bi2I9 with the P-type semiconductor BiOI, which greatly improves the catalytic performance, stability, etc. of the catalyst. Therefore, the present invention also provides the above-mentioned BiOI(010) / Cs3Bi2I9(006) photo-thermocatalytic water splitting hydrogen production catalyst with special exposed crystal planes and special electron transport channels, which is used in photocatalytic water splitting hydrogen production, photocatalytic organic matter splitting hydrogen production, photocatalytic reduction of CO2, photocatalytic degradation of organic pollutants, photothermal catalytic water splitting hydrogen production, photothermal catalytic organic matter splitting hydrogen production, photothermal catalytic reduction of CO2, photothermal catalytic degradation of organic pollutants, photoelectrocatalytic water splitting hydrogen production, photoelectrocatalytic organic matter splitting hydrogen production, photoelectrocatalytic reduction of CO2 or photoelectrocatalytic degradation of organic pollutants. Decompose ethanol, methanol, formic acid, and formaldehyde to produce hydrogen. Among them, splitting organic matter to produce hydrogen and degrading organic pollutants both belong to splitting organic matter, but their purposes are different. Photocatalytic, photothermal catalytic or photoelectrocatalytic splitting of organic matter to produce hydrogen can decompose, for example, ethanol, methanol, formic acid or formaldehyde, etc.; photocatalytic, photothermal catalytic or photoelectrocatalytic degradation of organic pollutants can degrade rhodamine, sunset yellow, tetracycline, nitrogen oxides, benzene, toluene or acetone, etc.

[0098] In particular, the present invention breaks the current situation that halide perovskites can only be used for decomposing ethanol and saturated acids to produce hydrogen, and endows the BiOI(010) / Cs3Bi2I9(006) halide perovskite with excellent hydrogen production rate. Therefore, preferably, the present invention provides its application in photocatalytic water splitting hydrogen production, photothermal catalytic water splitting hydrogen production or photoelectrocatalytic water splitting hydrogen production.

[0099] The present invention will be further described in detail below through examples, but the protection scope of the present invention is not limited to the scope of the examples.

[0100] Example 1

[0101] 1. Gradually drop 15 mL of KI (0.4 mol / L) aqueous solution into 15 mL of ethanol solution of Bi(NO3)3·5H2O (0.4 mol / L), and continuously stir;

[0102] 2. Adjust the pH of the solution obtained in step 1 to pH = 5 with 0.5 mol / L NaOH solution, and stir for 1 h;

[0103] 3. Then transfer the mixture obtained in step 2 to a hydrothermal reactor, heat it to 160 °C, and react for 5 h;

[0104] 4. Centrifuge the product obtained in step 3, wash it twice with deionized water and ethanol, and dry the obtained precipitate at 70 °C for 7 h to obtain BiOI(010) with special exposed crystal planes;

[0105] 5. Ultrasonically disperse the obtained BiOI(010) in step 4 in 45 mL of isopropanol, stir for 1 h, and control the mass percentage of BiOI(010) in BiOI(010) / Cs3Bi2I9(006) to be 5%, labeled as solution A;

[0106] 6. Dissolve 0.15 mmol of CsI, 0.10 mmol of BiI3, and 0.05 mmol of cetyltrimethylammonium bromide in 3 mL of dimethyl sulfoxide, labeled as solution B;

[0107] 7. Dropwise add the obtained solution B in step 6 to the obtained solution A in step 5, and stir for 1 h;

[0108] 8. Transfer the obtained solution in step 7 to a hydrothermal reactor, react at 90 °C for 1 h, then centrifuge the obtained product, wash it twice with isopropanol, and dry it at 50 °C for 10 h to obtain BiOI(010) / Cs3Bi2I9(006).

[0109] Example 2

[0110] 1. Dropwise add 20 mL of an aqueous solution of KI (0.5 mol / L) into 20 mL of an ethanol solution of Bi(NO3)3·5H2O (0.5 mol / L) drop by drop, and continuously stir;

[0111] 2. Adjust the pH of the obtained solution in step 1 to 6 with 0.5 mol / L NaOH solution, and stir for 2 h;

[0112] 3. Then transfer the obtained mixture in step 2 to a hydrothermal reactor, heat it up to 200 °C, and react for 6 h;

[0113] 4. Centrifuge the obtained product in step 3, wash it three times with deionized water and ethanol, and dry the obtained precipitate at 80 °C for 8 h to obtain BiOI(010) with exposed special crystal planes;

[0114] 5. Ultrasonically disperse the obtained BiOI(010) in step 4 in 50 mL of isopropanol, stir for 2 h, and control the mass percentage of BiOI(010) in BiOI(010) / Cs3Bi2I9(006) to be 10%, labeled as solution A;

[0115] 6. Dissolve 0.18 mmol of CsI, 0.12 mmol of BiI3, and 0.10 mmol of cetyltrimethylammonium bromide in 6 mL of dimethyl sulfoxide, labeled as solution B;

[0116] 7. Dropwise add the obtained solution B in step 6 to the obtained solution A in step 5, and stir for 2 h;

[0117] 8. Transfer the solution obtained in step 7 to a hydrothermal reactor and react at 100 °C for 2 h. Then, centrifuge the obtained product, wash it three times with isopropanol, and dry it at 60 °C for 12 h to obtain BiOI(010) / Cs3Bi2I9(006).

[0118] Example 3

[0119] 1. Slowly add 25 mL of an aqueous KI (0.5 mol / L) solution dropwise to 25 mL of an ethanol solution of Bi(NO3)3·5H2O (0.5 mol / L) while continuously stirring.

[0120] 2. Adjust the pH of the solution obtained in step 1 to 5 with 1.5 mol / L NaOH solution and stir for 2 h.

[0121] 3. Then transfer the mixture obtained in step 2 to a hydrothermal reactor, heat it to 160 °C, and react for 6 h.

[0122] 4. Centrifuge the product obtained in step 3, wash it three times with deionized water and ethanol, and dry the obtained precipitate at 80 °C for 8 h to obtain BiOI(010) with exposed special crystal planes.

[0123] 5. Ultrasonically disperse the BiOI(010) obtained in step 4 in 45 mL of isopropanol, stir for 2 h, and control the mass percentage of BiOI(010) in BiOI(010) / Cs3Bi2I9(006) to be 15%, labeled as solution A.

[0124] 6. Dissolve 0.18 mmol of CsI, 0.12 mmol of BiI3, and 0.15 mmol of cetyltrimethylammonium bromide in 4 mL of dimethyl sulfoxide, labeled as solution B.

[0125] 7. Slowly add the solution B obtained in step 6 dropwise to the solution A obtained in step 5 and stir for 2 h.

[0126] 8. Transfer the solution obtained in step 7 to a hydrothermal reactor and react at 100 °C for 2 h. Then, centrifuge the obtained product, wash it three times with isopropanol, and dry it at 60 °C for 12 h to obtain BiOI(010) / Cs3Bi2I9(006).

[0127] Example 4

[0128] 1. Slowly add 20 mL of an aqueous KI (0.6 mol / L) solution dropwise to 20 mL of an ethanol solution of Bi(NO3)3·5H2O (0.6 mol / L) while continuously stirring.

[0129] 2. Adjust the pH of the solution obtained in step 1 to 7 with 1 mol / L NaOH solution and stir for 2 h.

[0130] 3. Subsequently, transfer the mixed solution obtained in Step 2 into a hydrothermal autoclave, heat it to 180 °C, and react for 6 h;

[0131] 4. Centrifuge the product obtained in Step 3, wash it 3 times with deionized water and ethanol, and dry the obtained precipitate at 80 °C for 8 h to obtain BiOI(010) with exposed special crystal planes;

[0132] 5. Ultrasonically disperse the BiOI(010) obtained in Step 4 in 50 mL of isopropanol, stir for 2 h, and control the mass percentage of BiOI(010) in BiOI(010) / Cs3Bi2I9(006) to be 10%, marked as Solution A;

[0133] 6. Dissolve 0.20 mmol of CsI, 0.15 mmol of BiI3, and 0.15 mmol of cetyltrimethylammonium bromide in 4 mL of dimethyl sulfoxide, marked as Solution B;

[0134] 7. Dropwise add the Solution B obtained in Step 6 into the Solution A obtained in Step 5, and stir for 2 h;

[0135] 8. Transfer the solution obtained in Step 7 into a hydrothermal autoclave and react at 110 °C for 2 h. Subsequently, centrifuge the obtained product, wash it 2 times with isopropanol, and dry it at 70 °C for 12 h to obtain BiOI(010) / Cs3Bi2I9(006).

[0136] Example 5

[0137] 1. Dropwise add 20 mL of an aqueous solution of KI (0.5 mol / L) into 20 mL of an ethanol solution of Bi(NO3)3·5H2O (0.5 mol / L) while continuously stirring;

[0138] 2. Adjust the pH of the solution obtained in Step 1 to 6 with 1.0 mol / L NaOH solution and stir for 2 h;

[0139] 3. Subsequently, transfer the mixed solution obtained in Step 2 into a hydrothermal autoclave, heat it to 180 °C, and react for 6 h;

[0140] 4. Centrifuge the product obtained in Step 3, wash it 3 times with deionized water and ethanol, and dry the obtained precipitate at 80 °C for 8 h to obtain BiOI(010) with exposed special crystal planes;

[0141] 5. Ultrasonically disperse the BiOI(010) obtained in Step 4 in 48 mL of isopropanol, stir for 2 h, and control the mass percentage of BiOI(010) in BiOI(010) / Cs3Bi2I9(006) to be 10%, marked as Solution A;

[0142] 6. Dissolve 0.18 mmol of CsI, 0.12 mmol of BiI3, and 0.10 mmol of cetyltrimethylammonium bromide in 4 mL of dimethyl sulfoxide, and label it as solution B;

[0143] 7. Slowly add the solution B obtained in step 6 dropwise to the solution A obtained in step 5, and stir for 2 h;

[0144] 8. Transfer the solution obtained in step 7 to a hydrothermal autoclave and react at 100 °C for 2 h. Then, centrifuge the obtained product, wash it 3 times with isopropanol, and dry it at 60 °C for 12 h to obtain BiOI(010) / Cs3Bi2I9(006).

[0145] Example 6

[0146] 1. Slowly add 20 mL of an aqueous solution of KI (0.4 mol / L) dropwise to 20 mL of an ethanol solution of Bi(NO3)3·5H2O (0.4 mol / L), and continuously stir;

[0147] 2. Adjust the pH of the solution obtained in step 1 to 5 with 0.5 mol / L NaOH solution, and stir for 3 h;

[0148] 3. Then transfer the mixture obtained in step 2 to a hydrothermal autoclave, heat it to 200 °C, and react for 6 h;

[0149] 4. Centrifuge the product obtained in step 3, wash it 2 times with deionized water and ethanol, and dry the obtained precipitate at 80 °C for 8 h to obtain BiOI(010) with exposed special crystal planes;

[0150] 5. Ultrasonically disperse the BiOI(010) obtained in step 4 in 48 mL of isopropanol, stir for 1 h, and control the mass percentage of BiOI(010) in BiOI(010) / Cs3Bi2I9(006) to be 5%, and label it as solution A;

[0151] 6. Dissolve 0.15 mmol of CsI, 0.10 mmol of BiI3, and 0.05 mmol of cetyltrimethylammonium bromide in 3 mL of dimethyl sulfoxide, and label it as solution B;

[0152] 7. Slowly add the solution B obtained in step 6 dropwise to the solution A obtained in step 5, and stir for 2 h;

[0153] 8. Transfer the solution obtained in step 7 to a hydrothermal autoclave and react at 90 °C for 2 h. Then, centrifuge the obtained product, wash it 2 times with isopropanol, and dry it at 60 °C for 12 h to obtain BiOI(010) / Cs3Bi2I9(006).

[0154] Example 7

[0155] 1. Gradually add 20 mL of KI (0.5 mol / L) aqueous solution dropwise into 20 mL of ethanol solution of Bi(NO3)3·5H2O (0.5 mol / L), and continuously stir.

[0156] 2. Adjust the pH of the solution obtained in step 1 to 7 with 1.0 mol / L NaOH solution, and stir for 2 h.

[0157] 3. Subsequently, transfer the mixture obtained in step 2 to a hydrothermal autoclave, heat it to 180 °C, and react for 6 h.

[0158] 4. Centrifuge the product obtained in step 3, wash it 3 times with deionized water and ethanol, and dry the obtained precipitate at 80 °C for 8 h to obtain BiOI(010) with exposed special crystal planes.

[0159] 5. Ultrasonically disperse the BiOI(010) obtained in step 4 in 48 mL of isopropanol, stir for 2 h, and control the mass percentage of BiOI(010) in BiOI(010) / Cs3Bi2I9(006) to be 15%, marked as solution A.

[0160] 6. Dissolve 0.18 mmol of CsI, 0.12 mmol of BiI3, and 0.10 mmol of cetyltrimethylammonium bromide in 5 mL of dimethyl sulfoxide, marked as solution B.

[0161] 7. Gradually add the solution B obtained in step 6 dropwise into the solution A obtained in step 5, and stir for 1 h.

[0162] 8. Transfer the solution obtained in step 7 to a hydrothermal autoclave and react at 110 °C for 3 h. Subsequently, centrifuge the obtained product, wash it 3 times with isopropanol, and dry it at 70 °C for 14 h to obtain BiOI(010) / Cs3Bi2I9(006).

[0163] Detection

[0164] Figure 2 The XRD patterns of BiOI, Cs3Bi2I9, and BiOI / Cs3Bi2I9 are shown. PDF#23-0847 is the XDR standard card corresponding to Cs3Bi2I9, proving that the target catalyst has been successfully synthesized.

[0165] Figure 3 The SEM images of BiOI, Cs3Bi2I9, and BiOI / Cs3Bi2I9 are shown, indicating that BiOI has an irregular nanosheet structure, Cs3Bi2I9 is a hexagonal nanosheet, and the morphology after their combination is that irregularly shaped BiOI nanosheets with smaller particle sizes are loaded on the surface of Cs3Bi2I9 hexagonal nanosheets.

[0166] Figure 4Atomic structure simulation diagram of the special electron transport channel [Bi2O2]-[Bi2I9] formed in BiOI(010) / Cs3Bi2I9(006), verifying that the present invention combines the [Bi2O2] 2- unit of BiOI(010) with the [Bi2I9] 3- double octahedron unit of Cs3Bi2I9(006) in series, forming a stronger force and a unique electron transport channel, solving the problems of low carrier mobility and easy recombination of photo-generated electrons and holes.

[0167] Figure 5 It is the energy band structure diagram of Cs3Bi2I9 obtained by calculation. By judging whether the band gap width, conduction band and valence band energy levels of the perovskite meet the thermodynamic requirements for water splitting to produce hydrogen, as well as stability and environmental friendliness, etc., the present invention has obtained Figure 5 Cs3Bi2I9 suitable for water splitting to produce hydrogen as shown, and its energy band structure (band gap width, conduction band potential) meets the requirements for water splitting to produce hydrogen.

[0168] Figure 6 It is the time-resolved fluorescence spectrum and carrier lifetime simulation diagram of Cs3Bi2I9 and BiOI / Cs3Bi2I9. The carrier lifetime of BiOI / Cs3Bi2I9 is significantly reduced, indicating that a channel conducive to electron migration is formed in this system.

[0169] Figure 7 It is the physical diagram of the photo-thermal catalytic water splitting device for hydrogen production built by the present invention.

[0170] Figure 8 It is the photo-thermal catalytic water splitting hydrogen production activity diagram of BiOI, Cs3Bi2I9 and BiOI / Cs3Bi2I9, indicating that single Cs3Bi2I9 can be used for photo-thermal water splitting to produce hydrogen. Compared with Cs3Bi2I9, the hydrogen production activity of the BiOI(010) / Cs3Bi2I9(006) system is significantly improved.

[0171] Figure 9 It is the energy band and photocatalytic reaction mechanism diagram of the Z-type heterojunction BiOI(010) / Cs3Bi2I9(006) of the present invention. Tests show that the valence band potential of Cs3Bi2I9 is relatively close to the conduction band potential of BiOI, and a special Z-type heterojunction can be formed. The advantage compared with the conventional PN heterojunction is that the Z-type heterojunction can promote the separation of electrons and holes without reducing the reduction ability of photo-generated electrons on the conduction band of Cs3Bi2I9.

[0172] Test Examples

[0173] Photocatalytic water splitting for hydrogen production experiments were carried out using the composite photocatalysts of Examples 1 to 7. The reaction conditions were as follows: a PFLAB SOLAR-6A type comprehensive photocatalyst testing equipment was used, and the instrument consisted of a light source, a reaction device, a magnetron gas circulation device, a vacuum device, a collection device, a chromatographic testing device, etc. The water splitting for hydrogen production system was connected to a gas chromatograph, and the generated gas was injected into the gas chromatograph for analysis. The gas chromatograph was equipped with a thermal conductivity detector (TCD), 5A molecular sieve was used as the chromatographic column, and high-purity N2 was used as the carrier gas. The set experimental parameters were: the TCD device was set at 150 °C, the vaporization chamber was set at 110 °C, and the chromatographic column was set at 50 °C.

[0174] The specific operation of the photocatalytic hydrogen evolution experiment was as follows: 50 mg of the photocatalyst was fully dispersed in a quartz reaction device containing 90 mL of deionized water + 10 mL of lactic acid. The role of lactic acid was to consume holes. The simulated light source used was a 300 W xenon lamp, and an optical filter (λ>420 nm, AM = 1.5) was used to filter the light in the ultraviolet band. The hydrogen production rate was detected by a gas chromatograph. Before illumination, high-purity N2 was introduced to degas the entire system (including the solution) to remove O2 in the device. The temperature of the reaction system was maintained at 100 °C by a constant temperature water bath to vaporize the water in the device. The hydrogen production test results are shown in Table 1, and it can be obtained that the hydrogen production rate of the system for water splitting reached 15.5 mmol h -1 g -1 。

[0175] Table 1 Hydrogen production rate and stability of photo-thermal catalytic water splitting

[0176] <![CDATA[Hydrogen production rate (mmol h -1 g -1 )]]> Hydrogen production stability (h) Example 1 10.5 ≥12 Example 2 11.9 ≥12 Example 3 13.2 ≥12 Example 4 12.1 ≥12 Example 5 15.5 ≥12 Example 6 14.2 ≥12 Example 7 13.2 ≥12

Claims

1. Preparation method of BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with special electron transport channels, characterized in that: It includes the following steps: A. Drop the iodine source solution into the bismuth source solution and continuously stir to obtain solution X; B. Adjust the pH of solution X obtained in step A to 5 - 7 and stir to obtain solution Y; C. Heat solution Y obtained in step B to 160 - 200 °C for reaction; D. After the reaction in step C is completed, the obtained product is subjected to solid - liquid separation, washing and drying to obtain BiOI(010) with exposed special crystal planes; E. Disperse BiOI(010) obtained in step D in organic solvent A and stir to obtain solution A; F. Dissolve CsI, BiI3 and surfactant in organic solvent B to obtain solution B; G. Drop solution B obtained in step F into solution A obtained in step E and stir to obtain solution Z; H. Heat solution Z obtained in step G to 90 - 110 °C for reaction. After the reaction is completed, the obtained product is subjected to solid - liquid separation, washing and drying to obtain the BiOI(010) / Cs3Bi2I9(006) photo - thermal catalyst.

2. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step A, the iodine source is at least one of potassium iodide and sodium iodide.

3. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 2, characterized in that: In step A, the iodine source is potassium iodide.

4. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step A, the concentration of I in the iodine source solution is 0.4 - 0.6 mol / L.

5. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step A, the solvent of the iodine source solution is at least one of water, ethanol and ethylene glycol.

6. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 5, characterized in that: In step A, the solvent of the iodine source solution is water.

7. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step A, the bismuth source is at least one of bismuth nitrate, bismuth chloride, bismuth bromide, bismuth acetate and bismuth sulfate.

8. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 7, characterized in that: In step A, the bismuth source is bismuth nitrate.

9. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step A, the concentration of Bi in the bismuth source solution is 0.4 - 0.6 mol / L.

10. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step A, the volume ratio of the iodine source solution to the bismuth source solution is 3 - 5:3 - 5.

11. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step A, the solvent of the bismuth source solution is at least one of water, ethanol and ethylene glycol.

12. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 11, characterized in that: In step A, the solvent of the bismuth source solution is ethanol.

13. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step B, 0.5 - 1.5 mol / L NaOH aqueous solution is used to adjust the pH.

14. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step B, the stirring time is 1 - 3 h.

15. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step C, the reaction time is 5 - 7 h.

16. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step D, the washing is carried out by washing with water and ethanol 2 - 4 times.

17. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step D, the drying temperature is 70 - 90 °C.

18. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step D, the drying time is 7 - 9 h.

19. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step E, the dispersion is ultrasonic dispersion.

20. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step E, the stirring time is 1 - 3 h.

21. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step E, the organic solvent A is at least one of isopropanol and toluene.

22. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 21, characterized in that: In step E, the organic solvent A is isopropanol.

23. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step E, the dosage of solution A is controlled so that the mass percentage of BiOI(010) in the BiOI(010) / Cs3Bi2I9(006) photo - thermal catalyst is 5 - 15%.

24. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: The volume ratio of organic solvent A used in step E to organic solvent B used in step F is 45 - 50:3 - 5.

25. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step F, the molar ratio of CsI, BiI3 and surfactant is 0.15 - 0.20:0.10 - 0.15:0.05 - 0.

15.

26. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step F, the surfactant is at least one of cetyltrimethylammonium bromide, polyvinylpyrrolidone, and sodium dodecylbenzenesulfonate.

27. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 26, characterized in that: In step F, the surfactant is cetyltrimethylammonium bromide.

28. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step F, the organic solvent B is at least one of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, ethanol, and acetonitrile.

29. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 28, characterized in that: In step F, the organic solvent B is dimethyl sulfoxide.

30. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step F, the dosage of the organic solvent B is 3 - 5 mL / 0.15 - 0.20 mmol of CsI.

31. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step G, the stirring time is 1 - 3 h.

32. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step H, the reaction time is 1 - 3 h.

33. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step H, the washing is performed with isopropanol 2 - 4 times.

34. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step H, the drying temperature is 50 - 70 °C.

35. The preparation method of the BiOI(010) / Cs3Bi2I9(006) photo-thermal catalytic water splitting hydrogen production catalyst with a special electron transport channel according to claim 1, characterized in that: In step H, the drying time is 10 - 14 h.

36. A BiOI(010) / Cs3Bi2I9(006) photo-thermocatalytic water splitting hydrogen production catalyst with a special electron transport channel prepared by the preparation method according to any one of claims 1 - 35.

37. Application of a BiOI(010) / Cs3Bi2I9(006) photo-thermocatalytic water splitting hydrogen production catalyst with a special electron transport channel prepared by the preparation method according to any one of claims 1 - 35 in photocatalytic water splitting hydrogen production, photocatalytic organic matter splitting hydrogen production, photocatalytic CO2 reduction, photocatalytic organic pollutant degradation, photo-thermocatalytic water splitting hydrogen production, photo-thermocatalytic organic matter splitting hydrogen production, photo-thermocatalytic CO2 reduction, photo-thermocatalytic organic pollutant degradation, photo-electrocatalytic water splitting hydrogen production, photo-electrocatalytic organic matter splitting hydrogen production, photo-electrocatalytic CO2 reduction, or photo-electrocatalytic organic pollutant degradation.

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