A Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst and its preparation method and application

Abstract

The present invention discloses a Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst and its preparation method and application, the method includes: placing an FTO / CdS photoelectrode in an argon atmosphere for annealing, and treating it with an ozone cleaner to obtain a pretreated FTO / CdS photoelectrode; mixing anhydrous ethanol, N,N-dimethylformamide, a chiral H3L ligand, and 4,4'-bipyridine to form a ligand mixed solution; the chiral H3L ligand has the structural formula #imgabs0#; mixing a cadmium nitrate aqueous solution, a cobalt nitrate ethanol solution, and the ligand mixed solution to obtain a precursor solution; placing the pretreated FTO / CdS photoelectrode conductive surface downward in a hydrothermal reactor, injecting the precursor solution, sealing it, and hydrothermally reacting it at 60-80°C for 40-50h, and cooling it to room temperature. The method of the present invention is simple in process, low in cost, and has good repeatability. The product has uniform morphology and consistent size. As a catalyst, it exhibits excellent catalytic performance in photoelectrocatalytic water oxidation reactions.

Description

Technical Field

[0001] The present invention relates to the technical field of photoelectrocatalytic materials, and in particular to a Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst, preparation method and application thereof. Background Art

[0002] Photoelectrochemical (PEC) water splitting to produce hydrogen is an economical and environmentally friendly approach to addressing global fossil energy depletion and environmental challenges. PEC cells, which mimic natural photosynthesis, can efficiently and inexpensively convert sunlight into chemical fuels. However, due to low solar-to-hydrogen conversion efficiency, PEC cells remain far from practical application. Semiconductor photoelectrodes play a crucial role in PEC cells, harvesting solar energy and converting absorbed sunlight into photoexcited charge carriers to drive the PEC water splitting reaction. To date, significant effort has been devoted to developing efficient and stable semiconductor photoelectrodes, and significant progress has been made. Among the semiconductors studied, cadmium sulfide (CdS) is widely considered the best candidate for efficient PEC hydrogen production due to its suitable band gap (≈2.4 eV) and flat band potential. However, CdS photoanodes suffer from severe defects in photoelectrochemical water splitting, such as electron-hole recombination and photocorrosion, which hinder the efficient conversion of solar energy to hydrogen and hinder its industrialization. Therefore, improving the photoelectric conversion efficiency and stability of CdS photoanodes is a key research priority for anode catalysts in photoelectrochemical cells. Although some progress has been made in the modification of CdS photoanodes, their photocurrent density and photostability still do not meet the requirements of industrialization. Therefore, it is imperative to research and develop CdS composite photoanodes with higher photocurrent density and better stability.

[0003] Metal-organic frameworks (MOFs) are composed of metal nodes and organic linkers. Their porous structure and high specific surface area lend them to excellent adsorption and catalytic properties. Previous reports have shown that incorporating MOFs onto the surface of a CdS photoanode to form a passivation layer can effectively ameliorate the sluggish water oxidation kinetics and photocorrosion of CdS (DOI:10.1021 / acscatal.8b03233). Furthermore, studies have reported that doping the catalyst with transition metal ions such as cobalt and nickel can provide more active sites, effectively enhancing catalytic activity. Among various transition metals, cobalt, as one of the most catalytically active transition metal catalysts, has attracted considerable research attention (DOI:10.1039 / c8ra09660k). Its abundance and low price meet industrial standards; however, the catalytic performance of these materials remains suboptimal. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst and preparation method thereof.

[0005] The present invention solves the above technical problems through the following technical means:

[0006] A Co 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst comprises the following steps:

[0007] S1, annealing the FTO / CdS photoelectrode in an argon atmosphere, and then treating it with an ozone cleaner to obtain a pretreated FTO / CdS photoelectrode;

[0008] S2, mixing anhydrous ethanol, N,N-dimethylformamide, chiral H3L ligand, and 4,4'-bipyridine to form a ligand mixed solution; wherein the chiral H3L ligand has the structural formula:

[0009] S3, uniformly mixing the cadmium nitrate aqueous solution, the cobalt nitrate ethanol solution and the ligand mixed solution to obtain a precursor solution; wherein the molar ratio of the cadmium nitrate in the cadmium nitrate aqueous solution, the cobalt nitrate in the cobalt nitrate ethanol solution and the chiral H3L ligand in the ligand mixed solution is 2:1:0.38-7.67;

[0010] S4, placing the pretreated FTO / CdS photoelectrode with the conductive surface facing downward in a hydrothermal reactor, injecting the precursor solution, sealing it and reacting it, and cooling it to room temperature after the reaction to obtain the Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst; wherein the reaction temperature is 60-80°C and the reaction time is 40-50h.

[0011] Preferably, in S1, the annealing temperature is 400° C. and the time is 2 hours; the ozone cleaning machine treatment time is 1 hour.

[0012] Preferably, in S2, the volume ratio of anhydrous ethanol to N,N-dimethylformamide is 1:1.

[0013] Preferably, in S2, the mass ratio of the chiral H3L ligand to 4,4'-bipyridine is 5:1.

[0014] Preferably, in S3, the molar ratio of cadmium nitrate in the cadmium nitrate aqueous solution, cobalt nitrate in the cobalt nitrate ethanol solution, and the chiral H3L ligand in the ligand mixed solution is 2:1:0.77.

[0015] Preferably, in S3, the concentration of the chiral H3L ligand in the precursor solution is 1.9-39 mg / ml.

[0016] Preferably, in S4, the reaction temperature is 60° C. and the reaction time is 48 h.

[0017] Preferably, in S1, the preparation method of the FTO / CdS photoelectrode includes the following steps: dissolving cadmium nitrate hexahydrate, glutathione, and thiourea in ultrapure water to form a mixed solution; transferring the mixed solution and FTO to a polytetrafluoroethylene reactor, sealing it with a stainless steel hydrothermal reactor, and reacting; after the reaction is completed, cooling it to room temperature, washing and drying the obtained product to obtain the FTO / CdS photoelectrode.

[0018] FTO conductive glass is fluorine-doped SnO2 conductive glass (SnO2:F), referred to as FTO.

[0019] The present invention also proposes a Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst, using the Co 2+ The method is used to prepare a doped CdMOFs-cadmium sulfide photoanode catalyst.

[0020] The present invention also proposes a Co 2+ Application of doped CdMOFs-cadmium sulfide photoanode catalyst as photoelectrocatalyst for catalytic water oxidation reaction.

[0021] The principle of the present invention is to adopt the solvothermal method, take FTO / CdS nanoarray as substrate, and react with the metal salt CdS by chiral H3L ligand and auxiliary ligand 4,4'-bipyridine. 2+ Coordination, and then doping with Co 2+ , it is directly grown in situ on the FTO / CdS nanosubstrate to form a CdS / MOFs core-shell structure. The resulting product has uniform morphology and consistent size, and exhibits excellent catalytic performance as a catalyst in the photoelectrocatalytic water oxidation reaction.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] (1) The cadmium sulfide photoanode catalyst of the present invention has a more stable crystal form after annealing at 400° C. in argon, and the surface of the cadmium sulfide photoanode catalyst is cleaner after being treated by an ozone cleaning machine;

[0024] (2) The present invention adopts a solvothermal method to prepare the doped CdMOFs-cadmium sulfide photoanode catalyst, which has simple process, low cost and good reproducibility;

[0025] (3) The product prepared by the present invention has a CdS / MOFs core-shell structure and is of uniform size;

[0026] (4) Co prepared by the present invention 2+ Doped CdMOFs-cadmium sulfide photoanode catalysts were used for photoelectrocatalytic water oxidation, showing catalytic performance far higher than that of CdS. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The Co obtained in Example 1 of the present invention 2+ High-resolution scanning electron microscopy (SEM) images of CdMOFs-doped cadmium sulfide photoanode catalysts and cadmium sulfide nanophotoanode catalysts; the left image is the SEM image of the cadmium sulfide nanophotoanode catalyst, the middle image and the right image are Co 2+ SEM images of doped CdMOFs-cadmium sulfide photoanode catalyst at different magnifications;

[0028] Figure 2 Co obtained in Example 1 of the present invention 2+ Surface scanning element distribution map of CdMOFs-cadmium sulfide photoanode catalyst (Mapping); where af corresponds to the element distribution map of Cd, S, C, N, O, and Co respectively;

[0029] Figure 3 Co obtained in Example 1 of the present invention 2+ Element content analysis diagram of the surface scanning element distribution map of the doped CdMOFs-cadmium sulfide photoanode catalyst;

[0030] Figure 4 Co obtained in Example 1 of the present invention 2+ X-ray photoelectron spectroscopy (XPS) of doped CdMOFs-cadmium sulfide photoanode catalyst;

[0031] Figure 5 Co obtained in Example 1 of the present invention 2+ X-ray diffraction patterns (XRD) of CdMOFs-cadmium sulfide photoanode catalysts, CdMOFs, CdS, and FTO;

[0032] Figure 6 The ligand H3L used in Example 1 of the present invention, the CdMOFs-cadmium sulfide photoanode catalyst obtained in Comparative Example 1, and the Co 2+ FTIR spectra of doped CdMOFs-cadmium sulfide photoanode catalyst;

[0033] Figure 7 Co obtained in Example 1 of the present invention 2+ LSV curves of the doped CdMOFs-cadmium sulfide photoanode catalyst and the CdMOFs-cadmium sulfide photoanode catalyst obtained in Comparative Example 1 in 0.5M Na2SO4 solution; the cadmium sulfide nanophotoanode catalyst is the standard catalyst;

[0034] Figure 8 Co obtained in Example 1 of the present invention 2+ IT curves of the doped CdMOFs-cadmium sulfide photoanode catalyst and the CdMOFs-cadmium sulfide photoanode catalyst obtained in Comparative Example 1 in 0.5M Na2SO4 solution, where the cadmium sulfide nanophotoanode catalyst is the standard catalyst;

[0035] Figure 9 Ni obtained in Comparative Example 3 of the present invention 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst and Co obtained in Example 1 2+ Comparison of LSV curves of doped CdMOFs-cadmium sulfide photoanode catalysts;

[0036] Figure 10 Schematic diagram of the preparation method of Comparative Example 1 and Example 1 of the present invention;

[0037] Figure 11 Ni obtained in Comparative Example 3 of the present invention 2+ SEM images of doped CdMOFs-cadmium sulfide photoanode catalyst at different magnifications. DETAILED DESCRIPTION

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0039] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0040] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the field or according to the product instructions.

[0041] The chiral H3L ligand in the following examples and comparative examples is the chiral ligand H3L disclosed in the Chinese patent application publication number CN113354556A, and its structural formula is

[0042] Example 1

[0043] Reference Figure 10 , a Co 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst comprises the following steps:

[0044] (1) Dissolve cadmium nitrate hexahydrate, glutathione, and thiourea in ultrapure water to form a mixed solution, wherein the concentration of cadmium nitrate hexahydrate, glutathione, and thiourea in the mixed solution is 0.03M, 0.018M, and 0.03M; transfer the mixed solution and FTO conductive glass to a polytetrafluoroethylene reactor, seal it with a stainless steel hydrothermal reactor, and react at 200°C for 8 hours. After the reaction is completed, cool it to room temperature, wash and dry the obtained product to obtain an FTO / CdS photoelectrode; anneal the FTO / CdS photoelectrode at 400°C in an argon atmosphere for 2 hours, and then treat it with an ozone cleaner for 1 hour to obtain a pretreated FTO / CdS photoelectrode;

[0045] (2) 5 mL of N,N-dimethylformamide solution and 5 mL of anhydrous ethanol solution were mixed evenly, and then 50 mg of chiral H3L ligand and 10 mg of auxiliary ligand 4,4'-bipyridine were added, and the mixture was stirred and ultrasonically mixed to obtain a mixed solution;

[0046] (3) Dissolving cadmium nitrate hexahydrate and cobalt nitrate hexahydrate in ultrapure water and anhydrous ethanol respectively to form a 0.1M cadmium nitrate aqueous solution and a 0.1M cobalt nitrate ethanol solution, taking 2mL of the cadmium nitrate aqueous solution and 1mL of the cobalt nitrate ethanol solution and adding them to the mixed solution obtained in step (2), stirring evenly to obtain a precursor solution;

[0047] (4) The pretreated FTO / CdS photoelectrode was placed with the conductive surface facing downward in a polytetrafluoroethylene reactor, and the precursor solution obtained in step (3) was slowly injected along the non-conductive surface of the FTO / CdS photoelectrode. After sealing with a stainless steel hydrothermal reactor, the reaction was carried out at 60°C for 48 hours. After the reaction was completed, the reaction was cooled to room temperature. The obtained product was washed three times with a mixed solution of N,N-dimethylformamide and ethanol and dried at 60°C to obtain Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst.

[0048] Preparation of Cd-MOFs: Add 2 mL of 0.1 M cadmium nitrate hexahydrate aqueous solution to the mixed solution obtained in step (2), seal it with a stainless steel hydrothermal reactor, and react at 60°C for 48 hours to obtain Cd-MOFs.

[0049] Figure 1 The Co obtained in Example 1 of the present invention 2+ High-resolution scanning electron microscopy (SEM) images of CdMOFs-cadmium sulfide photoanode catalysts and cadmium sulfide nanophotoanode catalysts (i.e., the FTO / CdS photoelectrode in step (1)); Figure 1 It can be seen that the product obtained in this example has a nanorod core-shell structure and is of uniform size;

[0050] Figure 2 Co obtained in Example 12+ Surface scanning element distribution map of doped CdMOFs-cadmium sulfide photoanode catalyst (Mapping), Figure 3 Co obtained in Example 1 2+ Element content analysis diagram of the surface scanning element distribution map of the doped CdMOFs-cadmium sulfide photoanode catalyst (the left figure is the SEM image of the surface scanning area); Figures 2-3 It can be seen that the product obtained in this example successfully loaded CdMOFs and Co 2+ The ions were successfully doped.

[0051] Figure 4 Co obtained in Example 1 of the present invention 2+ The X-ray photoelectron spectrum (XPS) of the doped CdMOFs-cadmium sulfide photoanode catalyst reflects the elemental composition and element valence state of the sample surface; a is the full spectrum, indicating the presence and content of elements such as Cd, S, C, N, O, and Co, where the peak intensity indicates their relative content. b, c, d, e, and f are the spectra of Cd, S, C, O, and Co, respectively, revealing the valence state of these elements and their bonding types. The three peaks in Figure d represent the peaks of C=O (288.4eV), CN (285.4eV), and C=C (284.8eV) bonds, respectively, indicating the presence of MOFs. The peak in Figure f also indicates that Co 2+ The existence of Co 2+ Successful doping.

[0052] Comparative Example 1

[0053] The preparation method of the CdMOFs-cadmium sulfide photoanode catalyst in Comparative Example 1 is similar to that in Example 1, except that the cobalt nitrate ethanol solution is not added in step (3). The specific operation steps are as follows:

[0054] (1) Dissolve cadmium nitrate hexahydrate, glutathione, and thiourea in ultrapure water to form a mixed solution, wherein the concentration of cadmium nitrate hexahydrate, glutathione, and thiourea in the mixed solution is 0.03M, 0.018M, and 0.03M; transfer the mixed solution and FTO conductive glass to a polytetrafluoroethylene reactor, seal it with a stainless steel hydrothermal reactor, and react at 200°C for 8 hours. After the reaction is completed, cool it to room temperature, wash and dry the obtained product to obtain an FTO / CdS photoelectrode; anneal the FTO / CdS photoelectrode at 400°C in an argon atmosphere for 2 hours, and then treat it with an ozone cleaner for 1 hour to obtain a pretreated FTO / CdS photoelectrode;

[0055] (2) 5 mL of N,N-dimethylformamide solution and 5 mL of anhydrous ethanol solution were mixed evenly, and then 50 mg of chiral H3L ligand and 10 mg of auxiliary ligand 4,4'-bipyridine were added, and the mixture was stirred and ultrasonically mixed to obtain a mixed solution;

[0056] (3) dissolving cadmium nitrate hexahydrate in ultrapure water to form a 0.1 M cadmium nitrate aqueous solution, adding 2 mL of the cadmium nitrate aqueous solution to the mixed solution obtained in step (2), and stirring uniformly to obtain a precursor solution;

[0057] (4) The pretreated FTO / CdS photoelectrode was placed with the conductive surface facing downward in a polytetrafluoroethylene reactor, and the precursor solution obtained in step (3) was slowly injected along the non-conductive surface of the FTO / CdS photoelectrode. After sealing with a stainless steel hydrothermal reactor, the reaction was carried out at 60°C for 48 hours. After the reaction was completed, it was cooled to room temperature. The obtained product was washed three times with a mixed solution of N,N-dimethylformamide and ethanol and dried at 60°C to obtain a CdMOFs-cadmium sulfide photoanode catalyst.

[0058] Characterization showed that the product obtained in this comparative example had a nanorod core-shell structure and had consistent size.

[0059] Figure 5 Co obtained in Example 1 of the present invention 2+ X-ray diffraction patterns (XRD) of CdMOFs-cadmium sulfide photoanode catalyst (CdS-CdMOFs-Co), CdMOFs, FTO / CdS photoelectrode (CdS) and FTO in step (1); peaks of MOFs, CdS and FTO can be seen, indicating that Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst was successfully prepared;

[0060] Figure 6 The ligand H3L used in Example 1 of the present invention, the CdMOFs-cadmium sulfide photoanode catalyst (CdS-CdMOFs) obtained in Comparative Example 1, and the Co obtained in Example 1 2+ FTIR spectrum of doped CdMOFs-cadmium sulfide photoanode catalyst (CdS-CdMOFs-Co); Figure 6 The disappearance of the peak of -COOH group in the Cd 2+ Coordination to form MOFs.

[0061] Figure 7 and Figure 8 The Co obtained in Example 1 2+ LSV curves and it curves of the CdMOFs-cadmium sulfide photoanode catalyst (CdS-CdMOFs-Co) and the CdMOFs-cadmium sulfide photoanode catalyst (CdS-CdMOFs) obtained in Comparative Example 1 in 0.5M Na2SO4 solution, wherein the cadmium sulfide nano-photoanode catalyst (i.e., FTO / CdS photoelectrode) in step (1) is the standard catalyst (CdS shown in the figure). Figure 7 It can be seen that the Co prepared in Example 12+ Doped CdMOFs-cadmium sulfide photoanode catalyst at 1.23V RHE The photocurrent density under bias voltage reached 4.25 mA cm -2 Compared with pure CdS (photocurrent density of 1.48 mA cm -2 )’s photocurrent density is significantly improved. Figure 8 It can be seen that the Co prepared in Example 1 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst at 1.23V RHE There is no obvious decay of photocurrent density within 10 minutes under bias.

[0062] The same method as in Example 1 was used for testing. The CdMOFs-cadmium sulfide photoanode catalyst prepared in Comparative Example 1 was tested at 1.23V. RHE The photocurrent density under bias voltage reached 2.98 mA cm -2 , relative to Co 2+ The photocurrent density of the CdMOFs-cadmium sulfide photoanode catalyst was significantly reduced (see Figure 7 ), and the photocurrent density within 10 min relative to Co 2+ There is no obvious degradation of the CdMOFs-cadmium sulfide photoanode catalyst (see Figure 8 ).

[0063] Example 2

[0064] A Co 2+ The preparation method of the doped CdMOFs-cadmium sulfide photoanode catalyst is different from that of Example 1 only in that: in (2), 25 mg of chiral H3L ligand and 5 mg of auxiliary ligand 4,4'-bipyridine are added; the remaining steps are the same as those of Example 1.

[0065] Characterization showed that the product obtained in this example had a nanorod core-shell structure and was of uniform size.

[0066] The test was carried out in the same manner as in Example 1. 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst at 1.23V RHE The photocurrent density under bias voltage reached 3.33 mA cm -2 , the photocurrent density has no obvious decay within 10 min.

[0067] Example 3

[0068] A Co 2+ The preparation method of the doped CdMOFs-cadmium sulfide photoanode catalyst is different from that of Example 1 only in that: in (2), 250 mg of chiral H3L ligand and 50 mg of auxiliary ligand 4,4'-bipyridine are added; the remaining steps are the same as those of Example 1.

[0069] Characterization showed that the product obtained in this example had a nanorod core-shell structure and was of uniform size.

[0070] The test was carried out in the same manner as in Example 1. 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst at 1.23V RHE The photocurrent density under bias voltage reached 3.52 mA cm -2 , the photocurrent density has no obvious decay within 10 min.

[0071] Example 4

[0072] A Co 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst comprises the following steps:

[0073] (1) Dissolve cadmium nitrate hexahydrate, glutathione, and thiourea in ultrapure water to form a mixed solution, wherein the concentration of cadmium nitrate hexahydrate, glutathione, and thiourea in the mixed solution is 0.03M, 0.018M, and 0.03M; transfer the mixed solution and FTO conductive glass to a polytetrafluoroethylene reactor, seal it with a stainless steel hydrothermal reactor, and react at 200°C for 8 hours. After the reaction is completed, cool it to room temperature, wash and dry the obtained product to obtain an FTO / CdS photoelectrode; anneal the FTO / CdS photoelectrode at 400°C in an argon atmosphere for 2 hours, and then treat it with an ozone cleaner for 1 hour to obtain a pretreated FTO / CdS photoelectrode;

[0074] (2) 5 mL of N,N-dimethylformamide solution and 5 mL of anhydrous ethanol solution were mixed evenly, and then 500 mg of chiral H3L ligand and 100 mg of auxiliary ligand 4,4'-bipyridine were added, and the mixture was stirred and ultrasonicated and then mixed evenly to obtain a mixed solution;

[0075] (3) Dissolving cadmium nitrate hexahydrate and cobalt nitrate hexahydrate in ultrapure water and anhydrous ethanol respectively to form a 0.1M cadmium nitrate aqueous solution and a 0.1M cobalt nitrate ethanol solution, taking 2mL of the cadmium nitrate aqueous solution and 1mL of the cobalt nitrate ethanol solution and adding them to the mixed solution obtained in step (2), stirring evenly to obtain a precursor solution;

[0076] (4) The pretreated FTO / CdS photoelectrode was placed with the conductive surface facing downward in a polytetrafluoroethylene reactor, and the precursor solution obtained in step (3) was slowly injected along the non-conductive surface of the FTO / CdS photoelectrode. After sealing with a stainless steel hydrothermal reactor, the reaction was carried out at 60°C for 48 hours. After the reaction was completed, the reaction was cooled to room temperature. The obtained product was washed three times with a mixed solution of N,N-dimethylformamide and ethanol and dried at 60°C to obtain Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst.

[0077] Characterization showed that the product obtained in this example had a nanorod core-shell structure and was of uniform size.

[0078] The test was carried out in the same manner as in Example 1. 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst at 1.23V RHE The photocurrent density under bias voltage reached 3.36 mA cm -2 , the photocurrent density has no obvious decay within 10 min.

[0079] Example 5

[0080] A Co 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst comprises the following steps:

[0081] (1) Dissolve cadmium nitrate hexahydrate, glutathione, and thiourea in ultrapure water to form a mixed solution, wherein the concentration of cadmium nitrate hexahydrate, glutathione, and thiourea in the mixed solution is 0.03M, 0.018M, and 0.03M; transfer the mixed solution and FTO conductive glass to a polytetrafluoroethylene reactor, seal it with a stainless steel hydrothermal reactor, and react at 200°C for 8 hours. After the reaction is completed, cool it to room temperature, wash and dry the obtained product to obtain an FTO / CdS photoelectrode; anneal the FTO / CdS photoelectrode at 400°C in an argon atmosphere for 2 hours, and then treat it with an ozone cleaner for 1 hour to obtain a pretreated FTO / CdS photoelectrode;

[0082] (2) 5 mL of N,N-dimethylformamide solution and 5 mL of anhydrous ethanol solution were mixed evenly, and then 50 mg of chiral H3L ligand and 10 mg of auxiliary ligand 4,4'-bipyridine were added, and the mixture was stirred and ultrasonically mixed to obtain a mixed solution;

[0083] (3) dissolving cadmium nitrate hexahydrate and cobalt nitrate hexahydrate in ultrapure water and anhydrous ethanol respectively to form a 0.1M cadmium nitrate aqueous solution and a 0.1M cobalt nitrate ethanol solution, taking 1mL of the cadmium nitrate aqueous solution and 0.5mL of the cobalt nitrate ethanol solution to the mixed solution obtained in step (2), stirring evenly, to obtain a precursor solution;

[0084] (4) The pretreated FTO / CdS photoelectrode was placed with the conductive surface facing downward in a polytetrafluoroethylene reactor, and the precursor solution obtained in step (3) was slowly injected along the non-conductive surface of the FTO / CdS photoelectrode. After sealing with a stainless steel hydrothermal reactor, the reaction was carried out at 60°C for 48 hours. After the reaction was completed, the reaction was cooled to room temperature. The obtained product was washed three times with a mixed solution of N,N-dimethylformamide and ethanol and dried at 60°C to obtain Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst.

[0085] Characterization showed that the product obtained in this example had a nanorod core-shell structure and was of uniform size.

[0086] The test was carried out in the same manner as in Example 1. 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst at 1.23V RHE The photocurrent density under bias voltage reached 3.16 mA cm -2 , the photocurrent density has no obvious decay within 10 min.

[0087] Example 6

[0088] A Co 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst comprises the following steps:

[0089] (1) Dissolve cadmium nitrate hexahydrate, glutathione, and thiourea in ultrapure water to form a mixed solution, wherein the concentration of cadmium nitrate hexahydrate, glutathione, and thiourea in the mixed solution is 0.03M, 0.018M, and 0.03M; transfer the mixed solution and FTO conductive glass to a polytetrafluoroethylene reactor, seal it with a stainless steel hydrothermal reactor, and react at 200°C for 8 hours. After the reaction is completed, cool it to room temperature, wash and dry the obtained product to obtain an FTO / CdS photoelectrode; anneal the FTO / CdS photoelectrode at 400°C in an argon atmosphere for 2 hours, and then treat it with an ozone cleaner for 1 hour to obtain a pretreated FTO / CdS photoelectrode;

[0090] (2) 5 mL of N,N-dimethylformamide solution and 5 mL of anhydrous ethanol solution were mixed evenly, and then 50 mg of chiral H3L ligand and 10 mg of auxiliary ligand 4,4'-bipyridine were added, and the mixture was stirred and ultrasonicated and then mixed evenly to obtain a mixed solution;

[0091] (3) Dissolving cadmium nitrate hexahydrate and cobalt nitrate hexahydrate in ultrapure water and anhydrous ethanol respectively to form a 0.1M cadmium nitrate aqueous solution and a 0.1M cobalt nitrate ethanol solution, taking 3mL of the cadmium nitrate aqueous solution and 1.5mL of the cobalt nitrate ethanol solution and adding them to the mixed solution obtained in step (2), stirring evenly to obtain a precursor solution;

[0092] (4) The pretreated FTO / CdS photoelectrode was placed with the conductive surface facing downward in a polytetrafluoroethylene reactor, and the precursor solution obtained in step (3) was slowly injected along the non-conductive surface of the FTO / CdS photoelectrode. After sealing with a stainless steel hydrothermal reactor, the reaction was carried out at 60°C for 48 hours. After the reaction was completed, the reaction was cooled to room temperature. The obtained product was washed three times with a mixed solution of N,N-dimethylformamide and ethanol and dried at 60°C to obtain Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst.

[0093] Characterization showed that the product obtained in this example had a nanorod core-shell structure and was of uniform size.

[0094] The test was carried out in the same manner as in Example 1. 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst at 1.23V RHE The photocurrent density under bias voltage reached 3.27 mA cm -2 , the photocurrent density has no obvious decay within 10 min.

[0095] Example 7

[0096] A Co 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst comprises the following steps:

[0097] (1) Dissolve cadmium nitrate hexahydrate, glutathione, and thiourea in ultrapure water to form a mixed solution, wherein the concentration of cadmium nitrate hexahydrate, glutathione, and thiourea in the mixed solution is 0.03M, 0.018M, and 0.03M; transfer the mixed solution and FTO conductive glass to a polytetrafluoroethylene reactor, seal it with a stainless steel hydrothermal reactor, and react at 200°C for 8 hours. After the reaction is completed, cool it to room temperature, wash and dry the obtained product to obtain an FTO / CdS photoelectrode; anneal the FTO / CdS photoelectrode at 400°C in an argon atmosphere for 2 hours, and then treat it with an ozone cleaner for 1 hour to obtain a pretreated FTO / CdS photoelectrode;

[0098] (2) 5 mL of N,N-dimethylformamide solution and 5 mL of anhydrous ethanol solution were mixed evenly, and then 50 mg of chiral H3L ligand and 10 mg of auxiliary ligand 4,4'-bipyridine were added, and the mixture was stirred and ultrasonicated and then mixed evenly to obtain a mixed solution;

[0099] (3) Dissolving cadmium nitrate hexahydrate and cobalt nitrate hexahydrate in ultrapure water and anhydrous ethanol respectively to form a 0.1M cadmium nitrate aqueous solution and a 0.1M cobalt nitrate ethanol solution, taking 2mL of the cadmium nitrate aqueous solution and 1mL of the cobalt nitrate ethanol solution and adding them to the mixed solution obtained in step (2), stirring evenly to obtain a precursor solution;

[0100] (4) The pretreated FTO / CdS photoelectrode was placed with the conductive surface facing downward in a polytetrafluoroethylene reactor, and the precursor solution obtained in step (3) was slowly injected along the non-conductive surface of the FTO / CdS photoelectrode. After sealing with a stainless steel hydrothermal reactor, the reaction was carried out at 80°C for 48 hours. After the reaction was completed, the reaction was cooled to room temperature. The obtained product was washed three times with a mixed solution of N,N-dimethylformamide and ethanol and dried at 60°C to obtain Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst.

[0101] Characterization showed that the product obtained in this example had a nanorod core-shell structure and was of uniform size.

[0102] The test was carried out in the same manner as in Example 1. 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst at 1.23V RHE The photocurrent density under bias voltage reached 3.62 mA cm -2 , the photocurrent density has no obvious decay within 10 min.

[0103] Comparative Example 2

[0104] The preparation method of the CdMOFs-cadmium sulfide photoanode catalyst in Comparative Example 2 is similar to that in Example 1, except that the reaction temperature in step (4) is 120°C.

[0105] Characterization showed that the product obtained in this comparative example could not present a nanorod core-shell structure.

[0106] The same method as in Example 1 was used for testing. The CdMOFs-cadmium sulfide photoanode catalyst prepared in Comparative Example 2 was tested at 1.23V. RHE The photocurrent density under bias voltage reached 1.91 mA cm -2 , relative to Co in Example 1 2+ The photocurrent density of the CdMOFs-cadmium sulfide photoanode catalyst was significantly reduced, and the photocurrent density within 10 minutes was significantly lower than that of Co in Example 1. 2+ The doped CdMOFs-CdS photoanode catalyst showed obvious degradation.

[0107] Comparative Example 3

[0108] The preparation method of the CdMOFs-cadmium sulfide photoanode catalyst in Comparative Example 3 is similar to that in Example 1, except that nickel nitrate is used instead of cobalt nitrate in step (3). The specific steps are as follows:

[0109] (1) Dissolve cadmium nitrate hexahydrate, glutathione, and thiourea in ultrapure water to form a mixed solution, wherein the concentration of cadmium nitrate hexahydrate, glutathione, and thiourea in the mixed solution is 0.03M, 0.018M, and 0.03M; transfer the mixed solution and FTO conductive glass to a polytetrafluoroethylene reactor, seal it with a stainless steel hydrothermal reactor, and react at 200°C for 8 hours. After the reaction is completed, cool it to room temperature, wash and dry the obtained product to obtain an FTO / CdS photoelectrode; anneal the FTO / CdS photoelectrode at 400°C in an argon atmosphere for 2 hours, and then treat it with an ozone cleaner for 1 hour to obtain a pretreated FTO / CdS photoelectrode;

[0110] (2) 5 mL of N,N-dimethylformamide solution and 5 mL of anhydrous ethanol solution were mixed evenly, and then 50 mg of chiral H3L ligand and 10 mg of auxiliary ligand 4,4'-bipyridine were added, and the mixture was stirred and ultrasonically mixed to obtain a mixed solution;

[0111] (3) dissolving cadmium nitrate hexahydrate and nickel nitrate hexahydrate in ultrapure water and anhydrous ethanol respectively to form a 0.1M cadmium nitrate aqueous solution and a 0.1M nickel nitrate ethanol solution, taking 2mL of the cadmium nitrate aqueous solution and 1mL of the nickel nitrate ethanol solution and adding them to the mixed solution obtained in step (2), stirring evenly to obtain a precursor solution;

[0112] (4) The pretreated FTO / CdS photoelectrode conductive surface is placed in a polytetrafluoroethylene reactor with the conductive surface facing downward, and the precursor solution obtained in step (3) is slowly injected along the non-conductive surface of the FTO / CdS photoelectrode. After sealing with a stainless steel hydrothermal reactor, the reaction is carried out at 60°C for 48 hours. After the reaction is completed, the reaction is cooled to room temperature. The obtained product is washed three times with a mixed solution of N,N-dimethylformamide and ethanol and dried at 60°C to obtain Ni 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst.

[0113] The product obtained in this comparative example cannot be characterized as a nanorod core-shell structure, as shown in the SEM image. Figure 11 shown.

[0114] Tested in the same manner as in Example 1, Figure 9 Ni obtained in Comparative Example 3 of the present invention 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst (CdS-CdMOFs-Ni) and Co obtained in Example 1 2+ Comparison of LSV curves of doped CdMOFs-cadmium sulfide photoanode catalysts (CdS-CdMOFs-Co); Figure 9 As shown: Ni prepared in this comparative example 3 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst at 1.23V RHE The photocurrent density under bias voltage reached 3.12 mA cm -2 , relative to Co in Example 1 2+ The photocurrent density of the doped CdMOFs-cadmium sulfide photoanode catalyst is low.

[0115] Comparative Example 4

[0116] A Co 2+ The preparation method of the doped CdMOFs-cadmium sulfide photoanode catalyst is different from that of Example 1 only in that: in (2), 5 mg of chiral H3L ligand and 1 mg of auxiliary ligand 4,4'-bipyridine are added; the remaining steps are the same as those of Example 1.

[0117] Characterization showed that the product obtained in this example had a nanorod core-shell structure and was of uniform size.

[0118] The test was carried out in the same manner as in Example 1. 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst at 1.23V RHE The photocurrent density under bias voltage reached 2.81 mA cm -2 , the photocurrent density has no obvious decay within 10 min.

[0119] Comparative Example 5

[0120] A Co 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst comprises the following steps:

[0121] (1) Dissolve cadmium nitrate hexahydrate, glutathione, and thiourea in ultrapure water to form a mixed solution, wherein the concentration of cadmium nitrate hexahydrate, glutathione, and thiourea in the mixed solution is 0.03M, 0.018M, and 0.03M; transfer the mixed solution and FTO conductive glass to a polytetrafluoroethylene reactor, seal it with a stainless steel hydrothermal reactor, and react at 200°C for 8 hours. After the reaction is completed, cool it to room temperature, wash and dry the obtained product to obtain an FTO / CdS photoelectrode; anneal the FTO / CdS photoelectrode at 400°C in an argon atmosphere for 2 hours, and then treat it with an ozone cleaner for 1 hour to obtain a pretreated FTO / CdS photoelectrode;

[0122] (2) 5 mL of N,N-dimethylformamide solution and 5 mL of anhydrous ethanol solution were mixed evenly, and then 50 mg of chiral H3L ligand and 10 mg of auxiliary ligand 4,4'-bipyridine were added, and the mixture was stirred and ultrasonicated and then mixed evenly to obtain a mixed solution;

[0123] (3) Dissolving cadmium nitrate hexahydrate and cobalt nitrate hexahydrate in ultrapure water and anhydrous ethanol respectively to form a 0.1M cadmium nitrate aqueous solution and a 0.1M cobalt nitrate ethanol solution, taking 2mL of the cadmium nitrate aqueous solution and 1mL of the cobalt nitrate ethanol solution and adding them to the mixed solution obtained in step (2), stirring evenly to obtain a precursor solution;

[0124] (4) The pretreated FTO / CdS photoelectrode was placed with the conductive surface facing downward in a polytetrafluoroethylene reactor, and the precursor solution obtained in step (3) was slowly injected along the non-conductive surface of the FTO / CdS photoelectrode. After sealing with a stainless steel hydrothermal reactor, the reaction was carried out at 100°C for 48 hours. After the reaction was completed, the reaction was cooled to room temperature. The obtained product was washed three times with a mixed solution of N,N-dimethylformamide and ethanol and dried at 60°C to obtain Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst.

[0125] Characterization showed that the product obtained in this comparative example had a nanorod core-shell structure and had consistent size.

[0126] The test was carried out in the same manner as in Example 1. 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst at 1.23V RHE The photocurrent density under bias voltage reached 2.71 mA cm -2 , the photocurrent density has no obvious decay within 10 min.

[0127] Comparative Example 6

[0128] A Co 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst comprises the following steps:

[0129] (1) Dissolve cadmium nitrate hexahydrate, glutathione, and thiourea in ultrapure water to form a mixed solution, wherein the concentration of cadmium nitrate hexahydrate, glutathione, and thiourea in the mixed solution is 0.03M, 0.018M, and 0.03M; transfer the mixed solution and FTO conductive glass to a polytetrafluoroethylene reactor, seal it with a stainless steel hydrothermal reactor, and react at 200°C for 8 hours. After the reaction is completed, cool it to room temperature, wash and dry the obtained product to obtain an FTO / CdS photoelectrode; anneal the FTO / CdS photoelectrode at 400°C in an argon atmosphere for 2 hours, and then treat it with an ozone cleaner for 1 hour to obtain a pretreated FTO / CdS photoelectrode;

[0130] (2) 5 mL of N,N-dimethylformamide solution and 5 mL of anhydrous ethanol solution were mixed evenly, and then 50 mg of chiral H3L ligand and 10 mg of auxiliary ligand 4,4'-bipyridine were added, and the mixture was stirred and ultrasonicated and then mixed evenly to obtain a mixed solution;

[0131] (3) Dissolving cadmium nitrate hexahydrate and cobalt nitrate hexahydrate in ultrapure water and anhydrous ethanol respectively to form a 0.1M cadmium nitrate aqueous solution and a 0.1M cobalt nitrate ethanol solution, taking 2mL of the cadmium nitrate aqueous solution and 1mL of the cobalt nitrate ethanol solution and adding them to the mixed solution obtained in step (2), stirring evenly to obtain a precursor solution;

[0132] (4) The pretreated FTO / CdS photoelectrode was placed with the conductive surface facing downward in a polytetrafluoroethylene reactor, and the precursor solution obtained in step (3) was slowly injected along the non-conductive surface of the FTO / CdS photoelectrode. After sealing with a stainless steel hydrothermal reactor, the reaction was carried out at 60°C for 24 hours. After the reaction was completed, the reaction was cooled to room temperature. The obtained product was washed three times with a mixed solution of N,N-dimethylformamide and ethanol and dried at 60°C to obtain Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst.

[0133] Characterization showed that the product obtained in this comparative example had a nanorod core-shell structure and had consistent size.

[0134] The test was carried out in the same manner as in Example 1. 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst at 1.23V RHE The photocurrent density under bias voltage reached 2.42 mA cm -2 , the photocurrent density has no obvious decay within 10 min.

[0135] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A Co 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst is characterized by: The following steps are involved: S1, annealing the FTO / CdS photoelectrode in an argon atmosphere, and then treating it with an ozone cleaner to obtain a pretreated FTO / CdS photoelectrode; the CdS in the FTO / CdS photoelectrode forms a nanorod array; S2, mixing anhydrous ethanol, N,N-dimethylformamide, chiral H3L ligand, and 4,4'-bipyridine to form a ligand mixed solution; wherein the chiral H3L ligand has the structural formula: ; S3, uniformly mixing the cadmium nitrate aqueous solution, the cobalt nitrate ethanol solution and the ligand mixed solution to obtain a precursor solution; wherein the molar ratio of the cadmium nitrate in the cadmium nitrate aqueous solution, the cobalt nitrate in the cobalt nitrate ethanol solution and the chiral H3L ligand in the ligand mixed solution is 2:1:0.38-7.67; S4, placing the pretreated FTO / CdS photoelectrode with the conductive surface facing downward in a hydrothermal reactor, injecting the precursor solution, sealing it and reacting it, and cooling it to room temperature after the reaction to obtain the Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst; wherein the reaction temperature is 60-80°C and the reaction time is 40-50h.

2. Co according to claim 1 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst is characterized by: In S1, the annealing temperature is 400° C. and the time is 2 hours; the ozone cleaning machine treatment time is 1 hour.

3. Co according to claim 1 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst is characterized by: In S2, the volume ratio of anhydrous ethanol to N,N-dimethylformamide is 1:

1.

4. Co according to claim 1 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst is characterized by: In S2, the mass ratio of the chiral H3L ligand to 4,4'-bipyridine is 5:

1.

5. Co according to claim 1 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst is characterized by: In S3, the molar ratio of cadmium nitrate in the cadmium nitrate aqueous solution, cobalt nitrate in the cobalt nitrate ethanol solution, and chiral H3L ligand in the ligand mixed solution is 2:1:0.

77.

6. Co according to claim 1 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst is characterized by: In S3, the concentration of the chiral H3L ligand in the precursor solution is 1.9-39 mg / ml.

7. Co according to claim 1 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst is characterized by: In S4, the reaction temperature is 60° C. and the reaction time is 48 h.

8. Co according to any one of claims 1 to 7 2+ The preparation method of doped CdMOFs-cadmium sulfide photoanode catalyst is characterized by: In S1, the preparation method of the FTO / CdS photoelectrode includes the following steps: dissolving cadmium nitrate hexahydrate, glutathione, and thiourea in ultrapure water to form a mixed solution; transferring the mixed solution and FTO to a polytetrafluoroethylene reactor, sealing it with a stainless steel hydrothermal reactor, and reacting; after the reaction is completed, cooling it to room temperature, washing and drying the obtained product to obtain the FTO / CdS photoelectrode.

9. A Co 2+ Doped CdMOFs-cadmium sulfide photoanode catalyst, characterized by: Using Co as described in any one of claims 1-8 2+ The method is used to prepare a doped CdMOFs-cadmium sulfide photoanode catalyst.

10. A Co as claimed in claim 9 2+ Application of doped CdMOFs-cadmium sulfide photoanode catalyst as photoelectrocatalyst for catalytic water oxidation reaction.

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