Amide bridging type heterostructure photocatalyst and preparation and application thereof

Abstract

This invention discloses an amide-bridged heterostructure photocatalyst, its preparation, and its application. The photocatalyst is formed by covalently linking a phthalocyanine derivative and an amino-functionalized transition metal-organic framework (MOF) via amide bonds. The MOF is formed by coordination of a transition metal ion with two organic ligands; all organic ligands are organic acids containing two or more carboxyl groups. This invention solves the problem of existing technologies having limited functionality and lacking synergistic effects in purification and H2O2 production. The photocatalyst possesses a hierarchical nanoflower structure with a diameter of 20-30 μm, and the petals of the nanoflowers have irregular nanosheets. Under conditions where organic pollutants are present, H2O2 production and pollutant degradation exhibit a synergistic effect, with the H2O2 production increasing to 5517.4 μmol·g. ‑1 ·h ‑1 Meanwhile, the tetracycline degradation rate is >99.8%; it has a wide spectral response capability, excellent structural stability and strong universality.

Description

Technical Field

[0001] This invention relates to a heterostructured photocatalyst, specifically to an amide-bridged heterostructured photocatalyst and its preparation and application. Background Technology

[0002] Photocatalytic synthesis of hydrogen peroxide (H2O2) is an important pathway for converting solar energy into chemical energy, with broad application prospects in environmental remediation and energy conversion. The synthesis of H2O2 involves a complex proton-coupled electron transfer (PCET) process, requiring kinetic coordination between the two-electron oxygen reduction to H2O2 and the proton donation from water oxidation. A core technical challenge for traditional photocatalysts is that the water oxidation reaction requires a high overpotential, resulting in slow proton supply and becoming the rate-limiting step of the entire process, severely restricting the yield of H2O2. On the other hand, with the acceleration of industrialization and urbanization, the treatment of organic pollutants in water bodies (such as antibiotics, phenols, and dyes) has become an urgent environmental problem.

[0003] Traditional photocatalysis technology typically treats H2O2 synthesis and pollutant degradation as two separate research directions, failing to fully utilize the intrinsic connection between them. Existing literature 1 (Zhou YJ, Ji MT, Liang SQ, et al. SubPc-Br / BiOI S-scheme heterojunctions: efficient charge separation for enhanced photocatalytic degradation of tetracycline [J]. RSC Advances, 2025, 15:16799-16813. DOI:10.1039 / D5RA02536B.https: / / pubs.rsc.org / en / content / articlehtml / 2025 / ra / d5ra02536b) firstly demonstrated the self-assembly of boron phthalocyanine bromide (SubPc-Br) on the surface of a BiOI layer, forming an S-scheme heterojunction (SubPc-Br / BiOI) through halogen bonds and π-π stacking interactions. The results showed that the SubPc-Br / BiOI composite improved tetracycline removal efficiency by 1.6 times compared with pure BiOI. Notably, after five cycles, the composite material still maintained a high tetracycline removal rate, 2.62 times that of pure BiOI. DFT and TDDFT theoretical calculations, combined with synchrotron X-ray photoelectron spectroscopy (XPS) under synchrotron irradiation, indicated that the internal electric field generated between the [Bi2O2] layer and the subPc-Br macrocycle plays a dominant role in charge separation, while interfacial electron transfer contributes to the formation of the S-scheme heterojunction. Furthermore, the combination of molecular dynamics simulations (MD), Fukui function calculations, and HPLC-MS detection revealed the mechanism of pollutant degradation. However, Reference 1 only focused on tetracycline degradation, failing to achieve synergy between pollutant degradation and H2O2 generation, and its narrow spectral response range prevented the use of near-infrared light.

[0004] In existing technologies, some studies have attempted to combine photocatalytic H2O2 production with pollutant degradation. Reference 2 (Chinese invention patent application publication number CN120169430A) describes a PDI / PMSO composite photocatalytic system obtained by coupling a perylene imide (PDI) supramolecular photocatalyst with methyl phenyl sulfoxide (PMSO) wastewater at a specific concentration ratio. This PDI / PMSO composite photocatalytic system significantly improves the H2O2 yield; when the PMSO concentration is 10 mM, the H2O2 yield reaches 137.28 μM·g. -1 ·h -1The efficiency is 4.3 times higher than that of a pure water system. The system described in this invention promotes the separation of photogenerated electron-hole pairs (reducing steady-state fluorescence intensity by 37%) and enhances electron conduction efficiency (increasing photocurrent by 1.8 times) through synergistic effects, while maintaining excellent cycling stability (yield remains above 80% after 10 cycles) and practical applicability in water bodies. However, although Reference 2 can produce H2O2, it is only applicable to specific wastewater systems, cannot broadly degrade various antibiotics, phenols, and dye pollutants, lacks near-infrared light response capability, and does not achieve efficient synergy between wastewater purification and H2O2 production. Summary of the Invention

[0005] The purpose of this invention is to provide an amide-bridged heterostructure photocatalyst, its preparation and application, which solves the problems of existing technologies having single function and lacking synergy between purification and H2O2 production. Under full-spectrum irradiation, this catalyst achieves an H2O2 yield of 2091.5 μmol·g in a pure water system. -1 ·h -1 In the presence of tetracycline, the yield of H2O2 increased to 5517.4 μmol·g. -1 ·h -1 It has an increase of 2.6 times, and the tetracycline degradation rate is >99.8%; it has excellent stability and broad spectral response, and is green, environmentally friendly and easy to prepare.

[0006] To achieve the above objectives, the present invention provides an amide-bridged heterostructure photocatalyst with a nanoflower structure, which is formed by linking a phthalocyanine derivative and an amino-functionalized transition metal-organic framework via covalent amide bonds. The transition metal-organic framework is formed by coordination of a transition metal ion with two organic ligands. The organic ligands are all organic acids containing two or more carboxyl groups.

[0007] Preferably, the phthalocyanine derivative is a carboxyl-functionalized phthalocyanine.

[0008] Preferably, the photocatalyst self-assembles into a hierarchical nanoflower structure with a diameter of 20~30 μm, and the petals of the nanoflower have irregular nanosheets.

[0009] More preferably, the organic ligand is an organic acid containing two carboxyl groups or an organic acid containing three carboxyl groups; the transition metal ion is Cu. 2+ .

[0010] More preferably, the transition metal-organic framework is a CuBTC-NH2 framework, wherein Cu, O, C, N and B are uniformly spatially distributed throughout the photocatalyst nanoflower structure; the heterojunction absorption edge of the photocatalyst is broadened to 1400 nm.

[0011] This invention provides a method for preparing a photocatalyst with an amide-bridged heterostructure as described above, the method comprising: An organic acid containing two carboxyl groups and a phthalocyanine derivative are dispersed in an alcohol solution, sonicated, and kept at a sealed temperature of 120°C to 140°C. An organic acid containing three carboxyl groups and a transition metal salt are added, and the mixture is heated at 80°C, centrifuged, washed, and vacuum dried to obtain the final product.

[0012] Preferably, the holding time at 120°C to 140°C is 60 to 80 hours, and the heating rate and cooling rate are both 3 to 8°C / hour.

[0013] Preferably, the molar ratio of the organic acid containing two carboxyl groups, the phthalocyanine derivative, the organic acid containing three carboxyl groups, and the transition metal salt is (10~15):1:(8~12):(30~40).

[0014] More preferably, the organic acid containing two carboxyl groups is 1,3,5-benzenetricarboxylic acid, the organic acid containing two carboxyl groups is 5-aminoisophthalic acid, the phthalocyanine derivative is SubPc-1, the organic acid containing three carboxyl groups is 1,3,5-benzenetricarboxylic acid, and the transition metal salt is Cu(NO3)2·3H2O.

[0015] Preferably, the phthalocyanine derivative is prepared by the following method; Phthalocyanine and m-hydroxybenzoic acid were dissolved in toluene, stirred at room temperature under a nitrogen atmosphere, kept at 130 °C, cooled to room temperature, evaporated by rotary evaporation, washed, and dried.

[0016] More preferably, the heat preservation time is 72 hours; the heating time to 130 ℃ is 10 hours and the cooling rate is 5 ℃ / hour; the washing is carried out with methanol, and the drying temperature is 70 ℃ and the time is 8 hours.

[0017] This invention provides an application of the amide-bridged heterostructure photocatalyst as described above in the simultaneous enhancement of photocatalytic H2O2 production during the degradation of organic pollutants.

[0018] Preferably, the organic pollutant includes any one or more of antibiotics, phenols, and dyes; the application is: using the photocatalyst as described, in the presence of an aqueous solution containing the organic pollutant and oxygen, to carry out a reaction by irradiation with full-spectrum light.

[0019] More preferably, the organic pollutant is tetracycline, oxytetracycline, bisphenol A, or rhodamine B.

[0020] This invention discloses an amide-bridged heterostructure photocatalyst, its preparation, and its application. This invention solves the problems of existing technologies having limited functionality and lacking synergistic effects in purification and H2O2 production, and has the following advantages: 1. The catalyst of the present invention is obtained by reacting the carboxyl group of SubPc-1 with 5-aminoisophthalic acid to form an amide bond precursor using a simple two-step solvothermal method, followed by the addition of 1,3,5-benzenetricarboxylic acid and copper salt to grow a CuBTC-NH2 framework in situ; the photocatalyst is a nanoflower-like composite material with a hierarchical nanoflower structure with a diameter of 20~30 μm, and irregular nanosheets on the petals of its nanoflowers.

[0021] 2. In the presence of organic pollutants, the H2O2 yield of this catalyst is significantly increased compared to the pure water system, while the pollutants are efficiently degraded. The two exhibit a synergistic promoting relationship rather than an inhibitory one. In the presence of tetracycline, the H2O2 yield increases from 2091.5 μmol·g⁻¹ in the pure water system. -1 ·h -1 Increased to 5517.4 μmol·g -1 ·h -1 The increase reached 2.6 times; under the synergistic enhancement effect, the degradation rate of tetracycline was >99.8%, the degradation rate of oxytetracycline was 95.2%, the degradation rate of bisphenol A was 91.1%, and the degradation rate of rhodamine B was 84.8%, achieving the dual goals of wastewater purification and energy production.

[0022] 3. The photocatalyst provided by this invention possesses broad spectral response, excellent structural stability, and strong versatility. Specifically, the catalyst exhibits significant H2O2 yield across the entire spectral range (300-1100 nm), with apparent quantum efficiencies at different wavelengths of 17.47% at 400 nm, 15.35% at 600 nm, 17.1% at 808 nm, and 12.49% at 900 nm, effectively utilizing visible and near-infrared light. After five cycles of use, the catalyst maintains good catalytic activity and structural integrity, with XRD patterns almost identical to the original sample, showing no significant phase transition or loss of crystallinity, demonstrating promising application prospects. This catalyst can be applied to the degradation of various organic pollutants (antibiotics such as tetracycline and oxytetracycline, phenols such as bisphenol A, and dyes such as rhodamine B) while simultaneously producing H2O2, exhibiting broad applicability. Attached Figure Description

[0023] Figure 1 This is a SEM image of the SubPc1–CONH–CuBTC–NH2 heterostructure photocatalyst of this invention.

[0024] Figure 2This is a HAADF-STEM image of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention.

[0025] Figure 3 The image shows the Raman spectrum of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention.

[0026] Figure 4 The infrared spectrum of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention is shown.

[0027] Figure 5 The image shows the XRD pattern of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention.

[0028] Figure 6 The XPS spectrum of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention is shown.

[0029] Figure 7 The image shows the UV-vis-NIR diffuse reflectance spectrum of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention.

[0030] Figure 8 The graph shows the photocatalytic H2O2 production performance of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention under UV-vis-NIR irradiation.

[0031] Figure 9 This is a graph showing the apparent quantum yield of H2O2 at a specific wavelength for the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention.

[0032] Figure 10 The diagram shows the performance of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention in the production of hydrogen peroxide and the synergistic degradation of pollutants.

[0033] Figure 11 The figure shows the performance of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention in a five-cycle experiment to produce H2O2 and simultaneously degrade TC.

[0034] Figure 12 This is a SEM-EDS image of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of the present invention after five cycles.

[0035] Figure 13 This is an XDR image of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of the present invention after five cycles. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1 A method for preparing a SubPc1-CONH–CuBTC–NH2 heterostructure photocatalyst that simultaneously enhances photocatalytic H2O2 production through pollutant degradation, employing a two-step method, comprising: (1) SubPc-0 was synthesized according to the reference (Li Z, Wang B, Zhang BB, et al. Fabrication ofSubPc-Br / Ag3PO4 composites with high-efficiency and stable photocatalyticperformance[J]. Journal of Photochemistry and Photobiology A: Chemistry, 2021, 405: 112929.). A mixture of SubPc-0 (0.475 g, 1 mmol) and m-hydroxybenzoic acid (0.276 g, 2 mmol) was dissolved in 30 mL of toluene and stirred at room temperature under a nitrogen atmosphere for two hours. The mixture was then poured into an autoclave, and the temperature was raised from room temperature to 130 °C over 10 hours and maintained at 130 °C for 72 hours. The reaction mixture was then cooled to ambient temperature at a rate of 5 °C per hour. After cooling, the solvent was carefully removed using a rotary evaporator. The remaining solid residue was thoroughly washed with methanol (3 × 10 mL) and dried at 70 °C for 8 hours to obtain golden-purple microcrystals, namely carboxyl-functionalized phthalocyanine, denoted as SubPc-1.

[0038] (2) 5-Amino-isophthalic acid (0.1 g) and SubPc-1 (24.3 mg) were dispersed in an ethanol / water mixed solvent (v / v = 1:1, 60 mL) and sonicated for 30 minutes. The mixture was then transferred to a sealed autoclave and heated at 130°C for 72 hours (5 hours of heating followed by 10 hours of cooling) to promote amide coupling between the carboxyl group of SubPc-1 and the amino group of 5-amino-isophthalic acid. Without separating the intermediates, 1,3,5-benzenetricarboxylic acid (0.1 g) and Cu(NO3)2·3H2O (0.4 g) were directly added to the reaction vessel. The system was then heated at 80°C for 12 hours to allow the CuBTC-NH2 framework to crystallize around the pre-formed amide-linked SubPc1. The resulting solid was collected by centrifugation and then treated with deionized water (20 mL) and ethanol (20 mL) in sequence. The mixture was washed with mL and dried under vacuum at 60°C for 24 hours to obtain the final composite material, denoted as SubPc1–CONH–CuBTC–NH2.

[0039] Comparative Example 1 The preparation method of a SubPc1-CuBTC–NH2 (One pot) composite material is basically the same as that in Example 1, using a one-step synthesis method, with the difference being: No step (1); In step (2), Cu(NO3)2·3H2O (0.4 g), 1,3,5-benzenetricarboxylic acid (0.1 g), 5-aminoisophthalic acid (0.1 g), and carboxyl-functionalized phthalocyanine (SubPc-1, 24.3 mg) were dispersed in an ethanol / water mixed solvent (v / v = 1∶1, 60 mL). After ultrasonic treatment for 30 minutes, the mixture was transferred to a sealed container and heated at 80°C for 12 hours. The obtained solid was collected by centrifugation, washed successively with deionized water (20 mL) and ethanol (20 mL), and then dried under vacuum at 60°C for 24 hours to obtain the SubPc1-CuBTC–NH2 (One pot) composite material.

[0040] Comparative Example 2 The preparation method of the SubPc1 / CuBTC-NH2 composite material is basically the same as that in Example 1, using a physical mixing method for synthesis, with the difference being: No step (1); CuBTC-NH2 was synthesized according to the literature (Zhang X, Su Q, Zhang F, et al. Realizing High-FluxLi+ conduction and stable solid electrolyte interface by Iodine-and Amino-Functionalized MOFs doping in Solid-State electrolytes[J]. Chemical Engineering Journal, 2024, 500: 157242.). Cu(NO3)2·3H2O (0.4 g), 1,3,5-benzenetricarboxylic acid (0.1 g), and 5-aminoisophthalic acid (0.1 g) were dispersed in an ethanol / water mixed solvent (v / v = 1:1, 15 mL); the mixture was heated at 80 °C for 12 hours; the resulting blue crystals were collected by centrifugation and washed with deionized water (3 × 10 mL) and ethanol (3 × 10 mL) by solvent exchange to remove unreacted precursors; finally, the product was dried under vacuum at 80 °C for 12 hours to obtain activated CuBTC-NH2.

[0041] A physically mixed sample was prepared by simply grinding SubPc1-COOH (24.3 mg) and CuBTC-NH2 powder (0.6 g), synthesized separately, at a mass ratio corresponding to that used in the two-step method in Example 1. The mixture was thoroughly ground in an agate mortar for 30 minutes to ensure uniform mixing. The resulting powder was then dried under vacuum at 60°C for 12 hours and denoted as SubPc1 / CuBTC-NH2.

[0042] Experimental Example 1: Structural Characterization The photocatalysts prepared in Example 1 and Comparative Examples 1-2 were characterized structurally.

[0043] like Figure 1 The image shown is a SEM image of the SubPc1–CONH–CuBTC–NH2 heterostructure photocatalyst of this invention. Figure 1 It can be seen that the material self-assembles into a hierarchical nanoflower structure with a diameter of 20~30 μm, and its petals are further decorated with irregular SubPc-1 nanosheets.

[0044] like Figure 2 The image shown is a HAADF-STEM image of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention. Figure 2 This confirms the uniform spatial distribution of Cu, O, C, N, and B throughout the nanoflower structure.

[0045] like Figure 3 The Raman spectrum of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of the present invention is shown. SubPc1–CONH–CuBTC–NH2 is the photocatalyst prepared in Example 1; SubPc1-CuBTC–NH2 (One pot) is the photocatalyst prepared in Comparative Example 1; SubPc1 / CuBTC-NH2 is the photocatalyst prepared in Comparative Example 2; and SubPc-1 and CuBTC–NH2 are control groups.

[0046] like Figure 4 The infrared spectrum of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of the present invention is shown. SubPc1–CONH–CuBTC–NH2 is the photocatalyst prepared in Example 1; SubPc1-CuBTC–NH2 (One pot) is the photocatalyst prepared in Comparative Example 1; SubPc1 / CuBTC-NH2 is the photocatalyst prepared in Comparative Example 2; and SubPc-1 and CuBTC–NH2 are control groups.

[0047] Depend on Figures 3-4 The characteristic vibrational peaks (such as B-N stretching) of SubPc-1 in the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of the present invention were clearly detected, while the characteristic signal of the CuBTC-NH2 framework was still present, confirming the effective combination of the two components.

[0048] like Figure 5 The XRD pattern of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of the present invention is shown. SubPc1–CONH–CuBTC–NH2 is the photocatalyst prepared in Example 1; SubPc1-CuBTC–NH2 (One pot) is the photocatalyst prepared in Comparative Example 1; SubPc1 / CuBTC-NH2 is the photocatalyst prepared in Comparative Example 2; and SubPc-1 and CuBTC–NH2 are control groups. Figure 5It was found that the powder X-ray diffraction patterns of all composite samples highly matched the characteristic peaks of the original CuBTC–NH2. Furthermore, weak diffraction signals belonging to SubPc-1 were observed at specific locations (marked with gray circles), indicating that the MOF's main framework remained intact after composite formation. Compared to SubPc1-CuBTC–NH2 (One pot), the characteristic peak intensities of the sample SubPc1–CONH–CuBTC–NH2 were significantly reduced in the small-angle region (approximately 19.6° and 20.7°). This change can be attributed to local lattice distortion or structural perturbation caused by the introduction of the bulky SubPc1-COOH ligand. This controlled structural modification not only introduced functional sites but may also create a favorable microenvironment for subsequent catalytic reactions, while the overall crystal structure and crystallinity of the material were well maintained.

[0049] like Figure 6 The XPS spectra of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of the present invention are shown below. SubPc1–CONH–CuBTC–NH2 is the photocatalyst prepared in Example 1; SubPc1-CuBTC–NH2 (One pot) is the photocatalyst prepared in Comparative Example 1; SubPc1 / CuBTC-NH2 is the photocatalyst prepared in Comparative Example 2; and SubPc-1 and CuBTC–NH2 are control groups. Figure 6 As can be seen, compared with the sample prepared in Comparative Example 2, the C 1s, N 1s, and O 1s spectra of the photocatalyst SubPc1-CONH–CuBTC–NH2 prepared in Example 1 all showed obvious chemical shifts and changes in peak profiles. A new peak appeared in the C 1s spectrum at approximately 289.2 eV, which is attributed to the carbonyl carbon in the amide bond (–NH–C=O). A new peak appeared in the N 1s spectrum at 399.8 eV, corresponding to the nitrogen atom in the amide group. At the same time, the new component at approximately 531.7 eV in the O 1s spectrum can be attributed to the carbonyl oxygen in the amide bond. These features were not observed at all in the physically mixed sample of Comparative Example 2, and the X-ray photoelectron spectroscopy results directly confirmed the formation of covalent amide bonds at the material interface.

[0050] Experiment Example 2: Photocatalytic H2O2 Production Coupled Degradation Experiment The photocatalysts prepared in Example 1 and Comparative Examples 1-2 of this invention were used in a photocatalytic H2O2 production coupled degradation experiment. Specifically, 15 mg of the photocatalyst was dispersed in 50 mL of an aqueous solution (20 mg·L⁻¹) of oxytetracycline (OTC), tetracycline (TC), bisphenol A (BPA), or rhodamine B (RhB). -1 In the dark, the mixture was stirred for 30 min to reach adsorption-desorption equilibrium, and then subjected to a 300 W xenon lamp (400 nm~780 nm, 350 mW cm⁻¹).-2 The reaction is initiated by irradiation in air. Samples are periodically taken and filtered, and the H₂O₂ concentration is determined using iodometric titration: 1 mL of sample is mixed with 1 mL of 0.4 M KI and 1 mL of 0.1 M potassium hydrogen phthalate, and reacted in the dark for 30 min. The H₂O₂ concentration is then determined according to I₃. - The H2O2 content was calculated based on the absorbance at 350 nm, and the pollutant concentrations were detected at 356 nm, 357 nm, 278 nm, and 552 nm, respectively.

[0051] like Figure 7 The UV-vis-NIR diffuse reflectance spectrum of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of the present invention is shown below. SubPc1–CONH–CuBTC–NH2 is the photocatalyst prepared in Example 1; SubPc1-CuBTC–NH2 (Onepot) is the photocatalyst prepared in Comparative Example 1; SubPc1 / CuBTC-NH2 is the photocatalyst prepared in Comparative Example 2; and SubPc-1 and CuBTC–NH2 are both control groups. Figure 7 It can be seen that the SubPc1-CONH–CuBTC–NH2 heterojunction exhibits a significantly broadened absorption edge, up to ~1400 nm, indicating that the heterojunction catalyst has excellent full-spectrum light-harvesting ability and extremely high utilization rate under sunlight.

[0052] like Figure 8 The figure shows the photocatalytic H2O2 production performance of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of the present invention under UV-vis-NIR irradiation. In this figure, SubPc1–CONH–CuBTC–NH2 is the photocatalyst prepared in Example 1; SubPc1-CuBTC–NH2 (One pot) is the photocatalyst prepared in Comparative Example 1; SubPc1 / CuBTC-NH2 is the photocatalyst prepared in Comparative Example 2; and SubPc-1 and CuBTC–NH2 are both control groups. Figure 8 It can be seen that the SubPc1–CONH–CuBTC–NH2 photocatalytic material prepared in Example 1 of this invention can achieve a hydrogen peroxide yield of 2091.5 μmol·g. -1 ·h -1 These values ​​are 15.3 times, 7.5 times, and 2.8 times higher than those of the single SubPc-1 material, the SubPc1-CuBTC–NH2 composite material prepared by the one-step method in Comparative Example 1, and the physically mixed sample SubPc1 / CuBTC–NH2 in Comparative Example 2, respectively. This indicates that the composite modified material constructed using the two-step method possesses excellent photocatalytic performance in generating hydrogen peroxide.

[0053] like Figure 9The figure shows the apparent quantum yield of H2O2 at specific wavelengths for the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention. The SubPc1-CONH-CuBTC–NH2 composite material exhibits high apparent quantum efficiencies at wavelengths of 400 nm, 600 nm, 808 nm, and 900 nm, with corresponding values ​​of 17.47%, 15.35%, 17.1%, and 12.49%, respectively. The distribution of this quantum efficiency with wavelength is highly consistent with the light absorption spectrum of the material, demonstrating that this composite material can effectively convert photons into chemical energy in the visible and near-infrared wavelength range.

[0054] like Figure 10 The diagram shows the performance of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention in the synergistic degradation of pollutants using hydrogen peroxide. The degradation rates are as follows: TC 99.8%; OTC 95.2%; BPA 91.1%; and RhB 84.8%. Figure 10 It can be seen that the presence of organic matter (OTC, TC, BPA, and RhB) did not inhibit the formation of H2O2; on the contrary, it had a significant promoting effect. The yield in pure water was 2091.5 μmol·g⁻¹. -1 ·h -1 Compared to the above-mentioned pollutants, the yields of H2O2 increased to 4017.3 (OTC), 5517.4 (TC), 1415.1 (BPA), and 2295.6 (RhB) μmol·g, respectively. -1 ·h -1 The corresponding degradation efficiencies reached 95.2%, 99.8%, 91.1% and 84.8%, respectively, achieving the synergistic function of efficient H2O2 production and simultaneous degradation of pollutants.

[0055] like Figure 11 The figure shows the performance of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention in a five-cycle experiment for simultaneous H2O2 production and TC degradation. (Source: [Insert source here]) Figure 11 It can be seen that after five consecutive photocatalytic cycles, the H2O2 yield of the composite sample was 4814.66 μmol·g. -1 The degradation rate of TC was 85.5%, with both showing only a slight decrease, indicating that the prepared photocatalyst has excellent cycle stability and reusability.

[0056] like Figure 12 The image shown is a SEM-EDS image of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention after five cycles. (Source: [Insert source here]) Figure 12It can be seen that after repeated recycling, the elements Cu, C, N, O and B still maintain a uniform distribution, and the overall microstructure and elemental composition are stable.

[0057] like Figure 13 The image shown is an XDR image of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst of this invention after five cycles. (Source: [Insert source here]) Figure 13 It can be seen that the diffraction pattern of the SubPc1–CONH–CuBTC–NH2 heterojunction photocatalyst after five cycles is basically consistent with that of the fresh sample, and no obvious structural collapse or decrease in crystallinity is observed, further proving that the composite material has good structural stability and chemical stability.

[0058] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A photocatalyst with an amide-bridged heterostructure, characterized in that, This photocatalyst has a nanoflower structure, which is composed of phthalocyanine derivatives and amino-functionalized transition metal-organic frameworks linked by covalent amide bonds: The transition metal-organic framework is formed by coordination of transition metal ions with two organic ligands; The organic ligands are all organic acids containing two or more carboxyl groups.

2. The photocatalyst according to claim 1, characterized in that, The phthalocyanine derivative is a carboxyl-functionalized phthalocyanine.

3. The photocatalyst according to claim 1, characterized in that, The photocatalyst self-assembles into a hierarchical nanoflower structure with a diameter of 20~30μm, and the petals of the nanoflower have irregular nanosheets.

4. The photocatalyst according to claim 3, characterized in that, The organic ligand is an organic acid containing two carboxyl groups or an organic acid containing three carboxyl groups; the transition metal ion is Cu. 2+ .

5. The photocatalyst according to claim 4, characterized in that, The transition metal-organic framework is a CuBTC-NH2 framework, in which Cu, O, C, N and B are uniformly spatially distributed throughout the photocatalyst nanoflower structure; the heterojunction absorption edge of the photocatalyst is broadened to 1400 nm.

6. A method for preparing a photocatalyst with an amide-bridged heterostructure as described in any one of claims 1 to 5, characterized in that, The method includes: An organic acid containing two carboxyl groups and a phthalocyanine derivative are dispersed in an alcohol solution, sonicated, and kept at a sealed temperature of 120°C to 140°C. An organic acid containing three carboxyl groups and a transition metal salt are added, and the mixture is heated at 80°C, centrifuged, washed, and vacuum dried to obtain the final product.

7. The preparation method according to claim 6, characterized in that, The holding time at 120°C to 140°C is 60 to 80 hours, and the heating rate and cooling rate are both 3 to 8°C / hour; the molar ratio of the organic acid containing two carboxyl groups, the phthalocyanine derivative, the organic acid containing three carboxyl groups, and the transition metal salt is (10 to 15): 1: (8 to 12): (30 to 40).

8. The preparation method according to claim 6, characterized in that, The phthalocyanine derivative is prepared by the following method; Phthalocyanine and m-hydroxybenzoic acid were dissolved in toluene, stirred at room temperature under a nitrogen atmosphere, kept at 130 °C, cooled to room temperature, evaporated by rotary evaporation, washed, and dried.

9. The application of a photocatalyst with an amide-bridged heterostructure as described in any one of claims 1 to 5 in the simultaneous enhancement of photocatalytic H2O2 production during the degradation of organic pollutants.

10. The application according to claim 9, characterized in that, The organic pollutants include any one or more of antibiotics, phenols, and dyes; the application is: using the photocatalyst as described in any one of claims 1 to 5, the reaction is carried out by irradiation with full-spectrum light in the presence of an aqueous solution containing organic pollutants and oxygen.

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