Z-type heterojunction bifunctional composite photocatalyst ndi / pta and preparation and application thereof

Abstract

The application relates to the field of energy and environment technology, in particular to a preparation of a Z-type heterojunction visible light response bifunctional organic composite photocatalyst NDI / PTA and application of the bifunctional organic composite photocatalyst NDI / PTA in photocatalytic decomposition of water to produce hydrogen and degradation of antibiotics such as ofloxacin, tetracycline hydrochloride and sulfamethoxazole. The application comprises the preparation of an organic photocatalyst 3,4,9,10-perylenetetracarboxylic acid (PTA) and NDI / PTA (1,4,5,8-naphthalene tetracarboxylic diimide / 3,4,9,10-perylenetetracarboxylic acid); the prepared composite catalyst is used for photocatalytic decomposition of water to produce hydrogen and degradation of ofloxacin, tetracycline hydrochloride and sulfamethoxazole antibiotics. The organic composite photocatalyst NDI / PTA has excellent redox performance, and the composite catalyst has the advantages of simple preparation method, low cost, reusability, greenness and good photocatalytic efficiency.

Description

Technical Field

[0001] This invention relates to the preparation and application of a Z-type heterojunction visible-light-responsive bifunctional organic composite catalyst NDI / PTA, specifically its application in photocatalytic water splitting for hydrogen production and the degradation of antibiotics such as ofloxacin, tetracycline hydrochloride, and sulfamethoxazole. This composite photocatalyst is applied to photocatalytic water splitting for hydrogen production and the degradation of antibiotics such as ofloxacin, tetracycline hydrochloride, and sulfamethoxazole. In photocatalytic water splitting for hydrogen production, it exhibits a high rate of hydrogen production; the photocatalytic H2 evolution rate of 8% NDI / PTA reaches 45.59 mmol / g / h, which is 2.73 times that of single PTA and 45.59 times that of single NDI. Simultaneously, at a wavelength of 450 nm, the apparent quantum efficiency (AQY) of 8% NDI / PTA reaches 3.16%. Furthermore, 8% NDI / PTA achieved a photocatalytic degradation rate of over 80% for both ofloxacin (OFL) and tetracycline hydrochloride (TC-HCl) within 90 min. Finally, the intermediate products of the degraded OFL were determined, and possible degradation pathways were proposed. Background Technology

[0002] Energy crisis and environmental pollution are two major problems brought about by rapid global economic and social development. Semiconductor photocatalysis technology, which can utilize solar energy, is widely regarded as an ideal method to solve these problems.

[0003] Since the ultraviolet spectrum accounts for less than 5% of total solar energy, there is an urgent need for commercially viable visible-light-responsive photocatalysts. To achieve a visible-light response, the band gap needs to match the energy of the visible light, typically between 1.8 eV and 3.2 eV. However, the band gaps of many common semiconductor materials are either too large to be excited by visible light, or too small, causing most semiconductors to fail to meet the overpotential requirements for hydrogen production or the redox reactions of organic pollutants. Therefore, only a few visible-light-responsive photocatalysts can achieve photocatalytic water splitting for hydrogen evolution or degradation of organic pollutants.

[0004] In actual reactions, photogenerated electrons and holes readily recombine rather than participate in the redox reaction on the photocatalyst surface, leading to low photocatalytic efficiency and severely limiting further practical applications. Therefore, improving charge separation / transport efficiency is a key scientific issue for enhancing photocatalytic efficiency. Inorganic semiconductors are common photocatalysts for water splitting, and various inorganic semiconductor photocatalysts have been developed, such as metal-based sulfides, oxides, nitrides, carbides, and perovskites.

[0005] In recent years, organic semiconductors, composed of elements such as C, H, and O that are abundant on Earth, have attracted widespread attention due to their excellent structural tunability, which allows for the adjustment of their absorption spectra and photoelectric properties, thereby enhancing their oxidation or reduction capabilities. Furthermore, organic semiconductors exhibit better processability due to their inherent flexibility.

[0006] Currently, organic catalysts such as covalent organic frameworks (COFs), hydrogen-bonded organic frameworks (HOFs), conjugated microporous polymers (CMPs), and metal-organic frameworks (MOFs) have been developed. Among them, perylene-based materials and their derivatives have attracted widespread attention due to their good thermal stability, excellent optical and carrier transport properties, light transmittance, mechanical stability, and good visible light capture performance. Therefore, they have been applied in photocatalytic water reduction / oxidation, organic photovoltaic devices, H2O2 preparation, photocatalytic degradation, and disinfection. However, the exciton diffusion length in organic photocatalysts is shorter than that in inorganic photocatalysts. The difficulty in exciton separation makes it hard for them to dissociate into unbound charge carriers, and the driving force for photogenerated charge separation is insufficient, severely affecting photocatalytic activity.

[0007] However, there are few reports on the construction of Z-type heterojunction photocatalysts based on the perylene planar material PTA. Therefore, an efficient Z-type interface electron transport channel was constructed by co-assembling naphthalimide (NDI), an aromatic compound with excellent light-harvesting ability, good carrier mobility, and excellent thermal stability and electronic defects, with perylene tetracarboxylic acid (PTA). A huge built-in electric field exists within this channel, thereby achieving highly efficient and stable photocatalytic water splitting for hydrogen production and antibiotic degradation. Summary of the Invention

[0008] The purpose of this invention is to synthesize two organic semiconductor catalysts, NDI and PTA, to obtain a novel composite catalyst, NID / PTA. This composite catalyst is bifunctional. Due to the stacking of its π-plane, the uneven distribution of electrons results in a large dipole moment, which in turn generates a strong built-in electric field. This enables efficient photocatalytic water splitting to produce hydrogen, and it can also efficiently degrade antibiotics such as ofloxacin, tetracycline hydrochloride, and sulfamethoxazole.

[0009] Technical solution of the present invention

[0010] The preparation method of NID / PTA composite photocatalyst, with specific steps as follows:

[0011] (1) Specific process for preparing PTA: Using 3,4,9,10-perylenetetracarboxylic acid dianhydride, potassium hydroxide and glacial acetic acid as raw materials, organic semiconductor 3,4,9,10-perylenetetracarboxylic acid (PTA, or 3,4,9,10-perylenetetracarboxylic acid) was prepared by alkaline hydrolysis and acidic self-assembly.

[0012] 1) Weigh 35.0-60.0 mg (preferably 35.0-60.0%, more preferably 40.0-55.0%, most preferably 47.0-52.0%) of 3,4,9,10-perylenetetracarboxylic dianhydride into a container, add 150.0-300.0 ml of ultrapure water, and sonicate for 30.0-60.0 min at an ultrasonic amplitude of 40.0-100.0 Hz; 2) Weigh 350.0-650.0 mg (preferably 400.0-600.0 mg, more preferably 450.0-550.0 mg, most preferably 490.0-510.0 mg) of potassium hydroxide and add it to the sonicated solution. ; after stirring at 40.0-55.0℃ for 4.0h, a PTA precursor is obtained; 3) 350.0-650.0μl (preferably 400.0-600.0μl, more preferably 450.0-550.0μl, most preferably 490.0-510.0μl) of glacial acetic acid is added to a container of 50.0-100.0ml of water; 4) the PTA precursor obtained in step 2) after alkaline hydrolysis with potassium hydroxide is added to the glacial acetic acid solution obtained in step 3), and PTA is obtained after acidic self-assembly for 6.0-10.0h; 5) solid-liquid separation is performed, the solid is washed with water and dried to obtain PTA.

[0013] (2) Preparation of composite catalyst NDI / PTA (1,4,5,8-naphthalenetetracarboxylic acid diimide / 3,4,9,10-perylenetetracarboxylic acid): 1) Weigh 35.0-60.0 mg (preferably 35.0-60.0%, more preferably 40.0-55.0%, most preferably 47.0-52.0%) of 3,4,9,10-perylenetetracarboxylic acid dianhydride into a container, add 150.0-300.0 ml of ultrapure water, and sonicate. 1) Ultrasonication for 30.0-60.0 min, with an ultrasonic amplitude of 40.0-100.0 Hz; 2) Weigh 400.0-600.0 mg (preferably 400.0-600.0 mg, more preferably 450.0-550.0 mg, and most preferably 490.0-510.0 mg) of potassium hydroxide and add it to the above-ultrasonicated solution; then place it in a container at 40.0-55.0℃ and stir for 2.0-4.0 h to obtain the precursor of PTA. 3) Weigh 1.0-15.0 mg of NDI (1,4,5,8-naphthalenetetracarboxylic diimide) (preferably 1.0-15.0 mg, more preferably 1.5-9.0 mg, most preferably 1.85-2.5 mg) and add it to a container containing 490.0-510.0 μl (preferably 400.0-600.0 μl, more preferably 450.0-550.0 μl, most preferably 490.0-510.0 μl) of glacial acetic acid. 4) Add the PTA precursor to the NDI acidic aqueous solution and stir at 35.0-45.0℃ (preferably 35.0-45.0℃, optimally 37.0-42.0℃) for 6-10 hours; 5) Separate the solid and liquid, wash the solid with water and dry to obtain the NDI / PTA composite catalyst.

[0014] An 8% NDI / PTA composite photocatalyst was used in the photocatalytic water splitting reaction to produce hydrogen.

[0015] Test conditions: The photocatalytic hydrogen evolution performance of the samples was tested using a glass-sealed gas system (Labsolar-6A, Beijing Perfectlight). 9.0-15.0 mg (preferably 5.0-13 mg, optimal 9.0-11.0 mg) of photocatalyst powder was ultrasonically dispersed in 100.0 mL of deionized water. Chloroplatinic acid (H₂PtCl₆·6H₂O) was photocatalytically oxidized to Pt on the sample surface using in-situ photodeposition as a cocatalyst, with a cocatalyst loading of 1.0-8.0 mg (preferably 1.0-8.0 mg, optimal 3.0-7.0 mg). 0.15-0.3 M ascorbic acid (AA) was used as a sacrificial agent, and chloroplatinic acid (H₂PtCl₆·6H₂O) was photocatalytically oxidized to Pt on the sample surface using in-situ photodeposition as a cocatalyst. A 300 W xenon lamp with visible light (420 < λ < 780 nm) was used as the light source. H2 generation was detected at given time intervals using an online gas chromatograph (TCD detector, Ar support, 5 μm molecular sieve column). Hydrogen evolution experiments were investigated with different NDI loadings (preferably 1.0–15.0 mg, more preferably 1.5–9.0 mg, optimal 1.85–2.5 mg), different Pt loadings (preferably 1.0–8.0 mg, optimal 3.0–7.0 mg), and optimal catalyst dosages (preferably 5.0–13 mg, optimal 9.0–11.0 mg).

[0016] The apparent quantum yield (AQY) was measured under different monochromatic lights (365 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, and 700 nm) with different bandpass filters (FWHM = 15 nm). The illumination area was 1.0 cm². -2 (300W xenon lamp, PerfectLight). Average intensity was determined using a power meter (PL-MW2000). 10mg of photocatalyst was used. AQY was calculated using the following formula, taking monochromatic light at 450nm as an example:

[0017]

[0018] An 8% NDI / PTA composite photocatalyst was used for the photocatalytic degradation of antibiotics ofloxacin, tetracycline hydrochloride, and sulfamethoxazole.

[0019] Test conditions: A 300W xenon lamp (420 < λ < 780 nm) was used for photocatalytic degradation studies. The photocatalytic degradation reaction was carried out in a double-jacketed quartz tube reactor using 5.0-13.0 mg (preferably 5.0-13 mg, most preferably 9.0-11.0 mg) of photocatalyst and 100 mL of antibiotic solution at a concentration of 10.0-50.0 mg / L (preferably 10.0-40.0 mg / L, more preferably 17.0-30 mg / L, most preferably 20.0-25.0 mg). The reaction temperature was maintained at 20-25℃ using a circulating cooling water system. Before light irradiation, the suspension was stirred in the dark for 30 minutes to reach adsorption-desorption equilibrium. Every 10 minutes, the solution was sampled and passed through a needle filter (13 mm, 0.54 μm) to obtain the supernatant, which was analyzed by liquid ultraviolet (UV-VIS SPECTROPHOTOMETER T9) to obtain the degradation rate.

[0020] Advantages of this invention: It utilizes an organic semiconductor NDI and PTA to form a Z-shaped heterojunction catalyst, with Pt as a co-catalyst for the photocatalyst. An organic composite photocatalyst NDI / PTA was prepared, which is simple to prepare, abundant in reserves, and low in cost. Photocatalytic hydrogen production tests show that under optimal conditions (8% NDI mass loading, 5% Pt mass loading, and optimal catalyst dosage of 2 mg), the photocatalytic hydrogen production activity of 8% NDI / PTA is 45.56 mmol / g / h, which is 45.56 times that of NDI alone and 2.73 times that of PTA alone. The apparent quantum efficiency (AQY) reaches 3.16% (monochromatic light at 450 nm). Furthermore, after 90 minutes of degradation, the removal rate of OFL by 8% NDI / PTA reaches 81%, with a degradation rate of 0.021 min. -1 ) is NDI(0.0006min -1 35 times that of PTA (0.01 min) -1 The removal rate of TC-HCl by 8% NDI / PTA was 2.1 times that of 0.018 min. The removal rate of TC-HCl by 8% NDI / PTA also reached 86.5%, with a degradation rate of 0.018 min. -1 ) is NDI(0.0001min -1 180 times that of PTA (0.014 min) -1 The photocatalyst can also degrade SMX; within 90 minutes, the removal rate of 8% NDI / PTA is 21%, and the degradation rate (0.0026 min) is 1.3 times that of SMX. -1 ) is NDI(0.0002min -1 13 times that of PTA (0.0013 min) -1 It is twice that of OFL. Finally, the intermediate products of OFL were determined, and possible degradation pathways of OFL were given.

[0021] The organic composite photocatalyst NDI / PTA described in this invention exhibits excellent redox performance. The composite catalyst has advantages such as simple preparation method, low cost, reusability, greenness, and good photocatalytic efficiency. Attached Figure Description

[0022] Figure 1 Example 2: Synthesis route of x% NDI / PTA using an organic composite catalyst

[0023] Figure 2 XRD patterns of NDI, PTA, and x% NDI / PTA composite photocatalysts in Examples 1 and 2;

[0024] Figure 3 FT-IR spectra of NDI, PTA, and x% NDI / PTA composite photocatalysts in Examples 1 and 2;

[0025] Figure 4 SEM images of the NDI, PTA, and NDI / PTA composite photocatalysts in Examples 1 and 2;

[0026] Figure 5 Example 2: a) Three-dimensional morphology image; b) and c) Thickness of NDI nanowires scanned along the red line using atomic force microscopy;

[0027] Figure 6 Example 1: a) Three-dimensional morphology image; b) and c) Thickness of PTA nanowires scanned along the red line using atomic force microscopy;

[0028] Figure 7 Implementation Case 2a: UV-Vis diffuse reflectance spectrum of sample; b: Tauc plot of sample; c: Mott-Schottky plot of NDI; d: Mott-Schottky plot of PTA;

[0029] Figure 8 In Implementation Case 2, a Kelvin probe was used to measure the work function (WF) of a NDI and b PTA.

[0030] Figure 9 Example 1, 2a: Hydrogen production activity graph of NDI / PTA photocatalyst with different DNI loadings; b: Hydrogen production activity graph of Pt cocatalyst loading; c: Hydrogen production activity graph of photocatalyst with optimal 8% NDI / PTA catalyst loading.

[0031] Figure 10 The 8% NDI / PTA catalyst in Implementation Cases 2 and 3 and the hydrogen evolution wavelength dependence and apparent quantum efficiency (AQY) in Example 5;

[0032] Figure 11 Stability graphs of hydrogen production from 8% NDI / PTA photocatalysts in Examples 2 and 3;

[0033] Figure 12 0.8% NDNI / PTA fresh sample and used XRD pattern; b. FT-IR spectrum; c. used 8% NDNI / PTA scanning electron microscope image;

[0034] Figure 13 In Example 5, different samples showed the following degradation rates of ofloxacin: a) degradation rate; b) degradation rate.

[0035] Figure 14 Example 5: Degradation rate of tetracycline hydrochloride (a) and degradation rate (b) of different samples;

[0036] Figure 15 Example 5: Degradation rate of sulfamethoxazole (a) and degradation rate (b) in different samples;

[0037] Figure 16 In Example 5, the ultraviolet wavelength scans of solutions of a) ofloxacin, b) tetracycline hydrochloride, and c) sulfamethoxazole at different degradation times were performed.

[0038] Figure 17 LC-MS spectra of OFL photocatalysis in Example 7;

[0039] Figure 18 Total ion chromatogram (TIC) of OFL photocatalytic degradation in Example 7;

[0040] Figure 19 The OFL photocatalytic degradation pathway in Example 6. Detailed Implementation

[0041] The above-mentioned and other technical features and advantages of the present invention will be described in more detail below with reference to the accompanying drawings.

[0042] Example 1

[0043] A method for preparing organic semiconductor PTA includes the following steps:

[0044] Weigh 50 mg of 3,4,9,10-perylenetetracarboxylic acid dianhydride into a 250 ml beaker, add 150 ml of ultrapure water to the beaker, and sonicate for 30 min at an amplitude of 40 Hz; weigh 500 mg of potassium hydroxide and add it to the sonicated solution; place the solution in a 50 °C water bath and stir for 4 h to obtain a transparent yellow-green solution; add 500 μl of glacial acetic acid to a 250 ml beaker containing 50 ml of ultrapure water; add the PTA precursor obtained by alkaline hydrolysis with potassium hydroxide to the glacial acetic acid solution, and after 8 h of acidic self-assembly, filter the solid and wash it three times with ultrapure water, then dry it in an 80 °C oven for 2 h to obtain 3,4,9,10-perylenetetracarboxylic acid (PTA).

[0045] Depend on Figure 2 XRD analysis reveals that the PTA XRD pattern is indexed to a monoclinic structure, with diffraction peaks at 17.2, 22.8, and 30.1, belonging to the (002), (021), and (500) crystal planes. The peak centered at 22.8° corresponds to the π-π packing of PTA, with a distance of [missing information]. Depend on Figure 3 FT-IR analysis shows that at 1685, 1587, and 1284 cm⁻¹ -1 The stretching vibrations at that point correspond to the C=O, C=C, and CH functional groups of PTA. Figure 4 It can be seen that PTA is an irregular block shape, from Figure 6 The thickness of PTA is approximately 184.4 nm. The above tests demonstrate the successful fabrication of the organic semiconductor PTA and the acquisition of its microstructure characteristics.

[0046] The photocatalyst PTA was added at a concentration of 10 mg, the sacrificial agent ascorbic acid (AA) was added at a final concentration of 0.2 M, the co-catalyst Pt was loaded on PTA at a concentration of 5.0 wt%, and the rest were carried out according to the process and conditions of Example 3 for photocatalytic hydrogen production. When glacial acetic acid was used, the hydrogen evolution performance of the obtained PTA was 5.5 mmol / g / h.

[0047] Comparative Example 1

[0048] An organic semiconductor PTA catalyst and its preparation method, comprising the following steps:

[0049] 1) Weigh 50 mg of 3,4,9,10-perylenetetracarboxylic acid dianhydride into a container, add 150.0 ml of ultrapure water, and sonicate for 30.0 min at an ultrasonic amplitude of 40.0 Hz;

[0050] 2) Weigh 500.0 mg of potassium hydroxide and add it to the above-sonicated solution; stir it at 50 °C for 4.0 h to obtain the PTA precursor;

[0051] 3) Add 500.0 μl of hydrochloric acid (mass concentration 36-38%) to 50.0 ml of water;

[0052] 4) The PTA precursor obtained by alkaline hydrolysis with potassium hydroxide in step 2) is added to the hydrochloric acid solution obtained in step 3), and PTA is obtained after acidic self-assembly for 8 hours.

[0053] 5) Solid-liquid separation: the solid is washed with water and dried to obtain PTA.

[0054] The photocatalyst PTA was added at a concentration of 10 mg, the sacrificial agent ascorbic acid (AA) was added at a final concentration of 0.2 M, the co-catalyst Pt was loaded on PTA at a concentration of 5.0 wt%, and the rest were carried out according to the process and conditions of Example 3 for photocatalytic hydrogen production. When hydrochloric acid was used, the hydrogen evolution performance of the obtained PTA was 1.3 mmol / g / h.

[0055] Comparative Example 2

[0056] An organic semiconductor PTA catalyst and its preparation method, comprising the following steps:

[0057] 1) Weigh 50 mg of 3,4,9,10-perylenetetracarboxylic acid dianhydride into a container, add 150 ml of ultrapure water, and sonicate for 30 min at an ultrasonic amplitude of 40 Hz.

[0058] 2) Weigh 500.0 mg of potassium hydroxide and add it to the above-sonicated solution; stir it at 50 °C for 4.0 h to obtain the PTA precursor;

[0059] 3) Add 500.0 μl of phosphoric acid (85% by mass) to 50 ml of water;

[0060] 4) The PTA precursor obtained by alkaline hydrolysis with potassium hydroxide in step 2) is added to the phosphoric acid solution obtained in step 3), and PTA is obtained after acidic self-assembly for 8 hours.

[0061] 5) Solid-liquid separation: the solid is washed with water and dried to obtain PTA.

[0062] The photocatalyst PTA was added at a concentration of 10 mg, the sacrificial agent ascorbic acid (AA) was added at a final concentration of 0.2 M, the co-catalyst Pt was loaded on PTA at a concentration of 5.0 wt%, and the rest were carried out according to the process and conditions of Example 3 for photocatalytic hydrogen production. When phosphoric acid was used, the hydrogen evolution performance of the obtained PTA was 2.4 mmol / g / h.

[0063] Example 2

[0064] A method for preparing x% NDI / PTA composite organic semiconductor with Z-type heterojunction, such as Figure 1 As shown, the composite organic semiconductor x% NDI / PTA was prepared by alkaline hydrolysis and acidic self-assembly, including the following steps:

[0065] 50 mg of 3,4,9,10-perylenetetracarboxylic acid dianhydride was weighed into a 250 ml beaker, and 150 ml of ultrapure water was added. The mixture was sonicated for 30 min at an amplitude of 40 Hz. 500 mg of potassium hydroxide was weighed and added to the sonicated solution. The solution was stirred in a 50°C water bath for 4 h to obtain a transparent yellow-green solution, which is the precursor of PTA. 2, 4, 8, 16, and 24 mg of NDI (1,4,5,8-naphthalenetetracarboxylic diimide) were weighed and added to a 250 ml beaker containing 500 μl of glacial acetic acid and 50 ml of ultrapure water, respectively. The mixture was sonicated for 1 h at an amplitude of 40 Hz to obtain an acidic aqueous solution of NDI. The PTA precursor was added to the NDI acidic aqueous solution, and the mixture was stirred in a constant temperature water bath at 40°C for 8 h. The solid was filtered and washed three times with ultrapure water. The solid was then dried in an 80°C oven for 2 h. The resulting catalyst was denoted as: 4%. NDI / PTA (4% represents NDI of PTA by weight), 8% NDI / PTA (8% represents NDI of PTA by weight), 16% NDI / PTA (16% represents NDI of PTA by weight), 24% NDI / PTA (24% represents NDI of PTA by weight), 32% NDI / PTA (32% represents NDI of PTA by weight), 48% NDI / PTA (48% represents NDI of PTA by weight).

[0066] Depend on Figure 2 XRD analysis showed that the characteristic diffraction peaks of x% NDI / PTA with different NDI mass ratios matched the characteristic diffraction patterns of NDI and PTA, indicating the successful preparation of the composite catalyst. Figure 3 By comparing the Fourier transform spectra of NDI and PTA, the characteristic spectral band C = N (1102 cm⁻¹) is found. -1 ) and NH (3071cm -1 This discovery further confirms the successful preparation of NDI / PTA. Figure 4 Irregular NDI nanoparticles, approximately 1 μm in size, can be observed loaded onto irregular PTA nanosheets, approximately 1 nm in size. This is achieved through... Figure 5 The thickness of NDI was found to be approximately 849.1 nm. These tests demonstrate the successful preparation of the Z-type heterojunction composite catalyst NID / PTA. To confirm the formation of a Z-type heterojunction between NDI and PTA, the band structures of NDI and PTA were investigated using UV-Vis DRS and Mott-Schottky spectroscopy. Figure 7 As shown. The ultraviolet-visible diffuse reflectance test... Figure 7a. The absorption ranges of PTA, NDI, and x% NDI / PTA were determined and obtained using the Kubelka-Munk function. Figure 7 b. The calculated band gaps for NDI and PTA are 2.74 eV and 1.91 eV, respectively. The Mott-Schottky band gaps for NDI and PTA were obtained through electrochemical testing. Figure 7 As shown in c and d, the conduction band (CB) positions of NDI and PTA are -0.61V and -0.42V, respectively (relative to NHE, pH=7). Mott-Schottky measurements show that both NDI and PTA have positive slopes, indicating they are n-type semiconductors. For n-type semiconductors, the flat band potential approximates the conduction band potential. Combining the calculated band gap and the measured CB positions, the band structure of NDI and PTA exhibits a Z-type electron transfer channel. That is, under light irradiation, photogenerated electrons at the CB of NDI transfer across the interface to the VB of PTA and recombine with photogenerated holes. Simultaneously, the spatially separated electrons at the CB in PTA and the holes at the VB in NDI can undergo reduction and oxidation reactions, respectively. To further demonstrate the interfacial electron transfer between NDI and PTA, the work function (WF) of NDI and PTA was measured using an atomic force microscope (KPFM) equipped with a Kelvin probe, as shown below. Figure 8 As shown in a and b, the work functions of NDI and PTA can be calculated to be 4.4 eV and 4.1 eV, respectively. This indicates that when NDI and PTA are in close contact, electrons spontaneously transfer from NDI to PTA through the heterojunction interface until they reach Fermi level equilibrium.

[0067] Example 3

[0068] The photocatalytic hydrogen production reaction conditions for the x% NDI / PTA catalysts prepared in Examples 1 (PTA catalyst) and 2 were all tested using a glass-enclosed gas system (Labsolar-6A, Beijing Perfectlight).

[0069] First, 10 mg of catalyst powder was ultrasonically dispersed in 100.0 mL of water in a reaction vessel. Chloroplatinic acid was then added to the reaction system. Chloroplatinic acid (H₂PtCl₆·6H₂O) was photocatalytically oxidized to Pt on the surface of the composite catalyst using in-situ photodeposition as a co-catalyst. The amount of co-catalyst added was determined based on the amount of composite catalyst added to the photocatalytic reaction vessel during photocatalytic hydrogen production. The NDI loading ratio was determined by adding 1 wt% Pt co-catalyst to PTA or x% NDI / PTA and 0.2 M (final concentration) of ascorbic acid (AA) sacrificial agent. Figure 9As shown in figure a, the loading masses of NDI relative to PTA were 2%, 4%, 8%, 16%, 24%, 32%, and 48%, respectively. A xenon lamp with visible light was used as the light source (420 < λ < 780 nm). H2 production was detected by sampling every 30 minutes using an online gas chromatograph (TCD detector, Ar support, 5 μm molecular sieve column) for a total testing time of 3 hours.

[0070] Next, 10 mg of 8% NDI / PTA catalyst powder was ultrasonically dispersed in 100.0 mL of water in the reaction vessel. Ascorbic acid (AA) was added as a sacrificial agent at a final concentration of 0.2 M. Chloroplatinic acid was then added to the reaction system. Chloroplatinic acid (H₂PtCl₆·6H₂O) was photocatalytically oxidized to Pt on the surface of the composite catalyst using in-situ photodeposition as a co-catalyst. The amount of co-catalyst added was determined based on the amount of composite catalyst added in the photocatalytic reaction vessel during photocatalytic hydrogen production. The loading of Pt relative to the 8% NDI / PTA catalyst was determined to be: 0.5, 1.0, 3.0, 5.0, 7.0, 9.0 wt%. Figure 9 As shown in b. A 300W xenon lamp with visible light was used as the light source (420 < λ < 780 nm). H2 production was detected by sampling every 30 minutes using an online gas chromatograph (TCD detector, Ar support, 5 μm molecular sieve column) for a total testing time of 3 hours.

[0071] Finally, 1, 2, 3, 5, 7, 10, 15, and 20 mg of 8% NDI / PTA catalyst powder were ultrasonically dispersed in 100.0 mL of water. Ascorbic acid (AA) was added as a sacrificial agent at a final concentration of 0.2 M. Chloroplatinic acid was then added to the reaction system, and chloroplatinic acid (H₂PtCl₆·6H₂O) was photocatalytically oxidized to Pt on the surface of the composite catalyst using in-situ photodeposition as a co-catalyst. The optimal amount of 8% NDI / PTA catalyst was determined by the co-catalyst Pt loading relative to the 8% NDI / PTA catalyst being 5.0 wt%. Figure 9 As shown in c. A 300W xenon lamp with visible light was used as the light source (420 < λ < 780 nm).

[0072] H2 production was detected by taking samples every 30 minutes using an online gas chromatograph (TCD detector, Ar support, 5μm molecular sieve column) for a total testing time of 3 hours.

[0073] First, the optimal loading of NDI was determined. Test conditions: 10 mg of photocatalyst, 0.2 M of sacrificial agent, and a co-catalyst loading of 1.0% relative to the main catalyst. Figure 9As can be seen from the data, the catalytic performance of the NDI / PTA combination gradually improves with increasing NDI content. The best H2 evolution performance (13.50 mmol / g / h) is achieved when the NDI loading relative to PTA is 8%. As the NDI loading continues to increase, the performance of the NDI / PTA combination begins to decline slightly. This is mainly because the heterostructure formed at the interface between NDI and PTA effectively separates photogenerated carriers. Although the heterostructure at the interface between NDI and PTA effectively separates photogenerated carriers, excessive NDI prevents the interface from absorbing sufficient light. A balance exists between charge separation and light absorption, and 8% NDI / PTA may be the equilibrium point. Appropriate NDI content can enhance the separation of photogenerated carriers and improve catalytic activity, while excessive NDI will mask PTA, leading to a decrease in catalytic activity. Since PTA plays a dominant role in the composite photocatalyst, the gradual increase in NDI leads to a decrease in PTA, thus also reducing photocatalytic activity.

[0074] Figure 9 b. The optimal loading of Pt as a co-catalyst was determined. The test conditions were as follows: 10 mg of 8% NDI / PTA as the main catalyst and 0.2 M of ascorbic acid as a sacrificial agent were added to the photocatalytic hydrogen evolution test system. The co-catalyst was added at loadings of 0.5, 1, 3, 5, 7, and 9 wt% on 10 mg of the main catalyst. The deposition amount of Pt was investigated by reducing H2PtCl6·H2O to Pt via in-situ photodeposition using an aqueous solution of H2PtCl6·H2O, which was then loaded onto the photocatalyst. The photocatalytic hydrogen evolution performance increased continuously from 0.5-5 wt% Pt loading, with 5 wt% Pt exhibiting the highest H2 evolution rate. Further increasing the Pt loading from 5 wt% to 9 wt% resulted in a decrease in photocatalytic hydrogen evolution performance, because excessive Pt had a shielding effect, hindering the photocatalyst's light absorption. In addition, although Pt can provide active sites for hydrogen evolution, excessive Pt will accumulate excessively on the surface of the photocatalyst, causing some active sites on the original surface of the photocatalyst to be covered or occupied by Pt particles.

[0075] Figure 9 c. Determine the optimal catalyst dosage. Test conditions were: 5 wt% Pt co-catalyst and 0.2 M ascorbic acid sacrificial agent. When the amount of 8% NDI / PTA increased from 1 mg to 2 mg, the photocatalytic hydrogen evolution performance increased to 45.56 mmol / g / h. Further increasing the amount of 8% NDI / PTA resulted in a decrease in hydrogen evolution performance. This may be because the catalyst blocks light, preventing the lower catalyst layer from absorbing light energy, thus leading to a decrease in photocatalytic hydrogen evolution performance.

[0076] Example 4

[0077] Stability testing of the 8% DNI / PTA catalyst prepared in Example 2. Test conditions: 10 mg of the 8% DNI / PTA catalyst was ultrasonically dispersed in 100.0 mL of water. Chloroplatinic acid was added to the reaction system, and chloroplatinic acid (H₂PtCl₆·6H₂O) was photocatalytically oxidized to Pt on the surface of the composite catalyst using in-situ photodeposition as a co-catalyst. The amount of Pt co-catalyst added was 5 wt% of the 8% DNI / PTA catalyst. The amount of ascorbic acid sacrificial agent added was 0.2 M (final concentration). The reaction was cycled every 5 hours, and samples were taken every 30 minutes. Figure 11 It can be seen that the catalyst exhibits good stability, maintaining a high level of hydrogen evolution performance within 50 hours. After 20 hours, the hydrogen evolution performance gradually decreases due to the depletion of the sacrificial ascorbic acid. Subsequently, XRD, FT-IR, and TEM tests were performed on the 8% NID / PTA catalyst after approximately 50 hours of testing. Figure 12 As shown in the figure, the catalyst did not undergo significant changes before and after use, indicating that the catalyst has good stability and recyclability in the photocatalytic reaction process.

[0078] Example 5

[0079] The apparent quantum efficiency (AQY) of the 8% NDI / PTA catalyst prepared in Example 2 was measured under different monochromatic light (365 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, and 700 nm) with different bandpass filters. The irradiation area was 1 cm². -2 (300W xenon lamp, PerfectLight). Average intensity was determined using a power meter (PL-MW2000). 7mg of photocatalyst was used.

[0080] 8% NDI / PTA hydrogen evolution wavelength dependence and apparent quantum efficiency (AQY) Figure 10 As shown, the good consistency between light absorption and AQY in different wavelength regions indicates that the H2 precipitation reaction is indeed a photoinduced process. Furthermore, the AQY of 8% NDI / PTA at 450 nm is 3.16%, significantly higher than that of most previously reported organic semiconductor photocatalysis.

[0081] Example 6

[0082] The photocatalytic degradation reaction conditions for the x% NDI / PTA prepared in Example 1 and Example 2 were all: continuous simulated sunlight irradiation using a 300W xenon lamp (420 < λ < 780 nm). The photocatalytic degradation reaction was conducted in a double-jacketed quartz tube reactor using 10 mg of 8% NDI / PTA catalyst and 100 mL of antibiotic (ofloxacin, ofloxacin, tetracycline hydrochloride) solution (20 mg / L). -1 The reaction was carried out using a suspension of antibiotics. The reaction temperature was maintained at 20°C using a jacketed internal circulating cooling water system. Before light irradiation, the suspension was stirred in the dark for 30 minutes to reach adsorption-desorption equilibrium. Every 10 minutes, the solution was aspirated from the reaction vessel and passed through a needle filter (13 mm, 0.54 μm) to obtain the supernatant. The supernatant was analyzed by liquid ultraviolet (UV-VIS SPECTROPHOTOMETER T9) to obtain the degradation rate and degradation percentage of different antibiotics.

[0083] An experiment on the photocatalytic degradation of ofloxacin (OFL). For example... Figure 13 As shown, after 90 minutes of irradiation, the removal rate of OFL by 8% NDI / PTA reached 81%, and the degradation rate (0.021 min) was [not specified]. -1 ) is NDI(0.0006min -1 35 times that of PTA (0.01 min) -1 It is 2.1 times that of ofloxacin and 70 times that of ofloxacin without catalyst and only under light.

[0084] The experiment on the photocatalytic degradation of tetracycline hydrochloride (TC-HCl) is as follows: Figure 14 As shown, 8% NDI / PTA also achieved a removal rate of up to 86.5% for TC-HCl, with a degradation rate of 0.018 min. -1 ) is NDI(0.0001min -1 180 times that of PTA (0.014 min) -1 It is 1.3 times that of 180 times the rate at which tetracycline hydrochloride is degraded by light alone without a catalyst.

[0085] The experiment on the photocatalytic degradation of sulfamethoxazole (SMX) is as follows: Figure 15 As shown, the photocatalyst can also degrade SMX. Within 90 minutes, the removal rate of 8% NDI / PTA was 21%, and the degradation rate was 0.0026 min. -1 ) is NDI(0.0002min -1 13 times that of PTA (0.0013 min) -1 It is twice that of 1, and 12 times that of the rate at which sulfamethoxazole degrades under light alone without a catalyst.

[0086] The catalyst prepared in Example 2 was subjected to UV full-spectrum scanning for antibiotics at different degradation times according to the test method in Example 5. Figure 16 As shown, the intensity of the characteristic diffraction peaks of OFL and TC-HCl decreased significantly with increasing photocatalytic time, and the intensity of the characteristic diffraction peak of SMX also decreased. Furthermore, no new absorption peaks appeared during the degradation process, indicating that photocatalysis effectively degraded these three antibiotics. The characteristic diffraction peaks of OFL and TC-HCl almost disappeared, indicating that their molecular structures had been destroyed. This suggests that most of the antibiotics in the solution had been degraded at this point, leading to a weakening of the absorption peaks in the characteristic diffraction patterns.

[0087] Example 7

[0088] The intermediates from the degradation of OFL using an 8% NDI / PTA catalyst in Example 5 were determined using ultra-high performance liquid chromatography-electrostatic field orbital trap high-resolution mass spectrometry (LTQOrbitrap XL). A C18 column (Waters, USA) was used for chromatographic separation. Mobile phases A and B were methanol and water containing 0.1% formic acid, respectively. The eluent (mobile phase) flow rate was 0.3 mL / min, the injection volume was 5 μg, and the column temperature was 40 °C. The mobile phase gradient program started with A:B at 10 / 90 (v / v) for 1 minute, then linearly increased A to A:B = 95 / 5 within 5 minutes and held for 1 minute, before returning to A:B = 10 / 90 and holding for 2 minutes. A positive ionization electrospray interface was used. Electrospray ionization was controlled at 4 kV, and the N2 flow rate was 12 L / min.

[0089] like Figure 17 As shown, a total of 16 intermediate products were detected. The total ion chromatogram (TIC) obtained by OFL degradation is also presented. Figure 18 As shown, the untreated OFL solution exhibited only one OFL peak with a retention time of 4.55 minutes. After 30 minutes of reaction, numerous product peaks appeared, with retention times of 7.07 minutes, 7.13 minutes, 7.59 minutes, 7.88 minutes, 8.13 minutes, and 8.46 minutes, respectively. These product peaks gradually decreased in size over time and disappeared after 90 minutes, indicating that the OFL and intermediate products generated during the reaction gradually decomposed into inorganic substances.

[0090] The possible degradation pathways of the intermediate products obtained from the catalyst prepared in Example 2 according to the test method of Example 6 are inferred, such as... Figure 19 As shown, the photocatalytic degradation of OFL by 8% NDI / PTA may occur via four pathways. In the first possible pathway, OFL degradation begins with the cleavage of the tetrahydropyridine ring and the removal of the ethyl group, generating the intermediate P1 (m / z = 339). Subsequently, the N42 atom on the piperazine ring undergoes h...+ The attack and demethylation of ofloxacin produce P2 (m / z = 296), which then undergoes carboxyl, carbonyl, and methyl separation to produce P3 (m / z = 182). A second possible pathway involves ofloxacin undergoing ring-opening, deethylation, and methyl separation to produce P5 (m / z = 325). Then, P5 undergoes methyl separation to produce P6 (m / z = 311), which then undergoes carboxyl, amino, ethyl, and methyl separation to produce P7 (m / z = 226). P7 then undergoes ring-opening, amino, carbonyl, and methyl separation to obtain P8 (m / z = 163). Finally, P8 undergoes fluorine removal and ring-opening to form P4 (m / z = 121). A third possible pathway is... First, the tetrahydropyridine of OFL is attacked, followed by ring-opening, ethyl and methyl separation to generate P9 (m / z = 296). Then, P9 undergoes methyl, amino, ethyl and hydroxyl separation to generate P10 (m / z = 223), and P10 undergoes fluorine, amino, carboxyl separation and ring-opening to generate P11 (m / z = 149). A fourth possible pathway is OFL undergoing ring-opening, methyl, ethyl and hydroxyl separation to generate P12 (m / z = 319). P12 then undergoes amino, carbonyl and methyl separation to generate P13 (m / z = 277), and P13 undergoes methyl separation to obtain P14 (m / z = 263). Then, P14 undergoes a series of oxidation reactions to generate P15 (m / z = 87). Finally, these small molecules are oxidized and decomposed into CO2 and H2O, thereby achieving the purpose of degrading OFL.

[0091] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, all of which will fall within the protection scope of the present invention.

Claims

1. A Z-type heterojunction bifunctional composite photocatalyst NDI / PTA, characterized in that: The composite catalyst NDI / PTA is 1,4,5,8-naphthalene tetracarboxylic diimide / 3,4,9,10-perylenetetracarboxylic acid, wherein the mass percentage of NDI is 1.0-30.0% of the mass of PTA, The specific preparation process is as follows: 1) 50 mg of 3,4,9,10-perylenetetracarboxylic dianhydride is weighed into a container, 150.0-300.0 ml of water is added, and a solution is obtained; 2) 400.0-600.0 mg of potassium hydroxide is weighed and added to the solution of step 1); After stirring at 40.0-55.0 ℃ for 2.0-4.0 h, the precursor of 3,4,9,10-perylenetetracarboxylic acid PTA is obtained; 3) 0.5-25.0 mg of 1,4,5,8-naphthalene tetracarboxylic diimide NDI is weighed and added to 50.0-100.0 ml of water containing 400.0-600.0 μl of glacial acetic acid to obtain an acidic aqueous solution of NDI; 4) The PTA precursor is added to the acidic aqueous solution of NDI and stirred at 35.0-45.0 ℃ for 6-10 h; 5) Solid-liquid separation, the solid is washed with water, and dried to obtain the NDI / PTA composite catalyst.

2. A preparation method of the composite photocatalyst NDI / PTA according to claim 1, and the specific process is as follows: 1) 50 mg of 3,4,9,10-perylenetetracarboxylic dianhydride is weighed into a container, 150.0-300.0 ml of water is added, and a solution is obtained; 2) Weigh 400.0-600.0 mg of potassium hydroxide and add to the solution of step 1) above; After stirring at 40.0-55.0 ℃ for 2.0-4.0 h, the precursor of 3,4,9,10-perylenetetracarboxylic acid PTA is obtained; 3) 0.5-25.0 mg of 1,4,5,8-naphthalene tetracarboxylic diimide NDI is weighed and added to 50.0-100.0 ml of water containing 400.0-600.0 μl of glacial acetic acid to obtain an acidic aqueous solution of NDI; 4) The PTA precursor is added to the acidic aqueous solution of NDI and stirred at 35.0-45.0 ℃ for 6-10 h; 5) Solid-liquid separation, the solid is washed with water, and dried to obtain the NDI / PTA composite catalyst.

3. The preparation method according to claim 2, wherein: In step 1), 50 mg of 3,4,9,10-perylenetetracarboxylic dianhydride is weighed into a container, 150.0-300.0 ml of water is added, and ultrasonic treatment is performed for 30.0-60.0 min at an ultrasonic amplitude of 40.0-100.0 Hz; In step 3), NDI is weighed and added to water containing glacial acetic acid, and ultrasonic treatment is performed for 1.0-2.0 h at an ultrasonic amplitude of 40-100 Hz to obtain an acidic aqueous solution of NDI.

4. The application of the composite photocatalyst NDI / PTA according to claim 1 in photocatalytic decomposition of water to produce hydrogen.

5. The application according to claim 4, wherein: The application conditions are: 1.0-20.0 mg of the composite catalyst powder is ultrasonically dispersed in 100.0 mL of water; chloroplatinic acid is added to the reaction system, and Pt is photo-catalytically oxidized from chloroplatinic acid H2PtCl6·6H2O on the surface of the composite catalyst as a co-catalyst by an in-situ photodeposition method; the addition amount of the co-catalyst is determined according to the amount of the composite catalyst added in the photocatalytic reaction container during the photocatalytic hydrogen production, and the mass loading of the co-catalyst relative to the composite catalyst is 0.5-9.0 wt% in terms of Pt; 0.15-0.3 M of ascorbic acid AA is used as a sacrificial agent, a xenon lamp is used as a light source, and 420<λ<780 nm.

6. Application of the composite photocatalyst NDI / PTA according to claim 1 in the degradation process of one or two or more of the antibiotics ofloxacin, tetracycline hydrochloride and sulfamethoxazole.

7. The application according to claim 6, characterized in that: The application conditions are: a xenon lamp with 420<λ<780 nm is used for photocatalytic degradation, 5.0-13.0 mg of the photocatalyst and 100 mL of the antibiotic solution with an antibiotic concentration of 10.0-50.0 mg / L are used for the reaction; and the reaction temperature is kept at 20-25℃.

8. The application according to claim 7, characterized in that: Before light irradiation, the suspension is stirred in the dark for more than 30 minutes to achieve adsorption-desorption equilibrium.

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