Photocatalyst capable of spatially and orderly supporting double promoters as well as preparation method and application of photocatalyst
By orderly supporting oxidation and reduction co-catalysts under the built-in electric field between different crystal planes of the photocatalyst, the problem of insufficient oxygen production performance of the photocatalyst in [Fe(CN)6]3- and [Fe(CN)6]4- media is solved, and a highly efficient photocatalytic oxygen production effect is achieved, which has industrialization potential.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANKAI UNIV
- Filing Date
- 2026-01-26
- Publication Date
- 2026-05-12
AI Technical Summary
Existing photocatalysts have difficulty achieving efficient and stable oxygen production performance in [Fe(CN)6]3- and [Fe(CN)6]4- redox media, and traditional co-catalyst support methods suffer from problems such as uneven distribution, weak binding force, and masking of active sites.
By utilizing the built-in electric field between different crystal planes of the photocatalyst, the orderly loading of oxidation and reduction co-catalysts on the surface of the photocatalyst is achieved. The oxidation co-catalyst and reduction co-catalyst are deposited on the electron and hole aggregation surface regions respectively by photodeposition, forming a spatially ordered dual co-catalyst system.
It significantly improves the charge separation ability and catalytic conversion performance of photocatalysts, enhances oxygen production performance, and has a simple process that is easy to scale up, showing good prospects for industrialization.
Smart Images
Figure CN122006755A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photocatalytic materials technology, specifically relating to a photocatalyst with spatially ordered dual co-catalysts, its preparation method, and its application. Background Technology
[0002] Photocatalytic water splitting is one of the potential solutions to the energy crisis and environmental pollution problems. Among these, the photocatalytic water oxidation half-reaction (i.e., oxygen production reaction, OER) is the rate-determining step in the entire water splitting process due to its slow kinetics involving a four-electron transfer process. To improve the performance of photocatalytic oxygen production, co-catalysts are typically modified on the surface of the photocatalyst to promote the separation and migration of photogenerated carriers and provide effective reaction sites.
[0003] Currently, most research focuses on supporting single cocatalysts on the surface of photocatalysts to enhance their photocatalytic activity. However, single cocatalysts typically only promote one type of reaction, either oxidation or reduction, making it difficult to simultaneously achieve efficient separation and utilization of holes and electrons, thus limiting further improvements in photocatalytic efficiency. Furthermore, traditional cocatalyst support methods, such as impregnation-calcination or physical adsorption, often suffer from uneven distribution, weak binding forces, and masking of active sites, affecting the overall performance of the catalyst.
[0004] In recent years, photocatalysts with inter-crystal charge separation characteristics have attracted widespread attention due to their ability to enhance charge separation efficiency by driving the directional migration of photogenerated electrons and holes through the built-in electric fields between different crystal planes. For example, Li Can et al. reported that selective deposition of co-catalysts on specific crystal planes can effectively improve the photocatalytic water oxidation performance of BiVO4 (Nature Communications 4, 1432 (2013)). However, existing methods mostly focus on the selective loading of single co-catalysts, and research on achieving spatially ordered oxidation and reduction dual co-catalyst loading on photocatalysts and their efficient synergistic effect in redox media is still relatively lacking. This is especially true for [Fe(CN)6] 3- In systems where electron acceptors are the primary electron acceptor, existing research has largely focused on BiVO4 materials, resulting in a very limited range of photocatalysts suitable for the oxygen-growth half-reaction in this system, and a lack of systematic research in this area. Therefore, developing a photocatalyst capable of handling [Fe(CN)6]... 3- and [Fe(CN)6] 4- Novel photocatalytic materials that achieve efficient and stable oxygen production in redox media have significant research value and application potential. Summary of the Invention
[0005] To address the problems mentioned in the background section, the present invention aims to provide a photocatalyst with spatially ordered dual co-catalysts, its preparation method, and its applications. The present invention utilizes the built-in electric field created by the potential difference between different crystal planes of the photocatalyst to promote the separation and directional migration of photogenerated carriers. This allows for the selective loading of reduction and oxidation co-catalysts, respectively, in the electron and hole aggregation regions via photodeposition, significantly improving the charge separation capability of the photocatalyst. Furthermore, the ordered distribution of active sites on different crystal planes makes the redox reactions occurring on the photocatalyst surface more independent, further enhancing the photocatalytic oxygen production performance.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On the one hand, the present invention provides a photocatalyst with spatially ordered dual co-catalysts, including a basic photocatalyst, an oxidation co-catalyst, and a reduction co-catalyst, wherein the oxidation co-catalyst and the reduction co-catalyst are simultaneously deposited on the basic photocatalyst;
[0007] The basic photocatalyst is a chlorine oxide compound.
[0008] Further, the chlorine oxychloride compound includes at least one of Bi4XO8Cl and doped Bi4XO8Cl, wherein X is Ta or Nb;
[0009] And / or, the oxidation co-catalyst is CoO x MnO x IrO2, RuO2, NiO x Fe-modified CoO x At least one of them;
[0010] And / or, the reduction co-catalyst is at least one of Au, Ru, Pt, Pd, Rh, and Ni.
[0011] Furthermore, the loading of metal ions in the oxidation co-catalyst is 0.2 wt%~1.0 wt% (loading = mass of metal ions in the oxidation co-catalyst / mass of the basic photocatalyst).
[0012] And / or, the loading of the reduction co-catalyst is 0.1 wt% to 0.4 wt% (loading = mass of reduction co-catalyst / mass of base photocatalyst). This loading results in high photocatalytic water oxidation activity.
[0013] By combining the aforementioned basic photocatalyst with the aforementioned oxidation and reduction cocatalysts, a significant improvement in catalytic conversion efficiency can be achieved.
[0014] On the other hand, the present invention provides a method for preparing a photocatalyst with spatially ordered dual co-catalysts as described above, comprising the following steps:
[0015] (1) The basic photocatalyst was dispersed in a phosphate buffer containing K3[Fe(CN)6], and then an oxidation cocatalyst source and a reduction cocatalyst source were added to the system, and the dispersion system was obtained by sonication;
[0016] (2) Irradiate the dispersion system described in step (1) under a xenon lamp to deposit the oxidation co-catalyst and the reduction co-catalyst, thereby obtaining the photocatalyst with the spatially ordered dual co-catalyst.
[0017] Furthermore, the dispersion method for dispersing the basic photocatalyst in a phosphate buffer containing K3[Fe(CN)6] is ultrasonication.
[0018] Further, the concentration of the phosphate buffer in step (1) is 25 mmol / L, and the pH of the phosphate buffer is 6;
[0019] And / or, the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] in step (1) is 0.1 mmol / L to 0.5 mmol / L, preferably 0.3 mmol / L;
[0020] And / or, the mass ratio of the metal ions in the basic photocatalyst, the oxidation cocatalyst source, and the reduction cocatalyst source in step (1) is 100:(0.2~1):(0.1~0.4).
[0021] Furthermore, the power of the ultrasound in step (1) is 200 W, and the duration of the ultrasound is 2 min to 5 min.
[0022] Furthermore, the power of the xenon lamp mentioned in step (2) is 300 W, and the illumination time mentioned in step (2) is 1 h to 3 h.
[0023] On the other hand, the present invention provides an application of the photocatalyst with spatially ordered dual co-catalysts as described above or the photocatalyst with spatially ordered dual co-catalysts prepared by any of the preparation methods described above in photocatalytic reactions in the presence of redox media.
[0024] Furthermore, the redox medium is [Fe(CN)6]. 3- and [Fe(CN)6] 4- .
[0025] Furthermore, the photocatalytic reaction is a photocatalytic water splitting reaction to produce oxygen.
[0026] In another aspect, the present invention provides an application of the photocatalyst with spatially ordered dual co-catalysts as described above, or the photocatalyst with spatially ordered dual co-catalysts prepared by any of the preparation methods described above, in the degradation of pollutants.
[0027] Those skilled in the art will understand that the numerical range in this application should be understood to specifically disclose each intermediate value between the upper and lower limits of the range. Each smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this application. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0028] Compared with the prior art, the present invention has the following beneficial effects:
[0029] (1) This invention utilizes the built-in electric field formed by the charge separation characteristics between the crystal planes of a basic photocatalyst to promote the separation and directional migration of photogenerated carriers. This allows for the selective loading of oxidation and reduction co-catalysts at the hole and electron aggregation planes via photodeposition, significantly improving the charge separation and catalytic conversion performance of the photocatalyst, thereby enhancing the [Fe(CN)6] catalytic conversion. 3- and [Fe(CN)6] 4- The material exhibits excellent oxygen production performance in redox media, which deepens the research on photocatalytic oxygen production reactions.
[0030] (2) The present invention uses photodeposition to deposit cocatalysts. This process is simple, easy to scale up, and can realize the directional loading of oxidation and reduction cocatalysts on the surface of the basic photocatalyst.
[0031] (3) The photocatalyst with spatially ordered dual co-catalysts and its preparation method of the present invention have simple process, low equipment requirements, low cost and easy control of reaction conditions, and have good prospects for industrial production. Attached Figure Description
[0032] Figure 1 The graph shows the photocatalytic water splitting and oxygen production performance of the catalyst prepared in Example 1 of this invention.
[0033] Figure 2 This is a graph showing the photocatalytic water splitting and oxygen production performance of the catalyst prepared in Comparative Example 3 of this invention.
[0034] Figure 3 The graphs show the photocatalytic water splitting and oxygen production performance of the catalysts prepared in Comparative Examples 4 and 5 of this invention.
[0035] Figure 4 The graphs show the photocatalytic water splitting and oxygen production performance of the catalysts prepared in Examples 6, 4, and 6 of this invention.
[0036] Figure 5 The left image shows the photocatalytic water splitting oxygen production reaction performance of the catalysts prepared in this invention, Example 2, Example 3, Example 4, Example 5, and Example 6, and the right image shows a comparison of the oxygen production rate.
[0037] Figure 6 The left image shows the photocatalytic water splitting oxygen production reaction performance of the catalysts prepared in Comparative Examples 1, 6, 7, 8, 9, and 14 of this invention, and the right image shows the oxygen production rate volcano plot.
[0038] Figure 7 The left image shows the photocatalytic water splitting oxygen production reaction performance of the catalysts prepared in Comparative Examples 2, 10, 11, 12, and 14 of this invention, and the right image shows the oxygen production rate volcano plot.
[0039] Figure 8 The left image shows the photocatalytic water splitting and oxygen production reaction performance of the catalysts prepared in Examples 1, 13, and 14 of this invention, and the right image shows the oxygen production rate volcano diagram.
[0040] Figure 9 The graphs show the photocatalytic water splitting and oxygen production performance of the catalysts prepared in Examples 1 and 15 of this invention.
[0041] Figure 10 The UV-Vis absorption spectra of the filtrate before and after the photocatalytic water splitting and oxygen production reaction of the catalyst prepared in Example 1 of this invention are shown.
[0042] Figure 11 The graph shows the performance of the catalyst prepared in Example 16 of this invention in degrading tetracycline. Detailed Implementation
[0043] To better understand the content of this invention, the following detailed description is provided in conjunction with specific implementation methods. However, the scope of protection of this invention is not limited to the following embodiments.
[0044] Although this application only describes preferred methods and materials, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this application.
[0045] Example 1
[0046] Preparation of photocatalysts with spatially ordered dual co-catalysts:
[0047] (1) 100 mg Bi4TaO8Cl was dispersed in a phosphate buffer containing K3[Fe(CN)6] (100 mL of phosphate buffer, concentration 25 mmol / L, pH = 6), and then 40 µL of HAuCl4 aqueous solution (concentration of Au ions in HAuCl4 aqueous solution is 5 mg / mL) and 300 µL of Co(NO3)2 aqueous solution (concentration of Co ions in Co(NO3)2 aqueous solution is 2 mg / mL) were added to the system. The dispersion system was obtained by sonication at 200 W for 5 min. The concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] was 0.3 mmol / L.
[0048] (2) The dispersion system in step (1) was irradiated under a 300 W xenon lamp for 2 h, and Au and CoO were deposited after reduction and oxidation reactions. x After filtration, the sample was dried in a vacuum oven to obtain a photocatalyst with two co-catalysts supported in a spatially ordered manner, which includes the basic photocatalyst Bi4TaO8Cl and the oxidation co-catalyst CoO. x (CoO oxidation co-catalyst) x The catalyst Au-CoO has a Co ion loading of 0.6 wt%, which is the mass of Co ions divided by the mass of Bi₄TaO₈Cl, and a reduction co-catalyst Au (with a loading of 0.2 wt%, which is the mass of Au divided by the mass of Bi₄TaO₈Cl). x / Bi4TaO8Cl.
[0049] Example 2
[0050] The preparation method in this embodiment is the same as that in Example 1. The difference is that in step (1), 40 µL of HAuCl4 aqueous solution (the concentration of Au ions in the HAuCl4 aqueous solution is 5 mg / mL) is replaced with 52 µL of H2PtCl6 aqueous solution (the concentration of Pt ions in the H2PtCl6 aqueous solution is 3.833 mg / mL), the volume of Co(NO3)2 aqueous solution is 100 µL (the concentration of Co ions in the Co(NO3)2 aqueous solution is 2 mg / mL), and the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] is 0.5 mmol / L.
[0051] Example 3
[0052] The preparation method in this embodiment is the same as that in Example 1. The difference is that in step (1), 40 µL of HAuCl4 aqueous solution (the concentration of Au ions in the HAuCl4 aqueous solution is 5 mg / mL) is replaced with 74 µL of RuCl3 aqueous solution (the concentration of Ru ions in the RuCl3 aqueous solution is 2.72 mg / mL), the volume of Co(NO3)2 aqueous solution is 100 µL (the concentration of Co ions in the Co(NO3)2 aqueous solution is 2 mg / mL), and the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] is 0.5 mmol / L.
[0053] Example 4
[0054] The preparation method in this embodiment is the same as that in Example 1. The difference is that in step (1), instead of adding 40 µL of HAuCl4 aqueous solution (the concentration of Au ions in the HAuCl4 aqueous solution is 5 mg / mL), 40 µL of Na3RhCl6 aqueous solution (the concentration of Rh ions in the Na3RhCl6 aqueous solution is 5 mg / mL) is added, the volume of Co(NO3)2 aqueous solution is 100 µL (the concentration of Co ions in the Co(NO3)2 aqueous solution is 2 mg / mL), and the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] is 0.5 mmol / L.
[0055] Example 5
[0056] The preparation method in this embodiment is the same as that in Example 1. The difference is that in step (1), 40 µL of HAuCl4 aqueous solution (the concentration of Au ions in the HAuCl4 aqueous solution is 5 mg / mL) is replaced with 56 µL of Na2PdCl4 aqueous solution (the concentration of Pd ions in the Na2PdCl4 aqueous solution is 3.6 mg / mL), the volume of Co(NO3)2 aqueous solution is 100 µL (the concentration of Co ions in the Co(NO3)2 aqueous solution is 2 mg / mL), and the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] is 0.5 mmol / L.
[0057] Example 6
[0058] The preparation method in this embodiment is the same as in Example 1, except that the volume of the Co(NO3)2 aqueous solution in step (1) is 100 µL (the concentration of Co ions in the Co(NO3)2 aqueous solution is 2 mg / mL), and the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] is 0.5 mmol / L. In the spatially ordered photocatalyst with dual co-catalysts prepared, the oxidation co-catalyst CoO... xThe loading of Co ions in the medium is 0.2 wt%.
[0059] Example 7
[0060] The preparation method in this embodiment is the same as in Example 1, except that the volume of the Co(NO3)2 aqueous solution in step (1) is 200 µL (the concentration of Co ions in the Co(NO3)2 aqueous solution is 2 mg / mL), and the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] is 0.5 mmol / L. In the spatially ordered photocatalyst with dual co-catalysts prepared, the oxidation co-catalyst CoO... x The loading of Co ions was 0.4 wt%.
[0061] Example 8
[0062] The preparation method in this embodiment is the same as in Example 1, except that the volume of the Co(NO3)2 aqueous solution in step (1) is 400 µL (the concentration of Co ions in the Co(NO3)2 aqueous solution is 2 mg / mL), and the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] is 0.5 mmol / L. In the photocatalyst prepared with spatially ordered dual co-catalysts, the oxidation co-catalyst CoO... x The loading of Co ions was 0.8 wt%.
[0063] Example 9
[0064] The preparation method in this embodiment is the same as in Example 1, except that the volume of the Co(NO3)2 aqueous solution in step (1) is 500 µL (the concentration of Co ions in the Co(NO3)2 aqueous solution is 2 mg / mL), and the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] is 0.5 mmol / L. In the spatially ordered photocatalyst with dual co-catalysts prepared, the oxidation co-catalyst CoO... x The loading of Co ions in the medium is 1.0 wt%.
[0065] Example 10
[0066] The preparation method in this embodiment is the same as in Example 1, except that the volume of the HAuCl4 aqueous solution in step (1) is 20 µL (the concentration of Au ions in the HAuCl4 aqueous solution is 5 mg / mL), and the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] is 0.5 mmol / L. In the spatially ordered photocatalyst with dual co-catalysts prepared, the loading of the reducing co-catalyst Au is 0.1 wt%.
[0067] Example 11
[0068] The preparation method in this embodiment is the same as in Example 1, except that the volume of the HAuCl4 aqueous solution in step (1) is 60 µL (the concentration of Au ions in the HAuCl4 aqueous solution is 5 mg / mL), and the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] is 0.5 mmol / L. In the spatially ordered photocatalyst with dual co-catalysts prepared, the loading of the reducing co-catalyst Au is 0.3 wt%.
[0069] Example 12
[0070] The preparation method in this embodiment is the same as in Example 1, except that the volume of the HAuCl4 aqueous solution in step (1) is 80 µL (the concentration of Au ions in the HAuCl4 aqueous solution is 5 mg / mL), and the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] is 0.5 mmol / L. In the spatially ordered photocatalyst with dual co-catalysts prepared, the loading of the reducing co-catalyst Au is 0.4 wt%.
[0071] Example 13
[0072] The preparation method in this embodiment is the same as that in Example 1, except that the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] in step (1) is 0.1 mmol / L.
[0073] Example 14
[0074] The preparation method in this embodiment is the same as that in Example 1, except that the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] in step (1) is 0.5 mmol / L.
[0075] Example 15
[0076] The preparation method in this embodiment is the same as that in embodiment 1, except that the illumination time in step (2) is 1 h.
[0077] Example 16
[0078] Preparation of photocatalysts with spatially ordered dual co-catalysts:
[0079] (1) 100 mg Bi4NbO8Cl was dispersed in a phosphate buffer containing K3[Fe(CN)6] (100 mL of phosphate buffer, concentration 25 mmol / L, pH = 6), and then 40 µL of HAuCl4 aqueous solution (concentration of Au ions in HAuCl4 aqueous solution is 5 mg / mL) and 300 µL of Co(NO3)2 aqueous solution (concentration of Co ions in Co(NO3)2 aqueous solution is 2 mg / mL) were added to the system and the dispersion system was obtained by sonication at 200 W for 5 min; the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] was 0.3 mmol / L.
[0080] (2) The dispersion system in step (1) was irradiated under a 300 W xenon lamp for 2 h, and Au and CoO were deposited after reduction and oxidation reactions. x After filtration, the sample is dried in a vacuum oven to obtain a photocatalyst with two co-catalysts supported in a spatially ordered manner, which includes the basic photocatalyst Bi4NbO8Cl and the oxidation co-catalyst CoO. x (CoO oxidation co-catalyst) x The catalyst Au-CoO has a Co ion loading of 0.6 wt%, which is the mass of Co ions divided by the mass of Bi₄NbO₈Cl, and a reduction co-catalyst Au (with a loading of 0.2 wt%, which is the mass of Au divided by the mass of Bi₄NbO₈Cl). x / Bi4NbO8Cl.
[0081] Comparative Example 1
[0082] Preparation of photocatalysts using only photodeposited Au reduction co-catalysts:
[0083] (1) Disperse 100 mg Bi4TaO8Cl in 100 mL methanol solution (20 vol%), and then add 40 µL of HAuCl4 aqueous solution (the concentration of Au ions in HAuCl4 aqueous solution is 5 mg / mL) to the system. Sonicate at 200 W for 5 min to obtain the dispersion system.
[0084] (2) The dispersion system in step (1) was irradiated under a 300 W xenon lamp for 2 h to photodeposit Au. After filtration, it was dried in a vacuum oven to obtain a photocatalyst supported on Au, which includes the basic photocatalyst Bi4TaO8Cl and the reduction co-catalyst Au (the loading is 0.2 wt%, that is, the mass of Au divided by the mass of Bi4TaO8Cl).
[0085] Comparative Example 2
[0086] The preparation method of this comparative example is the same as that of Example 1, except that HAuCl4 aqueous solution is not added in step (1), and the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] is 0.5 mmol / L.
[0087] Comparative Example 3
[0088] Preparation of photocatalysts that only adsorb IrO2 oxidation co-catalysts:
[0089] (1) 100 mg Bi4TaO8Cl was dispersed in an aqueous solution containing IrO2 colloid to obtain a dispersion system, wherein the mass ratio of Ir ions in IrO2 to Bi4TaO8Cl was 1:100.
[0090] (2) The above dispersion system was stirred and adsorbed in the dark for 1 h. After the adsorption was completed, it was filtered and then dried in a vacuum oven to obtain a photocatalyst that only adsorbed IrO2 oxidation cocatalyst, denoted as IrO2 / Bi4TaO8Cl.
[0091] Comparative Example 4
[0092] Photodeposition of CoO x Preparation of photocatalysts:
[0093] (1) 100 mg Bi4TaO8Cl was dispersed in a phosphate buffer containing K3[Fe(CN)6] (100 mL of phosphate buffer, concentration 25 mmol / L, pH = 6), and then 100 µL of Co(NO3)2 aqueous solution (the concentration of Co ions in the Co(NO3)2 aqueous solution was 2 mg / mL) was added to the system. The dispersion system was obtained by sonication at 200 W for 5 min. The concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] was 0.5 mmol / L.
[0094] (2) Irradiate the dispersion system in step (1) under a 300 W xenon lamp for 2 h to allow CoO to precipitate. x After deposition and filtration, the sample was dried in a vacuum oven to obtain photodeposited CoO. x The photocatalysts include the basic photocatalyst Bi₄TaO₈Cl and the oxidation cocatalyst CoO₂. x (CoO oxidation co-catalyst) x The loading of Co ions is 0.2 wt%, which is the mass of Co ions divided by the mass of Bi4TaO8Cl.
[0095] Comparative Example 5
[0096] Photodeposition of CoO x Preparation of photocatalysts:
[0097] (1) 100 mg Bi4TaO8Cl was dispersed in 100 mL of ultrapure water containing NaIO3, and 100 µL of Co(NO3)2 aqueous solution (the concentration of Co ions in the Co(NO3)2 aqueous solution was 2 mg / mL) was added to the system. The dispersion system was obtained by sonication at 200 W for 5 min. The concentration of NaIO3 in the ultrapure water containing NaIO3 was 10 mmol / L.
[0098] (2) Irradiate the dispersion system in step (1) under a 300 W xenon lamp for 2 h to allow CoO to precipitate. x After deposition and filtration, the sample was dried in a vacuum oven to obtain photodeposited CoO. x The photocatalysts include the basic photocatalyst Bi₄TaO₈Cl and the oxidation cocatalyst CoO₂. x (CoO oxidation co-catalyst) x The loading of Co ions is 0.2 wt%, which is the mass of Co ions divided by the mass of Bi4TaO8Cl.
[0099] Comparative Example 6
[0100] Photodeposition stepwise loading of Au and CoO x Preparation of photocatalysts:
[0101] (1) 100 mg Bi4TaO8Cl was dispersed in a phosphate buffer containing K3[Fe(CN)6] (100 mL of phosphate buffer, concentration 25 mmol / L, pH = 6), and then 100 µL of Co(NO3)2 aqueous solution (the concentration of Co ions in the Co(NO3)2 aqueous solution was 2 mg / mL) was added to the system. The dispersion system was obtained by sonication at 200 W for 5 min. The concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] was 0.5 mmol / L.
[0102] (2) The dispersion system in step (1) was irradiated under a 300 W xenon lamp for 2 h to photodeposit CoO. x After filtration, the sample was dried in a vacuum oven to obtain photodeposited CoO. x Photocatalyst.
[0103] (3) The CoO obtained in step (2) is photodeposited and loaded with it. x The photocatalyst was dispersed in 100 mL of methanol solution (20 vol%), and then 40 µL of HAuCl4 aqueous solution (the concentration of Au ions in HAuCl4 aqueous solution was 5 mg / mL) was added to the system. The dispersion system was obtained by sonication at 80 W for 1 min.
[0104] (4) The dispersion system in step (3) was irradiated under a 300 W xenon lamp for 2 h to photodeposit Au. After filtration, it was dried in a vacuum oven to obtain stepwise supported Au and CoO. x The photocatalysts include the basic photocatalyst Bi₄TaO₈Cl and the oxidation cocatalyst CoO₂. x (CoO oxidation co-catalyst) x The loading of Co ions is 0.2 wt%, which is the mass of Co ions divided by the mass of Bi4TaO8Cl, and the loading of Au (0.2 wt%, which is the mass of Au divided by the mass of Bi4TaO8Cl) is a reduction co-catalyst.
[0105] Performance Evaluation
[0106] The catalytic performance of the catalysts prepared in Examples 1-15 and Comparative Examples 1-6 for photocatalytic water splitting and oxygen production was tested. The photocatalytic oxygen production reaction was carried out in a Pyrex reaction vessel connected to a closed glass circulation system under a 300 W xenon lamp with a cutoff filter (λ > 420 nm). 100 mg of photocatalyst was dispersed in a phosphate buffer containing K3[Fe(CN)6] (100 mL, 25 mmol / L, pH = 6), where the concentration of K3[Fe(CN)6] in the phosphate buffer was 10 mmol / L. Before irradiation, the reaction mixture was thoroughly evacuated to remove air, and a temperature-controlled circulating cooling system maintained the reaction temperature at 283 K. The evolved gases were analyzed by online gas chromatography. The results are as follows: Figure 1-9 As shown.
[0107] Figure 1 The catalyst prepared in Example 1 was tested according to the above method to determine its photocatalytic performance in water splitting for oxygen production. Figure 1 As can be seen, the oxygen production rate can reach 84 µmol / h, and it has good stability.
[0108] Figure 2 The catalyst prepared in Comparative Example 3 was tested according to the above method to determine its photocatalytic water splitting and oxygen production performance. (From...) Figure 2 As can be seen from the data, the catalyst that only adsorbs IrO2 shows an induction period of 2 h in the oxygen production activity curve in the redox medium, which is considered to be the redox reaction of the adsorbed IrO2 under light conditions.
[0109] Figure 3 The catalysts prepared in Comparative Examples 4 and 5 were tested according to the above method to determine their photocatalytic water splitting and oxygen production performance. Figure 3As can be seen from the data, photodeposition of CoO3 was achieved when NaIO3 was used as a sacrificial reagent. x The oxygen production activity curve in the redox medium showed an induction period of 2 hours before oxygen was produced. This indicates that the photocatalyst obtained by this method has low activity, therefore this approach was discarded.
[0110] Figure 4 The catalysts prepared in Example 6, Comparative Example 4, and Comparative Example 6 were tested according to the above method to determine their photocatalytic water splitting and oxygen production performance. Figure 4 As can be seen, if oxidation and reduction co-catalysts are supported in steps, the catalyst activity will be greatly reduced. However, the oxygen production rate is greatly improved when dual co-catalysts are supported by synchronous photodeposition compared to supporting only one co-catalyst. This also confirms the advantages of dual co-catalyst support and the importance of the support method.
[0111] Figure 5 The graph shows a comparison of the photocatalytic water splitting and oxygen production performance of the catalysts prepared in Examples 2, 3, 4, 5, and 6, tested using the methods described above. Figure 5 As can be seen, the oxygen production rate is highest when Au is selected as the reduction co-catalyst.
[0112] Figure 6 The graph shows a comparison of the photocatalytic water splitting and oxygen production performance of the catalysts prepared in Comparative Examples 1, 6, 7, 8, 9, and 14, tested using the methods described above. Figure 6 As can be seen from this, with CoO x As the loading of Co ions increases, the oxygen production rate initially increases and then decreases. x The oxygen production rate is highest when the Co ion loading is 0.6 wt%.
[0113] Figure 7 The graph shows a comparison of the photocatalytic water splitting and oxygen production performance of the catalysts prepared in Comparative Examples 2, 10, 11, 12, and 14, tested using the methods described above. Figure 7 As can be seen, the oxygen production rate first increases and then decreases with the increase of Au loading. The oxygen production rate is highest when the Au loading is 0.2 wt%.
[0114] Figure 8 The chart shows a comparison of the photocatalytic performance of the catalysts prepared in Examples 1, 13, and 14 for oxygen production through water splitting, tested using the methods described above. Figure 8As can be seen, the oxygen production rate first increases and then decreases with the increase of K3[Fe(CN)6] concentration. The oxygen production rate is highest when the K3[Fe(CN)6] concentration is 0.3 mmol / L.
[0115] Figure 9 The catalysts prepared in Examples 1 and 15 were tested according to the above method to determine their photocatalytic water splitting and oxygen production performance. Figure 9 As can be seen, photodeposition time has little effect on the oxygen production rate.
[0116] The UV-Vis absorption spectra of the filtrate (filtered solution) before and after the photocatalytic water splitting and oxygen production reaction of the catalyst prepared in Example 1 are as follows: Figure 10 As shown. From Figure 10 As can be seen from the data, the redox medium in the filtrate before the reaction was Fe[(CN)6]. 3- Fe[(CN)6] is absent. 4- Yes, it exists. After the catalytic reaction in Example 1, Fe[(CN)6]-attributable to Fe appeared in the filtrate. 4- The absorption peak indicates that Fe[(CN)6] has occurred in the system. 3- To Fe[(CN)6] 4- The transformation reaction.
[0117] 2 mg of tetracycline was ultrasonically dispersed in 100 mL of deionized water, and the catalyst prepared in Example 16 was then ultrasonically dispersed in the above solution. The solution was then irradiated under a 300 W xenon lamp for 2 h. Specific results are as follows: Figure 11 As shown. From Figure 11 As can be seen, the spatially ordered dual-co-catalyst method is still applicable to other chlorine oxychloride-based photocatalysts, such as Bi4NbO8Cl, and exhibits a high degradation rate in the degradation of tetracycline.
[0118] The above description is only a specific embodiment of the present invention and not all embodiments. Any equivalent modifications made by those skilled in the art to the technical solutions of the present invention by reading the present invention specification shall be covered by the claims of the present invention.
Claims
1. A photocatalyst with spatially ordered dual co-catalysts, characterized in that, It includes a basic photocatalyst, an oxidation cocatalyst, and a reduction cocatalyst, wherein the oxidation cocatalyst and the reduction cocatalyst are simultaneously deposited on the basic photocatalyst; The basic photocatalyst is a chlorine oxide compound.
2. The photocatalyst with spatially ordered dual co-catalysts according to claim 1, characterized in that, The chlorine oxychloride compound includes at least one of Bi4XO8Cl and doped Bi4XO8Cl, wherein X is Ta or Nb; And / or, the oxidation co-catalyst is CoO x MnO x IrO2, RuO2, NiO x Fe-modified CoO x At least one of them; And / or, the reduction co-catalyst is at least one of Au, Ru, Pt, Pd, Rh, and Ni.
3. The photocatalyst with spatially ordered dual co-catalysts according to claim 2, characterized in that, The loading of metal ions in the oxidation co-catalyst is 0.2 wt%~1.0 wt%; And / or, the loading of the reduction co-catalyst is 0.1 wt% to 0.4 wt%.
4. A method for preparing a photocatalyst with spatially ordered dual co-catalysts as described in any one of claims 1 to 3, characterized in that, Includes the following steps: (1) The basic photocatalyst was dispersed in a phosphate buffer containing K3[Fe(CN)6], and then an oxidation cocatalyst source and a reduction cocatalyst source were added to the system, and the dispersion system was obtained by sonication; (2) Irradiate the dispersion system described in step (1) under a xenon lamp to obtain the photocatalyst with spatially ordered dual co-catalysts.
5. The preparation method according to claim 4, characterized in that, The concentration of the phosphate buffer in step (1) is 25 mmol / L, and the pH of the phosphate buffer is 6; And / or, the concentration of K3[Fe(CN)6] in the phosphate buffer containing K3[Fe(CN)6] in step (1) is 0.1 mmol / L to 0.5 mmol / L, preferably 0.3 mmol / L; And / or, the mass ratio of the metal ions in the basic photocatalyst, the oxidation cocatalyst source, and the reduction cocatalyst source in step (1) is 100:(0.2~1):(0.1~0.4).
6. The preparation method according to claim 4, characterized in that, The power of the xenon lamp mentioned in step (2) is 300 W, and the illumination time mentioned in step (2) is 1 h to 3 h.
7. The application of the photocatalyst with spatially ordered dual cocatalysts as described in any one of claims 1 to 3, or the photocatalyst with spatially ordered dual cocatalysts prepared by the preparation method described in any one of claims 4 to 6, in photocatalytic reactions in the presence of a redox medium.
8. The application according to claim 7, characterized in that, The redox medium is [Fe(CN)6]. 3- and [Fe(CN)6] 4- .
9. The application according to claim 7, characterized in that, The photocatalytic reaction is a photocatalytic water splitting reaction to produce oxygen.
10. The application of the photocatalyst with spatially ordered dual co-catalysts as described in any one of claims 1 to 3, or the photocatalyst with spatially ordered dual co-catalysts prepared by the preparation method described in any one of claims 4 to 6, in the degradation of pollutants.