A Yttrium Oxide / Polytriazine Imine Composite Photocatalyst
The Y2O3/PTI composite photocatalyst was prepared by molten salt method, which solved the problems of low separation efficiency of photogenerated carriers and severe hydrogen-oxygen reverse reaction in photocatalysts. It achieved efficient photocatalytic water splitting for hydrogen production and degradation of organic pollutants, and has the characteristics of low cost and environmental friendliness.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- FUZHOU UNIV
- Filing Date
- 2026-02-28
- Publication Date
- 2026-06-02
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of photocatalytic materials technology, specifically relating to a yttrium oxide / polytriazine imine (Y2O3 / PTI) composite photocatalyst, its preparation method, and its application. Background Technology
[0002] Photocatalytic water splitting for hydrogen production is an important pathway that mimics photosynthesis to directly convert solar energy into hydrogen energy. However, it is limited by problems such as low photogenerated carrier separation efficiency and severe hydrogen-oxygen reverse reactions. Polytriazine imine (PTI), as a structural variant of graphitic carbon nitride, possesses a two-dimensional conjugated framework and good chemical stability, but its photocatalytic performance still needs improvement. Yttrium oxide (Y₂O₃) is a wide-bandgap (~5.6 eV) rare-earth oxide that is optically transparent, chemically stable, and does not compete with PTI for photoresponse, thus avoiding incident light loss. Combining band-matched PTI with Y₂O₃ can promote the spatial separation of photogenerated electrons and holes in PTI, suppress reverse reactions, and avoid photon energy loss, overcoming the inherent defects of traditional S-type heterojunctions. Therefore, developing a simple, low-cost, and environmentally friendly method for preparing Y₂O₃ / PTI composite photocatalysts is of great significance. Summary of the Invention
[0003] The purpose of this invention is to provide a method for preparing a Y₂O₃ / PTI composite photocatalyst and its applications. This method is simple, low-cost, and environmentally friendly, making it suitable for large-scale production. The Y₂O₃ / PTI composite photocatalyst obtained by this invention exhibits high carrier separation efficiency and excellent photocatalytic activity, making it suitable for photocatalytic water splitting for hydrogen production, degradation of organic pollutants, and carbon dioxide reduction.
[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a Y2O3 / PTI composite photocatalyst: Bromine molten salt, Y2O3, and nitrogen-rich organic matter are thoroughly ground evenly in a mortar, transferred to a covered corundum crucible, and calcined in a muffle furnace at 450-600 ℃ for 0.5-5 h, then naturally cooled to room temperature; the obtained product is washed with deionized water until the ion concentration is below 10 ppm, and then dried at 60-80 ℃ for 6-12 h to obtain the Y2O3 / PTI composite photocatalyst.
[0005] The nitrogen-rich organic compounds include any one or a mixture of melamine, dicyandiamide, and monocyanamide.
[0006] The mass ratio of Y2O3, nitrogen-rich organic matter, and low-melting-point water-soluble bromide molten salt used is 1:(0.1~10):(0.1~20).
[0007] The low-melting-point water-soluble bromide molten salt is a mixture of potassium bromide and lithium bromide, with a mass ratio of KBr:LiBr=(0.1~10):1, and a melting point range of 323~730 ℃.
[0008] The prepared Y2O3 / PTI composite photocatalyst is suitable for photocatalytic water splitting to produce hydrogen, degradation of organic pollutants, and carbon dioxide reduction; among which the photocatalytic water splitting to produce hydrogen performance is particularly outstanding.
[0009] The beneficial effects of this invention are as follows: (1) This invention is the first to prepare Y2O3 / PTI composite photocatalyst.
[0010] (2) The Y2O3 / PTI composite photocatalyst prepared in this invention has two components in close contact, which promotes the rapid migration and separation of photogenerated carriers, effectively inhibits the reverse reaction of hydrogen-oxygen recombination, and the total water splitting performance is significantly higher than that of single PTI.
[0011] (3) The present invention adopts a one-step synthesis process of molten salt method, which does not require templates or complex post-processing. Molten salt is easily soluble in water and can be recycled, which greatly reduces production costs and environmental burden. The process is green and efficient and has industrialization prospects. Attached Figure Description
[0012] Figure 1 X-ray powder diffraction pattern of the Y2O3 / PTI composite photocatalyst prepared in Example 1; Figure 2 (a) Scanning electron microscope (SEM) image and (b) High-resolution transmission electron microscope (HRTEM) image of the Y2O3 / PTI composite photocatalyst prepared in Example 1; Figure 3 The image shows a scanning electron microscope (SEM) image of the Y2O3 prepared in Comparative Example 2. Figure 4 The UV-Vis diffuse reflectance spectra of the samples from Example 1 (Y2O3 / PTI), Comparative Example 1 (PTI), and Comparative Example 2 (Y2O3) are shown. Figure 5 The contact potential difference between the Comparative Example 1 (PTI) and Comparative Example 2 (Y2O3) samples and the Au probe; Figure 6 This is a comparison of the activities of Example 1 (Y2O3 / PTI), Comparative Example 1 (PTI), and Comparative Example 2 (Y2O3) in the total water splitting reaction; Figure 7 The activity and stability of the Y2O3 / PTI composite photocatalyst prepared in Example 1 for the complete water splitting. Detailed Implementation
[0013] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.
[0014] Example 1: Preparation of Y2O3 / PTI composite photocatalyst 2.0 g potassium bromide, 2.0 g lithium bromide, 0.5 g Y2O3 and 1.0 g melamine were thoroughly ground and mixed in a mortar, transferred to a covered corundum crucible, and kept in a muffle furnace at 550 ℃ for 2 h, and then naturally cooled to room temperature. The resulting product was washed with deionized water until the ion concentration was <10 ppm, and dried at 60 ℃ for 6 h to obtain the Y2O3 / PTI composite photocatalyst.
[0015] Figure 1 The X-ray powder diffraction pattern of the Y2O3 / PTI composite photocatalyst prepared in Example 1 shows typical cubic Y2O3 (JCPDS:72-0927) diffraction peaks, with no PTI characteristic peaks observed.
[0016] Figure 2 Figure (a) shows a scanning electron microscope (SEM) image and (b) a high-resolution transmission electron microscope (HRTEM) image of the Y2O3 / PTI composite photocatalyst prepared in Example 1. Figure (a) shows that irregular Y2O3 particles with a particle size of 100–300 nm are uniformly loaded on the surface of PTI microsheets with a width of 0.5–4.5 μm. In Figure (b), the lattice spacings of 0.31 nm and 0.19 nm correspond to the (310) crystal plane of hexagonal Y2O3 and the (210) crystal plane of PTI, respectively.
[0017] Example 2: Preparation of Y2O3 / PTI composite photocatalyst 2.0 g potassium bromide, 2.0 g lithium bromide, 0.5 g Y2O3 and 1.0 g melamine were thoroughly ground and mixed in a mortar, transferred to a covered corundum crucible, and kept in a muffle furnace at 550 ℃ for 0.5 h, and then naturally cooled to room temperature. The resulting product was washed with deionized water until the ion concentration was <10 ppm, and dried at 60 ℃ for 6 h to obtain the Y2O3 / PTI composite photocatalyst.
[0018] Example 3: Preparation of Y2O3 / PTI composite photocatalyst 2.0 g potassium bromide, 2.0 g lithium bromide, 0.5 g Y2O3 and 1.0 g melamine were thoroughly ground and mixed in a mortar, transferred to a covered corundum crucible, and kept in a muffle furnace at 550 ℃ for 5 h, and then naturally cooled to room temperature. The resulting product was washed with deionized water until the ion concentration was <10 ppm, and dried at 60 ℃ for 6 h to obtain the Y2O3 / PTI composite photocatalyst.
[0019] Comparative Example 1: Preparation of PTI Weigh 2.0 g potassium bromide, 2.0 g lithium bromide and 1.0 g melamine, grind and mix them thoroughly in a mortar, transfer to a covered corundum crucible, keep warm in a muffle furnace at 550 ℃ for 2 h, and cool naturally to room temperature; wash the precipitate with deionized water until the ion concentration is <10 ppm, and dry at 60 ℃ for 6 h to obtain PTI.
[0020] Comparative Example 2: Preparation of Y2O3 Weigh 2.0 g potassium bromide, 2.0 g lithium bromide and 0.5 g Y2O3, grind and mix them thoroughly in a mortar, transfer to a covered corundum crucible, keep warm in a muffle furnace at 550 ℃ for 2 h, and cool naturally to room temperature; wash the product with deionized water until the ion concentration is <10 ppm, and dry at 60 ℃ for 6 h to obtain Y2O3.
[0021] Figure 3 The scanning electron microscope image of Y2O3 prepared for Comparative Example 2 shows that it is a particle aggregate of 100-300 nm.
[0022] Figure 4 The UV-Vis diffuse reflectance spectra of the samples from Example 1 (Y₂O₃ / PTI), Comparative Example 1 (PTI), and Comparative Example 2 (Y₂O₃) are shown. The absorption band edge of Y₂O₃ / PTI is approximately 385 nm, and its light absorption intensity is significantly higher than that of Y₂O₃ alone. The absorption band edge of PTI is approximately 405 nm.
[0023] Figure 5 The contact potential difference (CPD) between the Comparative Example 1 (PTI) and Comparative Example 2 (Y₂O₃) samples and the Au probe is shown. The CPDs of PTI and Y₂O₃ are approximately -400 mV and -700 mV, respectively, corresponding to work functions of 4.7 and 4.4 eV, indicating that the Fermi level of Y₂O₃ is higher than that of PTI. When the two are in close contact, electrons flow from Y₂O₃ to PTI, forming a built-in electric field.
[0024] Application Example 1: Hydrogen production performance of Y2O3 / PTI composite photocatalyst through total water splitting (1) The Y2O3 / PTI sample prepared in Example 1 was used for photocatalytic water splitting to produce hydrogen, while PTI of Comparative Example 1 and Y2O3 of Comparative Example 2 were used as controls. Before the reaction, 0.5 wt.% Pt and 0.2 wt.% Co co-catalysts were loaded on the sample surface by photodeposition: 100 mg of sample was dispersed in 100 mL of deionized water, 1 mL of methanol, appropriate amount of H2PtCl6 (corresponding to Pt content) and CoCl2 (corresponding to Co content) were added dropwise, vacuumed and irradiated for 1 h, and then washed and dried with deionized water.
[0025] (2) The photocatalytic reaction was carried out in a 250 mL sealed circulating reactor using a 300 W xenon lamp as the light source. 50 mg of the above Pt and Co-modified samples and 100 mL of ultrapure water were added, and the mixture was magnetically stirred until homogeneous. After evacuation, the light source was turned on. The gaseous products were introduced into the gas chromatograph via a four-way valve for online analysis at regular intervals. The results are as follows: Figure 6 As shown, after 3 h of illumination, Y2O3 / PTI produced 96.3 μmol H2 and 48 μmol O2, with the H2 / O2 molar ratio close to the theoretical value of 2:1; however, Y2O3 was inactive, and PTI only detected trace amounts of H2, with no O2 detected.
[0026] Application Example 2: Perform 5 cycles of photocatalytic water splitting test according to the conditions of Application Example 1. Each cycle is 3 hours. After each cycle, turn off the light and stop the pump, evacuate for 10 minutes, and then start the light source and circulation pump to enter the next cycle. Figure 7 The Y2O3 / PTI composite photocatalyst of Example 1 showed that its water splitting activity remained essentially unchanged over 5 cycles, indicating that it has excellent stability.
[0027] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.
Claims
1. A method for preparing a yttrium oxide / polytriazine imine composite photocatalyst, characterized in that: The yttrium oxide / polytriazine imine composite photocatalyst was synthesized by calcination in the next step at the melting temperature of yttrium oxide, nitrogen-rich organic matter and low-melting-point water-soluble bromide molten salt.
2. The preparation method according to claim 1, characterized in that: The nitrogen-rich organic compound is at least one of melamine, dicyandiamide, and monocyandiamide.
3. The preparation method according to claim 1, characterized in that: The mass ratio of yttrium oxide, nitrogen-rich organic matter, and low-melting-point water-soluble bromide molten salt is 1:0.1~10:0.1~20.
4. The preparation method according to claim 1, characterized in that: The low-melting-point water-soluble bromide molten salt is a mixture of potassium bromide and lithium bromide, with a mass ratio of KBr:LiBr = 0.1~10:1, and a melting point range of 323~730 °C.
5. The preparation method according to claim 1, characterized in that: The calcination temperature is 450~600 ℃, and the treatment time is 0.5~5 h.
6. A yttrium oxide / polytriazine imine composite photocatalyst prepared by the method according to any one of claims 1 to 5.
7. The application of a yttrium oxide / polytriazine imine composite photocatalyst prepared by the method according to any one of claims 1 to 5, characterized in that: The yttrium oxide / polytriazine imine composite photocatalyst is used for photocatalytic water splitting to produce hydrogen, degradation of organic pollutants, and reduction of carbon dioxide.