Composite photocatalytic material nickel sulfide / sulfur-doped polyimide and preparation method thereof
By preparing nickel sulfide/sulfur-doped π-conjugated polyimide composite catalytic materials, the problems of insufficient active sites and low separation efficiency of photogenerated electrons and holes in existing semiconductor photocatalytic materials were solved, achieving a wide response to visible light and high catalytic performance.
Patent Information
- Application Number
- CN202511724353.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-23
- Publication Date
- 2026-01-13
AI Technical Summary
Existing semiconductor photocatalytic materials have a small number of surface active sites and insufficient catalytic reaction sites. They also have low separation efficiency of photogenerated electrons and holes, cannot effectively prevent the recombination of photogenerated electrons and holes, have poor carrier utilization, and weak response to visible light, resulting in poor catalytic performance.
Nickel sulfide quantum dots were combined with sulfur-doped π-conjugated polyimide to prepare a nickel sulfide/sulfur-doped polyimide composite catalytic material via solid-state thermal polymerization. The introduction of metal ion doping increases the concentration of photogenerated electrons in the conduction band, enhances the separation efficiency of photogenerated electrons and holes, and expands the material's response to visible light.
It significantly increases the number of active sites, enhances the separation efficiency of photogenerated electrons and holes, expands the material's response to visible light, and achieves the ability to efficiently decompose organic pollutants in water and produce hydrogen under the full spectrum, demonstrating excellent catalytic performance.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of photocatalytic materials technology, and in particular to a method for preparing a nickel sulfide quantum dot sulfur-doped π-conjugated polyimide composite catalytic material. Background Technology
[0002] Energy is a key pillar of modern economic development and a vital foundation for human survival and progress, playing an irreplaceable role in driving economic and social progress. Currently, environmental pollution and energy shortages are becoming increasingly severe problems. Photocatalysis technology can effectively decompose organic pollutants in water or utilize solar energy to decompose water into clean hydrogen energy, and this process does not generate new pollutants. Therefore, developing novel photocatalytic materials that can efficiently utilize sunlight for environmental remediation or clean energy production has become a cutting-edge research hotspot in the field of new materials.
[0003] Semiconductor materials possess a unique band structure, consisting of a valence band (VB) and a conduction band (CB). The energy difference between these two bands is called the band gap, which determines the material's response range to light. A narrower band gap results in a wider spectral response range, enabling more efficient utilization of solar energy. Under illumination, the valence and conduction bands of photocatalytic materials exhibit oxidizing and reducing properties, respectively: when the photon energy (hv) is greater than or equal to the band gap energy (Eg), electrons in the valence band absorb energy and transition to the conduction band, forming photogenerated electrons and leaving holes in the valence band, thus creating photogenerated electron-hole pairs. Photogenerated electrons possess strong reducing power, while holes possess strong oxidizing power, allowing photocatalytic reactions to occur. Therefore, improving the generation efficiency of photogenerated electron-hole pairs and reducing their recombination process are key to enhancing photocatalytic performance. However, existing semiconductor materials have a small number of active sites on their surface, resulting in insufficient catalytic reaction sites; low separation efficiency of photogenerated electrons and holes, which cannot effectively prevent the recombination of photogenerated electrons and holes, leading to poor carrier utilization; and weak response to visible light, resulting in a narrow range of solar energy utilization, thus causing poor catalytic effects of existing semiconductor materials. Summary of the Invention
[0004] To address the shortcomings of existing photocatalytic technologies and the defects of existing photocatalytic materials, this invention aims to propose a novel photocatalytic material that combines nickel sulfide quantum dots with sulfur-doped π-conjugated polyimide. This material has advantages such as simple preparation process, low cost, and excellent catalytic effect.
[0005] This invention provides a nickel sulfide / sulfur-doped polyimide composite catalytic material, the main raw materials of which are: 0.85-1 parts SPI and 0.0049-0.1543 parts nickel chloride; wherein the nickel chloride is prepared by reacting thioacetamide and nickel chloride hexahydrate solution.
[0006] A method for preparing a nickel sulfide / sulfur-doped polyimide composite catalytic material includes the following steps: The first step is to synthesize SPI through a solid-state thermal polymerization reaction; The second step is to prepare nickel sulfide (NiS): 0.74 (mass) parts of nickel chloride hexahydrate and 1.64 (mass) parts of thioacetamide are dissolved in an appropriate amount of deionized water in a reaction vessel. After heating and reacting, the solution is removed by post-treatment, and the NiS precipitate generated at the bottom is retained. After drying, black powdery solid particles are obtained. The third step is to prepare nickel sulfide / sulfur-doped π-conjugated polyimide: Weigh SPI and nickel chloride, dissolve them in deionized water, and heat and stir to mix them thoroughly; after stirring, wash and dry the sample thoroughly, and then grind it into a fine powder. Place the obtained sample in a semi-closed container, heat it to carry out a solid-phase thermal polymerization reaction, and after cooling, a pale yellow powdery solid is still obtained.
[0007] The first step, synthesizing SPI, specifically involves: mixing 1.0 (by mass) parts of melamine, 1.70 (by mass) parts of pyromellitic anhydride, and 0.90 parts of sublimed sulfur evenly and grinding thoroughly; grinding for 20-40 minutes until the mixture is ground into powder without any abrasive feel; placing it in a semi-closed container; heating the semi-closed container to carry out a solid-phase thermal polymerization reaction, and obtaining a pale yellow powdery solid after cooling.
[0008] The solid-phase thermal polymerization reaction is specifically controlled by heating to 325°C at a rate of 7°C per minute, calcining at 325°C for 4 hours, and then cooling to room temperature at the same rate of 7°C per minute.
[0009] The second step, the heating reaction, is carried out by oil bath heating at a temperature of 110°C for a reaction time of 3 hours. The post-processing method is as follows: after the reaction is completed, the solution is subjected to ultrasonic treatment to remove the supernatant; the drying treatment is to dry at 70°C for 8 hours.
[0010] The reaction temperature of the solid-phase thermal polymerization reaction in the third step is 125°C, and the reaction time is 4 hours.
[0011] The third step of stirring is carried out using electromagnetic stirring, with a stirring temperature of 55-60℃ and a stirring speed of 550-600r / min.
[0012] The third step involves the following main raw material ratios: 0.85-1 (by mass) parts SPI and 0.0049-0.1543 (by mass) parts nickel sulfide.
[0013] The aforementioned photocatalytic material is used for the photocatalytic decomposition of organic pollutants in water.
[0014] The photocatalytic material described herein can be used with a light source that is full-spectrum light, ultraviolet light, or visible light; it can function under different light source conditions such as full-spectrum light, ultraviolet light, or visible light.
[0015] By introducing metal or non-metal ions into semiconductor photocatalytic materials, not only are lattice vacancies or lattice type regulated in the crystal structure, but the doping of metal ions also increases the concentration of photogenerated electrons in the conduction band (CB). This ion doping strategy effectively increases the number of active sites, enhances the separation efficiency of photogenerated electrons and holes, and significantly expands the material's response to visible light.
[0016] This photocatalytic material can be directly applied to hydrogen production from water splitting or the degradation of organic pollutants in wastewater. Its application is flexible; it can be added directly to wastewater or combined with other photocatalytic materials or functionalized before being used in water treatment.
[0017] Furthermore, UV-Vis absorption spectroscopy analysis shows that this material possesses a wide absorption capacity extending from the UV region to the visible light region, and even approaching the near-infrared region. Using methyl orange as a model organic pollutant, it can achieve most of its degradation within 6–8 hours under full-spectrum irradiation, demonstrating excellent photocatalytic performance.
[0018] The beneficial effects of this invention are as follows: by introducing metal or non-metal ions into semiconductor photocatalytic materials, not only are lattice vacancies induced or the lattice type controlled in the crystal structure, but the doping of metal ions also increases the concentration of photogenerated electrons in the conduction band (CB). This ion doping strategy effectively increases the number of active sites, enhances the separation efficiency of photogenerated electrons and holes, and significantly expands the material's response to visible light.
[0019] This photocatalytic material can be directly applied to hydrogen production from water splitting or the degradation of organic pollutants in wastewater. Its application is flexible; it can be added directly to wastewater or combined with other photocatalytic materials or functionalized before being used in water treatment.
[0020] Furthermore, UV-Vis absorption spectroscopy analysis shows that this material possesses a wide absorption capacity extending from the UV region to the visible light region, and even approaching the near-infrared region. Using methyl orange as a model organic pollutant, it can achieve most of its degradation within 6–8 hours under full-spectrum irradiation, demonstrating excellent photocatalytic performance. Attached Figure Description
[0021] Figure 1 The X-ray diffraction pattern of the composite catalytic material synthesized in Example 1 of this invention; Figure 2 The X-ray diffraction pattern of the composite catalytic material synthesized in Example 2 of this invention; Figure 3The X-ray diffraction pattern of the composite catalytic material synthesized in Example 3 of this invention; Figure 4 The image shows a SEM image of the composite catalytic material synthesized in Example 2 of this invention. Figure 5 These are TEM images of the composite catalytic material synthesized in Example 2 of this invention; Figure 6 This is an activity curve of the composite catalytic material synthesized in Example 1 of the present invention for degrading methyl orange solution; Figure 7 This is an activity curve of the composite catalytic material synthesized in Example 2 of the present invention for degrading methyl orange solution; Figure 8 This is an activity curve of the composite catalytic material synthesized in Example 3 of the present invention for degrading methyl orange solution. Detailed Implementation
[0022] Example 1, Synthesis of SPI for later use: Mix 1.0g melamine, 1.70g pyromellitic anhydride, and 0.90g sublimed sulfur evenly and grind thoroughly; grind for 20-40 minutes until the mixture is ground into powder and has no abrasive feel; place it in a covered boat-shaped porcelain crucible, and partially cover it to form a semi-closed system; place the porcelain crucible in a tube furnace and heat it to carry out a solid-phase thermal polymerization reaction, raising the temperature to 325°C at a rate of 7°C per minute, calcining at 325°C for 4 hours, and then cooling it to room temperature at a rate of 7°C per minute; after cooling, a light yellow powdery solid is obtained, which is SPI, for later use.
[0023] Preparation of nickel sulfide (NiS): Weigh 0.74 g of nickel chloride hexahydrate and 1.64 g of thioacetamide, dissolve them in an appropriate amount of deionized water, and stir thoroughly until completely dissolved. Transfer the resulting solution to a three-necked flask and react in an oil bath at 110 °C for 3 hours. After the reaction, sonicate the solution, then transfer it to a beaker, carefully discard the supernatant, and retain the NiS precipitate formed at the bottom. Dry the precipitate in an oven at 70 °C for 8 hours to obtain black powdery nickel sulfide solid particles, which is nickel sulfide.
[0024] Weigh 0.9907g of SPI and 0.0192g of nickel sulfide using an electronic balance and place them into a beaker. Add 90ml of deionized water to the beaker. Gently shake to completely dissolve the chemicals. Turn on the magnetic stirrer, set the temperature to 60℃ and the speed to 550-600 (r / min), and mix the two thoroughly.
[0025] After stirring the solution for 3 hours, stirring was stopped. The resulting material was poured into a vacuum filtration funnel and washed with deionized water. After washing, it was placed in an oven and dried at 60°C for 8 hours. Then, it was gently ground into a fine powder. The resulting sample was placed in a covered boat-shaped porcelain crucible, with the lid partially closed to form a semi-closed system. It was then placed in a tube furnace and heated at 125°C for 4 hours to obtain a 1 wt% nickel disulfide quantum dot / sulfur-doped π-conjugated polyimide composite catalyst.
[0026] XRD pattern of nickel sulfide quantum dot sulfur-doped π-conjugated polyimide composite catalyst as shown in the figure. Figure 1 As shown. Figure 4 and Figure 5 These are SEM and TEM images of the obtained photocatalytic material. The microstructure shows that the polymer material has a layered structure, and nickel sulfide is attached to the SPI surface in the form of nanoparticles.
[0027] 0.2 g of the synthesized nickel sulfide quantum dot / sulfur-doped π-conjugated polyimide composite catalyst was placed in a photocatalytic reactor, and 400 ml of 40 mg / L methyl orange solution was added (10 ml of 400 mg / L methyl orange solution was added and diluted to 100 ml with deionized water). After stirring for 1 h, the xenon lamp source (full-width light) was turned on for photo-irradiation reaction. The degradation curve is shown below. Figure 6 As shown, under full-amplitude illumination, the photocatalytic degradation of the organic pollutant methyl orange achieved a degradation rate of over 90% after 7 hours. This indicates that, compared to the base material SPI, the dense NiS-SPI interface in this composite photocatalytic material facilitates the transport of photogenerated carriers, thereby significantly enhancing its photocatalytic activity.
[0028] Example 2, Synthesis of SPI for later use: Mix 1.0g melamine, 1.70g pyromellitic anhydride, and 0.90g sublimed sulfur evenly and grind thoroughly; grind for 20-40 minutes until the mixture is ground into powder and has no abrasive feel; place it in a covered boat-shaped porcelain crucible, and partially cover it to form a semi-closed system; place the porcelain crucible in a tube furnace and heat it to carry out a solid-phase thermal polymerization reaction, raising the temperature to 325°C at a rate of 7°C per minute, calcining at 325°C for 4 hours, and then cooling it to room temperature at a rate of 7°C per minute; after cooling, a light yellow powdery solid is obtained, which is SPI, for later use.
[0029] Preparation of nickel sulfide (NiS): Weigh 0.74 g of nickel chloride hexahydrate and 1.64 g of thioacetamide, dissolve them in an appropriate amount of deionized water, and stir thoroughly until completely dissolved. Transfer the resulting solution to a three-necked flask and react in an oil bath at 110 °C for 3 hours. After the reaction, sonicate the solution, then transfer it to a beaker, carefully discard the supernatant, and retain the NiS precipitate formed at the bottom. Dry the precipitate in an oven at 70 °C for 8 hours to obtain black powdery nickel sulfide solid particles, which is nickel sulfide.
[0030] Weigh 0.9502g of SPI and 0.0509g of nickel sulfide using an electronic balance and place them into a beaker. Add 90ml of deionized water to the beaker. Gently shake to completely dissolve the chemicals. Turn on the magnetic stirrer, set the temperature to 60℃ and the speed to 550-600 (r / min), and mix the two thoroughly.
[0031] After stirring the solution for 3 hours, stirring was stopped. The resulting material was poured into a vacuum filtration funnel and washed with deionized water. After washing, it was placed in an oven and dried at 60°C for 8 hours. Then, it was gently ground into a fine powder. The resulting sample was placed in a covered boat-shaped porcelain crucible, with the lid partially closed to form a semi-closed system. It was then placed in a tube furnace and heated at 125°C for 4 hours to obtain a 1 wt% nickel disulfide quantum dot / sulfur-doped π-conjugated polyimide composite catalyst.
[0032] The XRD pattern of the nickel sulfide quantum dot / sulfur-doped π-conjugated polyimide composite catalytic material is shown in the figure. Figure 2 As shown in the figure, compared with the original SPI material, the composite catalyst material with added nickel sulfide metal ions exhibits changes in the intensity of multiple diffraction peaks in the XRD pattern. Simultaneously, new diffraction peaks appear in the composite material's pattern, located at 2θ=45.59° and 2θ=53.28°, indicating the successful introduction of the nickel sulfide phase into the material.
[0033] 0.2 g of the synthesized nickel sulfide quantum dot sulfur / doped π-conjugated polyimide composite catalyst was placed in a photocatalytic reactor, and 400 ml of 40 mg / L methyl orange solution was added. After stirring for 1 h, a xenon lamp (full-width light) was turned on for photo-irradiation. The degradation process is as follows: Figure 7 As shown, the results indicate that the composite catalytic material has good photocatalytic performance and can effectively decompose organic pollutants in water.
[0034] Example 3, Synthesizing SPI: Mix 1.0g melamine, 1.70g pyromellitic anhydride, and 0.90g sublimed sulfur evenly and grind thoroughly for 20-40 minutes until the mixture is powdery and has no abrasive feel; place it in a covered boat-shaped porcelain crucible, partially covering the lid to form a semi-closed system; place the porcelain crucible in a tube furnace and heat to carry out a solid-phase thermal polymerization reaction, raising the temperature to 325℃ at a rate of 7℃ per minute, calcining at 325℃ for 4 hours, and then cooling to room temperature at a rate of 7℃ per minute; after cooling, a pale yellow powdery solid is obtained, which is SPI, for later use.
[0035] Preparation of nickel sulfide (NiS): Weigh 0.74 g of nickel chloride hexahydrate and 1.64 g of thioacetamide, dissolve them in an appropriate amount of deionized water, and stir thoroughly until completely dissolved. Transfer the resulting solution to a three-necked flask and react in an oil bath at 110 °C for 3 hours. After the reaction, sonicate the solution, then transfer it to a beaker, carefully discard the supernatant, and retain the NiS precipitate formed at the bottom. Dry the precipitate in an oven at 70 °C for 8 hours to obtain black powdery nickel sulfide solid particles, which is nickel sulfide.
[0036] Weigh 0.9003 g of SPI and 0.1009 g of nickel sulfide using an electronic balance and place them sequentially into a beaker. Add 90 ml of deionized water to the beaker. Gently shake to completely dissolve the chemicals. Turn on the magnetic stirrer, set the temperature to 60°C and the speed to 550-600 rpm, and mix the two thoroughly.
[0037] After stirring the solution for 3 hours, stirring was stopped. The resulting material was poured into a vacuum filtration funnel and washed with deionized water. After washing, it was placed in an oven and dried at 60°C for 8 hours. Then, it was gently ground into a fine powder. The resulting sample was placed in a covered boat-shaped porcelain crucible, with the lid partially closed to form a semi-closed system. It was then placed in a tube furnace and heated at 125°C for 4 hours to obtain a 1 wt% nickel disulfide quantum dot / sulfur-doped π-conjugated polyimide composite catalyst.
[0038] The XRD pattern of the nickel sulfide quantum dot / sulfur-doped π-conjugated polyimide composite catalytic material is shown in the figure. Figure 3 As shown, it can be seen that as the amount of nickel disulfide increases, the peak intensity caused by the internal structure of SPI gradually decreases.
[0039] 0.2 g of the synthesized nickel sulfide quantum dot / sulfur-doped π-conjugated polyimide composite catalyst was placed in a photocatalytic reactor, and 400 ml of 40 mg / L methyl orange solution was added. After stirring for 1 h, a xenon lamp source (full-width light) was turned on for photo-irradiation reaction. The degradation curve is shown below. Figure 8 As shown.
Claims
1. A nickel sulfide / sulfur-doped polyimide composite catalytic material, characterized in that, The main raw materials are: 0.85-1 parts SPI and 0.0049-0.1543 parts nickel chloride; the nickel chloride is prepared by reacting thioacetamide and nickel chloride hexahydrate solution.
2. A method for preparing a nickel sulfide / sulfur-doped polyimide composite catalytic material, characterized in that, Includes the following steps: The first step is to synthesize SPI through a solid-state thermal polymerization reaction; The second step is to prepare nickel sulfide: 0.74 parts of nickel chloride hexahydrate and 1.64 parts of thioacetamide are dissolved in an appropriate amount of deionized water in a reaction vessel, heated to react, and then post-processed to remove the solution. The NiS precipitate generated at the bottom is retained and dried to obtain black powdery solid particles. The third step is to prepare nickel sulfide / sulfur-doped π-conjugated polyimide: weigh SPI and nickel chloride, dissolve them in deionized water, heat and stir to mix them thoroughly; after stirring, wash and dry the sample thoroughly, and then grind it into a fine powder; place the obtained sample in a semi-closed container, heat it to carry out solid-phase thermal polymerization reaction, and after cooling, a light yellow powdery solid is still obtained.
3. The method for preparing a nickel sulfide / sulfur-doped polyimide composite catalytic material according to claim 2, characterized in that, The first step, synthesizing SPI, specifically involves: mixing 1.0 part melamine, 1.70 parts pyromellitic anhydride, and 0.90 parts sublimed sulfur evenly and grinding thoroughly; grinding for 20-40 minutes until the mixture is ground into powder without any abrasive feel; placing it in a semi-closed container; heating the semi-closed container to carry out a solid-phase thermal polymerization reaction, and obtaining a pale yellow powdery solid after cooling.
4. The method for preparing a nickel sulfide / sulfur-doped polyimide composite catalytic material according to claim 3, characterized in that, The solid-phase thermal polymerization reaction is specifically controlled by heating to 325°C at a rate of 7°C per minute, calcining at 325°C for 4 hours, and then cooling to room temperature at the same rate of 7°C per minute.
5. The method for preparing a nickel sulfide / sulfur-doped polyimide composite catalytic material according to claim 4, characterized in that, The second step, the heating reaction, is carried out by oil bath heating at a temperature of 110°C for a reaction time of 3 hours; the post-treatment method is as follows: after the reaction, the solution is subjected to ultrasonic treatment to remove the supernatant; the drying treatment is carried out at 70°C for 8 hours.
6. The method for preparing a nickel sulfide / sulfur-doped polyimide composite catalytic material according to claim 5, characterized in that, The reaction temperature of the solid-phase thermal polymerization reaction in the third step is 125°C, and the reaction time is 4 hours.
7. The method for preparing a nickel sulfide / sulfur-doped polyimide composite catalytic material according to claim 6, characterized in that, The third step of stirring is carried out using electromagnetic stirring, with a stirring temperature of 55-60℃ and a stirring speed of 550-600r / min.
8. The method for preparing a nickel sulfide / sulfur-doped polyimide composite catalytic material according to claim 7, characterized in that, The third step involves the following main raw material ratios: 0.85-1 parts SPI and 0.0049-0.1543 parts nickel sulfide.
9. A nickel sulfide / sulfur-doped polyimide composite catalytic material, characterized in that, The photocatalytic material is prepared by the method described in claim 1 or any one of claims 2-8 and is used for the photocatalytic decomposition of organic pollutants in water.
10. The nickel sulfide / sulfur-doped polyimide composite catalytic material according to claim 9, characterized in that the light source used for the photocatalytic material can be full-width light, ultraviolet light, or visible light.