Gold nanoparticle modified graphite phase carbon nitride photocatalytic gel
By reducing gold nanoparticles in situ on the surface of graphite phase carbon nitride and dispersing them in PDMS gel, the efficiency and dispersion of g-C3N4 in photocatalytic applications are solved, and an efficient and stable photocatalytic reaction is achieved.
Patent Information
- Application Number
- CN202510111772.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-23
- Publication Date
- 2025-05-30
AI Technical Summary
In photocatalytic applications, graphite carbon nitride (g-C3N4) has problems such as high electron-hole recombination rate, large size, poor dispersion and low light absorption, resulting in limited photocatalytic efficiency and application range.
The gold nanoparticles-modified graphite phase carbon nitride photocatalytic gel is formed by reducing chloroaulic acid in situ to gold nanoparticles on the surface of g-C3N4 and dispersing it in a polydimethylsiloxane (PDMS) gel.
The photocatalytic activity and selectivity of the material are significantly improved, settling and aggregation are avoided, the efficiency of photocatalytic reactions is improved, and the stability and service life of the catalyst are enhanced.
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Figure CN120054567A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to a gold nanoparticle-modified graphitic carbon nitride photocatalytic gel, belonging to the technical field of photocatalysts. Background Art
[0002] Due to its high efficiency, greenness, and pollution-free characteristics, photocatalytic technology has broad application prospects in environmental governance and energy conversion. Graphitic carbon nitride (g-C 3 N 4 ) has stable chemical properties and a moderate bandgap (~2.7 eV), and is an excellent non-metallic semiconductor material, widely used in fields such as photocatalytic water splitting for hydrogen production and carbon dioxide reduction. However, g-C 3 N 4 has a high electron-hole recombination rate, which limits its photocatalytic efficiency.
[0003] Coupling plasmonic metal nanoparticles (such as gold) with g-C 3 N 4 can expand the visible light response range of g-C 3 N 4 and improve carrier migration, thereby enhancing its photocatalytic activity and selectivity. By in-situ reducing chloroauric acid on the surface of g-C 3 N 4 , it is possible to ensure the uniform distribution of gold nanoparticles on the surface of carbon nitride and reduce the agglomeration phenomenon; at the same time, in-situ reduction can enhance the interaction between the metal and carbon nitride, improve the stability of the metal, and thus maximize the catalytic efficiency.
[0004] However, the size of g-C 3 N 4 is usually in the micron scale, is unevenly dispersed in the solvent, is prone to sedimentation, and has a low light absorption rate, thus limiting its application range. Although methods such as grinding and ultrasonic fragmentation can reduce the size of g-C 3 N 4 to the nanoscale, there is still a problem of large loss of catalytic efficiency after loading metal nanoparticles. Summary of the Invention
[0005] In view of this, the present application provides a gold nanoparticle-modified graphitic carbon nitride photocatalytic gel. By in-situ reducing chloroauric acid on the surface of g-C 3 N 4 to gold nanoparticles, the photocatalytic activity of the material is significantly improved, and it is further dispersed in a polydimethylsiloxane (PDMS) gel to prepare Au / C 3 N 4A photocatalytic gel that can be uniformly dispersed in PDMS and can reduce carbon dioxide under visible light irradiation to produce carbon monoxide, to overcome the problem of poor dispersibility of carbon nitride in the prior art.
[0006] Specifically, the present application is achieved through the following solutions: A gold nanoparticle-modified graphitic carbon nitride photocatalytic gel, chloroauric acid trihydrate is dissolved in water, and g-C 3 N 4 is added and stirred. During the stirring process, it is irradiated with a xenon lamp, and the precipitate is collected by centrifugation and dried in vacuo to obtain Au / C 3 N 4 ; Au / C 3 N 4 is dispersed in a mixture of PDMS base components and a curing agent. After ultrasonic fragmentation, the resulting mixture is transferred to a mold, cured, and demolded to obtain a gold nanoparticle-modified graphitic carbon nitride photocatalytic gel.
[0007] In the present application, by encapsulating metal nanoparticle-modified g-C 3 N 4 (Au / C 3 N 4 ) in the PDMS gel, it can better maintain a uniformly dispersed state, avoid sedimentation and aggregation, thereby improving the efficiency of the photocatalytic reaction. This solvent-free gel form ensures high stability and high mechanical strength of the photocatalyst during use, while avoiding the problems of catalyst sedimentation and catalyst deactivation in the solution system, further improving the service life and photocatalytic performance of the catalyst.
[0008] Furthermore, as a preference: The preparation method of the g-C 3 N 4 is as follows: Melamine powder is spread flat in an alumina crucible. After calcining melamine in an inert gas environment and cooling to room temperature, it is ground to obtain g-C 3 N 4 powder. More preferably, the inert gas is an inert gas such as nitrogen or argon, the calcination temperature is 500 - 600 °C, such as 500 °C, 550 °C, 600 °C; the calcination time is 3 - 6 h, such as 3 h, 4 h, 5 h, 6 h; the temperature is raised from room temperature to the calcination temperature at a heating rate of 1 - 5 °C / min, such as 1 °C / min, 2 °C / min, 3 °C / min, 4 °C / min, 5 °C / min. The grinding duration is 0.5 - 3 h, such as 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h. By mechanical force, the agglomerated large particles of g-C 3 N 4 are reduced to a size of micron level and below in diameter.
[0009] The mass ratio of the g-C 3 N 4 and water is 1:100 to 500, such as 1:100, 1:200, 1:300, 1:400, 1:500. The mass ratio of chloroauric acid trihydrate and g-C 3 N 4 is 1:10 to 50, such as 1:10, 1:20, 1:30, 1:40, 1:50.
[0010] The power of the xenon lamp irradiation is 100 to 500 W, such as 100 W, 200 W, 300 W, 400 W, 500 W. The irradiation time is 1 to 5 h, such as 1 h, 2 h, 3 h, 4 h, 5 h.
[0011] The rotation speed of the centrifugation is 6000 to 10000 rpm, such as 6000 rpm, 7000 rpm, 8000 rpm, 9000 rpm, 10000 rpm. The centrifugation duration is 5 to 10 min, such as 5 min, 6 min, 7 min, 8 min, 9 min, 10 min.
[0012] The basic component is the A component of Dow Corning 184 PDMS, and the curing agent is the B component of Dow Corning 184 PDMS; the mass ratio of the curing agent and the basic component is 1:8 to 12, such as 1:8, 1:9, 1:10, 1:11, 1:12. Au / C 3 N 4 is dispersed in the curing agent, and after ultrasonic crushing, it is stirred and mixed evenly with the PDMS basic component. The mass ratio of Au / C 3 N 4 and the curing agent is 1:10 to 200, such as 1:10, 1:20, 1:50, 1:100, 1:200.
[0013] The power of the ultrasonic crushing is 200 to 600 W, such as 200 W, 300 W, 400 W, 500 W, 600 W. The duty cycle of the ultrasonic crushing is 30 to 70%, such as 30%, 40%, 50%, 60%, 70%. The time of the ultrasonic crushing is 1 to 5 min, such as 1 min, 2 min, 3 min, 4 min, 5 min.
[0014] The mold materials used for curing include silicone, polytetrafluoroethylene, etc., the shapes include cylinders, cuboids, etc., and the curing process is static. The curing temperature is 25 to 50 °C, such as 25 °C, 30 °C, 35 °C, 40 °C, 45 °C, 50 °C. The curing time is 12 to 48 h, such as 12 h, 24 h, 36 h, 48 h.
[0015] The photocatalytic gel obtained by the above method is a semi-transparent, Au / C3 N 4 An elastomer uniformly distributed in the whole. When irradiated by visible light, the photocatalytic gel can reduce carbon dioxide to carbon monoxide, and the light source can also be buried in the gel to construct an integrated photocatalytic carbon dioxide reduction device. The photocatalytic gel has good application prospects in the fields of renewable fuel production, carbon monoxide treatment, etc. Description of the Drawings
[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0017] Figure 1 TEM image of the sample obtained in Example 1; Figure 2 Relationship between the concentration of carbon monoxide photocatalytically produced by the sample obtained in Example 1 and the illumination time; Figure 3 Photograph of the photocatalytic gel obtained in Example 1. Detailed Description of the Embodiments
[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the following will further elaborate on the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the technical solutions of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.
[0019] Example 1
[0020] The method for obtaining the photocatalytic gel of graphitic carbon nitride modified with gold nanoparticles in this example is as follows: Step 1: Spread 3 g of melamine evenly in an alumina crucible, heat it to 550 °C at a heating rate of 3 °C / min in a nitrogen atmosphere, keep calcining for 3 hours, cool to room temperature, and then grind for 1 h to obtain a solid powder.
[0021] Step 2: Add 1 g of the solid powder obtained in Step 1 to 200 mL of water, add 25 mg of chloroauric acid trihydrate, irradiate with a 300 W xenon lamp for 3 hours under stirring, then centrifuge at 8000 rpm for 10 min to obtain a precipitate, and dry it under vacuum for standby.
[0022] Step 3: Disperse 50 mg of the precipitate obtained in Step 2 in 1 g of the curing agent. After ultrasonic fragmentation at a power of 500 W and a duty cycle of 50% for 1 minute, mix it evenly with 10 g of the basic component. Pour the mixture into a mold and let it stand and cure at 30 °C for 24 hours to obtain the photocatalytic gel; the basic component is Component A of Dow Corning 184 PDMS, and the curing agent is Component B of Dow Corning 184 PDMS.
[0023] Figure 1 The left figure in [reference] is a photo of the solid powder of the product in Step 1, and the right figure is a photo of the precipitate of the product in Step 2. By comparison, it can be seen that after the treatment in Step 2, many particles appear on the surface of the product in Step 1. Magnify this particle. As shown by the lattice spacing of gold in the upper right corner of the right figure, it indicates that gold nanoparticles are modified on the surface of carbon nitride.
[0024] Figure 2 shows the relationship between the concentration of carbon monoxide photocatalytically produced by the sample and the illumination time: when illuminated with a 300 W xenon lamp for 1 h, the concentration of carbon monoxide produced by the photocatalyst obtained in Example 1 is 3.1 μmol / g, and the g-C 3 N 4 only produces 1.2 μmol / g of carbon monoxide; when illuminated for 4 h, the concentration of carbon monoxide produced by the photocatalyst obtained in Example 1 is 5.2 μmol / g, and the g-C 3 N 4 only produces 4.0 μmol / g of carbon monoxide. This shows that Au / C 3 N 4 has a higher catalytic efficiency for carbon dioxide and selectivity for producing carbon monoxide compared to C 3 N 4 .
[0025] Figure 3 is a photo of the photocatalytic gel obtained in Example 1. It can be seen that: the photocatalytic gel prepared in this example is a blue-violet transparent elastomer, and the blue-violet Au / C 3 N 4 is evenly dispersed in the PDMS gel without visible particles to the naked eye.
[0026] Example 2
[0027] The method for obtaining the photocatalytic gel of graphitic carbon nitride modified with gold nanoparticles in this example is as follows: Step 1: Spread 3 g of melamine flat in an alumina crucible. Under a nitrogen atmosphere, heat it at a heating rate of 3 °C / min to 500 °C, keep calcining for 3 hours, cool to room temperature, and then grind for 1 h to obtain a solid powder.
[0028] Step 2: Add 1 g of the solid powder obtained in Step 1 to 200 mL of water, add 25 mg of chloroauric acid trihydrate, irradiate with a 200 W xenon lamp for 1 hour under stirring, then centrifuge at 8000 rpm for 10 min to obtain a precipitate, and dry it under vacuum for standby.
[0029] Step 3: Disperse 50 mg of the precipitate obtained in Step 2 in 2 g of curing agent, ultrasonically crush it at a power of 500 W and a duty cycle of 50% for 1 minute, and then mix it evenly with 20 g of the basic component. Pour the mixture into a mold and let it stand and cure at 30 °C for 24 hours to obtain a photocatalytic gel; the basic component is the A component of Dow Corning 184 PDMS, and the curing agent is the B component of Dow Corning 184 PDMS.
[0030] The obtained photocatalytic gel has a color and structure similar to those of Example 1 and shows selectivity for the catalytic reduction of carbon dioxide.
[0031] Example 3
[0032] The method for obtaining the photocatalytic gel modified with gold nanoparticles in this example is as follows: Step 1: Spread 4 g of melamine evenly in an alumina crucible, heat it to 450 °C at a heating rate of 5 °C / min in a nitrogen atmosphere, keep calcining for 3 hours, cool it to room temperature, and then grind it for 0.5 h to obtain a solid powder.
[0033] Step 2: Add 1 g of the solid powder obtained in Step 1 to 400 mL of water, add 10 mg of chloroauric acid trihydrate, irradiate with a 400 W xenon lamp for 3 hours under stirring, then centrifuge at 6000 rpm for 5 min to obtain a precipitate, and dry it under vacuum for standby.
[0034] Step 3: Disperse 50 mg of the precipitate obtained in Step 2 in 2 g of curing agent, ultrasonically crush it at a power of 300 W and a duty cycle of 40% for 2 minutes, and then mix it evenly with 20 g of the basic component. Pour the mixture into a mold and let it stand and cure at 30 °C for 24 hours to obtain a photocatalytic gel; the basic component is the A component of Dow Corning 184 PDMS, and the curing agent is the B component of Dow Corning 184 PDMS.
[0035] The obtained photocatalytic gel has a color and structure similar to those of Example 1 and shows selectivity for the catalytic reduction of carbon dioxide.
[0036] Comparative Example 1
[0037] The method for obtaining the photocatalytic gel in this comparative example is as follows: Step 1: Spread 3 g of melamine evenly in an alumina crucible, heat it to 550 °C at a heating rate of 5 °C / min in a nitrogen atmosphere, keep calcining for 3 hours, cool it to room temperature, and then grind it for 1 h to obtain a solid powder.
[0038] Step 2: Add 2 g of the solid powder obtained in Step 1 to 300 mL of water, add 10 mg of chloroauric acid trihydrate, irradiate with a 100 W xenon lamp for 3 hours under stirring, then centrifuge at 8000 rpm for 5 min to obtain a precipitate, and dry it under vacuum for standby.
[0039] Step 3: Disperse 50 mg of the precipitate obtained in Step 2 in 1 g of curing agent, ultrasonically crush it for 1 minute at a power of 300 W and a duty cycle of 40%, and then mix it evenly with 16 g of the basic component. Pour the mixture into a mold and let it stand and cure at 30 °C for 24 hours to obtain a gel.
[0040] In the above scheme, the low proportion of the curing agent results in incomplete curing of the obtained gel, which is viscous and difficult to demold, failing to meet the stability requirements.
[0041] Comparative Example 2
[0042] The method for obtaining the photocatalytic gel in this comparative example is the same as that in Example 1, except that in Step 1, only calcination and cooling to room temperature are carried out, and grinding is not performed.
[0043] The obtained product has relatively large solid particles, which are still visible to the naked eye when dispersed in the gel.
[0044] Comparative Example 3
[0045] The method for obtaining the photocatalytic gel in this comparative example is the same as that in Example 1, except that chloroauric acid is not added in Step 2. The obtained precipitate is still light yellow, but the selectivity for carbon dioxide is not good and the catalytic efficiency is low.
[0046] Comparative Example 4
[0047] The method for obtaining the photocatalytic gel in this comparative example is the same as that in Example 1, except that it is not irradiated with a xenon lamp in Step 2. The obtained precipitate is still light yellow, but the selectivity for carbon dioxide is not good and the catalytic efficiency is low.
[0048] Comparative Example 5
[0049] The method for obtaining the photocatalytic gel in this comparative example is the same as that in Example 1, except that ultrasonic crushing is not used in Step 3. There are still solids visible to the naked eye in the obtained photocatalytic gel, and the photocatalyst is not evenly dispersed.
[0050] Comparative Example 6
[0051] The method for obtaining the photocatalytic gel in this comparative example is the same as that in Example 1, except that in Step 3, curing is carried out at 4 °C for 72 h. The too low temperature results in almost no curing finally, and the photocatalyst settles to the bottom, with uneven dispersion.
[0052] In the process of obtaining the photocatalytic gel of the above embodiment, melamine is first calcined to obtain graphitic carbon nitride, and then the graphitic carbon nitride is dispersed in an aqueous solution of chloroauric acid. The chloroauric acid is in-situ reduced to gold nanoparticles on the surface of the carbon nitride by light irradiation. Finally, the graphitic carbon nitride modified with gold nanoparticles is uniformly dispersed in the polydimethylsiloxane gel by ultrasonic fragmentation, and the photocatalytic gel of graphitic carbon nitride modified with gold nanoparticles is obtained. The preparation method of the photocatalytic gel synthesized by the present invention is simple and efficient. Using it as a catalyst for reducing carbon dioxide to carbon monoxide has the advantages of high selectivity and uniform dispersion of the photocatalyst, and is suitable for applications such as the production of carbon monoxide renewable energy or carbon monoxide treatment in vivo.
[0053] The above embodiments only represent several feasible implementation modes of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. The embodiments are not intended to limit the protection scope in the claims of the present invention. For those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made. Any equivalent implementation or change made without departing from the present invention should be included in the technology of the present invention.
Claims
1. A gold nanoparticle-modified graphite phase carbon nitride photocatalytic gel, characterized in that: Chloroauric acid trihydrate is dissolved in water, g-C3N4 is added and stirred, and during the stirring process, the mixture is irradiated with a xenon lamp, and the precipitate is collected by centrifugation and vacuum dried to obtain Au / C3N4; Au / C3N4 is dispersed in a basic component of polydimethylsiloxane and a curing agent, and after ultrasonic crushing, the obtained mixture is transferred to a mold, cured, and demolded to obtain a graphite phase carbon nitride photocatalytic gel modified with gold nanoparticles.
2. The gold nanoparticle-modified graphite-phase carbon nitride photocatalytic gel according to claim 1, characterized in that: The preparation method of g-C3N4 is as follows: melamine powder is spread in an alumina crucible, melamine is calcined in an inert gas environment, cooled to room temperature, and ground to obtain g-C3N4 powder.
3. The gold nanoparticle-modified graphite-phase carbon nitride photocatalytic gel according to claim 2, characterized in that: The calcination temperature is 500~600℃, and the calcination time is 3~6h.
4. The gold nanoparticle-modified graphite-phase carbon nitride photocatalytic gel according to claim 2, characterized in that: The grinding time is 0.5 to 3 hours.
5. The gold nanoparticle-modified graphite-phase carbon nitride photocatalytic gel according to claim 2, characterized in that: The mass ratio of the g-C3N4 to water is 1:100-500, and the mass ratio of chloroauric acid trihydrate to g-C3N4 is 1:10-50.
6. The gold nanoparticle-modified graphite-phase carbon nitride photocatalytic gel according to claim 1, characterized in that: The xenon lamp irradiation power is 100-500W, and the irradiation time is 1-5h.
7. The gold nanoparticle-modified graphite-phase carbon nitride photocatalytic gel according to claim 1, characterized in that: The centrifugal speed is 6000-10000 rpm, and the centrifugal time is 5-10 min.
8. The gold nanoparticle-modified graphite-phase carbon nitride photocatalytic gel according to claim 1, characterized in that: The power of the ultrasonic crushing is 200-600W, the duty cycle of the ultrasonic crushing is 30-70%, and the time of the ultrasonic crushing is 1-5min.
9. The gold nanoparticle-modified graphite-phase carbon nitride photocatalytic gel according to claim 1, characterized in that: The basic component is component A of Dow Corning 184 PDMS, and the curing agent is component B of Dow Corning 184 PDMS; the mass ratio of the curing agent to the basic component is 1:8-12, and the mass ratio of Au / C3N4 to the curing agent is 1:10-200.
10. The gold nanoparticle-modified graphite-phase carbon nitride photocatalytic gel according to claim 1, characterized in that: The curing temperature is 25~50℃ and the curing time is 12~48h.