Ag2s@ta2o5 heterojunction photocatalyst and application in conversion of low concentration co2 into solar fuel
By preparing Ag2S@Ta2O5 heterojunction photocatalysts and forming 0D/1D heterojunction structures, the problem of low efficiency in converting low-concentration CO2 into solar fuels was solved, achieving efficient, green, and safe photocatalytic conversion, which is suitable for large-scale production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUBEI NORMAL UNIV
- Filing Date
- 2023-09-22
- Publication Date
- 2026-06-12
AI Technical Summary
Existing technologies are not effective at converting low-concentration CO2 into solar fuels, and the reusability of photocatalysts and carrier separation efficiency need to be improved.
Ag2S@Ta2O5 heterojunction photocatalysts were prepared by forming an 0D/1D heterojunction structure through Ta2O5 fiber membranes and Ag2S nanoparticles, and then using an electrospinning-assisted co-precipitation method. This method combines the advantages of nanoparticles and thin films to achieve trapezoidal charge transfer.
It improves light absorption capacity and carrier separation efficiency, and realizes the efficient conversion of low-concentration CO2 into solar fuel. The preparation process is simple, low-cost, and suitable for large-scale production.
Smart Images
Figure CN117427659B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photocatalysis technology, specifically to an Ag2S@Ta2O5 heterojunction photocatalyst and its application in converting low-concentration CO2 into solar fuel. Background Technology
[0002] The rapid development of the social economy and the continuous advancement of industrialization have brought about serious climate, environmental, and energy problems. How to effectively solve these problems has become a global challenge. The combustion of fossil fuels and human activities have led to a continuous increase in the amount of carbon dioxide (CO2) in the atmosphere, resulting in global warming. To alleviate the greenhouse effect and energy crisis, the development of innovative energy technologies is urgently needed. Therefore, it is crucial to seek new renewable energy supply methods while developing CO2 enrichment and conversion technologies to reduce atmospheric CO2 levels. Furthermore, the carbon-containing products obtained from catalytic conversion can be further used as energy sources or chemical raw materials, achieving the recycling of CO2. One-dimensional nanofibers, compared to particulate photocatalysts, have advantages such as shorter ion migration rates and unique one-dimensional electron transfer orbitals. The porous structure on the surface of nanofibers often has a high specific surface area and porosity, which is beneficial for the adsorption of low-concentration CO2 and the desorption of products during photocatalytic CO2 reduction. Simultaneously, it promotes the rapid diffusion and migration of low-concentration CO2 and products on the catalyst surface, thereby greatly improving the efficiency of photocatalytic reduction of low-concentration CO2. Summary of the Invention
[0003] The technical problem to be solved by the present invention is to provide an Ag2S@Ta2O5 heterojunction photocatalyst and its application in converting low-concentration CO2 into solar fuel, so as to overcome the shortcomings of the prior art.
[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: an Ag2S@Ta2O5 heterojunction photocatalyst, wherein the (001) diffraction crystal plane of the Ta2O5 fiber film and the (031) diffraction crystal plane of the Ag2S nanoparticles interweave to form a heterojunction interface, and the Ag2S nanoparticles are uniformly attached to the surface of the Ta2O5 fiber film to form a tightly contacted 0D / 1D heterojunction structure.
[0005] Based on the above technical solution, the present invention can be further improved as follows.
[0006] Furthermore, the mass fraction of Ag2S in the Ag2S@Ta2O5 heterojunction photocatalyst is 2% to 10%.
[0007] Furthermore, the mass fraction of Ag2S in the Ag2S@Ta2O5 heterojunction photocatalyst is 5%.
[0008] Based on the above technical solution, the present invention also provides a method for preparing Ag2S@Ta2O5 heterojunction photocatalyst, comprising the following steps:
[0009] S100. Disperse the Ta2O5 fiber membrane photocatalyst in deionized water, then add silver nitrate and sodium sulfide to dissolve and stir to obtain a black solution containing the Ta2O5 fiber membrane.
[0010] S200. Place the black solution in the dark and stir to obtain a solution containing a gray fiber membrane.
[0011] S300. The solution containing the gray fiber membrane is washed and dried to obtain the Ag2S@Ta2O5 heterojunction photocatalyst after impregnation and precipitation treatment.
[0012] Furthermore, the preparation method of the Ta2O5 fiber membrane photocatalyst used in S100 is as follows:
[0013] S110, take pentaethyl tantalum and polyvinylpyrrolidone K90 and dissolve them in a mixed solution of glacial acetic acid and anhydrous ethanol, and stir continuously to obtain a colorless and transparent solution;
[0014] S120. Electrospinning of a colorless and transparent solution at a certain flow rate and voltage yields a Ta2O5 intermediate fiber membrane.
[0015] S130. The Ta2O5 intermediate fiber membrane is calcined to obtain the Ta2O5 fiber membrane photocatalyst.
[0016] Furthermore, the flow rate is 0.2 mL / h to 0.8 mL / h, and the voltage is 15 kV to 21 kV.
[0017] Furthermore, the flow rate was 0.6 mL / h and the voltage was 18 kV.
[0018] Furthermore, the calcination temperature is 650℃~850℃, the time is 60min~180min, and the heating rate is 1℃ / min~7℃ / min.
[0019] Furthermore, the calcination temperature is 750℃, the time is 120 min, and the heating rate is 5℃ / min. Based on the above technical solution, this invention also provides an application of Ag2S@Ta2O5 heterojunction photocatalyst to convert low-concentration CO2 into solar fuel under sunlight irradiation.
[0020] Furthermore, the solar fuels are CO and CH4.
[0021] The beneficial effects of this invention are:
[0022] 1) Due to the formation of the ladder-shaped heterojunction, the Ag2S@Ta2O5 heterojunction photocatalyst has stronger light absorption capacity and higher carrier separation efficiency, resulting in superior performance. By changing the ratio of Ag2S to Ta2O5, ladder-shaped heterojunction photocatalysts with different mass ratios can be obtained. In-situ X-ray photoelectron spectroscopy analysis proves that this fiber membrane composite photocatalyst follows the ladder-shaped charge transfer mechanism.
[0023] 2) The Ag2S@Ta2O5 heterojunction photocatalyst combines the advantages of nanoparticles and thin films, which is beneficial for the reuse of photocatalysts and can be prepared on a large scale.
[0024] 3) An Ag2S@Ta2O5 heterojunction photocatalyst for photocatalytic low-concentration CO2 conversion was prepared by a simple electrospinning-assisted coprecipitation method. The reaction principle of coprecipitation is that the surface energy and large specific surface area of Ta2O5 fiber membrane facilitate the deposition of metal ions on the surface of nanofibers and the formation of metal sulfides. The entire synthesis process in this invention is simple, low-cost and highly efficient.
[0025] 4) Photocatalysis technology: Using simulated sunlight as energy, low-concentration CO2 can be converted into solar fuels represented by CO and CH4. It is an efficient, green, and safe clean energy technology. It has been proven that the Ag2S@Ta2O5 heterojunction photocatalyst has excellent photocatalytic activity under simulated sunlight irradiation. The catalyst is simple to prepare and has low cost. Attached Figure Description
[0026] Figure 1 Transmission electron microscope and high-resolution transmission electron microscope images of 5% Ag2S@Ta2O5;
[0027] Figure 2 In-situ X-ray photoelectron spectra of Ta 4f for Ta2O5 and 5% Ag2S@Ta2O5 samples;
[0028] Figure 3 In-situ X-ray photoelectron spectra of Ag₂S and 5% Ag₂S@Ta₂O₅ samples;
[0029] Figure 4 The image shows the photocatalytic reduction effect of a series of photocatalyst samples on low-concentration CO2. Detailed Implementation
[0030] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.
[0031] Example 1
[0032] An Ag2S@Ta2O5 heterojunction photocatalyst is provided. In the Ag2S@Ta2O5 heterojunction photocatalyst, the (001) diffraction crystal plane of the Ta2O5 fiber film and the (031) diffraction crystal plane of Ag2S nanoparticles interweave to form a heterojunction interface. The Ag2S nanoparticles are uniformly attached to the surface of the Ta2O5 fiber film to form a tightly contacted OD / 1D heterojunction structure. In this embodiment, the mass fraction of Ag2S in the Ag2S@Ta2O5 heterojunction photocatalyst is 2%.
[0033] Its preparation method is as follows:
[0034] Take 0.78g pentaethyltantalum and 0.45g polyvinylpyrrolidone K90 and dissolve them in a mixed solution of 1.5mL glacial acetic acid and 5mL anhydrous ethanol. Stir continuously for 60min to obtain a colorless and transparent solution.
[0035] Then, the colorless and transparent solution was electrospun at a flow rate of 0.6 mL / h and a voltage of 18 kV to obtain Ta2O5 intermediate fiber membrane.
[0036] The Ta2O5 intermediate fiber membrane was then calcined at 750℃ for 120 min with a heating rate of 5℃ / min to obtain the Ta2O5 fiber membrane photocatalyst.
[0037] Weigh 3.1g of Ta2O5 fiber membrane photocatalyst and disperse it in 25mL of deionized water. Then, dissolve 0.5mmol of silver nitrate and 0.5mmol of sodium sulfide in deionized water and stir at a constant speed of 550 rpm to obtain a black solution containing Ta2O5 fiber membrane.
[0038] The black solution was stirred in the dark for 24 hours to obtain a solution containing a gray fiber membrane.
[0039] Finally, the solution containing the gray fiber membrane was washed and dried to obtain the Ag2S@Ta2O5 heterojunction photocatalyst after impregnation and precipitation treatment. Since the mass fraction of Ag2S in the Ag2S@Ta2O5 heterojunction photocatalyst is 2%, it is labeled as: 2%Ag2S@Ta2O5.
[0040] Example 2
[0041] The difference between this embodiment and Example 1 is that 1.24g of Ta2O5 fiber membrane photocatalyst was weighed and dispersed in 25mL of deionized water. Since the mass fraction of Ag2S in the Ag2S@Ta2O5 heterojunction photocatalyst is 5%, it is labeled as: 5%Ag2S@Ta2O5.
[0042] Example 3
[0043] The difference between this embodiment and Example 1 is that 0.62g of Ta2O5 fiber membrane photocatalyst was weighed and dispersed in 25mL of deionized water. Since the mass fraction of Ag2S in the Ag2S@Ta2O5 heterojunction photocatalyst is 10%, it is labeled as: 10%Ag2S@Ta2O5.
[0044] from Figure 1 The transmission electron microscope images show that Ta₂O₅ exhibits a typical fibrous one-dimensional morphology, with numerous dispersed nanoparticles, namely Ag₂S nanoparticles, attached to its surface. Furthermore, from... Figure 1 The high-resolution transmission electron microscope images clearly show the heterojunction interface between the (031) diffraction crystal plane of Ag2S nanoparticles and the (001) diffraction crystal plane of Ta2O5 nanofiber film, confirming the formation of the heterojunction photocatalyst. In addition, in-situ X-ray photoelectron spectroscopy analysis proves that the Ag2S@Ta2O5 heterojunction photocatalyst follows the ladder charge transfer mechanism.
[0045] from Figure 2 It can be seen that the binding energy of the Ta 4f orbital in 5% Ag2S / Ta2O5 shifts towards lower binding energy compared to Ta2O5, while it shifts towards higher binding energy under ultraviolet irradiation. Figure 3 As can be seen, similarly, the Ag 3d orbital binding energy of 5% Ag2S / Ta2O5 is shifted towards higher binding energy compared to Ag2S, while under ultraviolet irradiation it is shifted towards lower binding energy. Ta2O5 and Ag2S, as well as 5% Ag2S / Ta2O5, exhibit opposite charge transport paths under ultraviolet irradiation. This result indicates that photogenerated electrons are shifted from Ta2O5 to Ag2S during hybridization, constructing a ladder-shaped electron transfer path with stable electron flow, and generating a built-in electric field at the heterojunction. This built-in electric field facilitates the separation of photogenerated carriers.
[0046] Combination Figure 2 and Figure 3 This confirms that the Ag2S nanoparticle-modified Ta2O5 nanofiber composite photocatalyst is a ladder-type heterojunction photocatalyst.
[0047] Figure 4The graph shows the photocatalytic reduction of low-concentration CO2 by Ta2O5, Ag2S, and their 5% Ag2S / Ta2O5 sample under simulated sunlight irradiation. The left column represents CO yield, and the right column represents CH4 yield. As can be seen, compared to the monomers Ta2O5 and Ag2S, the series of composite catalysts all exhibit superior photocatalytic reduction activity for low-concentration CO2. Among them, the 5% Ag2S / Ta2O5 sample shows the best photocatalytic reduction activity for low-concentration CO2, with an average methane production rate as high as 132.3 μmol g after 180 min of visible light irradiation. -1 .
[0048] This invention utilizes photocatalysis technology: using sunlight as energy, low-concentration CO2 can be converted into solar fuels represented by CO and CH4. It is a highly efficient, green, and safe clean energy technology. An Ag2S@Ta2O5 heterojunction photocatalyst for photocatalytic conversion of low-concentration CO2 was prepared by a simple electrospinning-assisted co-precipitation method. It combines the advantages of nanoparticles and thin films, with a simple synthesis process, low cost, and high efficiency. The Ag2S@Ta2O5 heterojunction photocatalyst has superior performance. Due to the formation of the ladder-shaped heterojunction, it has stronger light absorption capacity and higher carrier separation efficiency.
[0049] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.
Claims
1. An application of an Ag2S@Ta2O5 heterojunction photocatalyst, characterized in that, Ag2S@Ta2O5 heterojunction photocatalyst is used to convert low-concentration CO2 into solar fuel under sunlight irradiation. The solar fuel is CO and CH4. In the Ag2S@Ta2O5 heterojunction photocatalyst, the (001) diffraction crystal plane of Ta2O5 fiber film and the (031) diffraction crystal plane of Ag2S nanoparticles intertwine to form a heterojunction interface. Ag2S nanoparticles are uniformly attached to the surface of Ta2O5 fiber film to form a tightly contacted 0D / 1D heterojunction structure.
2. The application according to claim 1, characterized in that, The mass fraction of Ag2S in the Ag2S@Ta2O5 heterojunction photocatalyst is 2% to 10%.
3. The application according to claim 1, characterized in that, The mass fraction of Ag2S in the Ag2S@Ta2O5 heterojunction photocatalyst is 5%.
4. The application according to claim 1, characterized in that, The preparation method of Ag2S@Ta2O5 heterojunction photocatalyst is as follows: S100. Disperse the Ta2O5 fiber membrane photocatalyst in deionized water, then add silver nitrate and sodium sulfide to dissolve and stir to obtain a black solution containing the Ta2O5 fiber membrane. S200. Place the black solution in the dark and stir to obtain a solution containing a gray fiber membrane. S300. The solution containing the gray fiber membrane is washed and dried to obtain the Ag2S@Ta2O5 heterojunction photocatalyst after impregnation and precipitation treatment.
5. The application according to claim 4, characterized in that: The preparation method of the Ta2O5 fiber membrane photocatalyst used in S100 is as follows: S110, take pentaethyl tantalum and polyvinylpyrrolidone K90 and dissolve them in a mixed solution of glacial acetic acid and anhydrous ethanol, and stir continuously to obtain a colorless and transparent solution; S120. Electrospinning of a colorless and transparent solution at a certain flow rate and voltage yields a Ta2O5 intermediate fiber membrane. S130. The Ta2O5 intermediate fiber membrane is calcined to obtain the Ta2O5 fiber membrane photocatalyst.
6. The application according to claim 5, characterized in that: The flow rate is 0.2 mL / h to 0.8 mL / h, and the voltage is 15 kV to 21 kV.
7. The application according to claim 5, characterized in that: The calcination temperature is 650℃~850℃, the time is 60min~180min, and the heating rate is 1℃ / min~7℃ / min.