Preparation method and application of sulfuric acid protonation synergistic cerium monatomic doped g-C3N4 nano material photocatalyst
Through the synergistic doping of cerium single atoms through sulfuric acid protonation, the surface polarity and active sites of g-C3N4 are improved, and the problem of poor carbon dioxide reduction performance is solved, achieving a significant improvement in photocatalytic activity.
Patent Information
- Application Number
- CN202510232429.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-28
- Publication Date
- 2025-05-30
AI Technical Summary
g-C3N4 is poor in photocatalysis due to the low efficiency of non-polarity and photogenerated electron hole recombination.
Through the protonation of sulfuric acid and the doping of cerium single atoms, the surface polarity and active sites of g-C3N4 are improved, the photogenerating electron hole separation efficiency is enhanced, and the carboxyl group generation energy barrier is reduced, thereby promoting carbon dioxide reduction.
It significantly improves the activity of photocatalytic carbon dioxide reduction, enhances visible photocatalytic performance, and simplifies the preparation process, which is suitable for large-scale production.
Smart Images
Figure CN120054579A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of photocatalytic materials, and specifically relates to a preparation method and application of a sulfuric acid protonated and cerium single atom doped g-C 3 N 4 nano-material photocatalyst. Background Art
[0002] A large amount of carbon dioxide is emitted into the atmosphere by burning fossil fuels, leading to various environmental problems, overconsumption of fossil fuels, and energy crises. In this context, converting carbon dioxide into valuable solar fuels has attracted great attention. Among them, visible light catalysis can reduce carbon dioxide to carbon monoxide or hydrocarbons only relying on solar energy as the driving force, which can solve both environmental pollution problems and energy crises at the same time.
[0003] g-C 3 N 4 Due to its excellent chemical stability, visible light response, controllable composition and molecular structure, it has been widely used in the field of photocatalysis. However, since the electronegativity of carbon (C) is comparable to that of nitrogen (N), g-C 3 N 4 belongs to non-polar molecules, resulting in serious recombination of photo-generated electron-hole pairs, difficult adsorption and activation of carbon dioxide molecules, and poor carbon dioxide reduction performance. Based on this, considering starting from improving the surface polarization degree of g-C 3 N 4 and generating more active sites, surface sulfuric acid modification and cerium atoms are introduced, which can improve the separation efficiency of photo-generated electron-hole pairs, generate more active sites, and promote the adsorption of carbon dioxide molecules. At the same time, sulfuric acid modified C 3 N 4 can reduce the formation energy barrier of carboxyl groups and promote the formation of carboxyl groups, which are key intermediates for carbon dioxide reduction. Compared with the original g-C 3 N 4 (CN), the sulfuric acid protonated and cerium atom doped g-C 3 N 4 (Ce-CN-H) has greatly improved the photocatalytic activity for carbon dioxide reduction; and the sulfuric acid protonated and cerium single atom doped g-C 3 N 4 nano-material as a photocatalyst for carbon dioxide reduction has not been reported yet. Summary of the Invention
[0004] To solve the above problems, the present invention provides a preparation method and application of a sulfuric acid protonated and cerium single atom doped g-C 3 N 4 nano-material photocatalyst.
[0005] The technical solution adopted by the present invention is as follows:
[0006] A preparation method of a sulfuric acid protonated and cerium single-atom doped g-C 3 N 4 nano-material photocatalyst, comprising the following steps:
[0007] 1) Grind cerium nitrate hexahydrate and melamine until fully mixed, put them into a porcelain boat, and calcine them in a tube furnace to obtain cerium-doped C 3 N 4 , denoted as Ce-CN;
[0008] 2) Grind the obtained Ce-CN into powder, place it in a sulfuric acid solution and stir. After completion, wash the sample and dry it to obtain a sulfuric acid protonated and cerium single-atom doped g-C 3 N 4 nano-material photocatalyst, denoted as Ce-CN-H.
[0009] Further, in the above preparation method, in step 1), the molar ratio of cerium nitrate hexahydrate to melamine is 0.005 - 0.015:1.
[0010] Furthermore, in the above preparation method, in step 1), the amount of melamine used is 3 g.
[0011] Further, in the above preparation method, in step 1), the grinding time is 20 min.
[0012] Further, in the above preparation method, in step 1), the calcination temperature is 550 °C, the heating rate is 5 °C / min, the calcination time is 4 h, and the atmosphere in the tube furnace is a nitrogen atmosphere.
[0013] Further, in the above preparation method, in step 2), the concentration of the sulfuric acid solution is 0.5 M.
[0014] Further, in the above preparation method, in step 2), the stirring time is 24 h.
[0015] Further, in the above preparation method, in step 2), the drying temperature is 60 °C and the drying time is 24 h.
[0016] The application of the sulfuric acid protonated and cerium single-atom doped g-C 3 N 4 nano-material photocatalyst prepared by the preparation method described in any one of the above in photocatalytic carbon dioxide reduction.
[0017] Further, the above application is as follows: Take the Ce-CN-H photocatalyst and disperse it evenly in 0.5 mL of ethanol, and ultrasonicate for 5 minutes; evenly drop the obtained ethanol dispersion of the photocatalyst onto a circular crucible piece with a radius of 1 cm, and dry it; put the crucible piece loaded with the sample into the reactor, then add 0.5 mL of deionized water, and seal the reactor; evacuate and then introduce carbon dioxide, repeat three times; irradiate and catalyze the reduction of carbon dioxide under visible light conditions.
[0018] Furthermore, in the above application, the Ce-CN-H photocatalyst: deionized water = 20 mg: 0.5 mL.
[0019] The beneficial effects of the present invention are as follows:
[0020] 1. The sulfuric acid surface protonation and cerium-doped C co-prepared by the high-temperature heat shrinkage method and sulfuric acid surface modification in the present invention 3 N 4 nanomaterials photocatalyst has abundant active sites, which can improve the surface polarity of g-C 3 N 4 and improve the separation efficiency of carriers, enhancing the photocatalytic activity.
[0021] 2. The Ce-CN-H nanomaterials photocatalyst prepared in the present invention has a stronger ability to absorb visible light, which is an effective way to improve the visible light photocatalytic activity.
[0022] 3. The Ce-CN-H nanomaterials photocatalyst prepared in the present invention has good photocatalytic carbon dioxide reduction performance, and this method is simple to prepare, environmentally friendly, non-toxic, low-cost, and is conducive to large-scale production. Description of the Drawings
[0023] Figure 1 It is the X-ray diffraction pattern of the CN and Ce-CN-H nanomaterials photocatalyst.
[0024] Figure 2 It is the carbon dioxide reduction to carbon monoxide production-time curve graph of the CN and Ce-CN-H nanomaterials photocatalyst. Detailed Embodiments
[0025] Example 1
[0026] (I) Preparation of CN
[0027] Put 3 g of melamine into a porcelain boat, place it in a tube furnace, and under a nitrogen atmosphere, heat it to 550 °C at a heating rate of 5 °C / min and calcine for 4 h. After cooling, collect the product and grind it into powder, which is g-C 3 N 4 , denoted as CN.
[0028] (II) Preparation of Ce-CN-H
[0029] Grind 3 g of melamine and 0.103 g of cerium nitrate hexahydrate for 20 min until fully mixed. Put them into a porcelain boat and place it in a tube furnace. Under a nitrogen atmosphere, heat it to 550 °C at a heating rate of 5 °C / min and calcine for 4 h. After cooling, collect the product and grind it into powder. Put the obtained powder into 30 mL of sulfuric acid solution with a concentration of 0.5 M and stir for 24 h. After filtration, wash it three times with deionized water and anhydrous ethanol respectively, and dry it at 60 °C for 24 h to obtain the 1Ce-CN-H photocatalyst.
[0030] Figure 1 X-ray diffraction patterns of the CN and Ce-CN-H nanomaterial photocatalysts prepared in Example 1. Characteristic diffraction peaks appear at 2θ = 13.1° and 27.6° in the figure, corresponding to the (100) and (002) crystal planes, which are consistent with the diffraction peaks of g-C 3 N 4 However, compared with pure g-C 3 N 4 , the diffraction peak intensity of the doped sample decreases, and doping changes the long-range structure of the (002) crystal plane of g-C 3 N 4 .
[0031] Example 2
[0032] At normal temperature and pressure, take 20 mg of the 1Ce-CN-H photocatalyst prepared in Example 1 and disperse it evenly in 0.5 mL of anhydrous ethanol, and ultrasonicate for 5 min. Drop the ethanol dispersion of the sample onto a crucible piece with a radius of 1 cm and dry it in an oven at 60 °C. Put the dried crucible piece loaded with the sample into the reactor, then add 0.5 mL of deionized water into the reactor, seal the reactor, evacuate for 2 min, and then introduce carbon dioxide at a constant flow rate (80 mL / min). The above evacuation and carbon dioxide introduction processes are repeated three times. Then place the reactor under a xenon lamp for irradiation. Every 60 min of the photocatalytic reaction, extract 1000 μL of gas from the container with a syringe and detect the carbon monoxide concentration with a gas chromatograph.
[0033] Figure 2 It is the carbon monoxide production-time curve of the sample photocatalytic reduction of carbon dioxide to carbon monoxide. It can be seen that after 4 h of the photocatalytic reaction, the carbon monoxide production of 1Ce-CN-H is 39 μmol / g, which is twice that of pure g-C 3 N 4 . It shows that the doped and modified 2-Sr-CN-Vc has a great improvement in photocatalytic activity in the gas-phase photocatalytic reduction of carbon dioxide compared with pure g-C 3 N 4 .
Claims
1. A method for preparing a sulfuric acid protonated synergistic cerium single atom doped g-C3N4 nanomaterial photocatalyst, characterized in that: The steps include: 1) grinding cerium nitrate hexahydrate and melamine until fully mixed, placing them in a porcelain boat, and calcining them in a tube furnace to obtain cerium-doped C3N4, recorded as Ce-CN; 2) Grind the obtained Ce-CN into powder, place it in a sulfuric acid solution and stir it. After the powder is finished, wash the sample and dry it to obtain a sulfuric acid protonated synergistic cerium single atom doped g-C3N4 nanomaterial photocatalyst, which is recorded as Ce-CN-H.
2. The preparation method according to claim 1, characterized in that: In step 1), the molar ratio of cerium nitrate hexahydrate to melamine is 0.005-0.015:
1.
3. The preparation method according to claim 2, characterized in that: In step 1), the amount of melamine used is 3 g.
4. The preparation method according to claim 1, characterized in that: In step 1), the calcination temperature is 550° C., the heating rate is 5° C. / min, the calcination time is 4 h, and the atmosphere of the tubular furnace is nitrogen.
5. The preparation method according to claim 1, characterized in that: In step 2), the concentration of the sulfuric acid solution is 0.5M.
6. The preparation method according to claim 1, characterized in that: In step 2), the stirring time is 24h.
7. The preparation method according to claim 1, characterized in that: In step 2), the drying temperature is 60° C. and the drying time is 24 hours.
8. Use of the sulfuric acid protonation synergistic cerium single atom doped g-C3N4 nanomaterial photocatalyst prepared by the preparation method according to any one of claims 1 to 7 in photocatalytic carbon dioxide reduction.
9. The use according to claim 8, characterized in that: The method is as follows: evenly disperse the Ce-CN-H photocatalyst in 0.5 mL of ethanol and ultrasonicate for 5 minutes; evenly drop the obtained ethanol dispersion of the photocatalyst onto a circular crucible with a radius of 1 cm and dry it; put the crucible loaded with the sample into a reactor, add 0.5 mL of deionized water, and seal the reactor; introduce carbon dioxide after evacuating the reactor, and repeat three times; irradiate the catalytic carbon dioxide reduction under visible light conditions.
10. The use according to claim 9, characterized in that: Ce-CN-H photocatalyst: deionized water = 20 mg: 0.5 mL.