Phosphorus-aluminum co-doped nickel oxide material, its preparation method and application

Abstract

The present invention relates to a phosphorus-aluminum co-doped nickel oxide material, a preparation method thereof, and an application thereof, belonging to the technical field of photocatalytic degradation of pollutants such as antibiotics. The technical problem solved by the present invention is to provide a preparation method of a phosphorus-aluminum co-doped nickel oxide material with a simple and easy-to-control process flow. In this method, NaH2PO4·H2O and NiAl-LDH powder are respectively evenly spread on a porcelain boat. The porcelain boat containing NaH2PO4·H2O is placed in the upper stream of the gas flow in a tube furnace, and the porcelain boat containing NiAl-LDH powder is placed in the lower stream of the gas flow in the tube furnace. The tube furnace is heated to 250-350 °C and maintained for 1-3 hours in a protective atmosphere, and then cooled to obtain the product. The method of the present invention has a simple process, low energy consumption, and low cost, which is conducive to industrial production. The synthesized material has good photocatalytic performance. The degradation rate of tetracycline at 10 mg / L reaches 89.9%, which is 12.5 times that of its self-degradation and 1.82 times that of the degradation rate of the precursor NiAl-LDH, indicating that the catalyst has better photocatalytic degradation performance and can be used to better solve environmental pollution problems.

Description

Technical Field

[0001] The present invention relates to a phosphorus-aluminum co-doped nickel oxide material, a preparation method thereof and an application thereof, and belongs to the technical field of photocatalytic degradation of pollutants such as antibiotics. Background Art

[0002] Antibiotics remaining in the environment can not only disrupt the aquatic ecological balance, but even induce the generation of resistance genes in microorganisms, thereby generating superpathogens with stronger drug resistance.

[0003] In recent years, people have removed antibiotics through methods such as hydrolysis method, electrochemical oxidation method, and microbial degradation method. Among them, the hydrolysis method is generally applied in industry, but the hydrolysis method is sensitive to pH and temperature, and its degradation time is long and the efficiency is low; the electrochemical oxidation method can change the chemical properties of organic substances and improve the degradability of antibiotics, but the electrochemical oxidation method has high costs, and the by-products generated by the reaction may cause secondary pollution; the microbial degradation method is the main method for degrading antibiotics in the environment and can convert organic pollutants into environmentally harmless substances such as H2O and CO2. However, malodors are often generated during the reaction process. Photocatalysis is a green and safe technology that converts solar energy into chemical energy, which can help degrade organic substances, and this process is efficient, has a fast reaction time, and is green and safe. The catalyst plays an important role in the photocatalytic reaction, and a single catalyst often has the problem of rapid recombination of photogenerated electrons and holes, which is not conducive to the progress of the photocatalytic reaction. In addition, some popular catalysts such as TiO2, Fe2O3, and ZnO2 only absorb ultraviolet light, and in the proportion of sunlight, ultraviolet light accounts for about 1% - 2%, and visible light accounts for about 50%. Therefore, developing visible light-responsive catalysts can make more efficient use of solar energy.

[0004] Nickel oxide is a highly active catalyst with abundant surface active sites, which can effectively promote the progress of the photocatalytic reaction and has good stability. However, it also faces the problem of rapid recombination of photogenerated carriers. There are many methods for modifying nickel oxide, such as noble metal deposition, depositing or doping nickel oxide with noble metals such as gold, silver, and platinum, but the cost is high; selecting semiconductor materials with energy levels matching those of nickel oxide for compounding may not necessarily achieve better photocatalytic effects. Doping the catalyst is also a modification method.

[0005] The Chinese invention patent with the application number 201210143328.X discloses a preparation method of Ru-Li co-doped nickel oxide thin film. First, Ru-Li co-doped nickel sol is prepared, then coated and heat-treated for 1-2 h to obtain Ru-Li co-doped nickel oxide thin film. When preparing Ru-Li co-doped nickel sol, first stir for 30-40 min under water bath heating conditions, continue stirring for 90-100 min after adding doping elements, then leave it to stand and age in air for 24-48 h, and finally ultrasonically clean for 10-15 min and dry to obtain Ru-Li co-doped nickel sol. The method for preparing Ru-Li co-doped nickel has a long reaction time and is cumbersome and complex.

[0006] The Chinese invention patent with the application number 202311374555.8 discloses a preparation method of zinc and cobalt co-doped NiO-X thin film for perovskite solar cells, including the following steps: S1. Select a substrate, first ultrasonically clean it with detergent and deionized water, and then ultrasonically clean it in acetone and absolute ethanol respectively, and dry the substrate with a nitrogen gun; S2. Clean the substrate by applying radio frequency plasma superposed with pulsed negative bias voltage to the substrate; S3. Deposit NiOX thin film on the ITO surface of the cleaned substrate by using DC / RF coupled reactive sputtering process, and simultaneously co-deposit metal zinc and metal cobalt on the ITO surface by using DC sputtering process; S4. After sputtering, wait for the substrate to cool to room temperature, heat the substrate to a constant temperature, and then cool it to room temperature again and take out the sample to obtain zinc and cobalt co-doped NiOX thin film. The preparation process of this patent is complex and not conducive to the industrial production of products.

[0007] The Chinese invention patent with the application number 201811227041.9 discloses a lithium and silver co-doped nickel oxide thin film and its application in perovskite solar cells. By weighing a certain amount of Ni(NO3)2·6H2O, LiNO3 and AgNO3 and adding them to deionized water and stirring to dissolve, the molar ratio ranges from 0.989-0.98:0.001-0.005:0.01-0.015, then dropwise add NaOH solution until the pH reaches 9.8-10, and after washing and drying, calcine at 270 °C to obtain lithium and silver co-doped nickel oxide nanoparticles. It is applied to the hole transport layer of a reverse planar perovskite solar cell to improve its photoelectric conversion efficiency.

[0008] In summary, the existing doping is all used for perovskite solar cells or resistive memory devices, and its effect on photocatalytic degradation of antibiotics is limited, and its preparation method is complex and cumbersome, which is not conducive to the industrial production of products. Summary of the Invention

[0009] Aiming at the above defects, the first technical problem solved by the present invention is to provide a preparation method of phosphorus and aluminum co-doped nickel oxide material with a simple and easy-to-control process flow.

[0010] The preparation method of the phosphorus-aluminum co-doped nickel oxide material of the present invention includes the following steps:

[0011] NaH2PO4·H2O and NiAl-LDH powder are evenly spread on a porcelain boat respectively. The porcelain boat containing NaH2PO4·H2O is placed in the upper stream of the gas flow in the tube furnace, and the porcelain boat containing NiAl-LDH powder is placed in the lower stream of the gas flow in the tube furnace. The tube furnace is heated to 250-350 °C and maintained for 1-3 hours in a protective atmosphere, and then cooled to obtain the phosphorus-aluminum co-doped nickel oxide material.

[0012] In an embodiment of the present invention, the mass ratio of NaH2PO4·H2O to NiAl-LDH powder is 8-12:1; in a specific embodiment, the mass ratio of NaH2PO4·H2O to NiAl-LDH powder is 10:1.

[0013] In an embodiment of the present invention, the heating rate is 2-5 °C / min. In a specific embodiment, the heating rate is 2 °C / min.

[0014] In an embodiment of the present invention, the tube furnace is heated to 300 °C and maintained for 2 hours.

[0015] In an embodiment of the present invention, the NiAl-LDH powder is prepared by a hydrothermal method.

[0016] In an embodiment of the present invention, the NiAl-LDH powder is synthesized by the following method: Ni(NO3)2·6H2O, Al(NO3)3·9H2O, urea, NH4F and water are mixed evenly, heated at 100-140 °C for 10-14 hours, the precipitate is taken, washed and dried to obtain the NiAl-LDH powder; wherein, the molar ratio of Ni(NO3)2·6H2O, Al(NO3)3·9H2O, urea is 2.5-3.5:1:18-22.

[0017] In an embodiment of the present invention, the molar ratio of Ni(NO3)2·6H2O, Al(NO3)3·9H2O, urea is 3:1:20; and it is heated at 120 °C for 12 hours.

[0018] The second technical problem solved by the present invention is to provide a phosphorus-aluminum co-doped nickel oxide material.

[0019] The phosphorus-aluminum co-doped nickel oxide material of the present invention is prepared by the above-mentioned preparation method of the phosphorus-aluminum co-doped nickel oxide material. This material has a low cost and good photocatalytic performance.

[0020] The present invention also provides the application of the phosphorus-aluminum co-doped nickel oxide material described in the present invention in the photocatalytic degradation of antibiotics.

[0021] The phosphorus-aluminum co-doped nickel oxide material of the present invention can be applied to the photocatalytic degradation of antibiotics.

[0022] In one embodiment of the present invention, the antibiotic is tetracycline.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The method of the present invention has a simple process. By phosphating the precursor, the target product is obtained, saving processes, reducing energy consumption, and having a low cost, which is conducive to industrial production. The synthesized material has good photocatalytic performance. The degradation rate of 10 mg / L of tetracycline reaches 89.9%, which is 12.5 times that of its self-degradation and 1.82 times that of the degradation rate of the precursor NiAl-LDH, indicating that the catalyst has better photocatalytic degradation performance and can be used to better solve environmental pollution problems. Description of the Drawings

[0025] Figure 1 It is the XRD pattern of NiAl-LDH powder and P-Al-NiO in Example 1 of the present invention.

[0026] Figure 2 It is the SEM pattern of NiAl-LDH powder and P-Al-NiO and the EDS element mapping pattern of P-Al-NiO in Example 1 of the present invention.

[0027] Figure 3 It is the photocatalytic degradation performance pattern of P-Al-NiO in Example 1. Detailed Embodiments

[0028] The preparation method of the phosphorus-aluminum co-doped nickel oxide material of the present invention includes the following steps:

[0029] NaH2PO4·H2O and NiAl-LDH powder are evenly spread on a porcelain boat respectively. The porcelain boat containing NaH2PO4·H2O is placed in the upper stream of the gas flow of the tube furnace, and the porcelain boat containing NiAl-LDH powder is placed in the lower stream of the gas flow of the tube furnace. The tube furnace is heated to 250-350 °C and maintained for 1-3 hours in a protective atmosphere, and then cooled to obtain the phosphorus-aluminum co-doped nickel oxide material.

[0030] The protective atmosphere described in the present invention is an atmosphere that does not participate in the reaction, including but not limited to inert atmospheres such as helium and argon or nitrogen atmosphere.

[0031] In one embodiment of the present invention, the mass ratio of NaH2PO4·H2O to NiAl-LDH powder is 8-12:1; in a specific embodiment, the mass ratio of NaH2PO4·H2O to NiAl-LDH powder is 10:1.

[0032] In one embodiment of the present invention, the heating rate is 2 to 5 °C / min. In a specific embodiment, the heating rate is 2 °C / min.

[0033] In one embodiment of the present invention, the tubular furnace is heated to 300 °C and maintained for 2 hours.

[0034] In one embodiment of the present invention, the NiAl-LDH powder is prepared by a hydrothermal method.

[0035] In one embodiment of the present invention, the NiAl-LDH powder is synthesized by the following method: Ni(NO3)2·6H2O, Al(NO3)3·9H2O, urea, NH4F and water are mixed evenly, heated at 100 - 140 °C for 10 - 14 hours, the precipitate is taken, washed and dried to obtain the NiAl-LDH powder; wherein, the molar ratio of Ni(NO3)2·6H2O, Al(NO3)3·9H2O, urea is 2.5 - 3.5:1:18 - 22.

[0036] In one embodiment of the present invention, the molar ratio of Ni(NO3)2·6H2O, Al(NO3)3·9H2O, urea is 3:1:20; and it is heated at 120 °C for 12 hours.

[0037] In a specific embodiment of the present invention, the preparation method of the NiAl-LDH powder is as follows: Ni(NO3)2·6H2O, Al(NO3)3·9H2O, urea (0.48 mmol Ni(NO3)2·6H2O, 0.16 mmol Al(NO3)3·9H2O, 3.2 mmol urea) with a molar ratio of 3:1:20, and a certain amount of NH4F (1.28 mmol NH4F) are added to 60 mL of deionized water, and then sonicated for half an hour to obtain a homogeneous solution. The above solution is transferred to a 100 mL autoclave lined with polytetrafluoroethylene and heated at 120 °C for 12 hours. It is washed repeatedly with distilled water and ethanol and vacuum dried at 60 °C overnight to obtain the NiAl-LDH powder.

[0038] The nickel oxide material co-doped with phosphorus and aluminum of the present invention is prepared by the above preparation method of the nickel oxide material co-doped with phosphorus and aluminum. This material has a low cost and good photocatalytic performance.

[0039] The nickel oxide material co-doped with phosphorus and aluminum of the present invention can be applied to the photocatalytic degradation of antibiotics.

[0040] In one embodiment of the present invention, the antibiotic is tetracycline.

[0041] The following further describes the specific implementation manners of the present invention in conjunction with embodiments, and the present invention is not thus limited to the scope of the described embodiments.

[0042] Example 1

[0043] The nickel-aluminum co-doped nickel oxide material was prepared by the following method:

[0044] Step 1: Preparation of NiAl-LDH powder

[0045] First, NiAl-LDH was synthesized by a hydrothermal method: Ni(NO3)2·6H2O, Al(NO3)3·9H2O, and urea (0.48 mmol Ni(NO3)2·6H2O, 0.16 mmol Al(NO3)3·9H2O, 3.2 mmol urea) with a molar ratio of 3:1:20, and a certain amount of NH4F (1.28 mmol NH4F) were added to 60 mL of deionized water, and then ultrasonicated for half an hour to obtain a homogeneous solution. The above solution was transferred to a 100 mL autoclave lined with polytetrafluoroethylene and heated at 120 °C for 12 hours. It was washed repeatedly with distilled water and ethanol and vacuum dried at 60 °C overnight to obtain NiAl-LDH powder.

[0046] Step 2: Preparation of the nickel-aluminum co-doped nickel oxide material

[0047] NaH2PO4·H2O and the precursor NiAl-LDH powder were weighed at a mass ratio of 10:1 and evenly spread on a porcelain boat respectively. The porcelain boat containing NaH2PO4·H2O was placed upstream of the gas flow in a tube furnace, and the porcelain boat containing NiAl-LDH powder was placed downstream of the gas flow in the tube furnace. The temperature of the tube furnace was raised to 300 °C at a heating rate of 2 °C per minute and maintained for 2 hours in a N2 atmosphere (i.e., the reaction temperature was 300 °C and the reaction time was 2 hours), and then allowed to cool naturally to room temperature. The dark green powder obtained was nickel oxide co-doped with P and Al, named P-Al-NiO.

[0048] The X-ray diffraction pattern of the above material is shown in Figure 1The results show that the main diffraction peaks of the obtained product are in good agreement with the NiAl-LDH standard card (PDF#15-0087), and its peak shape is sharp, indicating that NiAl-LDH has high crystallinity. The three characteristic diffraction peaks of P-Al-NiO are respectively attributed to the three crystal planes of (111), (200) and (220), belonging to the NiO phase (PDF#47-1049), which indicates that a material change occurred during the high-temperature phosphating treatment of the precursor NiAl-LDH. In addition, it can be observed that the diffraction peaks of P-Al-NiO are broadened, and the intensity of its diffraction peaks is much lower than that of the standard nickel monoxide (PDF#47-1049). It can be speculated that the doping of P and Al results in low crystallinity of NiO and makes its lattice disordered.

[0049] Figure 2 Figure (a) is the SEM image of NiAl-LDH; (b) is the SEM image of P-Al-NiO; (c-g) are the EDS element mappings of P-Al-NiO. Among them, Figure (d) is the Ni element; Figure (e) is the O element; Figure (f) is the P element; Figure (g) is the Al element. It can be seen that the morphology of the P-Al-NiO obtained after high-temperature phosphating of the precursor NiAl-LDH (Figure b) has no obvious change and still maintains a nanoflower shape, and this unique nanoflower structure can provide a larger specific surface area. It can be seen from Figures (c-d) that the elements Al, P, Ni, and O are evenly distributed on the surface of the material, proving that P and Al are successfully doped into NiO.

[0050] The photocatalytic performance of this material was measured. Using tetracycline (TC) as the target pollutant, a xenon lamp was used to simulate the visible light source for the experiment. The specific steps are as follows: 10 mg of the sample was dispersed in an aqueous solution of TC (100 mL, 10 mg / L), and the suspension was stirred in the dark for 1 h to achieve the adsorption equilibrium between the photocatalyst and the tetracycline solution. Then, the solution was placed under the light source for illumination. The visible light was generated by a 300 W xenon lamp passing through an ultraviolet cut-off filter (λ>420 nm). 3 mL of the sample solution was centrifuged at fixed time intervals and measured by an ultraviolet-visible spectrophotometer.

[0051] Figure 3 Figure is the photocatalytic degradation performance diagram. Under visible light irradiation for 2 h, the self-degradation rate of TC is only about 7.2%, belonging to the type with unsatisfactory self-degradation performance. The degradation rate of the precursor NiAl-LDH is about 49.3%, and the degradation rate of P-Al-NiO is 89.9%, which is 12.5 times that of self-degradation and 1.82 times that of the precursor NiAl-LDH.

[0052] Example 2

[0053] Referring to the method of Example 1, by changing some parameters, nickel oxide co-doped with P and Al was obtained, and the changed parameters are shown in Table 1. The degradation rate under visible light irradiation for 2 h is shown in Table 1.

[0054] Table 1

[0055]

[0056] It can be seen that the method of the present invention can successfully prepare a phosphorus-aluminum co-doped nickel oxide material, which can be used for visible light catalytic degradation of tetracycline with a high degradation rate.

Claims

1. Application of phosphorus-aluminum co-doped nickel oxide material in photocatalytic degradation of antibiotics, characterized in that: The nickel oxide material co-doped with phosphorus and aluminum is prepared by a preparation method including the following steps: NaH2PO4·H2O and NiAl-LDH powder are respectively evenly spread on a porcelain boat. The porcelain boat containing NaH2PO4·H2O is placed in the upper stream of the gas flow in a tube furnace, and the porcelain boat containing NiAl-LDH powder is placed in the lower stream of the gas flow in the tube furnace. The tube furnace is heated to 250-350 °C and maintained for 1-3 hours in a protective atmosphere, and then cooled to obtain the nickel oxide material co-doped with phosphorus and aluminum; the mass ratio of NaH2PO4·H2O to NiAl-LDH powder is 8-12:1; The NiAl-LDH powder is synthesized by the following method: Ni(NO3)2·6H2O, Al(NO3)3·9H2O, urea, NH4F and water are mixed evenly and heated at 100-140 °C for 10-14 hours. The precipitate is taken, washed and dried to obtain the NiAl-LDH powder; among them, the molar ratio of Ni(NO3)2·6H2O, Al(NO3)3·9H2O to urea is 2.5-3.5:1:18-22.

2. Use of the nickel oxide material co-doped with phosphorus and aluminum according to claim 1 in photocatalytic degradation of antibiotics, characterized in that: The mass ratio of NaH2PO4·H2O to NiAl-LDH powder is 10:

1.

3. Use of the nickel oxide material co-doped with phosphorus and aluminum according to claim 1 in photocatalytic degradation of antibiotics, characterized in that: The heating rate is 2-5 °C / min.

4. Use of the nickel oxide material co-doped with phosphorus and aluminum according to claim 3 in photocatalytic degradation of antibiotics, characterized in that: The heating rate is 2 °C / min.

5. Use of the nickel oxide material co-doped with phosphorus and aluminum in photocatalytic degradation of antibiotics according to claim 1, characterized in that: The tube furnace is heated to 300 °C and maintained for 2 hours.

6. Use of the phosphorus-aluminum co-doped nickel oxide material according to claim 1 in photocatalytic degradation of antibiotics, characterized in that: The molar ratio of Ni(NO3)2·6H2O, Al(NO3)3·9H2O to urea is 3:1:20; and it is heated at 120 °C for 12 hours.

7. Use of the nickel oxide material co-doped with phosphorus and aluminum according to claim 1 in photocatalytic degradation of antibiotics, characterized in that: The antibiotic is tetracycline.

Images