A CeO x / MnCo2O 4.5 Coupling interface catalysts, methods of making and using same

Abstract

The application relates to the field of advanced oxidation processes, in particular to a CeO x / MnCo2O 4.5 coupling interface catalyst, a preparation method and application thereof. The preparation method comprises the following steps: dissolving Co salt and Mn salt in solvent A to obtain solution A; dissolving 2-methyl imidazole in solvent B to obtain solution B; uniformly mixing the solution B and the solution A, and then standing to obtain a precursor; dissolving the precursor in solvent C, adding Ce salt and stirring, centrifugally collecting the product, and then sequentially washing, drying and calcining to obtain the CeO x / MnCo2O 4.5 coupling interface catalyst. The catalyst has the advantages of significantly improved catalytic activity, greatly enhanced structural stability and cycle durability, effectively inhibited active metal ion leaching, excellent pH adaptability and anti-interference ability, high mineralization degree and actual application feasibility.

Description

Technical Field

[0001] This invention relates to the field of advanced oxidation processes, and in particular to a CeO2 process. x / MnCo2O 4.5 Coupled interface catalysts, their preparation methods and applications. Background Technology

[0002] Advanced oxidation processes (AOPs) are considered an efficient and low-cost method for removing recalcitrant pollutants. AOPs based on persulfate (PMS) activation generate sulfate radicals (SO42-). •- ), hydroxyl radicals (•OH), superoxide radicals (O2) •- ) and singlet oxygen ( 1 The ability of PMS to degrade reactive oxygen species (ROS) such as O2 has attracted widespread attention. However, PMS alone cannot effectively degrade pollutants; it needs to be activated to generate ROS for pollutant removal. Among the many activation methods, transition metals show great application potential due to their low energy requirements and high efficiency.

[0003] Metal-organic frameworks (MOFs) have attracted widespread attention in the field of catalysis due to their high porosity, surface area, and excellent structural tunability. Among them, zeolite imidazole ester frameworks (ZIFs) are among the most attractive MOFs due to their relatively simple synthesis methods, stable structures, and nitrogen-rich coordination environments. ZIF-67, in particular, is a typical MOF material with cobalt-centered nodes and 2-methylimidazolium as ligands, possessing a large specific surface area and highly dispersed cobalt active centers. These structural advantages make it an ideal precursor or template for preparing cobalt-based catalytic materials. Studies have shown that using ZIF-67 as a precursor, leveraging its regular framework structure and uniformly distributed metal nodes, composite materials with abundant oxygen vacancies and excellent electron transfer capabilities can be obtained through appropriate modification strategies. Furthermore, by introducing other metals (such as Mn, Fe, Cu, etc.) or non-metallic elements, the electronic states and adsorption behavior of the active centers can be further adjusted through component regulation, achieving synergistic optimization of catalytic performance. Based on these characteristics, CoMn-ZIF materials have attracted widespread attention in the field of PMS activation. However, the practical application of cobalt-manganese-based catalysts is severely limited by their poor long-term stability, and cobalt leaching is inevitable during the reaction process, especially in acidic water environments, which hinders the widespread application of these materials.

[0004] Therefore, it is urgent to improve the structural stability and reliability of cobalt-manganese-based catalysts in practical applications while maintaining their high catalytic activity through reasonable material design strategies, and effectively suppress the loss of active metal ions, thereby promoting the practical engineering application of this type of catalyst in the field of wastewater treatment. Summary of the Invention

[0005] Based on the above, the present invention provides a CeO x / MnCo2O 4.5 Coupled interface catalysts, their preparation methods and applications.

[0006] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is a CeO x / MnCo2O 4.5 The preparation method of the coupling interface catalyst includes the following steps: Co salt and Mn salt are dissolved in solvent A to obtain solution A; 2-Methylimidazole was dissolved in solvent B to obtain solution B; After mixing solution B with solution A, the mixture was allowed to stand to obtain the precursor. The precursor was dissolved in solvent C, Ce salt was added and stirred, the product was collected by centrifugation, and then washed, dried and calcined sequentially to obtain CeO. x / MnCo2O 4.5 Coupling interface catalyst.

[0007] In a preferred embodiment of the present invention, the Co salt is Co(NO3)2·6H2O; and the Mn salt is Mn(acac)3.

[0008] In a preferred embodiment of the present invention, the molar ratio of the Co salt to the Mn salt is (10~20):1.

[0009] In a preferred embodiment of the present invention, the molar ratio of the Co salt to the 2-methylimidazole is 1:(9~10).

[0010] In a preferred embodiment of the present invention, the settling time is 6 hours.

[0011] In a preferred embodiment of the present invention, the amount of cerium salt added is 2.5% to 20% of the mass of the precursor.

[0012] In this invention, adding too much or too little cerium salt will lead to a decrease in the activity of the prepared catalyst. Therefore, in this invention, the amount of cerium salt added is preferably limited to 2.5% to 20% of the mass of the precursor.

[0013] In a preferred embodiment of the present invention, the stirring time is 30 minutes; the present invention does not impose a particular limitation on the stirring speed, and a stirring speed commonly used by those skilled in the art can be used.

[0014] Solvent A, solvent B, and solvent C are all methanol.

[0015] In a preferred embodiment of the present invention, the calcination conditions are set as follows: calcination at 400°C for 2 h in an H2 / Ar atmosphere. The volume fraction of H2 in the H2 / Ar atmosphere is 5%.

[0016] The second technical solution of the present invention is a CeO prepared using the above-described preparation method. x / MnCo2O 4.5 Coupling interface catalyst. CeO x / MnCo2O 4.5 Ce in 3+ With Ce 4+ They can coexist, and the value of x ranges from 1 to 2.

[0017] The third technical solution of the present invention, the aforementioned CeO x / MnCo2O 4.5 Application of coupling interface catalysts in the degradation of organic pollutants by activated persulfate.

[0018] Preferably, the organic pollutant includes at least one of bisphenol A, sulfadiazine, 2,4-dichlorophenol, methyl orange, methylene blue, and rhodamine B; the pH value of the degradation reaction is 3 to 10.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) Significantly enhanced catalytic activity: CeO x / MnCo2O 4.5 It exhibits excellent catalytic activity in the degradation of bisphenol A (BPA) by activated PMS, achieving effective BPA removal within 3 minutes with a reaction rate constant of 3.95 min. -1 Higher than undoped MnCo2O 4.5 (3.58 min) -1 This catalyst exhibits excellent degradation capabilities for a variety of pollutants, including sulfadiazine, 2,4-dichlorophenol, methyl orange, methylene blue, and rhodamine B, demonstrating outstanding versatility.

[0020] (2) Significantly enhanced structural stability and cycle durability: After 6 consecutive cycles of use, CeO x / MnCo2O 4.5 The removal rate of BPA remained at around 97.5%, and the crystal structure and surface morphology of the catalyst did not change significantly; while the undoped MnCo2O 4.5 After four cycles, the degradation efficiency dropped sharply to 27.6%.

[0021] (3) Effectively inhibits the leaching of active metal ions: The introduction of CeO2 reduces the concentration of cobalt ions in the solution after the reaction from 2.54 mg / L to 0.40 mg / L, a reduction of 84.3%, which is far below the emission standard (cobalt ≤ 1 mg / L) stipulated in GB 25467-2010, effectively solving the problem of secondary pollution.

[0022] (4) Excellent pH adaptability and anti-interference ability: It can maintain high efficiency degradation in a wide pH range of 3~10, and is also effective against Cl. - SO4 2- NO3 - It is not sensitive to interference from common inorganic anions and humic acids, and shows good application potential in actual water bodies.

[0023] (5) High mineralization degree and feasible for practical application: The total organic carbon (TOC) removal rate of BPA reaches 92.6%. The verification of fixed bed reactor and in-situ floating water treatment device shows that the system has excellent continuous treatment capability for actual pharmaceutical wastewater. Attached Figure Description

[0024] Figure 1 CeO x / MnCo2O 4.5 A schematic diagram of the synthesis.

[0025] Figure 2 XRD patterns of catalysts with different Co / Mn ratios.

[0026] Figure 3 MnCo2O 4.5 and CeO x / MnCo2O 4.5 XRD pattern of the catalyst.

[0027] Figure 4 for (a)MnCo2O 4.5 (b) SEM image of 2.5% CeO x / MnCo2O 4.5 SEM images, (c) 10% CeO x / MnCo2O 4.5 SEM images, (d) 20% CeO x / MnCo2O 4.5 SEM image.

[0028] Figure 5 (a) 5% CeO x / MnCo2O 4.5 SEM images, (b) 5% CeO x / MnCo2O 4.5TEM image, (c) 5% CeO x / MnCo2O 4.5 HRTEM image, (d) 5% CeO x / MnCo2O 4.5 EDS element diagram.

[0029] Figure 6 MnCo2O 4.5 and 5% CeO x / MnCo2O 4.5 XPS spectra of (a) O 1s region, (b) Co 2p region, (c) Ce 3d region.

[0030] Figure 7 MnCo2O 4.5 and 5% CeO x / MnCo2O 4.5 The EPR spectrum.

[0031] Figure 8 MnCo2O 4.5 and 5% CeO x / MnCo2O 4.5 Raman spectra.

[0032] Figure 9 (a) Fenton-like activity tests of different catalysts, and (b) the corresponding degradation rate constants of BPA.

[0033] Figure 10 (a) represents the degradation efficiency of the catalyst under different Ce element addition amounts, and (b) represents the corresponding degradation rate constant.

[0034] Figure 11 (a) represents the degradation efficiency of the catalyst under different PMS addition amounts, and (b) represents the corresponding degradation rate constant.

[0035] Figure 12 (a) 5% CeO x / MnCo2O 4.5 +PMS system degradation of multiple pollutants (SD, 2-4D, BPA, MO, MB, RhB), (b) corresponding degradation rate constants.

[0036] Figure 13 (a) 5% CeO x / MnCo2O 4.5 The effect of the PMS system on the degradation of BPA by different anions (10 mM) and humic acid (5 mg / L), (b) 5% CeO x / MnCo2O 4.5 The effect of the +PMS system on BPA degradation at different pH values.

[0037] Figure 14 for (a)MnCo2O 4.5 Catalyst stability, (b) 5% CeO x / MnCo2O 4.5 Catalyst stability.

[0038] Figure 15 For newly prepared 5% CeO x / MnCo2O 4.5 and used 5% CeO x / MnCo2O 4.5 XRD pattern of the catalyst sample.

[0039] Figure 16 5% CeO x / MnCo2O 4.5 Scanning electron microscope image of the catalyst.

[0040] Figure 17 The concentration of Co leaching in the solution after the reaction in different systems is denoted as .

[0041] Figure 18 (a) 5% CeO x / MnCo2O 4.5 +PMS system degradation of BPA in different types of water, (b) 5% CeO x / MnCo2O 4.5 + TOC removal during the BPA degradation process in the PMS system.

[0042] Figure 19 For a PMS-only system, 5% CeO x / MnCo2O 4.5 +PMS system and 5% CeO x / MnCo2O 4.5 EPR spectra of the +PMS+BPA system: (a) DMPO-•OH and DMPO-SO4 •- (b) DMPO-O2 •- (c) TEMP- 1 O2.

[0043] Figure 20 For (a) 5% CeO in the presence of different scavengers x / MnCo2O 4.5 The degradation of BPA in the +PMS +BPA system, (b) in the presence of 5% CeO2 scavenger. x / MnCo2O 4.5 +PMS system for BPA removal efficiency.

[0044] Figure 21 For (a) different 1 In the presence of O2 scavenger, 5% CeO x / MnCo2O 4.5 The degradation of BPA in the PMS+BPA system, (b) in the presence of 5% CeO2 scavenger. x / MnCo2O 4.5 +PMS system for BPA removal efficiency.

[0045] Figure 22 The removal efficiency of BPA under different atmospheres.

[0046] Figure 23 Comparison of the electrochemical behavior of different catalysts: (a) CV curve at a scan rate of 100 mV / s, (b) LSV polarization curve, (c) electrochemical impedance spectroscopy, (d) current-time response curve (it).

[0047] Figure 24 (a) In-situ Raman spectra of different control systems, (b) 5% CeO x / MnCo2O 4.5 Dynamic in-situ Raman spectra of the reaction process of the +PMS+BPA system.

[0048] Figure 25 5% CeO x / MnCo2O 4.5 Possible pathways for BPA degradation in the +PMS system.

[0049] Figure 26 For (a) using a fixed-bed reactor with 5% CeO x / MnCo2O 4.5 Photographs of RhB wastewater before catalyst sponge treatment, (b) using a fixed-bed reactor with 5% CeO x / MnCo2O 4.5 Photograph of RhB wastewater after catalyst sponge treatment.

[0050] Figure 27 5% CeO2 is used in the in-situ floating water treatment reactor x / MnCo2O 4.5 Comparison photos of RhB wastewater before (a) and after (b) treatment with sponge catalyst.

[0051] Figure 28 These are photographs showing the color changes during the actual degradation process of pharmaceutical wastewater.

[0052] Figure 29 This represents the efficiency of pollutant removal during the degradation process.

[0053] Figure 30 This is the TOC change curve during the actual degradation process of pharmaceutical wastewater. Detailed Implementation

[0054] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0055] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0056] Example 1 1.1 Experimental Section 1.1.1 Experimental Reagents Potassium dichromate (K₂Cr₂O₇, AR), sodium hydroxide (NaOH, AR), sodium chloride (NaCl, AR), sodium sulfate (Na₂SO₄, AR), sodium bicarbonate (NaHCO₃, AR), and sodium nitrate (NaNO₃, AR) were purchased from Tianjin Bodi Chemical Co., Ltd. Cerium acetylacetonate trihydrate (Ce(C₅H₇O₂)₃•3H₂O, AR) was purchased from Sinopharm Chemical Reagent Co., Ltd. Manganese acetylacetonate (C... 15 H 21 MnO6 (AR) was purchased from Heinz Ltd. Potassium persulfate (PMS ≥ 99.5%) was purchased from Shanghai Maclean's Co., Ltd. Cobalt nitrate hexahydrate (Co(NO3)2•6H2O), dimethylimidazole (AR), rhodamine B (RhB, AR), methyl orange (MO, AR), methylene blue (MB, AR), 2,4-dichlorophenol (2,4-D, AR), bisphenol A (BPA, AR), acetaminophen (ACT, AR), p-benzoquinone (p-BQ, AR), furfuryl alcohol (FFA, AR), 5,5-dimethyl-1-pyrrolidone N-oxide (DMPO ≥ 97%), and 2,2,6,6-tetramethyl-4-piperidinone (TEMP ≥ 98%) were purchased from Aladdin Ltd. (Shanghai, China). Methanol (MeOH, AR) and ethanol (EtOH, AR) were purchased from Tianjin Zhiyuan Chemical Reagent Co., Ltd. Sulfuric acid (H2SO4, AR) and hydrogen chloride (HCl, AR) were purchased from Xilong Technology Co., Ltd.

[0057] 1.1.2 Experimental Apparatus Table 1 Main Experimental Instruments

[0058] 1.1.3 Material Preparation Preparation of MnCo2O 4.5 : 1.399 g of Co(NO3)2·6H2O and 84.5 mg of Mn(acac)3 were weighed and dissolved in 100 mL of methanol, denoted as solution A. Then, 3.745 g of 2-methylimidazole was weighed and dissolved in 100 mL of methanol, denoted as solution B. After the solid was completely dissolved, solution B was poured into solution A. The mixture was magnetically stirred for 30 min and then allowed to stand for 6 h. The precipitate was collected by centrifugation and washed repeatedly with deionized water and anhydrous ethanol. The washed sample was freeze-dried to obtain a purple powder, named Mn(acac)3@ZIF-67. Subsequently, Mn(acac)3@ZIF-67 was calcined at 400℃ for 2 hours under an H2 / Ar atmosphere (H2 volume fraction 5%) to finally obtain MnCo2O. 4.5 (i.e., MnCo2O) 4.5 (1:20)

[0059] In the above MnCo2O 4.5 Based on the preparation method, this invention also experimented with keeping the amount of Co(NO3)2·6H2O constant and adjusting the amount of Mn(acac)3 to make the Mn / Co molar ratio 1:40, 1:15, and 1:10, respectively, to obtain MnCo2O. 4.5 The corresponding label is MnCo2O 4.5 (1:40), MnCo2O 4.5 (1:15), MnCo2O 4.5 (1:10).

[0060] Preparation of CeO x / MnCo2O 4.5 (Synthesis diagram as shown) Figure 1 (as shown) 100 mg of Mn(acac)3@ZIF-67 was dispersed in 30 mL of methanol, followed by the addition of 5 mg of Ce(C5H7O2)3•3H2O. The mixture was magnetically stirred for 30 minutes. The resulting product was collected by centrifugation, washed repeatedly with methanol and ethanol, and then dried. The obtained material was calcined at 400 °C for 2 h under an H2 / Ar atmosphere to finally obtain CeO. x / MnCo2O 4.5 (i.e., 5% CeO) x / MnCo2O 4.5 Based on this, by changing the doping amount of Ce(acac)3 to 2.5 mg, 10 mg, and 20 mg, 2.5% CeO was prepared. x / MnCo2O 4.5 10% CeO x / MnCo2O 4.5 20% CeO x / MnCo2O4.5 .

[0061] 1.2 Experimental Methods 1.2.1 Material Characterization Methods Scanning electron microscopy (SEM) was used to characterize the surface morphology of the synthesized catalyst. Transmission electron microscopy (TEM) was used to analyze its microstructure. High-resolution transmission electron microscopy (HRTEM) was used to reveal the arrangement of the catalyst lattice fringes and the distribution of elements. X-ray diffraction (XRD) was used to confirm the crystal structure and phase composition of the catalyst. Raman spectroscopy was used to analyze the types of surface defects and chemical bonds of the catalyst. Energy dispersive X-ray spectroscopy (EDS) was used to determine the types and relative abundances of elements contained in the catalyst. X-ray photoelectron spectroscopy (XPS) was used to analyze the surface elemental composition and corresponding chemical states of the catalyst. Electron paramagnetic resonance spectroscopy was used to analyze the types and concentrations of lattice defects in the catalyst.

[0062] 1.2.2 Degradation Experimental Methods The degradation performance of catalyst-activated PMS was evaluated using bisphenol A (BPA) as the target pollutant. A 40 mL aqueous solution containing 20 mg / L BPA was prepared for the degradation experiment. Initially, 4 mg of the synthesized catalyst was dispersed in the BPA solution and sonicated for 20 minutes to ensure uniform dispersion and reach adsorption-desorption equilibrium. 1.2 g of PMS was accurately weighed into a 50 mL volumetric flask and diluted to the mark with deionized water to prepare a PMS solution. After adding 1 mL of the above PMS solution to initiate the reaction, 1 mL samples were taken periodically at fixed time intervals (0, 20 s, 40 s, 1 min, 2 min, 3 min). Each sample was immediately filtered and the reaction was terminated with sodium thiosulfate. The residual BPA concentration was then determined using a DGU-20A5R high-performance liquid chromatography system. To further verify the catalyst's suitability, its treatment performance for common organic dyes (including RhB, MO, and MB, all at a concentration of 20 mg / L) was also tested. The concentration changes of these dyes can be tracked by monitoring the absorbance changes at characteristic wavelengths using ultraviolet-visible spectrophotometry.

[0063] 1.2.3 Analysis and Testing Methods (1) Interference resistance and stability testing methods: To evaluate the compatibility of the catalyst in practical applications, interference tests were conducted using 10 mM inorganic salt and 5 mg / L humic acid, respectively. The initial pH of the reaction system was adjusted by adding H2SO4 or NaOH solution to investigate the effect of acidity and alkalinity. The natural water sample used in the actual water body experiment was collected from the Qiyu River near the West Lake Campus of Fuyang Normal University, while the tap water sample was taken from the laboratory of the new engineering building of the university. In the stability test, the catalyst was washed with water three times after each reaction, freeze-dried, and then recovered for direct use in the next cycle test.

[0064] (2) Leaching rate test method: The leaching concentration was determined using a PerkinElmer Optima 8000 inductively coupled plasma optical emission spectrometer (ICP-OES). The sample was digested with nitric acid until completely dissolved, and then diluted to a fixed volume before testing. A working curve was established using a series of standard solutions, and the leaching concentration of metal ions in the sample was calculated.

[0065] (3) Free radical identification test method: The reactive oxygen species generated during the reaction were detected using an EMX Plus electron paramagnetic resonance spectrometer. DMPO was used as a spin trapping agent to detect •OH and SO4. •- and O2 •- The free radical signal; TMPO is used to identify 1 Characteristic signals of O2. Furthermore, by using specific quenchers to distinguish the main active species in the reaction system, the dominant pathway for catalyst-activated PMS degradation of organic pollutants can be identified.

[0066] (4) In-situ Raman spectroscopy analysis: Using a LabRAM HR Evolution high-resolution confocal Raman spectrometer, the self-decomposition behavior of PMS in solution, catalyst-activated system, and pollutant coexistence state were tracked. By identifying characteristic Raman shifts and their intensity evolution, key intermediates in the reaction pathway were inferred.

[0067] (5) Electrochemical testing: Electrochemical performance was performed using a CHI 660E electrochemical workstation in a standard three-electrode system. The glassy carbon electrode was the working electrode, the Ag / AgCl electrode was the reference electrode, the platinum wire electrode was the counter electrode, the electrolyte was 50 mM Na2SO4 solution, and the scan rate was set to 100 mV / s.

[0068] (6) Degradation product analysis: The degradation intermediates were separated and identified by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS / MS, Triple TOF™ 5600+, AB SCIEX).

[0069] 1.3 Results 1.3.1 Material Structure Characterization To confirm the crystal structure and phase composition of the synthesized samples, a series of catalysts were characterized by X-ray diffraction (XRD), and the results are as follows: Figure 2 As shown, when the Mn / Co molar ratio is 1:40, there are no obvious diffraction peaks, indicating that its overall crystallinity is low. With the increase of Mn content, the intensity of the X-ray diffraction peaks gradually increases. When the Mn / Co molar ratio is 1:20, it is finally identified as being related to MnCo₂O₃. 4.5 The structure matches the standard card (PDF#32-0297) for the spinel phase. After further introducing Ce, the XRD pattern of the resulting sample is similar to that of undoped MnCo2O. 4.5 Compared to, there was no significant change ( Figure 3 This indicates that CeO2 is not doped into the spinel lattice, but rather loaded on the surface in a highly dispersed amorphous form or nanoclusters. These surface-dispersed CeO2 and MnCo2O 4.5 The formation of a strong coupling interface indirectly affects catalytic performance by modulating surface electronic states or inducing defects.

[0070] The SEM images clearly show the prepared MnCo2O 4.5 The catalyst retains the dodecahedral nanostructure characteristics of the precursor, with a rough surface and abundant porous structure. Figure 4 (a) Figure 5 (a) shows the effect of Ce doping on 5% CeO x / MnCo2O 4.5 MnCo2O was retained 4.5 It has a dodecahedral structure and a porous, rough surface. TEM images show 5% CeO. x / MnCo2O 4.5 Uniform hollow structure with folded edges ( Figure 5 (b)). For example Figure 5 As shown in (c), HRTEM images reveal lattice spacings of 0.204 nm and 0.277 nm, corresponding to MnCo2O, respectively. 4.5 The (400) crystal plane of CeO2 and the (200) crystal plane of MnCo2O clearly confirm that CeO2 and MnCo2O 4.5 Tight coupling at the nanoscale. Furthermore, as can be seen from the figure, CeO... x / MnCo2O 4.5 The heterojunction interface possesses abundant defects, which are beneficial for constructing highly active sites. The corresponding elemental mapping images show a uniform distribution of Ce, Co, Mn, and O, further confirming the presence of 5% CeO. x / MnCo2O 4.5Successful formation (5 in (d)). The above electron microscopy results indicate that in 5% CeO x / MnCo2O 4.5 CeO2 and MnCo2O 4.5 A strong coupling interface is formed, which facilitates charge transfer between the metals to achieve efficient Fenton-like catalytic degradation performance.

[0071] To further analyze the synthesized 5% CeO x / MnCo2O 4.5 The surface chemical composition of the catalyst was characterized by X-ray photoelectron spectroscopy (XPS). Figure 6 (a) is MnCo2O 4.5 and 5% CeO x / MnCo2O 4.5 High-resolution O 1s spectrum of the catalyst. The O 1s high-resolution XPS spectrum can be fitted to three characteristic sub-peaks with binding energies at 533.9 eV, 532.0 eV, and 529.9 eV, respectively, which are attributed to adsorbed oxygen (O2) on the catalyst surface. ads ), oxygen vacancy (O V ) and lattice oxygen (O L The results showed that, compared with MnCo2O 4.5 Compared to 5% CeO x / MnCo2O 4.5 Classified as O V The significantly increased peak area ratio suggests the potential presence of richer defect structures on its surface. To further investigate the material's structural characteristics, low-temperature electron paramagnetic resonance (EPR) testing was conducted. Figure 7 As shown, all samples exhibit a characteristic paramagnetic resonance signal at g=2.003, which originates from single electrons trapped by oxygen vacancies. In the EPR spectrum, 5% CeO... x / MnCo2O 4.5 The signal strength is much higher than that of MnCo2O 4.5 This indicates that the former possesses a higher density of oxygen vacancies. These results collectively confirm that Ce introduction induces the formation of a strongly coupled interface and abundant oxygen vacancies. High-resolution Co 2p spectroscopy reveals the prepared MnCo2O 4.5 and 5% CeO x / MnCo2O 4.5 Co is present at the same time. 2+ (~782.0 eV) with Co 3 + (~781.0 eV). Based on the peak area, MnCo2O 4.5 China Co 2+ / Co 3+The ratio is 0.86. When Ce is doped, Co... 2+ / Co 3+ The proportion increased to 1.40, a phenomenon attributed to Ce doping inducing the generation of more oxygen vacancies. These oxygen vacancies can act as electron donors, transferring electrons to adjacent Co atoms. 3+ Species, prompting its reduction to Co 2+ ( Figure 6 (b)). For example Figure 6 As shown in (c), 5% CeO x / MnCo2O 4.5 The Ce 3d spectrum shows peaks at 884.3 and 902.4 eV corresponding to Ce 3+ The peak values ​​at 880.7, 889.6, 899.0, 905.4, 909.5, and 916.9 eV are attributed to Ce. 4+ This indicates that 5% CeO x / MnCo2O 4.5 Ce 3+ With Ce 4+ Coexistence, its Ce 4+ / Ce 3+ The molar ratio is 2.65. This result further confirms that Ce 3+ The presence of CeO2 as a defect indicator promotes oxygen vacancy formation. The XPS characterization results above reveal the interaction between CeO2 and MnCo2O. 4.5 There are strong electronic interactions between them, a conclusion further confirmed by the increased peak broadening and blue shift in the Raman spectra before and after the introduction of Ce. Figure 8 ).

[0072] 1.3.2 Optimization of catalyst preparation and degradation conditions (1) Optimization of different Co / Mn ratios To investigate the effect of the Co / Mn ratio on BPA degradation performance, a series of prepared MnCo2O4 samples were examined. 4.5 The performance of the catalyst. For example... Figure 9 As shown, the degradation efficiency of BPA first increases and then decreases with the increase of the Mn / Co molar ratio. When the Mn / Co ratio is 1:20, MnCo2O 4.5 It exhibited the highest catalytic activity, with a corresponding degradation rate constant k of 3.58 min. -1 Therefore, this invention selects this ratio to synthesize the sample.

[0073] (2) Optimization of Ce element introduction By adjusting the Ce doping level, a series of CeO2 series were synthesized. x / MnCo2O 4.5The catalyst was investigated, and its catalytic performance in the PMS-activated degradation of BPA was systematically examined. Figure 10 The catalytic performance of this series of catalysts is clearly presented. When the Ce element content is 5%, the synthesized CeO x / MnCo2O 4.5 The catalyst exhibited optimal catalytic performance, achieving a 97.8% degradation rate of BPA within 1 minute, with a corresponding degradation rate constant of 3.95 min. -1 This demonstrates that such a strongly coupled structure is more conducive to electronic interactions, thereby enhancing catalytic activity.

[0074] (3) Effect of PMS concentration The dosage of PMS directly determines the concentration of active species in the reaction system, thus affecting the degradation efficiency of pollutants. Therefore, the effect of PMS dosage on 5% CeO2 was investigated. x / MnCo2O 4.5 The effect of PMS on BPA degradation is of significant research importance. In this experiment, under fixed catalyst dosage and initial pH conditions, four PMS concentration gradients (0.2, 0.4, 0.6, 0.8, and 1.0 g / L) were established. The results are as follows: Figure 11 As shown, the degradation efficiency was significantly improved with the introduction of PMS: when the PMS concentration increased from 0.2 g / L to 0.6 g / L, 5% CeO2 was observed to be reduced. x / MnCo2O 4.5 The rate constant for BPA degradation in the +PMS system decreased from 2.78 min. -1 Increased to 3.95 min -1 This is attributed to the fact that increased PMS concentration promotes the generation of more bioactive species, thereby accelerating BPA degradation. However, the degradation rate of BPA in this system does not exhibit a monotonically increasing trend. When the PMS concentration increases to 0.8 g / L, the corresponding degradation rate constant decreases to 3.62 min. -1 This phenomenon may be caused by the following two reasons: (1) the self-quenching effect of active species: excessive PMS will trigger SO4 in the system. •- (1) The mutual quenching reaction between free radicals leads to a decrease in the effective active species concentration; (2) Excessive PMS may occupy the active sites on the catalyst surface, thus interfering with the electron transfer process. Considering both degradation efficiency and oxidant economy, 0.6 g / L was selected as the optimal PMS dosage for subsequent studies. At this concentration, the system maintains the highest reaction kinetic constant while avoiding resource waste and ineffective consumption of active species due to excessive PMS.

[0075] 1.3.3 Catalyst universality test To evaluate 5% CeO x / MnCo2O 4.5 To assess the versatility of the catalyst in pollutant degradation, this invention selected six typical pollutants—SD, 2-4D, BPA, MO, MB, and RhB—for degradation tests. Under the same reaction conditions, the catalyst exhibited good removal efficiency for all of these pollutants, achieving rapid degradation in almost all of them within 5 minutes. The relevant results are as follows: Figure 12 As shown. To more intuitively compare catalytic efficiency, the apparent rate constants (k) of each pollutant were obtained by fitting a pseudo-first-order kinetic model. obs The respective times were 2.48 min. -1 3.96 min -1 3.95 min -1 2.68 min -1 3.28 min -1 4.58 min -1 The results above show that 5% CeO x / MnCo2O 4.5 The +PMS system exhibits strong degradation capabilities for various recalcitrant organic pollutants, demonstrating excellent versatility in practical applications. The 5% CeO2 of this invention... x / MnCo2O 4.5 The catalyst's catalytic performance surpasses that of most previously reported catalysts.

[0076] 1.3.4 Catalyst Interference Resistance Test To investigate 5% CeO x / MnCo2O 4.5 The potential application value of catalysts in complex water bodies was investigated, examining the effect of different initial pH values ​​on degradation efficiency. Figure 13 As shown in (a), the catalyst exhibits good catalytic activity over a wide pH range of 3–10, achieving complete removal of BPA from the system within 3 minutes. This result fully demonstrates that the catalytic system possesses excellent pH adaptability, maintaining high degradation efficiency under both acidic and alkaline conditions. Considering inorganic anions (such as Cl-), - SO4 2- NO3 - HCO3 2- CeO₂ is widely present in natural water bodies, leading to reduced reaction efficiency during wastewater treatment. To further verify the effects of 5% CeO₂... x / MnCo2O 4.5 To investigate the anti-interference ability of the +PMS system, this invention uses the four common inorganic anions and humic acid (HA) as representatives of environmental coexistence to explore their effects on BPA degradation efficiency. The results are as follows: Figure 13 As shown in (b), HCO3 2-The presence of [a substance] actually promoted the removal of BPA from the system, while Cl [was present]. - SO4 2- NO3 - The interference of HA on the system is not significant. This indicates that the catalyst has good anti-interference ability in complex real-world aquatic environments and has promising application prospects.

[0077] 1.3.5 Catalyst stability and practicality testing The cyclic stability of a catalyst directly determines its application value and operating cost in practical engineering, and is therefore a key indicator for evaluating material performance. To verify the effect of a strongly coupled interface on MnCo2O... 4.5 This study investigated the effect of catalyst stability enhancement on MnCo2O. 4.5 and 5% CeO x / MnCo2O 4.5 A continuous cyclic degradation experiment of BPA was conducted, and the results are as follows: Figure 14 As shown in the data, MnCo2O 4.5 The catalyst's performance was unsatisfactory. After four cycles, its degradation efficiency for BPA dropped sharply to 27.6%, indicating that MnCo2O... 4.5 The catalytic activity of [the catalyst] showed a severe decline during repeated use. In contrast, 5% CeO [catalyst] exhibited [a higher activity]. x / MnCo2O 4.5 The catalyst exhibits excellent stability and durability. Even after six consecutive cycles, it maintains high catalytic activity, with the BPA removal rate remaining at approximately 97.5% within three minutes during the sixth cycle. Figure 15 These are the XRD patterns of the catalyst before and after the reaction. It can be seen that the catalyst structure remained almost completely unchanged after the reaction. From... Figure 16 It can be seen that the surface morphology of the catalyst did not change significantly after use. The cobalt ion leaching rate of different systems was measured by ICP, and the results are as follows: Figure 17 As shown, MnCo2O 4.5 The cobalt ion leaching concentration was as high as 2.54 mg / L, but after introducing CeO2, it decreased to 0.40 mg / L, a reduction of 84.3%, far below the emission standard stipulated in my country's GB 25467-2010 (cobalt ≤ 1 mg / L). This confirms that the introduction of CeO2 not only stabilized the catalyst structure but also effectively inhibited the loss of active metal ions. In summary, 5% CeO2... x / MnCo2O 4.5 The construction of strongly coupled heterogeneous interfaces significantly enhanced the MnCo2O 4.5 Its structural stability effectively inhibits the loss of active components and structural collapse, providing a strong guarantee for its long-term application in actual water treatment.

[0078] To further evaluate 5% CeO x / MnCo2O 4.5 The potential application of the +PMS system in practical water treatment was demonstrated by selecting river water and tap water for degradation testing. Figure 18 As shown in (a), BPA degrades more readily in tap water and river water compared to deionized water. This is likely due to the synergistic effect of various inorganic ions and natural components present in actual water bodies. Total organic carbon (TOC) was used to assess the mineralization of BPA. Figure 18 As shown in (b), at 5% CeO x / MnCo2O 4.5 After reacting in the PMS system for 30 minutes, the TOC removal rate of BPA reached as high as 92.6%, indicating that this system can not only effectively degrade BPA, but also deeply mineralize it into CO2 and H2O. This result fully confirms the effectiveness of the prepared 5% CeO2. x / MnCo2O 4.5 The catalyst possesses excellent catalytic performance and potential for practical applications.

[0079] 1.3.6 Investigation into Degradation Mechanism To investigate 5% CeO x / MnCo2O 4.5 This invention identifies potential ROS types involved in BPA degradation within the +PMS system and employs electron paramagnetic resonance (EPR) technology to capture and analyze ROS during the reaction process. DMPO was selected as a spin trapping agent for the detection of •OH and SO4. •- and O2 •- The generation status; simultaneously using TEMP as a trapping agent for identification. 1 O2 generation. Analysis of EPR characteristic signals provides a clear picture of the state of each active species in the reaction system and their potential contribution to pollutant degradation. Results are as follows... Figure 19 As shown, no obvious EPR signal is observed when only PMS is present in the system. However, in the case of 5% CeO2... x / MnCo2O 4.5 DMPO-•OH and DMPO-SO4 were found in the PMS system. •- The peak. Similarly, at 5% CeO x / MnCo2O 4.5 In the +PMS system, DMPO-O2 •- The peaks are visible. These results confirm that •OH and SO42- are present. •- and O2 •- Generation of active species. Tripletic signals with an intensity ratio of 1:1:1 are attributed to TEMP- 1The O2 adduct signal rapidly increased 20 s after catalyst addition, then significantly weakened upon the addition of BPA. This phenomenon confirms the presence of 5% CeO. x / MnCo2O 4.5 +PMS system 1 Based on the generation of O2 and the above analysis, it can be inferred that 5% CeO2 is generated. x / MnCo2O 4.5 +PMS system 1 O2 is highly effective in the degradation of BPA.

[0080] To further investigate its activation mechanism and clarify the 5% CeO x / MnCo2O 4.5 Key active species involved in BPA degradation in the +PMS system were investigated using quenching experiments. TBA was selected for capturing •OH, and MeOH was selected for simultaneously capturing •OH and SO4. •- p-BQ was selected for O2 capture. •- Choose FFA as 1 O2 quencher. Experimental results are as follows: Figure 20 As shown, the degradation reaction was slightly inhibited upon the addition of p-BQ. Relatively speaking, TBA showed a more significant inhibitory effect than p-BQ, indicating that •OH in the system contributes more to the degradation of BPA than O2. •- When MeOH is present in the system, the inhibition effect is stronger than that of TBA; therefore, it can be inferred that SO42-... •- The contribution of is greater than that of •OH. Notably, the catalytic degradation of BPA was significantly inhibited upon the introduction of FFA, with the removal efficiency decreasing from 97.8% to 56.6% at 1 minute. This indicates that... 1 O2 is the main active species for BPA degradation. 1 O2 is a non-radical reactive species, and its degradation process is less affected by complex components in water, thus it can play a more stable role in actual wastewater treatment. To further investigate the role of non-radical pathways such as electron transfer and high-valence metal oxygen species in the degradation process, this invention selected K2Cr2O7 to investigate the electron transfer process. The results show that the degradation of BPA is inhibited when K2Cr2O7 is present in the system, indicating the presence of an electron transfer process in the system. In addition, ethanol was selected as a scavenger for high-valence metal oxygen species. It can be seen that when ethanol is added to the system, the degradation reaction is also inhibited to a certain extent, and the removal efficiency of BPA decreases from 97.8% to 79.8% after 1 minute. This indicates that HVMO also contributes to the degradation of BPA. In summary, based on the degree of inhibition of degradation, 1 O2 in 5% CeO x / MnCo2O 4.5The degradation of BPA played a dominant role in the +PMS system.

[0081] To further verify the reliability of the above results, NaN3 and L-histidine were selected as... 1 A specific O2 scavenger was used to conduct supplementary quenching experiments. By comparing the inhibitory effects of the two scavengers on BPA degradation efficiency, their findings can be mutually corroborated. 1 The actual contribution of O2 in this catalytic system. The results are as follows... Figure 21 As shown, in the control group without added scavenger, 5% CeO x / MnCo2O 4.5 The degradation rate constant of BPA in the +PMS system is 3.95 min. -1 The degradation of BPA was significantly inhibited upon the addition of NaN3 and L-histidine to the system, respectively. Specifically, the degradation rate constant decreased from 3.95 min⁻¹ to 3.95 min⁻¹. -1 Reduced to 1.35 min -1 The rate decreased by approximately 2.93 times. However, after adding L-histidine, the degradation rate constant significantly decreased to 0.30 min. -1 The decrease was approximately 13.17 times. This illustrates two... 1 All O2 scavengers significantly inhibited BPA degradation, with L-histidine showing a more pronounced inhibitory effect, which corroborates each other's findings. 1 O2 is 5% CeO x / MnCo2O 4.5 Key active species involved in BPA degradation in the +PMS system. To determine the generation of... 1 O2 is the oxygen source. This invention tested 5% CeO under different atmospheres. x / MnCo2O 4.5 +PMS system for BPA removal efficiency. For example... Figure 22 As shown, the removal efficiency of BPA was not significantly affected under air, nitrogen, and oxygen conditions, indicating that the generated... 1 O2 does not originate from dissolved oxygen. According to EPR spectra ( Figure 19 In (c), when only PMS is present, the detected 1 The O2 signal is extremely weak and can be ignored, indicating that the spontaneous decomposition of PMS cannot explain this. 1 The main source of O2. Therefore, 5% CeO x / MnCo2O 4.5 +PMS system 1 O2 may be generated by direct activation of PMS through a catalyst.

[0082] To further elucidate the potential reaction mechanism, this invention systematically analyzed the interfacial electron transfer behavior between the catalyst, PMS, and BPA using electrochemical testing methods such as CV, LSV, and EIS. Figure 23 The CV curve in (a) shows that 5% CeO x / MnCo2O 4.5 The corresponding integral area of ​​the curve is significantly larger, indicating that the material's electron storage and transfer capabilities have been significantly improved. Figure 23 The LSV curve in (b) shows that the current density of this catalyst is significantly higher than that of MnCo2O. 4.5 This reflects a faster interface reaction rate. From Figure 23 Similar conclusions can be drawn from the EIS results in (c), 5% CeO x / MnCo2O 4.5 The lower charge transfer resistance promotes electron transfer between the catalyst and PMS interface, resulting in higher transfer efficiency. Chorometric amperometry (it) was used to further monitor the electron transfer kinetics at the catalyst interface, and the results are as follows: Figure 23 As shown in (d), when PMS was added to the system at 500 s, the current response of the system increased significantly instantaneously. This was mainly due to electron transfer between PMS and the catalyst, promoting the formation of the catalyst-PMS* active intermediate. When BPA was added at 1000 s, the current increased, indicating electron transfer at the catalyst-PMS-BPA interface, which promoted a high redox potential and increased current intensity. (Compared to MnCo2O) 4.5 +PMS system, 5% CeO x / MnCo2O 4.5 The +PMS system exhibited a stronger current response signal throughout the process, and Ce doping effectively promoted the interfacial electron transfer efficiency. The above electrochemical results consistently indicate that the enhanced coupling interface optimizes the MnCo2O... 4.5 The electronic structure effectively enhances its electron transfer capability, thereby accelerating the activation of PMS.

[0083] The 5% CeO2 was further investigated using in-situ Raman spectroscopy. x / MnCo2O 4.5 The interaction between PMS molecules. For example... Figure 24 As shown in (a), the PMS solution at 884 cm⁻¹ -1 986 cm -1 and 1064 cm -1 A distinct peak was observed at [location], corresponding to HSO5 [value]. - Stretching vibration of the O-O bond, SO4 2- Symmetric stretching vibration and HSO5 -Symmetric stretching vibration of SO3-. Add 5% CeO2. x / MnCo2O 4.5 Then, a space located at 829 cm appeared. -1 New Peak (O) V -PMS*), followed by the introduction of BPA, and as the reaction proceeds, O V -PMS* peak intensity gradually decreases, and is attributed to HSO5. - 884 cm -1 The peak gradually disappeared. Figure 24 (b)). This observation indicates that O V -PMS* via O V Electron transfer is oxidized to form HSO5. - Subsequently, HSO5 - Rapid autolysis decomposition to generate SO5 - SO5 - It also generates rapidly through self-reaction. 1 O2.

[0084] 1.3.7 Possible degradation pathways of bisphenol A 5% CeO₂ was analyzed by LC-MS. x / MnCo2O 4.5 The degradation products of BPA in the PMS system were identified, and the possible degradation pathways of bisphenol A were inferred as follows: Figure 25 As shown. In pathway 1, BPA first interacts with water molecules to form a hydroxylated product (p1, m / z = 260), which is further oxidized to a carbonyl group to generate an intermediate (p2, m / z = 255), subsequently transforming into an intermediate (p3). In pathway 2, ROS first attacks the benzene ring of BPA, forming a monohydroxylated BPA (p5, m / z = 243) through dehydrogenation. p5 further transforms into an intermediate (p6, m / z = 241), which then undergoes further hydroxylation and dehydrogenation to generate an intermediate (p3). In pathway 3, the benzene ring of BPA is subjected to nucleophilic oxidants (•OH and...). 1 The influence of O2 leads to the generation of P5. Due to... 1 The further action of O2 leads to the formation of p7 and p8. In pathway 4, BPA is first converted to p5, then nucleophilic attack by water molecules triggers hydroxylation of the aromatic ring (p9), followed by dehydration to generate quinones and carboxylic acid compounds (p10). 1.3.8 Application Testing in Real-World Environments like Figure 26 As shown, this is for evaluating 5% CeO x / MnCo2O 4.5The continuous water treatment performance of the catalyst was demonstrated by loading it onto a melamine sponge carrier and placing it in a fixed-bed column reactor with a working volume of approximately 1 L. Under conditions of a hydraulic retention time of approximately 300 min, the system cumulatively treated 5.5 L of wastewater. Specifically, 5% CeO2 was used... x / MnCo2O 4.5 The catalyst was ultrasonically dispersed in ethanol and then loaded onto the pores of a melamine sponge via extrusion adsorption. The sponge was then repeatedly soaked in ethanol three times to fix the catalyst. Using tap water containing RhB (20 mg / L) as simulated wastewater, a Fenton-like catalytic reaction occurred as the catalyst flowed through the loaded sponge in the presence of PMS. The purified water continuously flowed out from the top of the reactor. To verify the feasibility of large-scale application of the catalyst, a 5% CeO2 loading was used. x / MnCo2O 4.5 The melamine sponge was kept suspended and fixed in the reactor. The experimental results showed that the color of the wastewater changed from bright pink to almost colorless within 50 minutes. Figure 27 In addition, real pharmaceutical wastewater was selected as the target matrix for testing. Figure 28 and Figure 29 As shown, the system achieved a removal rate of 72.7% for complex pollutants in pharmaceutical wastewater within 5 hours. Figure 30 The graph shows the TOC change during the degradation process. It can be seen that the TOC removal rate is 71.89%, indicating that the pollutants were effectively mineralized. This confirms the 5% CeO2 reduction. x / MnCo2O 4.5 The +PMS system exhibits excellent degradation capabilities for complex organic matter in real pharmaceutical wastewater, demonstrating promising potential for practical applications.

[0085] This invention introduces the rare earth element cerium (Ce) via ion exchange to successfully construct CeO. x / MnCo2O 4.5 Strongly coupled heterostructure. This catalyst exhibits excellent catalytic performance and superior stability in the PMS-activated BPA degradation process. (The text abruptly shifts to a seemingly unrelated topic about undoped MnCo2O.) 4.5 In comparison, CeO x / MnCo2O 4.5 The reaction rate constant is from 3.58 min. -1 Improved to 3.95 min -1 Furthermore, after six consecutive cycles, the bisphenol A removal rate still reached 97.5%, significantly better than the undoped sample (whose activity decreased to 27.6% after four cycles). These results indicate that the redox pairs and oxygen vacancies induced by the strongly coupled heterojunction interface can promote charge separation and conversion into active substances, thereby improving the activation efficiency of PMS. Quenching experiments and electron paramagnetic resonance spectroscopy confirmed that… 1 O2 is CeO x / MnCo2O 4.5 The main active species in the +PMS system. The catalytic membrane filtration system and in-situ floating water treatment device further validated the practical application potential of this system in wastewater treatment.

[0086] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A CeO x / MnCo2O 4.5 A method for preparing a coupled interface catalyst, characterized in that, Includes the following steps: Co salt and Mn salt are dissolved in solvent A to obtain solution A; 2-Methylimidazole was dissolved in solvent B to obtain solution B; After mixing solution B with solution A, the mixture was allowed to stand to obtain the precursor. The precursor was dissolved in solvent C, Ce salt was added and stirred, the product was collected by centrifugation, and then washed, dried and calcined sequentially to obtain CeO. x / MnCo2O 4.5 Coupling interface catalyst.

2. The preparation method according to claim 1, characterized in that, The Co salt is Co(NO3)2·6H2O; the Mn salt is Mn(acac)3.

3. The preparation method according to claim 1, characterized in that, The molar ratio of the Co salt to the Mn salt is (10~20):

1.

4. The preparation method according to claim 1, characterized in that, The molar ratio of the Co salt to the 2-methylimidazole is 1:(9~10).

5. The preparation method according to claim 1, characterized in that, The settling time is 6 hours.

6. The preparation method according to claim 1, characterized in that, The amount of cerium salt added is 2.5% to 20% of the precursor mass.

7. The preparation method according to claim 1, characterized in that, The stirring time is 30 minutes; solvents A, B, and C are all methanol.

8. The preparation method according to claim 1, characterized in that, The calcination conditions are set as follows: calcination at 400℃ for 2 h under an H2 / Ar atmosphere.

9. CeO prepared by the preparation method according to any one of claims 1 to 8 x / MnCo2O 4.5 Coupling interface catalyst.

10. The CeO as described in claim 1 x / MnCo2O 4.5 Application of coupling interface catalysts in the degradation of organic pollutants by activated persulfate.

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