CuO / Co3O4 heterojunction catalyst and its application in the degradation of bisphenol A

Abstract

This invention proposes a CuO / Co3O4 heterojunction catalyst and its application in the degradation of bisphenol A (BPA), relating to the field of antibiotic degradation technology. Addressing the shortcomings of existing catalysts in terms of insufficient catalytic activity and stability in complex aquatic matrices with high salt and high organic matter content, this invention provides a CuO / Co3O4 heterojunction catalyst. This catalyst combines MOF-derived CuO as the catalyst core with Co3O4, providing a high specific surface area, abundant defects / functional groups, and good mass transfer characteristics. This enhances the catalytic performance for PMS activation while reducing the aggregation of metal oxides within the catalyst structure. Furthermore, MOF-derived carbon can serve as an electron transport channel and interface regulation scaffold, promoting the construction of a stable heterojunction interface and improving recyclability. Accordingly, the interfacial coupling of the copper-based MOF-derived CuO / carbon composite material with Co3O4 ensures high activity while achieving precise control of the PMS activation pathway through interfacial electronic structure regulation.

Description

Technical Field

[0001] This invention relates to the field of antibiotic degradation technology, and more particularly to CuO / Co3O4 heterojunction catalysts and their application in the degradation of bisphenol A. Background Technology

[0002] In recent years, the widespread presence of antibiotics in aquatic environments has drawn increasing global attention, primarily due to their pseudo-persistence and the potential risk of inducing antibiotic-resistant bacteria. Bisphenol A (BPA), a broad-spectrum antibiotic widely used in aquaculture and livestock farming, is frequently detected in surface water and wastewater discharges. Given its high environmental persistence, bioaccumulation potential, and toxicity, there is an urgent need to develop efficient and environmentally friendly BPA degradation strategies.

[0003] Peroxymonosulfate (PMS)-based advanced oxidation processes (SR-AOPs) have emerged as a potential technology for eliminating recalcitrant pollutants due to their ability to generate highly reactive species such as sulfate and hydroxyl radicals. Compared to traditional AOPs, PMS activation can occur not only through free radical pathways but also through non-free radical pathways. Although the free radical pathway is highly reactive, it is easily affected by matrix components commonly found in actual water bodies (such as Cl-). - and HCO3 - Radical quenching can lead to the formation of undesirable byproducts. Conversely, non-radical pathways, while having slightly lower redox potentials, offer higher selectivity and stronger tolerance to matrix interference. In natural surface water environments, electrochemically active phosphorus is mainly found downstream of intensive aquaculture areas and in waters surrounding pharmaceutical industrial parks. These water bodies typically have complex backgrounds, are rich in dissolved organic matter, and have high salinity. These factors significantly reduce treatment efficiency through competition and radical scavenging. Therefore, to achieve efficient and robust catalysis in complex aquatic matrices, it is crucial to regulate the balance between radical-dominated and non-radical pathways. Achieving a tunable PMS activation mechanism while maintaining high activity and stability remains a key research frontier.

[0004] The PMS activation pathway is closely related to the catalyst's microstructure and surface charge distribution. For example, in the Cu2O / BiVO4 (Cu-BVO) heterostructure constructed by Chen et al., photoinduced directional carrier migration restructured the surface charge distribution, thus shifting the PMS activation pathway from a radical pathway to a non-radical pathway. Gu et al. prepared the FeCoCu-NC (TNC) catalyst by integrating three metal ions into MOFs, utilizing the unique electron transfer tendency between the three metals to restructure the surface charge distribution, forming highly electron-deficient copper sites, thus driving PMS activation from a radical pathway to a non-radical pathway dominated by high-valence metal species. In these studies, the optimized oxidation systems all exhibited strong tolerance to complex aquatic matrices. Compared to single-metal catalysts, multi-metal catalysts may form pn or nn-type heterojunctions between dissimilar metal oxides. The interaction at the heterojunction interface can induce directional migration of surface charges, thereby reconfiguring the electron density of active sites. This fundamentally changes the adsorption energy of PMS and its intermediates on the catalyst surface, providing a possibility for regulating the PMS activation pathway.

[0005] Metal-organic frameworks (MOFs), assembled from metal ions / clusters and organic ligands, provide a unique platform for constructing "metal oxide / carbon" composite catalysts. Calcined materials derived from MOFs typically possess high specific surface area, abundant defects / functional groups, and excellent mass transfer properties, making them ideal precursors for composite synthesis. Notably, in existing research, copper-based heterostructures offer particularly diverse PMS activation pathways.

[0006] Therefore, developing a novel MOF-derived cobalt-based heterojunction catalyst (such as CuO / Co3O4) and achieving its efficient and tunable activation of PMS for bisphenol A degradation in complex aquatic matrices is of great scientific and engineering value for addressing key technical issues such as the lack of targeted design of current non-radical pathway catalysts, the unclear electron transfer mechanism at the heterojunction interface, and insufficient catalytic activity and stability in actual high-salt / high-organic-matter wastewater. It is also crucial for promoting the practical application of non-radical-dominated SR-AOPs technology and achieving precise treatment of new pollutants in aquatic environments. Summary of the Invention

[0007] To address the problem of insufficient catalytic activity and stability of existing catalysts in complex aquatic matrices with high salt / high organic matter, this invention proposes a novel MOF-derived CuO / Co3O4 heterojunction catalyst and its application. By constructing a crystal plane coupled heterojunction interface and uniformly dispersing the active components with the help of a carbon skeleton, the activation pathway of PMS can be effectively controlled, exhibiting high efficiency in degrading bisphenol A and good stability in complex aquatic matrices.

[0008] This invention provides a CuO / Co3O4 heterojunction catalyst, wherein the heterojunction catalyst is formed by CuO and Co3O4 composite, wherein a heterojunction interface with crystal plane coupling is formed between CuO and Co3O4, and Co and Cu elements are uniformly distributed in the carbon framework.

[0009] A method for preparing a CuO / Co3O4 heterojunction catalyst includes the following steps: Cu-MOFs were calcined to obtain Cu-NC; A CuO / Co3O4 heterojunction catalyst was obtained by thermally reacting a suspension of Co3O4 nanoparticles with a dispersion of Cu-NC; the mass ratio of Cu-NC to Co3O4 nanoparticles was 100:40~80.

[0010] Furthermore, the calcination includes a first stage and a second stage; The first stage includes: heating to 300℃~500℃ at a first heating rate, calcining for 1~5 hours, and then cooling to 23℃~28℃; The second stage includes: heating to 300℃~500℃ at a second heating rate and calcining for 1~5 hours.

[0011] Furthermore, the first heating rate is 1~5℃ / min; the second heating rate is 1~5℃ / min.

[0012] Furthermore, the first heating rate is 2°C / min; the second heating rate is 2°C / min.

[0013] Furthermore, the mass ratio of Cu-NC to Co3O4 nanoparticles is 100:60.

[0014] Furthermore, the conditions for the thermal reaction are: 40~80℃, heating and stirring at 500rpm until the water evaporates.

[0015] Furthermore, the conditions for the thermal reaction are: 60°C, 500 rpm heating and stirring until the water evaporates.

[0016] The present invention also provides the application of the CuO / Co3O4 heterojunction catalyst described in the above technical solution or the CuO / Co3O4 heterojunction catalyst prepared by the method described in the above technical solution in the degradation of bisphenol A.

[0017] Furthermore, the application includes: mixing the CuO / Co3O4 heterojunction catalyst with bisphenol A-containing wastewater, adding peroxymonosulfate, and carrying out a degradation reaction.

[0018] Furthermore, the bisphenol A content in the wastewater is 10~100 mg / L.

[0019] Furthermore, the amount of CuO / Co3O4 heterojunction catalyst used is 5~20 mg / L wastewater; the amount of peroxymonosulfate used is 300 mg / L wastewater.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention proposes a targeted strategy for regulating the PMS activation pathway. Co3O4 nanoparticles are immobilized on the surface of a copper-based MOF-derived CuO / carbon composite material (Cu-NC) using a simple ethanol-hydrothermal assembly method to construct a CuO / Co3O4 heterojunction catalyst (CuCo-NC). This system integrates the conductive carbon network inherited from the MOF precursor with the strong redox capabilities of Co3O4, forming a highly efficient catalytic platform. The study focuses on how the heterojunction-induced built-in electric field regulates the reaction mechanism: density functional theory calculations and quenching experiments confirm that the built-in electric field effectively promotes electron transfer, shifting the PMS activation pathway from a radical to a non-radical pathway. This pathway regulation enables the catalyst to maintain excellent bisphenol A degradation performance in complex aquatic matrices, providing a new approach for selective water purification targeting antibiotic pollutants. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a flowchart of the method for preparing CuO / Co3O4 heterojunction catalyst according to the present invention; Figure 2 The XRD pattern of the CuO / Co3O4 heterojunction catalyst prepared in the embodiments of the present invention; Figure 3 CuCo-NC in this embodiment of the invention 60 Surface elemental valence state analysis results; Figure 4 The effects of catalysts with different Co3O4 loadings on the degradation of BPA in the CuCo-NCX+PMS system were investigated. Figure 5 CuCo-NC under different reaction conditions 60 BPA removal efficiency in the PMS system; Figure 6 The effect of adding different inorganic anions and natural organic substances on BPA removal efficiency; Figure 7These are the results of experiments on the quenching of reactive oxygen species. Figure 8 Results of PMSO conversion experiments; Figure 9 The image shows the XPS spectrum of CuCo-NC60 after the catalytic reaction. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0025] The chemical reagents used in the embodiments of this invention are as follows: 1,3,5-Benzotricarboxylic acid (H3BTC, 98.0%, purchased from Shanghai Aladdin Industrial Co., Ltd.); Copper nitrate trihydrate (Cu(NO3)2·3H2O, 99.0%, purchased from Shanghai Aladdin Industrial Co., Ltd.); Cobalt nitrate hexahydrate (Co(NO3)2·6H2O, 99.0%, purchased from Shanghai Aladdin Industrial Co., Ltd.); Bisphenol A (98.0%, purchased from Shanghai Aladdin Industrial Co., Ltd.); Hexamethylenediamine (HMDA, 98%, purchased from Sigma-Aldrich); Ethanol (EtOH, 99.9%, purchased from Chengdu Kelon Chemical Co., Ltd.); Methanol (MeOH, 99.9%, purchased from Chengdu Kelon Chemical Co., Ltd.); Tert-Butanol (TBA, 99.0%, purchased from Chengdu Kelon Chemical Co., Ltd.); Furfuryl alcohol (L-his, 99.0%, purchased from Chengdu Kelon Chemical Co., Ltd.); p-Benzoquinone (p-BQ, 99.0%, purchased from Chengdu Kelon Chemical Co., Ltd.).

[0026] Example 1 according to Figure 1 The process shown is used to prepare CuO / Co3O4 heterojunction catalysts. Synthesis of Cu-NC A typical preparation process is as follows: 1.55 g Cu(NO3)2·3H2O and 0.665 g PVP were dissolved in a mixed solution of 15 mL DMF and 15 mL ethanol, denoted as solution A; 0.735 g H3BTC was dissolved in a mixed solution of 15 mL DMF and 15 mL ethanol, denoted as solution B. Solution A was slowly added to solution B under stirring for 30 min. The mixed solution was transferred to a stainless steel high-pressure reactor lined with polytetrafluoroethylene and reacted at 120 °C for 4 h. The resulting product was centrifuged (10000 rpm, 3 min), repeatedly washed with DMF and ethanol solutions, and finally vacuum dried. The resulting product was labeled as a Cu-MOFs precursor.

[0027] MOF-derived materials were prepared by a two-step calcination method: the dry Cu-MOF precursor was heated to 400°C at 2°C / min in a nitrogen atmosphere, held at that temperature for 2 hours, and then cooled to room temperature; in the second stage, it was calcined at 400°C for 2 hours in an air atmosphere with the same heating program, and the resulting powder was labeled Cu-NC.

[0028] Synthesis of Co3O4 nanoparticles The preparation of Co3O4 nanoparticles followed existing literature methods: 0.708 g HMDA was dissolved in 12 mL of ethanol, thoroughly mixed, and then slowly added dropwise to a 20 mL ethanol solution containing 0.291 g Co(NO3)2·6H2O, with continuous stirring for 30 min. The mixture was transferred to a stainless steel high-pressure reactor lined with polytetrafluoroethylene and reacted at 180 °C for 15 h. The product was centrifuged (3000 rpm, 10 min), repeatedly washed with ethanol, and dried at room temperature overnight. The resulting powder was calcined in air at 300 °C for 1 h to obtain Co3O4 nanoparticles.

[0029] CuCo-NC X Synthesis First, 100 mg of the prepared Cu-NC was dispersed in 30 mL of an ethanol-water mixture (ethanol to water volume ratio 2:1) and stirred thoroughly; this solution is denoted as solution C. A specific mass of Co3O4 nanoparticles was dispersed in 20 mL of an ethanol-water mixture (volume ratio 2:1) until completely dispersed; this solution is denoted as solution D. Then, under conditions of heating and stirring in an oil bath at 60 °C, solution D was slowly added to solution C, and heating and stirring continued until the water evaporated, yielding a black powder labeled CuCo-NC. X (That is, CuO / Co3O4 heterojunction catalyst). Where X represents the mass of Co3O4 nanoparticles weighed during the synthesis process (X=20, 40, 60, 80, 100 correspond to 20, 40, 60, 80, 100mg of Co3O4 nanoparticles, respectively).

[0030] Test Example 1 CuCo-NC prepared in the examplesX XRD pattern analysis was performed, and the results are as follows: Figure 2 As shown. By Figure 2 In (a), it can be observed that the main characteristic peaks in the initial Cu-NC appear at 2θ values ​​of 32.49°, 35.51°, 38.74°, and 48.83°, which correspond to the (110), (002), (111), and (-202) crystal planes of CuO (JCPDS NO.40-1917), respectively, indicating that Cu in Cu-NC mainly exists in the form of CuO. With the addition of Co3O4, CuCo-NC... X The XRD pattern showed new characteristic peaks at 2θ values ​​of 19.0°, 31.27°, 36.85°, 44.81°, and 55.66°. These characteristic peaks were attributed to the (111), (220), (311), (400), and (422) crystal planes of Co3O4 (JCPDS NO. 43-1003), respectively, and the intensity of these characteristic peaks gradually increased with increasing Co3O4 content. The microstructure of CuCo-NCX was characterized by SEM and TEM. Figure 2 As shown in (b) and (c), the microstructure of CuCo-NCX consists of a large number of irregularly packed particles, and no regular morphology belonging to Cu-MOF-derived materials was observed. Further TEM characterization revealed that CuCo-NCX... X The lattice fringes of the internal metal oxides show spacings d1 and d2 of 0.23 nm and 0.47 nm, respectively, corresponding to the (111) crystal plane of CuO and Co3O4. Furthermore, Figure 2 Image (d) shows that the (111) crystal plane of CuO and the (111) crystal plane of Co3O4 are closely connected, and there is a clear grain boundary between the two different crystal planes, which indicates that in CuCo-NC 60 Successful construction of heterogeneous structures in materials. Meanwhile, Figure 2 In the middle (e), CuCo-NC is used. 60 The elemental distribution image also demonstrates the uniform distribution of Co and Cu elements on the carbon framework formed by the pyrolysis of H3BTC.

[0031] Test Example 2 Further analysis of CuCo-NC using XPS characterization from Test Example 1 60 The valence states of elements on the surface of a material, such as Figure 3 As shown in (a), CuCo-NC 60 The high-resolution spectrum of Co 2p can be fitted to four characteristic peaks and two satellite peaks. Among them, the characteristic peaks with binding energies of 780.29 eV and 795.28 eV correspond to CuCo-NC. 60 Co present in3+ The characteristic peaks at 781.52 and 797.52 are similar to the oxidation state of Co, indicating that Co is also present in the structure. 2+ Species. Figure 3 Image (b) shows a high-resolution Cu 2p spectrum, with characteristic peaks at 934.32 and 954.32 corresponding to Cu. 2+ The species, and the satellite peaks located at 941.09, 943.62, and 962.31 also show Cu. 2+ The consistency in oxides. Furthermore, it can be observed that although CuCo-NC 60 The valence states of Co and Cu in the structure are consistent with those in Co3O4 nanoparticles and Cu-NC, but the positions of their characteristic peaks show a significant shift. Specifically, CuCo-NC 60 Co in the structure 3+ and Co 2+ The values ​​shifted by 0.69 eV and 0.91 eV respectively towards directions with higher binding energy, while Cu... 2+ This indicates a shift of 0.44 eV towards a lower binding energy. This suggests that electron transfer may have occurred between Co3O4 and CuO during the construction of the Co3O4 / CuO heterostructure, with electrons transferring from Co3O4 (the electron donor) to CuO (the electron acceptor). Furthermore, a similar trend was observed in the Augustiner electron spectroscopy of the copper atomic layer microregions, where Cu²⁺… + The characteristic peaks shift toward lower binding energies.

[0032] To further verify CuCo-NC 60 To investigate the changes in the electronic structure, this test case also calculated the work functions of the Co3O4(111) and CuO(111) crystal planes using DFT. Figure 3 (c) and Figure 3 As shown in (d), the work functions of Co3O4 and CuO are 4.723 eV and 5.179 eV, respectively. The work function of Co3O4 is significantly lower than that of CuO. To achieve Fermi level equilibrium in the CuCo-NCX composite phase, electrons will transfer from Co3O4 with the lower work function to CuO with the higher work function, consistent with the electron transfer trend observed in XPS analysis. Furthermore, Kelvin probe force microscopy was used for further investigation of Co3O4, Cu-NC, and CuCo-NC. 60 Surface potential, where Figure 3 In the middle (e), Cu-NC is represented. Figure 3 In the middle (f), Co3O4 is represented. Figure 3 (g) corresponds to CuCo-NC 60 Obviously, CuCo-NC 60The surface potential of CuCo-NC (207.52 mV) is much higher than that of Co3O4 (148.17 mV) and Cu-NC (132.3 mV), indicating that an internal electric field may exist at the interface between Co3O4 and Cu-NC in CuCo-NC60. Under the influence of this internal electric field, electrons will transfer from Co3O4 to Cu-NC.

[0033] Test Example 3 Catalysts with different Co3O4 loadings were used in CuCo-NC X +PMS system used for BPA degradation. : 10mg CuCo-NC X 1L of bisphenol A-containing wastewater was added, followed by 300mg of persulfate, to initiate a degradation reaction. The results were as follows: Figure 4 As shown, by Figure 4 As shown in Figure (a), the removal rate of BPA by the catalyst gradually increases with the increase of Co3O4 loading, reaching its highest value at a loading of 60 mg, at which all BPA is removed. CuCo-NC 60 The corresponding reaction rate constant is 0.1111 min. -1 This is much higher than that of Cu-NC (0.0406 min). -1 ) and Co3O4 (0.0653 min) -1 The reaction rate constant of the nanoparticles was determined. However, as the proportion of Co3O4 nanoparticles further increased to 80 mg and 100 mg, the BPA removal rate gradually decreased to 90.85% and 90.82%, respectively, and the corresponding reaction rate constants also decreased to 0.0353 min. -1 and 0.0394 min -1 This indicates that the proper combination of Cu-NC and Co3O4 nanoparticles can significantly improve the removal efficiency of BPA, while excessive Co3O4 nanoparticles can hinder the removal of BPA.

[0034] CuCo-NC under different reaction conditions 60 The BPA removal efficiency in the +PMS system was also compared. For example... Figure 5 As shown, different catalyst dosages, PMS concentrations, and initial pH all affect BPA removal efficiency to varying degrees. Furthermore, different inorganic anions and typical natural organic compounds were added to the reaction system to simulate BPA removal in a real environment. Figure 5 (d) and Figure 6 It was observed that CuCo-NC 60 The +PMS system exhibits high resistance to common inorganic anions and humic acid (HA). Among the four selected inorganic anions, only HCO3-... 3-It significantly inhibits the removal of BPA, which may be due to HCO3-. 3- The addition of [a substance] altered the pH of the reaction solution. HA will then coat CuCo-NC [a solution]. 60 The active sites on the surface thus affect the treatment effect of the reaction system.

[0035] Test Example 4 To further investigate the degradation process of BPA removal using the CuCo-NCX+PMS system, a systematic reactive oxygen species quenching experiment was conducted. Tert-butanol and methanol were used to study potential free radical pathways during BPA degradation. Figure 7 As shown in (a), in CuCo-NC 60 In the PMS system, tert-butanol has almost no negative impact on the degradation of BPA, while... Figure 7 From (b), it can be seen that the rate constant for the degradation of BPA by methanol is 0.1111 min. -1 Slightly decreased to 0.0856 min -1 This indicates that hydroxyl radicals may not have participated in the BPA removal process in the free radical pathway, while sulfate radicals still contribute to BPA degradation. On the other hand, L-his showed a very significant inhibitory effect on the reaction system, with the BPA reaction rate constant significantly reduced to 0.0671 min⁻¹. -1 This shows 1 O2 is likely one of the main reactive species leading to BPA degradation. Furthermore, DMSO was used to capture potentially high-valence metal species that might be generated in the system. Clearly, only 53.26% of the BPA was removed within 60 min in the presence of 5 mM DMSO, and the corresponding BPA reaction rate constant was only 0.0704 min. -1 This indicates that high-valence metal species may have been generated in the reaction system.

[0036] EPR characterization further confirmed the reactive oxygen species involved in the BPA removal process. For example... Figure 7 As shown in (c), when TEMP is used as a spin trap, it can be observed that the TEMP- 1 The O2 (1:1:1) signal exhibits a distinct characteristic peak, and its intensity gradually increases over time. This indicates that O2 is continuously generated during BPA removal. 1 O2, which is consistent with the results of the quenching experiment. When DMPO acts as a spin trapping agent to capture •OH and SO4• - At that time, the expected DMPO-•OH and DMPO-SO4• did not appear. - Instead of the characteristic peak signal, a seven-peak signal of DMPO-X appeared. Figure 7As shown in (d), the intensity of the DMPO-X signal gradually increases over time. The formation of DMPO-X may be related to the formation of high-valence metal species, indicating that high-valence metal species also participate in the degradation of BPA, which is consistent with the results of the quenching experiment.

[0037] Furthermore, because Co(IV) can oxidize PMSO to PMSO2 via oxygen transfer, PMSO was chosen as a chemical probe to further confirm the presence of high-valence metal species in the reaction system. Figure 8 As shown, in all reaction systems, a portion of PMSO was converted to PMSO2, indicating that high-valence metal species contributed to the conversion in all systems. The Cu-NC+PMS system produced the lowest concentration of PMSO2, with only 7.67% of PMSO converted to PMSO2. In the CuCo-NC system… 60 In the +PMS system, 82.49% of PMSO was converted to PMSO2, which may indicate a relatively high contribution from higher-priced metals within this system. In summary, CuCo-NC 60 Activation of PMS in the +PMS system 1 O2 and Co(IV) are the most dominant non-radical pathways, while SO4• - It also contributes to the removal of BPA.

[0038] Test Example 5 To further elucidate the potential reaction mechanism, the reaction-induced CuCo-NC... 60 The XPS spectra were analyzed. For example... Figure 9 As shown, after the reaction, Co 3+ Co 2+ and Cu 2+ The characteristic peaks of Co all showed significant shifts, and the trend of these shifts was opposite to that during the construction of the heterostructure. 3+ and Co 2+ The characteristic peaks shifted from 780.29 eV and 781.51 eV before the reaction to 780.15 eV and 781.26 eV, respectively, while Cu 2+ The characteristic peak shifts from 934.3 eV to 934.72 eV, indicating a higher directional shift in CuCo-NC. 60 During BPA degradation, Co acts as the electron acceptor while Cu acts as the electron donor. Furthermore, CuCo-NC... 60 China Co 3+ The proportion also decreased from 54.59% to 48.21% after the reaction, and the corresponding Co... 2+ The proportion rose from 45.41% to 51.79%.

[0039] Therefore, in CuCo-NC 60 The mechanism of PMS activation in the +PMS system is as follows: First, the heterostructure between Co3O4 and CuO promotes the establishment of an internal electric field and the redistribution of electrons at the interface, which optimizes the electronic structure of Co sites at the interface. This allows Co... 2+ and Co 3+ It became CuCo-NC 60 The main active sites in the catalyst, the electron-deficient Co sites, combine with PMS adsorbed on the catalyst surface and generate Co(IV)=O through two-electron or one-electron transfer pathways. During the degradation of BPA, SO42-... •– There is still a 22.59% contribution percentage and post-reaction Co 3+ The decrease in the proportion of Co(IV)=O suggests that it may be generated more through single-electron transfer. The generated Co(IV)=O will rapidly oxidize pollutants and be reduced to Co after the reaction is complete. 2+ or Co 3+ Furthermore, the strong adsorption of PMS by the electron-deficient Co sites promotes the formation of Co(IV), corresponding to... 1 The amount of O2 generated decreased slightly. Meanwhile, CuO, in an electron-rich state at the heterostructure interface, acted as a highly efficient electron donor in the reaction, contributing to the formation of Co. 3+ / Co 2+ The redox cycle provides electrons, promoting the reduction and regeneration of Co sites.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A CuO / Co3O4 heterojunction catalyst, characterized in that, The heterojunction catalyst is formed by combining CuO and Co3O4, wherein a heterojunction interface with crystal plane coupling is formed between CuO and Co3O4, and Co and Cu elements are uniformly distributed in the carbon framework.

2. The method for preparing the heterojunction catalyst according to claim 1, characterized in that, Includes the following steps: Cu-MOFs were calcined to obtain Cu-NC; A CuO / Co3O4 heterojunction catalyst was obtained by thermally reacting a suspension of Co3O4 nanoparticles with a dispersion of Cu-NC; the mass ratio of Cu-NC to Co3O4 nanoparticles was 100:40~80.

3. The preparation method according to claim 2, characterized in that, The calcination includes a first stage and a second stage; The first stage includes: heating to 300℃~500℃ at a first heating rate, calcining for 1~5 hours, and then cooling to 23℃~28℃; The second stage includes: heating to 300℃~500℃ at a second heating rate and calcining for 1~5 hours.

4. The preparation method according to claim 2, characterized in that, The first heating rate is 1~5℃ / min; the second heating rate is 1~5℃ / min.

5. The preparation method according to claim 2, characterized in that, The mass ratio of Cu-NC to Co3O4 nanoparticles is 100:

60.

6. The preparation method according to claim 2, characterized in that, The conditions for the thermal reaction are: 40~80℃, heating and stirring at 500rpm until the water evaporates.

7. The application of the CuO / Co3O4 heterojunction catalyst of claim 1 or the CuO / Co3O4 heterojunction catalyst prepared by the method of any one of claims 2 to 6 in the degradation of bisphenol A.

8. The application as described in claim 7, characterized in that, The CuO / Co3O4 heterojunction catalyst was mixed with wastewater containing bisphenol A, and peroxymonosulfate was added to carry out a degradation reaction.

9. The application as described in claim 8, characterized in that, The bisphenol A content in the wastewater is 10~100 mg / L.

10. The application as described in claim 8, characterized in that, The CuO / Co3O4 heterojunction catalyst is used at a concentration of 5-20 mg / L wastewater; the peroxymonosulfate is used at a concentration of 300 mg / L wastewater.

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