Bimetallic single-atom modified defective tiotanium electrocatalyst, preparation method and application thereof in catalytic degradation of organic pollutants

Abstract

This invention relates to a bimetallic single-atom modified defective TiO2 electrocatalyst, its preparation method, and its application in the catalytic degradation of organic pollutants, belonging to the field of electrocatalysis technology. This invention provides a bimetallic single-atom modified defective TiO2 material, wherein the metal is dispersed in single-atom form on a defective TiO2 substrate, forming a first metal-O-Ti and a second metal-O-Ti coordination structure, with oxygen atoms completely separating the first and second metal atoms. It also provides a bimetallic single-atom modified defective TiO2 electrode, comprising an electrode substrate and a film containing bimetallic single-atom modified defective TiO2 formed on the surface of the electrode substrate. Its application in the electrocatalytic degradation of organic pollutants is also discussed. The catalytic material of this invention, under an O2 atmosphere, CuCo@TiO2... 2‑x The degradation rate constant of FLO (30 × 10) ‑3 min ‑1 TiO 2‑x It is 30 times that of other chemicals, with a dechlorination rate of 98.6%, a defluorination rate of 91.77%, and a TOC removal rate of 92.89%.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis technology, specifically relating to bimetallic single-atom modified defective TiO2 electrocatalysts, their preparation methods, and their applications in electrocatalytic redox reactions. Background Technology

[0002] Halogenated organic pollutants (such as florfenicol (FLO), polychlorinated biphenyls (PCBs), and perfluorinated compounds) are widely present in wastewater discharged from industries such as pharmaceuticals, chemicals, and livestock farming. The strongly polar carbon-halogen (CX, X = Cl, F) covalent bonds in their molecular structure endow these pollutants with high chemical stability, bioaccumulation, and toxicity. Conventional biological treatment processes are difficult to achieve effective degradation due to the inhibitory effect of microbial metabolism. While advanced oxidation processes (AOPs) can oxidize and destroy the organic carbon skeleton through hydroxyl radicals (·OH), they are inefficient at breaking the strongly inert CX bonds, easily forming more toxic halogenated intermediates. In contrast, decomposition and dehalogenation reactions can be effectively promoted based on atomic hydrogen (H*) and hydrated electrons (eaq-). However, everything has two sides; dehalogenation products cannot be further decomposed and mineralized by reduction alone. The redox characteristics of the original halogenated organic pollutants and degradation products change, making it impossible to effectively degrade the initial pollutants and their intermediates by reduction or oxidation methods alone. Furthermore, incompletely degraded intermediates still possess certain ecotoxicities, and in some cases, their toxicity even exceeds that of the original pollutants. Therefore, how to achieve deep dehalogenation and mineralization of recalcitrant halogenated organic pollutants remains a major environmental problem.

[0003] Combining reduction and oxidation processes is an effective method for achieving deep dehalogenation and mineralization. Recently, single-system reduction-oxidation has been achieved in a dual-photoelectrode electrochemical system, where H* is generated at the cathode and ·OH at the anode. However, the synergistic effect of cathodic reduction and anodic oxidation is essentially a relay race because, at the molecular level, the reduction products at the cathode and the oxidation products at the anode are far apart. In-situ oxidation of reduction products or reduction of oxidation products could significantly accelerate contaminant removal.

[0004] The simultaneous generation of H* and ·OH during reduction and oxidation is easily achieved in electrocatalytic reactions, mainly because the catalytic material efficiently reduces H2O / H+ to H* at the cathode; in addition, oxygen (O2) undergoes oxygen reduction reaction (ORR) at the cathode to produce H2O2 or ·OH. The main processes of ORR are: (1) adsorption of O2 on the surface of the catalytic material, (2) activation of adsorbed oxygen, and (3) desorption of intermediate products from the active sites. In traditional cathode electrocatalytic reduction reaction systems, ORR mainly follows two-electron, three-electron, or four-electron transfer pathways. The two-electron transfer pathway mainly generates active species H2O2. H2O2 cannot degrade halogenated organic pollutants and requires additional chemical agents or active sites to activate H2O2 to generate active species (·OH). For example, in carbon-based material (such as reduced graphene oxide) catalytic systems, H2O2 generated by the two-electron ORR pathway needs to pass through Fe 2+ Only activation (Fenton reaction) allows it to be converted to ·OH; the four-electron transfer pathway is the complete reduction of O2, mainly producing OH. - Because it contains no strongly oxidizing active species (such as H2O), it cannot degrade halogenated organic pollutants. The three-electron pathway is a special reaction pathway that can generate ·OH in one step. Compared to two / four-electron pathways, the advantage of the three-electron ORR pathway lies mainly in the fact that it requires no additional activation step and can generate ·OH in situ. Studies have shown that defective structures can promote the formation of H2O2; therefore, single-defect TiO2... 2-x The ORR activity is limited, mainly generating H2O2 through a two-electron pathway, making it difficult to generate strong oxidizing ·OH in situ. This results in insufficient deep mineralization of the dehalogenation products. Furthermore, the poor conductivity of the material and the single active site further limit its catalytic performance improvement.

[0005] The rise of single-atom catalysis (SACs) technology has provided a new direction for overcoming the aforementioned bottlenecks. Single-atom catalysts, with their atomically dispersed metal active sites (such as transition metals like Cu, Co, and Ni), combine the high selectivity of homogeneous catalysis with the stability of heterogeneous catalysis. Their unique electronic structure and metal-support interactions can significantly modulate the ORR reaction pathway and enhance the generation efficiency of active species (·OH, H*). For example, the Co single-atom system can optimize the adsorption energy barrier of O2 through Co-N4 or Co-O4 active sites, promoting the ORR transition from a two-electron to a four-electron transfer pathway. Liu et al. synthesized a series of transition metal SACs (Mn, Fe, Co, and Ni) via high-temperature pyrolysis and explored their ORR performance in acidic media. The results showed that these SACs in the 0.1 M HClO4 system tended to produce H2O2 via a two-electron transfer pathway rather than a four-electron transfer pathway. However, single-metal single-atom catalysts still have the limitation of single-function active sites: they can only enhance one process in oxidative degradation, making it difficult to achieve synergistic effects of "dehalogenation-mineralization". In addition, the loading of homonuclear SACs is relatively low, resulting in unsatisfactory intermediate adsorption, catalytic activity and stability.

[0006] Existing technologies, such as the patent application with publication number CN114602462A, disclose a TiO2-supported single-atom noble metal catalyst with defect sites. This catalyst can be used for the selective hydrogenation of alkynes, exhibiting excellent alkyne conversion and olefin selectivity. However, the application of this catalyst is for the selective hydrogenation of alkynes, which relies on the dissociation of hydrogen gas on the catalyst to H* (reducing species), followed by nucleophilic attack on the alkynes to achieve the conversion to olefins. It cannot simultaneously achieve the effect of simultaneous generation / action of reducing / oxide species. Summary of the Invention

[0007] To address the shortcomings of the existing technologies, the present invention aims to design and provide a bimetallic single-atom modified defect-type TiO2 electrocatalyst, its preparation method, and its application in the catalytic degradation of organic pollutants. The present invention constructs CuCo bimetallic single-atom supported defect-type TiO2 (CuCo@TiO2). 2-x An electrocatalytic oxygen reduction system was developed, using an alkaline co-precipitation method to achieve the deposition of Cu and Co single atoms in TiO₂. 2-x Atomic-level dispersion on the surface, utilizing the synergistic regulation of bimetallic sites and oxygen vacancies (OVs), enhances the ability of ORR to produce ·OH and H*, constructing a "reduction dehalogenation-oxidation mineralization" synergistic catalytic system.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] On the one hand, the present invention provides a bimetallic single-atom modified defective TiO2 electrocatalyst, wherein the metal is dispersed in the form of single atoms on a defective TiO2 substrate to form a first metal atom-O-Ti and a second metal atom-O-Ti coordination structure;

[0010] The first and second metal atoms are completely separated by oxygen atoms. There is no direct contact between the two metal atoms. Cu and Co are not bonded together. Each metal atom is surrounded by positively valent oxygen atoms.

[0011] The aforementioned bimetallic single-atom modified defect-type TiO2 electrocatalyst uses Cu and Co as the metals. In this configuration, +2 valence Cu and +2 / +3 valence cobalt are dispersed as single atoms on the defect-type TiO2 substrate, forming Cu-O-Ti and Co-O-Ti coordination structures.

[0012] Mechanism of Action: The core mechanism of the bimetallic single-atom modified defect-type TiO2 electrocatalyst of this invention lies in the efficient and independent execution of reduction and oxidation reactions during electrocatalysis through a "spatially segmented" dual-active-site design and the defect-single-atom synergistic effect. Under the applied current, a current effect is generated inside the catalyst, simultaneously driving both reduction and oxidation reactions. Specifically, the catalyst anchors a first metal atom (e.g., Cu) and a second metal atom (e.g., Co) in single-atom form onto a defect-type TiO2 substrate, forming a coordination structure of first metal atom-O-Ti and second metal atom-O-Ti. Since the two metal atoms are completely separated by oxygen atoms, there is no direct contact or bonding (e.g., Cu-Co bond), and each is surrounded by O atoms in a saturated positive valence state. This "segmented design" ensures that the two metal active centers do not interfere with each other, effectively avoiding side reactions caused by direct metal contact in traditional bimetallic catalysts (e.g., the reaction of the two metals to produce water), thus ensuring the stability and selectivity of the catalytic process.

[0013] The catalytic effect of this invention mainly occurs at the following two types of synergistic sites: (1) Oxygen vacancy sites: as the main catalytic active centers, they provide unique electronic structures to adsorb and activate reactants. (2) Co single-atom sites: mainly responsible for generating active hydrogen species. Cu single-atom sites: by regulating the electron density of adjacent oxygen vacancies, they promote the three-electron reduction process of oxygen, efficiently generate hydroxyl radicals (·OH), and assist in the generation of hydroxyl radicals on oxygen vacancy sites. Through this synergistic cooperation of multiple active sites, the catalyst can precisely regulate the electron transfer path under the action of an electric field, and realize specific oxidation or reduction reactions at different active sites, thereby significantly improving the overall electrocatalytic efficiency.

[0014] Secondly, the present invention provides a method for preparing a bimetallic single-atom modified defect-type TiO2 electrocatalyst, comprising the following steps:

[0015] Weigh out the defective TiO2 material, dissolve and disperse it in water, add a salt solution of the first metal and a salt solution of the second metal dropwise under stirring, add alkali to dissolve until the pH is neutral, dry, and obtain a bimetallic single-atom modified defective TiO2 electrocatalyst.

[0016] The main purpose of adding an alkali is to make the precipitate formed by the metal salt ions already anchored in the -O-Ti structure more stable. The alkali can be selected from ammonia, sodium hydroxide, etc. The neutral pH is approximately 6.5-8.0.

[0017] In the preparation method described above, the molar ratio of the defective TiO2 material, the salt solution of the first metal, and the salt solution of the second metal is 500:1:1 to 633:1:1.

[0018] Thirdly, the present invention provides a bimetallic single-atom modified defect type TiO2 electrode, comprising an electrode substrate and a film containing bimetallic single-atom modified defect type TiO2 formed on the surface of the electrode substrate.

[0019] Fourthly, the present invention provides a bimetallic single-atom modified defect-type TiO2 electrode, comprising the following steps:

[0020] A bimetallic single-atom modified defect-type TiO2 electrocatalyst is added to an organic solvent system containing a binder to form a mixture. The mixture is then ultrasonically treated to form an ink, which is transferred to a pretreated electrode substrate until a uniform film is formed on both sides, thus obtaining a bimetallic single-atom modified defect-type TiO2 electrode.

[0021] The preparation method described herein includes a pretreatment method comprising: contacting the electrode substrate with the components of a hydrophilic modification treatment solution, washing to remove impurities, and then drying to obtain the electrode.

[0022] In the preparation method described above, the mass-to-volume ratio of the bimetallic single-atom modified defect-type TiO2 electrocatalyst to the organic solvent system containing the binder is 7.5:(11.5~16.5) mg / μL.

[0023] Fifthly, the present invention provides the application of the aforementioned bimetallic single-atom modified defect-type TiO2 material, or the aforementioned bimetallic single-atom modified defect-type TiO2 electrode, in the electrocatalytic degradation of organic pollutants.

[0024] In the aforementioned application, the organic pollutant is a halogenated organic pollutant.

[0025] Preferably, the bimetallic single-atom modified defect-type TiO2 material, or the bimetallic single-atom modified defect-type TiO2 electrode, degrades and removes organic pollutants, such as FLO, in an O2 atmosphere. The gaseous atmosphere is a core influencing factor on ORR (Organic Reduction Ratio). The introduction of O2 will create a competitive / coupled reaction system between ORR and FLO reduction at the cathode, and the reaction products (such as H2O2, ·OH, etc.) may alter the degradation pathway of FLO.

[0026] CuCo@TiO2-x exhibited excellent performance in the electrocatalytic removal of FLO, with catalytic activity significantly superior to TiO2. 2-x Cu@TiO 2-x Co@TiO 2-x Furthermore, different reaction characteristics are observed under N2 and O2 atmospheres. Based on the experimental results, it can be concluded that the synergistic effect of bimetallic single atoms in CuCo@TiO2-x enhances the performance of the ORR system through two major pathways: (1) reducing the charge transfer resistance and improving the electron transfer efficiency through electronic coupling, providing sufficient electron supply for the ORR reaction; (2) by regulating the adsorption energy barrier of active sites for O2 and intermediates, the ORR reaction pathway is transformed from the traditional two-electron (n≈2.7) to three-electron (n=3.1) transfer, realizing the in-situ efficient generation of ·OH. At the same time, the Co site accelerates the water dissociation process, and the Cu site optimizes the H* adsorption strength, synergistically improving the H generation and utilization efficiency, ultimately achieving the synergistic degradation effect of ·OH oxidation and H* reduction, significantly enhancing the dehalogenation and mineralization efficiency of halogen-containing pollutants.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. This invention, through process control, uses HRTEM, XRD, HAADF-STEM and EXAFS analysis to confirm that Cu (+2 valence) and Co (+2 / +3 valence) are uniformly dispersed in single-atom form and form a stable metal-oxygen-titanium (MO-Ti, M=Cu, Co) active interface, Cu-O-Ti and Co-O-Ti coordination structures; XPS reveals the "Co→O→Ti" charge transfer pathway.

[0029] 2. In an O2 atmosphere, CuCo@TiO 2-x The degradation rate constant of FLO (30 × 10) -3 min -1 TiO 2-x It is 30 times more efficient than the single reduction system (N2 atmosphere, TOC removal rate 23.67%), with a dechlorination rate of 98.6%, a defluorination rate of 91.77%, and a TOC removal rate of 92.89%.

[0030] 3. The present invention demonstrates through RRDE testing that CuCo@TiO 2-x With an electron transfer number of 3.1 and H2O2 selectivity reduced to 42.2%, the ORR pathway was successfully modulated from 2e- to 3e-, achieving in-situ synchronous generation of ·OH and H* at the interface. DFT calculations showed that the bimetallic synergy significantly reduced the ·OH generation energy barrier (4.41 eV), with Co sites dominating water dissociation and accelerating H* generation, while Cu sites modulated the H* adsorption strength.

[0031] 4. Practical Application Verification: CuCo@TiO in an electrocatalysis-biological coupling system 2-x After treatment, the abundance of loR genes decreased to the level of the blank group, achieving the integrated treatment goal of "deep dehalogenation-efficient mineralization-ARGs elimination" for halogenated antibiotics. Attached Figure Description

[0032] Figure 1 CuCo@TiO 2-x A schematic diagram of the synthesis process;

[0033] Figure 2 This is a material morphology characterization diagram, where A represents TiO2. 2-x The scanning electron microscope (SEM) image, a1 is TiO2. 2-x High-resolution TEM image, a2 is TiO 2-x HAADF plot, a3 is TiO 2-x The lattice fringe pattern, a4 is TiO 2-x Ti element mapping diagram, a4 is TiO 2-x The O element mapping diagram, where B is CuCo@TiO 2-x SEM images, b1 is CuCo@TiO 2-x High-resolution TEM image, b2 is CuCo@TiO 2-x The Ti element mapping diagram, b3 is CuCo@TiO 2-x Co elemental mapping, b4 is CuCo@TiO 2-x The O element mapping diagram, b5 is CuCo@TiO 2-x Cu elemental mapping diagram;

[0034] Figure 3 TiO in Example 1 2-x Comparative Example 1: Co@TiO 2-x Comparative Example 2 Cu@TiO 2-x In Example 1, CuCo@TiO 2-x XRD patterns;

[0035] Figure 4Comparative Example 1: Co@TiO 2-x Comparative Example 2Cu@TiO 2-x Example 1: CuCo@TiO 2-x XPS spectra: where A represents Ti and B represents O;

[0036] Figure 5 TiO in Example 1 2-x Comparative Example 1: Co@TiO 2-x Comparative Example 2 Cu@TiO 2-x In Example 1, CuCo@TiO 2-x EPR spectra of OVs;

[0037] Figure 6 The XPS spectra are Cu and Co sub-spectrums; where A represents Cu@TiO. 2-x CuCo@TiO 2-x XPS spectrum of Cu, B is Co@TiO 2-x CuCo@TiO 2-x XPS spectrum Co fraction;

[0038] Figure 7 CuCo@TiO 2-x AC-HAADF-STEM plots, where 1 is a visualization intensity profile analysis plot and 2 is a visualization intensity profile analysis plot at another different location;

[0039] Figure 8 To perform wavelet transform on the EXAFS data, where A is the EXAFS two-dimensional contour map of Cu element, B is the EXAFS two-dimensional contour map of standard Cu foil, C is the EXAFS two-dimensional contour map of CuO, and D is the EXAFS two-dimensional contour map of Cu2O.

[0040] Figure 9 To perform wavelet transform on EXAFS data, where A is CuCo@TiO 2-x B is CoPc, C is CoO, D is Co3O4, and E is Co foil;

[0041] Figure 10 CuCo@TiO 2-x XANES spectra of near-edge Cu K-side and Co K-side structures, where A represents CuCo@TiO. 2-x Cu K-edge XANES spectra of the reference sample and B, where B represents CuCo@TiO. 2-x Fourier transform EXAFS spectra of the sample and the reference sample, where C represents CuCo@TiO. 2-xCo K-edge XANES spectra of the reference sample and the reference sample, where D represents CuCo@TiO. 2-x Fourier transform EXAFS spectra of the reference sample;

[0042] Figure 11 The results are from degradation experiments, where A represents Cu@TiO. 2-x Co@TiO 2-x CuCo@TiO 2-x TiO 2-x The curve of the change of the electrode's decomposition FLO in N2 atmosphere, where B is the apparent rate constant kobs, FLO;

[0043] Figure 12 CuCo@TiO 2-x Co@TiO 2-x Cu@TiO 2-x TiO 2-x The explanation effect under different atmospheres, where A is the change curve of the descending solution FLO in O2 atmosphere, B is the apparent rate constant kobs, FLO in O2 atmosphere, C is the change curve of the descending solution FLO in H2O2 atmosphere, and D is the apparent rate constant kobs, FLO in H2O2 atmosphere.

[0044] Figure 13 CuCo@TiO 2-x The degradation curves of FLO after adding TBA under different atmospheres, where A is O2 atmosphere and B is N2 atmosphere;

[0045] Figure 14 The results show the dehalogenation conversion, where A represents the EPR spectra of DMPO-H* in N2 saturated solution and DMPO-OH in O2 saturated solution, and B represents the CuCo@TiO2 conversion. 2-x The hydrogen overflow effect causes WO3 to change color, and C is CuCo@TiO 2-x Cyclic voltammetry curve of the cathode in O2 saturated solution, where D is CuCo@TiO 2-x Cyclic voltammetry curves of the cathode in N2 saturated solution;

[0046] Figure 15 CuCo@TiO 2-x Co@TiO 2-x Cu@TiO 2-x TiO 2-x The electrochemical performance is shown in the figure, where A is the electrochemical impedance spectroscopy, B is the LSV curve based on the oxygen reduction reaction, C is the number of electrons transferred, and D is the H2O2 selectivity.

[0047] Figure 16The results show the bimetallic active site regulation mechanism in CuCo@TiO2-x. In this diagram, A is the Gibbs free energy diagram of O2 reduction by different materials (difference between 2e- and 3e-), B is the Gibbs free energy diagram of O2 reduction to H2O2, C is the H2O dissociation, and D is the adsorption energy of hydrogen at different active sites.

[0048] Figure 17 The FLO degradation effect is represented by A, where A is CuCo@TiO. 2-x TOC removal rate and dehalogenation rate of FLO under different atmospheres, B is the curve of the change of chloride ion and fluoride ion concentration;

[0049] Figure 18 This is a schematic diagram of the degradation pathway of FLO;

[0050] Figure 19 The data represent the antibacterial effect, where A is the E. coli growth curve fitted by the model, and B is the inhibition zone agar plate plot (10 μL of cathode solution impregnated with glass fiber filter element is CuCo@TiO). 2-x (Removal of samples taken under different conditions after 60 minutes of FLO)

[0051] Figure 20 The relative abundance of microbial communities at the genus level in the treated FLO, FLO, and blank group water samples;

[0052] Figure 21 The data represent the microbial community structure, where A represents the abundance of floR in different groups of water samples, and B represents the principal coordinate analysis (PCoA) of the top 10 genera in the treated floR, floR, and blank water samples.

[0053] Figure 22 The relative abundance of microbial communities at the genus level in the sludge samples from the Treated FLO, FLO, and blank control groups.

[0054] Figure 23 To quantify ARGs (loR), where A is the abundance of floR in each group of sludge samples, and B is the principal coordinate analysis (PCoA) of the first 8 genera in the treated FLO, FLO and blank group sludge samples.

[0055] Figure 24 This study compares the removal rates of floR in water and sludge samples. Detailed Implementation

[0056] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0057] The relevant experimental reagents and equipment involved in this invention are shown in Tables 1 and 2. The resistivity of the deionized water used in the experiment is 18.2 MΩ cm. -1 .

[0058] Table 1 Chemical Reagents and Materials

[0059] Table 2 Experimental Instruments and Equipment

[0060] Degradation experiment:

[0061] All degradation experiments involved in this invention were conducted in an H-type electrolytic cell, which is divided into an anode chamber and a cathode chamber. The anode chamber mainly consists of a Pt sheet (counter electrode), and the cathode chamber mainly consists of a working electrode (catalytic material) and a reference electrode (Ag / AgCl); the electrolyte is 50 mM Na2SO4, and 10 mg L of Na2SO4 is added to the cathode chamber. -1 FLO contaminants were detected. During the reaction, samples were taken at time points of 0 min, 5 min, 10 min, 20 min, 30 min, 60 min, 120 min, and 180 min. The obtained solutions were added to liquid chromatography vials pre-filled with Na2S2O3 for subsequent liquid chromatography analysis.

[0062] As a typical chloramphenicol antibiotic, FLO contains chlorine (-Cl) and fluorine (-F) atoms in its molecular structure, giving it strong chemical stability and biological toxicity. Evaluating its electrocatalytic removal efficiency requires considering two core indicators: first, the total organic carbon (TOC) removal rate, reflecting the degree of carbon skeleton destruction; and second, the dehalogenation rate (dechlorination rate, defluorination rate), characterizing the halogen removal effect. These two indicators together constitute the evaluation criteria for the harmless transformation of FLO.

[0063] Example 1: CuCo@TiO 2-x Material preparation

[0064] (1) TiO 2-x Preparation

[0065] First, TiO2 was prepared by a hydrothermal method. Then, TiO2 was obtained by mixing and grinding it with sodium borohydride (NaBH4) and calcining it under oxygen-limited conditions for 2 hours. 2-xIn short, 25 mL of tetrabutyl titanate (TBOT) and 0.4 mL of deionized (DI) water were mixed and magnetically stirred for 30 minutes in a 50 mL PTFE-lined autoclave. Then, 3 mL of hydrofluoric acid (HF) was added dropwise under vigorous stirring, and stirring was maintained for 2 hours. The autoclave was then kept at 180°C for 24 hours. After cooling to ambient temperature, the white gel powder was washed and centrifuged several times with deionized water and ethanol, dried overnight at 80°C, and then calcined in a muffle furnace at 500°C for 2 hours to remove impurities. This process was used to obtain TiO2 enriched with surface OVs. 2-x The prepared TiO2 was further mixed and thoroughly ground with an appropriate amount of sodium borohydride (NaBH4), and then calcined at a specific temperature for 2 hours under a N2 atmosphere. Finally, the cooled sample was washed with deionized water and anhydrous ethanol to remove residual NaBH4 and its decomposition products. The resulting sample was designated as TiO2. 2-x .

[0066] Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) were used to study TiO2. 2-x Morphological characterization was performed, and the results are as follows: Figure 1 As shown.

[0067] (2) Single-atom CuCo supported defect type TiO2 (CuCo@TiO 2-x Preparation of )

[0068] like Figure 2 As shown, firstly, 240 mg of the above TiO2 was... 2-x The material was ultrasonically dispersed in 240 mL of deionized water for half an hour. Then, 8 mL of 0.0077 M Co(NO3)2 was added dropwise to the mixed solution under vigorous stirring. At this point, Co and oxygen combined to form a Co-O-Ti coordination structure. Next, 8 mL of Cu(NO3)2 solution was added dropwise to the mixed solution under vigorous stirring, forming a Co-O-Ti coordination structure. Co and Cu are both positively charged and repel each other, completely separated by oxygen. Then, 0.6 g of sodium hydroxide (NaOH) was added and dissolved ultrasonically. After stirring for 6 hours, the precipitate was washed repeatedly with deionized water until the pH value reached 7. Finally, the washed precipitate was vacuum dried at 80 °C to obtain CuCo@TiO2. 2-x The sample. ICP testing revealed that CuCo@TiO 2-x The sample contained 0.84% ​​Co and 0.76% Cu. SEM and HRTEM methods were used to analyze CuCo@TiO₂. 2-x Morphological characterization is performed.

[0069] The results are as follows Figure 1As shown, in the control group, under alkaline synthesis conditions (pH=12), metal hydroxides were generated. However, the TiO₂ of this application… 2-x The above method, after adding cobalt nitrate hexahydrate and ferrous chloride hexahydrate, still maintains the ordered nanosheet structure of the material, and no obvious structural collapse or aggregation was observed. It is worth noting that... Figure 1 The HRTEM image of b1 did not show any obvious metal nanoparticles (>1 nm) or clusters, indicating that Cu and Co are dispersed in TiO in the form of single atoms or very small metal clusters. 2-x On the substrate. This phenomenon may be attributed to the reaction between the metal precursor and TiO2 under alkaline conditions. 2-x The strong interaction of surface hydroxyl groups (-OH) inhibits the aggregation of metal atoms.

[0070] To further verify the dispersion state of Cu and Co, this invention employs aberration-corrected high-angle annular dark-field scanning electron microscopy (HAADF-STEM) combined with energy-dispersive X-ray spectroscopy (EDS) to analyze the elemental distribution of the samples. As shown in Figure 1, the EDS elemental surface scans of b2, b3, b4, and b5 reveal that the signals of Cu and Co are uniformly distributed in the TiO2 sample. 2-x On the substrate, the distribution of Ti and O elements highly overlapped, with no local enrichment observed. This result is highly consistent with HRTEM observations, ruling out the possibility of metal nanoclusters forming.

[0071] Comparative Example 1:

[0072] The steps are the same as in Example 1, except that the step of "subsequently adding a certain amount of 0.0077 M Co(NO3)2 and Cu(NO3)2 solution dropwise to the mixed solution under vigorous stirring" is changed to adding only 8 mL of 0.0077 M Co(NO3)2 to obtain Co@TiO2. 2-x After ICP testing, Co@TiO 2-x The content of Co in the middle is 0.97%.

[0073] Comparative Example 2:

[0074] The steps are the same as in Example 1, except that the step of "subsequently adding a certain amount of 0.0077 M Co(NO3)2 and Cu(NO3)2 solution dropwise to the mixed solution under vigorous stirring" is changed to adding only 8 mL of 0.0077 M Cu(NO3)2 solution to obtain Cu@TiO 2-x After ICP testing, Cu@TiO 2-x The Cu content is 0.88%.

[0075] like Figure 3As shown, TiO2 was analyzed using a high-resolution X-ray diffractometer. 2-x Cu@TiO 2-x Co@TiO 2-x CuCo@TiO 2-x Crystal structure characterization analysis was performed on four materials. All samples exhibited typical anatase (PDF#86-1157, Ti) characteristics. 0.72 Characteristic response peaks for O2 and titanium monoxide (PDF#77-2170, TiO2) phases were observed; no discernible metal diffraction peaks were detected near 2θ = 43.3° and 44.2° (detection limit ~ 2 nm). This is consistent with HRTEM and HAADF-STEM observations, confirming that single metal atoms or extremely small metal clusters are dispersed on the TiO2 substrate. 2-x The XRD characterization results clearly show the dispersion characteristics of single metal atoms or very small metal clusters, but cannot provide specific information on the chemical valence state of the metal and its interaction with the support. Therefore, this invention further employs X-ray photoelectron spectroscopy (XPS) to conduct in-depth analysis of the chemical state and electronic structure of the elements on the material surface, clarifying the electron transfer at the material interface.

[0076] As shown in Figure 4A, the Ti 2p spectrum is used for Cu@TiO. 2-x Co@TiO 2-x CuCo@TiO 2-x Analysis of the three materials showed that Cu@TiO 2-x Co@TiO 2-x Both materials exhibit distinct characteristic peaks at 458.57 eV and 464.22 eV, which are the fitting peaks for Ti 2p1 / 2 and Ti 2p3 / 2, respectively. In the CuCo@TiO2-x material, the fitting peaks for Ti 2p1 / 2 and Ti 2p3 / 2 shifted towards lower binding energies. The fitting peak position for Ti 2p1 / 2 decreased from 458.57 eV to 458.17 eV, and the fitting peak position for Ti 2p3 / 2 decreased from 464.22 eV to 463.81 eV. This is likely because the incorporation of the two transition metals altered the electron cloud density on the material surface, causing Ti... 4+ The electrons are reduced to Ti 3+ The increased electron cloud density around Ti means that Ti, as an electron acceptor, may accept electrons from other components.

[0077] like Figure 4 In the O 1s spectra shown in Figure B, all three materials exhibit fitted peaks at 530.02 eV, 531.5 eV, and 533.3 eV, belonging to lattice oxygen, OVs, and Ti-OH, respectively. TiO2-x Cu@TiO 2-x Co@TiO 2-x CuCo@TiO 2-x The proportions of OVs in the materials were 19.83%, 20.93%, 27.63%, and 29.82%, respectively. The increase in OVs proportion may be due to the rearrangement of electronic structure or the disordering of atomic-scale structure caused by the introduction of Cu and Co metal atoms, thus forming more OVs. After the incorporation of bimetallic single atoms, the O 1s shifted to a lower binding energy of about 0.2 eV, indicating that O may also be one of the electron acceptors or due to the interaction between metal species and Ti-O. To verify the above XPS results of O 1s, since the OVs increased with the incorporation of metal single atoms, EPR technology was further used to detect the OVs.

[0078] The results are as follows Figure 5 The results show that with the introduction of metal single atoms, the OVs signal at g=2.003 gradually increases, with the overall trend being TiO2. 2-x > Cu@TiO 2-x > Co@TiO 2- x > CuCo@TiO 2-x The EPR results are consistent with XPS. Since there is an electron acceptor, there must be an electron donor in the material. Therefore, this invention focuses on Cu@TiO. 2-x and CuCo@TiO 2-x The material contains Cu 2p and Co@TiO 2-x and CuCo@TiO 2-x The Co 2p spectra of the materials were analyzed.

[0079] like Figure 6 As shown in Figure A, elemental analysis of Cu reveals that the Cu 2p spectrum indicates that Cu@TiO 2-x and CuCo@TiO 2-x There is no shift in the overall binding energy. The three characteristic peaks at 932.7 eV, 942.8 eV, and 952.7 eV belong to Cu 2p1 / 2, the satellite peak, and Cu 2p3 / 2, respectively, and can be further subdivided into 932.6 eV (Cu + 2p1 / 2), 934.3 eV (Cu) 2+ 2p1 / 2), 942.8 eV (satellite peak), 952.6 eV (Cu) + 2p3 / 2) and 954.3 eV (Cu 2+2p3 / 2). The characteristic peak of Cu(0) did not appear in the result, further ruling out the possibility that Cu exists in the form of metal clusters.

[0080] like Figure 6 As can be seen from the Co 2p spectrum shown in Figure B, in Co@TiO 2-x In the spectrum, the peaks at 780.6 eV, 787.1 eV, 796.4 eV, and 803.2 eV correspond to the Co 2p1 / 2, satellite, and Co 2p3 / 2 satellite peaks, respectively. The fitted peak positions for Co 2p1 / 2 and Co 2p3 / 2 in CuCo@TiO2-x have shifted. The fitted peak position for Co 2p1 / 2 increased from 780.6 eV to 781.5 eV, and the fitted peak position for Co 2p3 / 2 increased from 796.4 eV to 797.2 eV. This phenomenon indicates a decrease in the valence state of the Co atom, possibly due to the effective regulation of the electronic structure of the Co atom by the interaction between Cu and Co atoms, making it easier for the Co atom to lose electrons. Combining the results of the Ti and O spectra, the charge transfer direction can be inferred to be Co→Ti or Co→O→Ti, further proving the possibility of forming Cu-O-Ti and Co-O-Ti structures. The XPS spectra of Co and Cu showed no characteristic peaks for Co(0) and Cu(0), proving that Cu and Co in this invention are dispersed in TiO in the form of single atoms. 2-x On a substrate. This invention was verified using an aberration-corrected electron microscope.

[0081] As shown in Figure 7, TiO2 is displayed in the high-angle annular dark-field image of a spherical aberration electron microscope. 2-x Numerous bright spots are distributed on the substrate, confirming that atomically dispersed Cu and Co do not exhibit obvious aggregates or nanoparticles. These bright spots are uniformly distributed, with some areas marked by red circles in the figure. The locations selected by orange boxes correspond to the spacing between two single-atom bright spots, which are 1 and 2, respectively. The specific spacings are 3 Å and 6 Å, respectively. The 3 Å distance may be the spacing between two single atoms of Co and Co, or Cu and Co, while the 6 Å distance may be the spacing between Cu and Co. This indicates that Cu and Co bimetallic sites coexist at a distance of 3 Å or 6 Å.

[0082] like Figure 8 As shown, synchrotron X-ray absorption spectroscopy was used to analyze the Cu element in the material, CuCo@TiO. 2-x The EXAFS two-dimensional contour plot of the catalytic material shows that in the range of 3 < k < 5 Å... -1The location exhibits a significant characteristic signal, indicating a metal-oxygen bond, as shown in the two-dimensional contour plots of standard Cu foil, CuO, and Cu2O. Figure 8 Compared with B, C, and D, CuCo@TiO 2-x When k > 6Å -1 The absence of obvious characteristic signals in the region (which is a metal-metal bond) indicates that Cu exists in the form of single atoms.

[0083] like Figure 9 As shown, the Co element in the material was also analyzed, CuCo@TiO 2-x Comparison of the catalytic material with standards CoPc, Co foil, CoO, and Co3O4 also proved that Co exists in a monatomic form. This provides a basis for the precise analysis of CuCo@TiO. 2-x The chemical state and local coordination structure of Cu and Co sites were determined by collecting X-ray absorption near-edge structure (XANES) spectra of Cu K-edge and Co K-edge.

[0084] like Figure 10 As shown in Figures A and C, Cu foil, CuO, Cu2O, Co foil, CoO, and Co3O4 were used as standard references, respectively, for CuCo@TiO 2-x The absorption edge of Cu is close to that of the CuO reference sample, while the absorption edge of Co is close to that of the CoO and Co3O4 reference samples. This indicates that Cu species in the material are predominantly in the +2 oxidation state, while Co species are in the +2 to +3 valence range. This result is consistent with XPS. To better understand the local coordination of Cu and Co atoms, further investigation using Fourier transform extended X-ray absorption fine structure (FT-EXAFS) is needed.

[0085] The results are shown in Figures 10B and 10D. Figure 10B shows CuCo@TiO 2-x The Cu K-edge FT-EXAFS spectra of Cu-based standard samples are shown. For comparison, the FT-EXAFS spectrum of Cu foil exhibits a strong and sharp characteristic peak at R=2.23 Å, corresponding to the first coordination shell signal of the Cu-Cu metallic bond (coordination number ≈ 12), reflecting its close-packed bulk metal structure. The CuO standard sample, on the other hand, shows a characteristic peak at R=1.53 Å, attributed to the first shell signal of the Cu-O coordination bond (coordination number ≈ 4). For CuCo@TiO... 2-xThe Cu K-edge FT-EXAFS spectrum of the sample showed only a single strong characteristic peak at R=1.50 Å, and no characteristic signal of Cu-Cu metallic bond was detected in the range of R=2.1~2.3 Å, indicating that Cu atoms in the material did not form metal clusters or nanoparticles and were in a monodisperse state.

[0086] Consistent with the analysis logic of CuK edge, by comparing the 10D FT-EXAFS spectrum of Co K edge with standard samples, Cofoil exhibits a strong characteristic peak at R=2.16 Å, corresponding to the first coordination shell of the Co-Co metallic bond; the CoO standard sample shows two characteristic peaks, located at R=1.7 Å (Co-O bond, coordination number ≈6) and R=2.6 Å (Co-Co bond, coordination number ≈4); the Co3O4 standard sample also shows two characteristic peaks, located at R=1.5 Å (Co-O bond, coordination number ≈6) and R=2.45 Å (Co-Co bond, coordination number ≈4). For CuCo@TiO 2-x The Co K-edge FT-EXAFS spectrum of the sample showed only a single characteristic peak at R=1.5 Å, with no signal peaks for Co-Co or Co-O-Co bonds in the R=2.2~2.6 Å range, directly confirming that Co atoms are also dispersed in the material as single atoms. The coordination number, bond length, and other information in Tables 3 and 4 were used to determine the CuCo@TiO₂ composition. 2-x The model.

[0087] Table 3 CuCo@TiO 2-x EXAFS fitted structure parameters

[0088] Table 4 CuCo@TiO 2-x EXAFS fitted structure parameters

[0089] In summary, oxygen-rich defect TiO2 (i.e., CuCo@TiO2) with bimetallic single-atom loading was successfully prepared. 2- x Furthermore, Cu@TiO prepared using the same experimental procedures... 2-x Co@TiO 2-x In the material, the metal elements are all dispersed in the TiO substrate in the form of single atoms. 2-x superior.

[0090] Example 2:

[0091] A bimetallic single-atom modified defective TiO2 electrocatalyst is prepared in the same way as in Example 1 above, except that the molar ratio of the defective TiO2 material, the salt solution of the first metal, and the salt solution of the second metal is 500:1:1.

[0092] Example 3:

[0093] A bimetallic single-atom modified defective TiO2 electrocatalyst is prepared in the same way as in Example 1 above, except that the molar ratio of the defective TiO2 material, the salt solution of the first metal, and the salt solution of the second metal is 633:1:1.

[0094] Example 4: CuCo@TiO 2-x Electrode preparation

[0095] 1. Pretreatment of carbon paper:

[0096] Before using carbon paper as an electrode substrate, it needs to be pretreated, generally by treating it immediately before use. Use a utility knife to cut the carbon paper into sheets with pre-drilled electrode tabs and a fixed working area (2cm × 2cm). Soak the cut carbon paper in a 0.5 M H₂SO₄ solution for 5 hours to improve its hydrophilicity, and then wash it sequentially with DI water and ethanol in an ultrasonic bath for 20 minutes each to remove impurities.

[0097] 2. CuCo@TiO 2-x Electrode preparation method:

[0098] The CuCo@TiO prepared in Example 1 2-x The sample was transferred to pretreated carbon paper using a brush application method. The specific steps are as follows: 7.5 mg of sample was added to a mixture containing 7.5 μL of Nafion. ® A mixture was prepared by adding 5 wt% (5 wt%), 5 mL of ethanol, and 1.5 mL of isopropanol. The mixture was sonicated for at least 10 minutes to form an ink. The ink was then transferred using a brush to pre-treated carbon paper under an infrared baking lamp. The above steps were repeated to coat both sides of the carbon paper with the ink from the centrifuge tube, forming a uniform film, thus completing the CuCo@TiO₂ process. 2-x electrode.

[0099] Comparative Example 3: Co@TiO 2-x Electrode preparation

[0100] Compared with CuCo@TiO in Example 4 above 2-x The electrode preparation method is the same, only the sample is changed to Co@TiO prepared in Comparative Example 1. 2-x , to obtain Co@TiO 2-x electrode.

[0101] Comparative Example 4: Cu@TiO 2-x Electrode preparation

[0102] Compared with CuCo@TiO in Example 4 above 2-x The electrode preparation method is the same, only the sample is changed to Cu@TiO prepared in Comparative Example 2. 2-x , to obtain Co@TiO 2-x electrode.

[0103] Comparative Example 5: TiO 2-x Electrode preparation

[0104] Compared with CuCo@TiO in Example 4 above 2-x The electrode preparation method is the same, only the sample is changed to TiO2 prepared in step (1) of Example 1. 2-x TiO 2-x electrode.

[0105] Example 5: CuCo@TiO 2-x Oxygen reduction enhances degradation performance

[0106] This embodiment uses TiO2 2-x Based on a single-atom modified catalytic material (Cu@TiO2) 2-x Co@TiO 2-x CuCo@TiO 2-x The oxygen reduction performance of the transition metal single-atom modified catalytic material and the electrocatalytic removal performance of FLO were tested.

[0107] First, experiments were conducted under a N2-saturated atmosphere. This condition effectively isolates O2 interference, allowing FLO to primarily undergo electrocatalytic reduction dehalogenation (avoiding competition from ORR). Different materials (TiO2) prepared in Examples 4 and Comparative Examples 3-5 were compared. 2-x Cu@TiO 2-x Co@TiO 2-x CuCo@TiO 2-x The performance of the electrode cathode electrocatalytic reduction and degradation of FLO was tested.

[0108] The results are as follows Figure 11 As shown, the degradation rate constants are 1, 2.1, 2.9, and 9 × 10⁻⁶, respectively. -3 min -1 TiO 2-x The degradation activity was the lowest, while CuCo@TiO 2-x It exhibits optimal catalytic performance, with a degradation rate constant that is TiO₂. 2-xIt is 9 times more efficient than the other two functional materials modified with a single transition metal atom, and superior to them. The reasons for this significant difference may include: ① Improved electron transfer efficiency: the efficiency of single transition metal atom (Cu, Co) and TiO2 is significantly higher than that of TiO2. 2-x A strong metal-support interaction (SMSI) forms between the substrates. This interaction can modulate the band structure of the substrate, lower the electron transfer barrier, promote the direct transfer of electrons from the cathode surface to FLO molecules (DET pathway), and accelerate the reduction and breaking of CX bonds (halogenated bonds) in FLO molecules; ② The mediating role of active hydrogen (H*): Metal single atoms can act as active sites for water dissociation, promoting the reaction process of H2O→H*+OH- on the cathode surface. The generated H* has extremely strong reducing properties and can undergo hydrogenation and dehalogenation reactions with halogenated groups in FLO molecules through nucleophilic attack, which not only achieves pollutant degradation but also effectively reduces its biotoxicity and improves biodegradability; ③ Bimetallic synergistic effect: Cu and Co single atoms in TiO2 2-x Electron transfer coupling exists between the two active sites formed on the surface, which may further enhance the catalytic activity of the catalytic material. In summary, the synergistic advantages of bimetallic single-atom modification enhance the catalytic activity of CuCo@TiO₂. 2-x It exhibits the best catalytic conversion efficiency in the FLO reduction dehalogenation process.

[0109] Example 6: FLO removal effect of catalytic material under O2 and N2 atmosphere

[0110] This embodiment compares the FLO removal efficiency of four catalytic materials under O2 and N2 atmospheres. As shown in Figures 12A and 12B, CuCo@TiO 2-x The removal effect of FLO was further improved under O2 atmosphere, and the degradation rate was significantly improved compared with N2 atmosphere. TiO2 2-x Upgraded to 4×10 -3 min -1 Co@TiO 2-x Upgraded to 13×10 -3 min -1 Cu@TiO 2-x Upgraded to 12×10 -3 min -1 CuCo@TiO 2-x Upgraded to 30×10 -3 min -1 This phenomenon indicates that ORR has a significant promoting effect on FLO degradation, and its underlying mechanism is speculated as follows: When O2 undergoes ORR on the cathode surface, there are mainly two reaction pathways—the two-electron reduction pathway (O2 + 2H2O + 2e-) - → H2O2 + 2OH -) and the three-electron reduction pathway (O2 + 3H2O + 3e) - →·OH + 5OH - If the two-electron pathway is dominant, the H2O2 generated in situ at the cathode can undergo a Fenton-like reaction catalyzed by a transition metal single-atom site, transforming into a strongly oxidizing ·OH. If the three-electron pathway is dominant, ·OH can be directly generated at the cathode. Both pathways can destroy the FLO molecular structure through oxidation, forming a synergistic effect with the reductive dehalogenation reaction, thereby significantly improving degradation efficiency.

[0111] To clarify the dominant pathway of FLO degradation under an O2 atmosphere, this invention designed a verification experiment with added H2O2: the H2O2 concentration was controlled to the steady-state H2O2 concentration measured in the system under an O2 atmosphere, and the FLO degradation performance of four materials under this condition was compared (e.g., Figure 12 (As shown in C and D). The experimental results show that all four materials can activate H2O2 to degrade FLO to a certain extent, but the degradation rates are relatively similar. The reason for this result may be: (1) TiO2 2-x ① The activation ability of surface OVs and transition metal single atoms for H2O2 is limited, making it difficult to efficiently generate ·OH; ② The steady-state H2O2 concentration in the system is low, insufficient to provide enough precursors to generate ·OH with strong oxidizing power to drive efficient FLO degradation. These results indicate that the H2O2-mediated oxidation pathway is not the core mechanism for efficient FLO degradation under an O2 atmosphere, thus ruling out the dominant role of the "ORR two-electron pathway - in-situ H2O2 activation".

[0112] After initially ruling out the H2O2-mediated oxidation pathway, further analysis based on the previous patterns revealed that all four materials exhibited "TiO2" under both N2 and O2 atmospheres. 2-x <Cu@TiO 2-x <Co@TiO 2-x <CuCo@TiO 2-x The activity order of the bimetallic and monometallic systems was observed, and the performance difference between the bimetallic and monometallic systems was more significant under an O2 atmosphere. This suggests that the synergistic effect between bimetallic single atoms may be a key intrinsic factor in regulating the ORR reaction pathway and enhancing FLO degradation.

[0113] Based on the above experimental results, CuCo@TiO 2-x The mechanism by which the material enhances the FLO removal efficiency can be summarized into two core points: ① The introduction of transition metal single atoms (Cu, Co) constructs highly efficient ORR active sites, and regulates TiO2 through metal-support interactions. 2-xThe electronic structure significantly enhances the oxygen reduction reaction capability of the material; ② There is a clear synergistic effect between Cu and Co single atoms. This effect not only enhances the electron transfer efficiency and water dissociation capability, but also makes the reaction more inclined to the three-electron reduction pathway by regulating the ORR reaction selectivity, generating more highly active ·OH in situ, realizing the synergistic enhancement of reduction dehalogenation and oxidative degradation, and finally achieving the efficient conversion of FLO.

[0114] Example 7: FLO in CuCo@TiO 2-x The dehalogenation conversion mechanism on the surface (10 min)

[0115] like Figure 13 As shown, quenching tests of tert-butanol (TBA, considered a scavenger of ·OH and H*) were first conducted under different gas atmospheres. In an O2-saturated atmosphere, after adding 100 mM TBA, CuCo@TiO 2-x The removal efficiency of FLO decreased significantly to 69%. The inhibition effect on FLO degradation was significant before 10 minutes, but this effect diminished over time. This suggests that the degradation of FLO under an O2 atmosphere may involve the synergistic effect of multiple pathways: ·OH and H* accumulated in the system at the initial stage of the reaction were effectively removed by TBA, leading to a sharp drop in the degradation rate; while as the reaction proceeded, the contribution of the DET pathway gradually became prominent, and CuCo@TiO 2-x The metal-support interaction on the surface can accelerate the direct transfer of electrons from the cathode to the FLO molecule. This pathway is not affected by TBA, thus weakening the later degradation inhibition effect.

[0116] To eliminate interference from the DET pathway, parallel quenching experiments were further conducted under a N2 saturated atmosphere (excluding O2, inhibiting the ORR reaction, and weakening ·OH formation). As shown in Figure 13B, the degradation of FLO was significantly and continuously inhibited after TBA addition, with a removal rate of only 15.1% after 60 min of reaction. Furthermore, the phenomenon of "inhibition effect weakening over time" observed under an O2 atmosphere was not observed. Combined with the characteristic of no ·OH formation under an N2 atmosphere, it can be inferred that the conversion of FLO in this system is not primarily DET-based—if DET were dominant, the addition of TBA should have no significant inhibitory effect. Therefore, under an N2 atmosphere, CuCo@TiO2 degradation is not significantly inhibited. 2-x The dehalogenation conversion mechanism of FLO is based on H * The reduction is mainly mediated by indirect methods. Based on the comprehensive quenching experimental results, it can be preliminarily determined that CuCo@TiO₂... 2-x The removal and transformation of FLO under an O2 atmosphere involves ·OH oxidation and H2O. * As a result of reduction-synergistic dominance, the synergistic effect of the two active species constructed CuCo@TiO₂. 2-x It exhibits highly efficient catalytic activity.

[0117] like Figure 14 As shown in Figure 14A, using 5,5-dimethyl-1-pyrrolline-N-oxide (DMPO) as a spin trapping agent, the reaction system was characterized in situ using electron paramagnetic resonance (EPR) under O2 and N2 atmospheres. In the O2-saturated system, a distinct DMPO-·OH adduct characteristic quartet was observed, indicating that the ORR reaction can generate a large amount of ·OH in situ. Under the N2 atmosphere, only a significant signal of the DMPO-H adduct characteristic nintet was observed, which corroborates the quenching experimental results, indicating that ·OH and H... * The synergistic presence in an O2 atmosphere provides direct evidence.

[0118] like Figure 14 The hydrogen overflow phenomenon was visually characterized using a tungsten trioxide (WO3) color change test. WO3, as a typical proton-responsive material, reacts with hydrogen tungsten bronze (HWO3). 3-x The interconversion of CuCo@TiO₂ exhibits reversible electrochemical proton insertion / extraction characteristics, accompanied by a significant color change (from bright yellow to deep blue). Experimental results show that after electrolysis for 10 min under an O₂ atmosphere, the CuCo@TiO₂ loaded… 2-x The electrode surface changed from bright yellow to dark blue, confirming the presence of H during the reaction. * The formation and migration of H to WO3. CV tests further confirmed this from an electrochemical perspective. * The presence and ORR reaction characteristics are shown in Figures 14C and D. As the scanning window increases, the absorption of hydrogen (H+) increases. abs ) and adsorbed hydrogen (H ads The characteristic peak of H also increases accordingly. This characteristic peak is present in both O2 and N2 saturated solutions, indicating that H * The generation of H is not fundamentally inhibited by the gaseous atmosphere. In an O2-saturated solution... * The peak intensity was significantly lower than that in the N2 atmosphere. This is because the presence of O2 triggers the ORR reaction, and oxidizing active substances such as ·OH react with H+. * A partial reaction occurs, leading to H * The accumulation amount decreased; at the same time, there was a significant O2 reduction peak in the O2 saturated solution.

[0119] In summary, through multi-dimensional verification including quenching experiments, EPR characterization, WO3 color change tests, and CV analysis, it can be clearly determined that CuCo@TiO 2-x The system can simultaneously generate ·OH and H under an O2 atmosphere. * The synergistic effect of the two active species breaks the efficiency limitation of a single reaction pathway and significantly accelerates the dehalogenation conversion process of FLO, which is one of the core reasons for its improved catalytic performance.

[0120] Example 8: CuCo@TiO 2-x Synergistic effect of bimetals

[0121] First, this invention investigates the charge transfer behavior of catalytic materials, recording their EIS spectra at a constant voltage of -1.2 V, as follows: Figure 15 As shown in Figure A, the quist plots of all samples are semicircular in the high-frequency region and almost vertical in the low-frequency region, corresponding to the interfacial charge transfer and mass transfer between the electrode and electrolyte, respectively. All EIS data can be well fitted by software. The model consists of the electric double-layer capacitance (Cd), electrolyte solution volume resistivity (Rs), material charge transfer resistance (Rct), and coating capacitance (Cd).

[0122] Test results show that TiO 2-x (47.25 Ω cm) 2 Cu@TiO 2-x (38.31 Ω cm) 2 ), Co@TiO 2-x (39.52 Ω cm) 2 ) and CuCo@TiO 2-x (27.5 Ω cm) 2 This study confirms that the electronic coupling between bimetallic single atoms can effectively optimize the electron transport channels of materials, improve electron transfer efficiency, and provide sufficient electron supply for the ORR reaction. The improvement in electron transfer capability often changes the number of electrons transferred (n) and the H2O2 selectivity in the ORR reaction, and these two parameters directly determine the type of ORR product (H2O2 or ·OH).

[0123] To clarify CuCo@TiO 2-x The ORR reaction pathway was investigated using the rotating ring-disk electrode (RRDE) technique, and the results are shown in Figures 15B, C, and D. In the RRDE test, the disk current corresponds to the total ORR reaction current, and the ring current corresponds to the oxidation current of H₂O₂ diffused to the ring electrode. The ratio of these two currents can be used to calculate the electron transfer number (n) and H₂O₂ selectivity. From the characteristics of the ring current variation, CuCo@TiO₂... 2-x The ring current of CuCo@TiO is significantly lower than that of the other three materials, suggesting a reduction in H2O2 formation and a possible shift in the ORR reaction pathway. Preliminary speculation suggests that CuCo@TiO 2-x The ORR pathway shifts from the traditional two-electron transfer (generating H₂O₂) to a three-electron transfer (directly generating ·OH). By fitting the data, TiO₂... 2-x Cu@TiO 2-x Co@TiO 2-x CuCo@TiO 2-xThe electron transfer numbers were 2.7, 2.75, 2.6, and 3.1, respectively, and the selectivity for H2O2 was 62.6%, 67.6%, 60.2%, and 42.2%, respectively. These results confirm that CuCo@TiO 2-x The ORR reaction is mainly based on the three-electron transfer pathway, which can efficiently generate ·OH through the in-situ one-step generation pathway of O2→·OH, avoiding the energy barrier loss of secondary activation by H2O2.

[0124] like Figure 16 As shown, to clarify CuCo@TiO 2-x The synergistic regulation mechanism of bimetallic active sites in this invention is analyzed by density functional theory (DFT) calculations to quantify the O2 adsorption energy and intermediate conversion barrier. Intermediates in the O2 three-electron transfer pathway are compared (Figure 16A), CuCo@TiO 2-x (-4.41eV) compared to Co@TiO 2-x (-3.40eV), Cu@TiO 2-x (-3.30 eV) is more favorable for the generation of ·OH. This result indicates that the synergistic effect of bimetals can significantly reduce the thermodynamic energy barrier for ·OH generation, making the three-electron transfer pathway more likely to occur, and providing a thermodynamic advantage for the efficient in-situ generation of ·OH.

[0125] The formation of the OOH intermediate is crucial to the ORR reaction and directly determines its kinetic efficiency. Results are as follows: Figure 16 As shown in Figure B, the 2e-ORR process is in thermodynamic equilibrium under the condition of U = 0.7V vs RHE. Specifically, CuCo@TiO 2-x It has the lowest overpotential (0.12 eV) for the formation of H2O2, followed by Co@TiO. 2-x (0.14 eV), finally Cu@TiO 2-x (0.24 eV). The lower the overpotential, the better the reaction kinetics. This result suggests that the Co site may be the core active site of the ORR reaction, and the introduction of Cu optimizes the electronic structure of the Co site through electronic coupling effect, further reducing the reaction energy barrier and improving the overall catalytic activity.

[0126] The HRR process is a crucial prerequisite for electrocatalytic reductive dehalogenation, and its core steps include the Volmer and Tafer steps. The results of the water dissociation energy barrier for the Volmer step (Figure 16C) show that CuCo@TiO₂... 2-x The water dissociation energy barrier (-0.068 eV) is much lower than that of Co@TiO. 2-x (0.27eV), Cu@TiO 2-x(0.63 eV), indicating that the bimetallic synergistic effect can significantly accelerate the water dissociation process, H * The generation of hydrogen provides an ample source. The hydrogen adsorption free energy is a key parameter for measuring the H adsorption-desorption equilibrium; an ideal hydrogen adsorption free energy is close to 0 eV (ensuring effective H adsorption while avoiding excessive adsorption that could passivate active sites). Results are as follows... Figure 16 As shown in D, Cu@TiO 2-x The hydrogen adsorption free energy is highest at (0.41 eV) (as shown in Figure 16D), followed by CuCo@TiO. 2-x (0.15eV), finally Co@TiO 2-x (-0.21 eV). This result indicates that CuCo@TiO 2-x The superior HRR activity stems from the synergistic regulation of bimetallic sites: the Co site dominates the water dissociation process, accelerating H generation; the adjacent Cu site regulates H through electronic effects. * Adsorption strength is crucial to avoid activity loss caused by excessively strong or weak adsorption. This phenomenon corroborates the results of the hydrogen overflow experiment described earlier, further confirming the synergistic mechanism of the bimetallic sites.

[0127] Example 9: Degradation of FLO (H) * N2 ORR

[0128] This invention constructs three types of characteristic reaction systems for comparison: N2 saturated reduction system (H only) * ·OH-mediated reduction reaction), H2O2 oxidation system (·OH-mediated oxidation reaction only), and O2 saturated electrocatalytic system (·OH and H2O mediated oxidation reaction). * A synergistic reduction-oxidation coupling reaction was used to systematically investigate the regulatory effects of different reaction pathways on FLO removal and conversion. The results are shown in Figure 17. The FLO conversion efficiency data of the three systems showed significant differences: the O2 saturated electrocatalytic system exhibited the best dehalogenation and mineralization performance, with a dechlorination rate of 98.58%, a defluorination rate of 91.77%, and a corresponding TOC removal rate as high as 92.89%; the H2O2 oxidation system had the worst conversion efficiency, with dechlorination and defluorination rates of only 17.29% and 13.11%, respectively, and a TOC removal rate as low as 4.96%, indicating that single ·OH oxidation is insufficient to efficiently destroy the carbon-halogen bonds and benzene rings of FLO; the N2 saturated reduction system had efficiency between the two, with a dechlorination rate of 48.55%, a defluorination rate of 13.52%, and a TOC removal rate of 23.67%. These data fully confirm that ·OH and H2O2 oxidation under an O2 atmosphere can effectively decompose FLO carbon-halogen bonds and benzene rings. * The synergistic effect of H creates a dual-drive mechanism of "reduction-oxidation," achieving a synergistic enhancement of FLO removal efficiency: *The O2 system preferentially breaks the relatively reactive C-Cl bond through nucleophilic attack, while ·OH weakens the conjugated structure of the benzene ring through oxidation and promotes the activation and breaking of the CF bond. The "1+1>2" effect formed by the two not only significantly improves the dehalogenation rate, but also promotes the deep mineralization of the carbon skeleton. This is the core reason why the O2 system is far more efficient than a single reduction or oxidation system.

[0129] like Figure 18 To elucidate the degradation mechanism of FLO in different systems at the molecular level, this invention employs high-performance liquid chromatography-mass spectrometry (LC-MS / MS) to perform full-process sampling and analysis of the reaction solutions in three types of systems. Combining mass spectrometry fragment information with molecular structure analysis, intermediate products are systematically identified and degradation pathways are deduced. In the N2 saturated reduction system, the reaction intermediates are mainly reductive dehalogenation products, and no oxidative degradation products were detected. Figure 18 Reduction). Its degradation pathway begins with "H". * The core concept is "mediated stepwise dehalogenation": FLO molecules first undergo dehalogenation in H+. * Under nucleophilic hydrogenation, a C-Cl bond is broken, generating a single dechlorination intermediate (R1, m / z=323); subsequently, this intermediate can be transformed through two branching pathways, one of which involves further H+ ionization. * The mediated dechlorination reaction generates a double dechlorination intermediate (R2, m / z=289), and the selective defluorination reaction generates a dechlorination-defluorination intermediate (R3, m / z=305); finally, all intermediates undergo further dehalogenation to generate the major end product FLO-2Cl-F (R4, m / z=271). In this pathway, H... * The selectivity for C-Cl bonds is higher than that for CF bonds, and it can only remove halogens without destroying the overall molecular structure, which is consistent with the previous result that "the TOC removal rate of the reduction system is low".

[0130] In the H2O2 oxidation system, the intermediates are characterized by oxidation products and oxidative dehalogenation products. Figure 18Based on product structure analysis, four degradation pathways are proposed: In pathway 1, ·OH first electrophilically attacks the benzene ring structure of the FLO molecule to generate a hydroxylated intermediate (O1, m / z=389). Subsequently, ·OH further attacks the C-Cl bond on the benzene ring substituent, achieving oxidative dechlorination and combining with a proton to generate a monodechlorinated-hydroxylated product (O2, m / z=355). Pathways 2 and 3 both start with the oxidative substitution of the CF bond by ·OH as the initial step, generating a monodefluorinated intermediate (O3, m / z=355). This intermediate can either undergo a ring contraction reaction to generate a derivative (O4, m / z=339) or be further attacked by ·OH to achieve dechlorination, generating a defluorinated-dechlorinated intermediate (O5, m / z=337). Pathway 4 involves ·OH directly attacking the C-Cl bond of the piperazine ring side chain, generating a monodechlorinated intermediate (O6, m / z=33,9) through oxidative cleavage. The single ·OH oxidation has a weak ability to break carbon-halogen bonds, and the intermediates generated are mostly hydroxylated derivatives, while the carbon skeleton still maintains a cyclic structure, resulting in extremely low mineralization efficiency of the system.

[0131] In the O2-saturated co-factor system, intermediates are most abundant, including reductive dehalogenation, oxidative hydroxylation, and deep bond-breaking products (Figure 18 Redox). Its degradation process is characterized by "reduction initiation-oxidative enhancement," involving six co-factor transformation pathways, as follows: The FLO molecule first undergoes degradation in H... * Under the influence of [a specific chemical process], nucleophilic hydrogenation and dechlorination occur, generating the key intermediate P1 (m / z=323), which is the core precursor for subsequent co-transformation. Pathway 1: The benzene ring of P1 is electrophilically oxidized by ·OH to generate the hydroxylation intermediate P2 (m / z=355), followed by H [a specific chemical reaction]. * Further nucleophilic hydrogenation and defluorination yields a dechlorinated, defluorinated, and hydroxylated product, P3 (m / z = 337). ·OH further attacks P3, resulting in carbon chain cleavage and the formation of a chlorine-containing small organic molecule, P4 (m / z = 151). This small molecule undergoes H2 oxidation. * Under the action of [a specific chemical process], final dechlorination is completed, generating the halogen-free product P5 (m / z=117). Pathway 2: After hydroxylation by ·OH, the benzene ring of P1 directly undergoes H [a specific chemical reaction]. * The mediated dechlorination reaction yields P6 (a didechlorination-hydroxylation product, m / z = 321), the side chain of which is located at H... * Under the influence of hydroxylation, hydrodefluorination occurs, generating a fully dehalogenated-hydroxylated intermediate P7 (m / z=303). Pathway 3: The carbon chain at the tail of P6 is oxidized by ·OH, generating intermediate P8 (m / z=335), followed by H… *Defluorination is achieved by attacking its CF bond, generating the defluorinated product P9 (m / z=317). Pathway 4: The ring structure of P8 breaks under the oxidation of ·OH, generating the fluorinated intermediate P10 (m / z=149). * Nucleophilic attack on its C-Cl bond yields the halogen-free product P11 (m / z=131). Pathways 5 and 6: P1 undergoes oxidation with ·OH and H+. * Under the synergistic effect of reduction, dechlorination and defluorination reactions occur simultaneously, directly generating the fully dehalogenated intermediate P13 (m / z=287); this intermediate is further oxidized and broken down by ·OH to generate small molecule products, which are eventually mineralized into CO2 and H2O.

[0132] In summary, in the O2 saturated synergistic system, H * The reduction of ·OH provides the starting active site for FLO dehalogenation, while the oxidation of ·OH achieves hydroxylation and bond breaking of the carbon skeleton. The synergistic transformation of the two breaks the limitations of a single reaction pathway, which not only improves the dehalogenation efficiency but also promotes the deep mineralization of the carbon skeleton. This is the microscopic essence of the optimal FLO removal efficiency of this system.

[0133] Example 10: Effect of FLO dehalogenation on antibacterial activity

[0134] This invention preliminarily investigates the effect of FLO dehalogenation on antibacterial activity. Firstly, by adding cathode solutions from different FLO removal systems, the growth curves of *E. coli* in liquid media were compared to evaluate the effect of reduction-oxidation synergistic dehalogenation on the antibacterial activity of FLO. As shown in Figure 19A, during the cultivation process, except for the H2O2 system, the growth curves in other systems exhibited obvious lag phases (0–4 h), exponential phases (4–12 h), plateau phases (12–18 h), and decline phases (18–32 h), perfectly consistent with the growth characteristics of microorganisms. The presence of H2O2 itself has a bactericidal effect on *E. coli*, therefore the growth curve of H2O2 does not conform to the growth characteristics of microorganisms. After electrocatalytic dehalogenation of FLO under N2 and O2 atmospheres, the growth curves were similar to the control group, and the growth curve at 0 min was also inhibited, mainly due to the antibacterial properties of FLO. The size of the inhibition zone can be used to determine the effectiveness of its antibacterial ability. Experiments were conducted on cathode solutions in different systems. As shown in Figure 19B, FLO loses its antibacterial activity after dehalogenation treatment. Since the loss of antibacterial activity increases its biodegradability, electrocatalytic reduction oxidation dehalogenation can improve the biological treatment capacity of chlorine / fluoride-containing wastewater.

[0135] 1. Analyze the microbial community succession and ARGs abundance changes in the secondary effluent and subsequent receiving units of a pig farm.

[0136] High-throughput 16S rRNA gene sequencing was employed to analyze the microbial community succession at the genus level in the secondary effluent from the pig farm. Figure 20 shows the 10 genus-level microbial communities with significant differences across the three groups. Overall, the Blank and Treated FLO groups exhibited similar microbial community structures at the genus level. This result indicates that the electrocatalytic reduction oxidation pretreatment step significantly reduces the antibacterial activity of FLO, effectively reshaping the microbial community structure and making its composition closer to that of the Blank group. Comparing the Blank and FLO groups, after the addition of FLO, the relative abundances of *Lactococcus*, *Burkholderia-Caballeronia-Paraburkholderia*, and *Alcaligenes* decreased sharply from 63.43%, 4.75%, and 1.66% to 21.09%, 0.029%, and 0%, respectively. However, *Salmonella*, *Dechloromonas*, *Aeromonas*, *Rhodocyclus*, *Comamonas*, and *Ellin6067* all increased. The relative abundances of *Salmonella*, *Dechloromonas*, and *Rhodocyclus* increased from 21.61%, 2.33%, and 1.31% to 50.22%, 7.55%, and 6.02%, respectively. This result indicates a change in the dominant bacterial genera. *Rhodocyclus* and *Dechloromonas* are potential degraders of benzene compounds and dechlorinated / mineralized aromatic hydrocarbons such as 2,4-dichlorophenol, respectively. Since *Aeromonas* and *Comamonas* are potential hosts for multiple AGRs, they produce more resistance genes when these two bacterial groups become dominant. Comparing the results of the FLO and Treated FLO groups, the relative abundance of the dominant bacterial groups in the FLO group decreased in the Treated FLO group, while their abundance was basically consistent with that in the Blank group.

[0137] In summary, the electrocatalytic reduction-oxidation system plays a regulatory role in the microbial community structure. This invention also quantitatively evaluates the fate of ARGs (floR) in different groups within the FLO group. As shown in Figure 21A, the FLO group exhibits a significantly higher floR gene copy number than the Blank group. The floR in the Blank group may originate from pig farm wastewater containing added FLO, which proliferates under FLO stimulation. However, the floR gene copy number in the treated Treated FLO group shows a clear, monotonically decreasing trend, similar to the Blank group. The elimination of floR in the Treated FLO group may be due to I) directly destroying ARGs by disrupting their host cells through electroreduction treatment, and II) preventing ARG proliferation through FLO dehalogenation. Principal coordinate analysis (PCoA) combined with Bray-Curtis distance also indicates ( Figure 21 B) There was no significant difference between the Treated FLO group and the Blank group, reflecting that the electrocatalytic reduction oxidation system plays a regulatory role in the microbial community structure.

[0138] like Figure 22 Wastewater from a pig farm contaminated with FLO (Frequency-Locking Oxidation) that underwent electrocatalytic reduction oxidation treatment was added to a biological treatment unit and cultured for 15 days. Sludge samples collected were then analyzed (designated as the Treated FLO group). For reference, parallel groups were established with sludge samples pre-cultured with FLO-contaminated pig farm wastewater for 15 days (designated as the FLO group), and original sludge samples containing only pig farm wastewater were also included (designated as the blank group). High-throughput 16S rRNA gene sequencing was performed, similar to that used for secondary biological treatment effluent. The results showed that under FLO stress, the relative abundance of Commonas and Actinomyces increased from 4.85% to 67.95% and 0.16% to 11.35%, respectively. However, the relative abundance of the other five genera decreased compared to the Blank group: Pseudomonas, Brevundimonas, and Flavobacterium decreased from 30.27%, 16.12%, and 36.85% to 3.71%, 5.98%, and 0.51%, respectively. Commonas and Actinomyces were reported as major potential hosts for ARGs. Notably, the microbial community composition of the Treated FLO group was consistent with that of the Blank group, reflecting that electrocatalytic oxygen reduction technology can fundamentally remove the antibacterial activity of FLO.

[0139] like Figure 23The differences in ARGs (floR) among different groups of activated sludge were quantitatively analyzed. The FLO group showed a high floR gene copy number, further illustrating that the presence of resistance genes can lead to horizontal transfer within the microbial community, thereby increasing microbial resistance and the risk of superbugs. However, the floR gene copy number in the treated FLO group showed a clear and monotonically decreasing trend, similar to the Blank group, indicating a reduction in the influence of resistance genes. Figure 23 A). Figure 23B Principal Coordinate Analysis (PCoA) combined with Bray-Curtis distance also shows that there is no significant difference between the Treated FLO group and the Blank group.

[0140] As shown in Figure 24, the removal of the resistance gene floR in the secondary biological treatment effluent was almost identical. However, compared to the reaction time, the reduction-oxidation synergistic system significantly shortened the reaction time, making it more suitable for practical application. Reductive dehalogenation cannot completely mineralize FLO, and the intermediate products produced can induce microorganisms to produce resistance genes, which are then transferred to the sludge. Therefore, in the sludge sample, the reduction-oxidation synergistic system had a better floR removal capacity than the reduction system, which is attributed to the complete dehalogenation and mineralization of FLO by the reduction-oxidation system. This further verifies the application prospects of the reduction-oxidation system in real-world environments.

[0141] In summary, this invention successfully constructed CuCo@TiO through a bimetallic single-atom modification strategy. 2-x The electrocatalytic reduction-oxidation synergistic system enabled the regulation of the ORR pathway from two electrons to three electrons. * Simultaneous in-situ generation of ·OH, and deep dehalogenation of FLO (dechlorination rate 98.58%, defluorination rate 91.77%) and efficient mineralization (TOC removal rate 92.89%). This study reveals the mechanism of bimetallic single-atom synergistic regulation of the ORR pathway, elucidates the synergistic degradation essence of "reduction initiation-oxidation enhancement," and establishes a complete research chain of "structure-performance-mechanism-application," providing theoretical basis and technical support for the application of bimetallic single-atom catalytic materials in the deep treatment of halogenated antibiotic wastewater and the control of ARGs.

Claims

1. A bimetallic single-atom modified defect-type TiO2 electrocatalyst, characterized in that, The metal is dispersed in the form of single atoms on a defective TiO2 substrate, forming a first metal atom-O-Ti and a second metal atom-O-Ti coordination structure; The first metal atom and the second metal atom are completely separated by oxygen atoms.

2. The bimetallic single-atom modified defect-type TiO2 electrocatalyst as described in claim 1, characterized in that, The metals are Cu and Co.

3. The preparation method of the bimetallic single-atom modified defect-type TiO2 electrocatalyst as described in claim 1, characterized in that, Includes the following steps: Weigh out the defective TiO2 material, dissolve and disperse it in water, add a salt solution of the first metal and a salt solution of the second metal dropwise under stirring, add alkali to dissolve until the pH is neutral, dry, and obtain a bimetallic single-atom modified defective TiO2 electrocatalyst.

4. The preparation method according to claim 3, characterized in that, The molar ratio of the defective TiO2 material, the salt solution of the first metal, and the salt solution of the second metal is 500:1:1 to 633:1:

1.

5. A bimetallic single-atom modified defect-type TiO2 electrode, characterized in that, It includes an electrode substrate and a film formed on the surface of the electrode substrate containing a defect-type TiO2 modified with a bimetallic single atom.

6. The bimetallic single-atom modified defect-type TiO2 electrode as described in claim 5, characterized in that, Includes the following steps: The bimetallic single-atom modified defect-type TiO2 electrocatalyst as described in claim 1 is added to an organic solvent system containing a binder to form a mixture. The mixture is ultrasonically treated to form an ink, which is then transferred to a pretreated electrode substrate until a uniform film is formed by double-sided coating, thereby obtaining a bimetallic single-atom modified defect-type TiO2 electrode.

7. The preparation method according to claim 6, characterized in that, The pretreatment method is as follows: the electrode substrate is brought into contact with the components of the hydrophilic modification treatment solution, washed to remove impurities, and then dried.

8. The preparation method according to claim 6, characterized in that, The mass-to-volume ratio of the bimetallic single-atom modified defect-type TiO2 electrocatalyst to the organic solvent system containing the binder is 7.5:(11.5~16.5) mg / μL.

9. The application of the bimetallic single-atom modified defect-type TiO2 material as described in claim 1, or the bimetallic single-atom modified defect-type TiO2 electrode as described in claim 5, in the electrocatalytic degradation of organic pollutants.

10. The application as described in claim 9, characterized in that, The organic pollutant is a halogenated organic pollutant.

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