A single-atom ruthenium modified blue-black titanium dioxide film electrode, a preparation method and application thereof

Abstract

The application provides a single-atom ruthenium modified blue-black titanium dioxide film electrode and a preparation method and application thereof, the single-atom ruthenium modified blue-black titanium dioxide film electrode has a pore size of 200-500 mu m, a porosity of 75%-90%, and a ruthenium loading of 0.2-1.0 wt%. The preparation method comprises the following steps: step S1, 3D printing a three-dimensional ordered porous titanium dioxide film electrode; step S2, performing electrochemical reduction treatment on the three-dimensional ordered porous titanium dioxide film electrode to obtain a blue-black titanium dioxide film electrode; and step S3, placing the blue-black titanium dioxide film electrode in a ruthenium precursor dispersion liquid and performing ultraviolet light treatment to obtain the single-atom ruthenium modified blue-black titanium dioxide film electrode. The single-atom ruthenium modified blue-black titanium dioxide film electrode according to the embodiment of the application has excellent chlorine evolution, · OH excitation activity and stability, and can significantly strengthen electrode mass transfer and electron transfer, thereby more efficiently and greenly oxidizing and removing refractory organic pollutants in a salt-containing waste liquid.

Description

Technical Field

[0001] This invention relates to the field of saline wastewater treatment technology, specifically to a single-atom ruthenium-modified blue-black titanium dioxide film electrode, its preparation method, and its application. Background Technology

[0002] Zero discharge of saline wastewater is a global challenge, and efficient removal of organic pollutants from the wastewater is key to its treatment. Electrochemical oxidation, as an advanced oxidation technology, can achieve this through direct electron transfer on the electrode surface and the generation of highly reactive species (such as hydroxyl radicals). · Electrochemical oxidation removes recalcitrant organic matter from water through various methods such as OH-, and is therefore considered a very promising technology for treating saline wastewater. Currently, the most researched and applied method in electrochemical oxidation is the planar electrode, which mainly suffers from problems such as low electrochemical activity, reaction limitation by mass transfer, and high energy consumption.

[0003] To address the issues of the aforementioned planar electrodes, a wastewater treatment method based on electrochemically active membrane electrodes is proposed. This method combines electrochemical oxidation and membrane filtration functions, and by allowing wastewater to pass through the electrode, it reduces the diffusion layer thickness and enhances pollutant mass transfer, thereby improving the energy efficiency of electrochemical oxidation. Titanium suboxide and blue-black titanium dioxide nanotube arrays, due to their excellent conductivity and electrocatalytic activity, can both be fabricated as through electrodes. However, currently reported electrochemical membrane electrodes still have some drawbacks, such as disordered and insufficient pore structure, making it difficult to achieve optimal electron transport and mass transfer performance; limited and easily deactivated active sites on the electrode surface, making it difficult to guarantee good electrocatalytic activity and stability; and the presence of many inorganic ions (such as chloride ions) in saline wastewater, with electrocatalytic active sites not designed and regulated based on water quality characteristics. Summary of the Invention

[0004] Therefore, the purpose of this invention is to provide a three-dimensionally ordered porous, highly catalytically active single-atom ruthenium-modified blue-black titanium dioxide film electrode for the treatment of saline wastewater.

[0005] The present invention also aims to provide a method for preparing a single-atom ruthenium-modified blue-black titanium dioxide film electrode.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] According to a first aspect embodiment of the present invention, a single-atom ruthenium-modified blue-black titanium dioxide film electrode has a pore size of 200-500 μm, a porosity of 75%-90%, and a ruthenium loading of 0.2-1.0 wt%.

[0008] A method for preparing an iron-cobalt bimetallic anchored porous carbon electrode according to a second aspect of the present invention includes the following steps:

[0009] Step S1: 3D printing a three-dimensional ordered porous titanium dioxide film electrode;

[0010] Step S2: The three-dimensional ordered porous titanium dioxide film electrode is subjected to electrochemical reduction treatment to obtain a blue-black titanium dioxide film electrode.

[0011] Step S3: Place the blue-black titanium dioxide film electrode in a ruthenium precursor dispersion and subject it to ultraviolet light irradiation to obtain a single-atom ruthenium-modified blue-black titanium dioxide film electrode.

[0012] Further, step S1 includes:

[0013] Step S11: Weigh titanium and titanium dioxide powder with a particle size of 50-200nm in a ratio of 9:1 to 1:9, and put them into a ball mill for thorough mixing;

[0014] Step S12: Place the titanium and titanium dioxide mixed powder in a vacuum drying oven at 40-60℃ and dry for 4-7 hours;

[0015] Step S13: The dried titanium and titanium dioxide mixed powder is spread on the printing platform and 3D printed under an inert gas atmosphere to obtain a titanium dioxide film electrode sample.

[0016] Step S14: Sinter the titanium dioxide film electrode sample at 350-500℃ for 1-3 hours to obtain the three-dimensional ordered porous titanium dioxide film electrode.

[0017] Furthermore, the 3D printing employs a selective laser melting method, with a laser power range of 100-200W, a scanning speed of 100-300mm / s, a scanning spacing of 30-100μm, a powder layer thickness of 20-50μm, and a scanning pattern from the inside out.

[0018] The inert gas includes either argon or nitrogen.

[0019] Further, step S2 includes:

[0020] Step S21: The titanium dioxide film electrode sample is cleaned and etched to remove impurities, oil stains, oxide film, etc. on the electrode surface, thereby increasing the electrode exposure area and modification sites.

[0021] Step S22: Place the cleaned and etched titanium dioxide film electrode in a 0.5-2M sodium perchlorate electrolyte at 3-10 mA / cm². 2 Under current density conditions, electrochemical reduction for 10-30 minutes yields the blue-black titanium dioxide film electrode.

[0022] The cathode material in the electrochemical reduction process is the titanium dioxide film electrode, and the anode material includes any one of titanium plate, titanium plating platinum, titanium plating ruthenium iridium, and stainless steel electrode.

[0023] Further, step S21 includes:

[0024] S211, The titanium dioxide film electrode is placed in anhydrous ethanol and ultrasonically washed for 10 minutes;

[0025] S212, the alcohol-washed titanium dioxide film electrode is placed in a 4.0 wt% sodium hydroxide solution and treated with alkali at 90°C for 30 minutes;

[0026] S213, the alkali-treated titanium dioxide film electrode is placed in a 10.0 wt% oxalic acid solution and etched at 90°C for 2 hours;

[0027] S214, the etched titanium dioxide film electrode sample is placed in pure water and ultrasonically cleaned for 10 minutes to obtain the cleaned and etched titanium dioxide film electrode.

[0028] Further, step S3 includes:

[0029] Step S31: Disperse the ruthenium precursor in an organic solvent to obtain a ruthenium precursor dispersion;

[0030] Step S32: Immerse the blue-black titanium dioxide film electrode in the ruthenium precursor dispersion to adsorb the ruthenium precursor and organic solvent on the surface of the blue-black titanium dioxide film electrode.

[0031] Step S33: Irradiate the blue-black titanium dioxide film electrode, which has adsorbed the ruthenium precursor and organic solvent, with ultraviolet light for 20-60 minutes.

[0032] Step S34: Wash and dry the blue-black titanium dioxide film electrode after ultraviolet irradiation to obtain the single-atom ruthenium-modified blue-black titanium dioxide film electrode.

[0033] Furthermore, the ruthenium precursor includes one or more of ruthenium trichloride, ruthenium acetate, ruthenium bromide, ruthenium iodide, and their hydrates.

[0034] The organic solvent includes any one of acetonitrile, phenylacetonitrile, and propionitrile.

[0035] The dosage of ruthenium precursor in organic solvent is 0.5-1.0 wt%.

[0036] The above-described technical solution of the present invention has at least one of the following beneficial effects:

[0037] According to embodiments of the present invention, a single-atom ruthenium-modified blue-black titanium dioxide membrane electrode, constructed using 3D printing to create a three-dimensional ordered porous structure, enhances the electron transport and mass transfer performance of the membrane electrode. Furthermore, electrochemical reduction increases oxygen vacancies on the electrode surface, which is beneficial for improving the electron transport performance and exciting production processes of the membrane electrode. · OH activity; furthermore, under UV excitation, lattice oxygen on the membrane electrode and nitrogen atoms in the organic solvent can anchor single-atom ruthenium onto the membrane electrode. Single-atom ruthenium can not only electrocatalyze the generation of active chloride species from chloride ions in saline wastewater, but also modify and regulate oxygen vacancies on the electrode surface, enhancing its OH activity; · OH excitation activity and stability, thus enabling the membrane electrode to possess both high chlorine evolution and high efficiency. · OH activation enhances the performance of membrane electrodes in multiple aspects, including electrode mass transfer, electron transport, electrocatalytic activity, and stability, providing a more efficient, economical, and green technological option for the enhanced removal of organic pollutants from saline wastewater. Attached Figure Description

[0038] Figure 1 This is a flowchart illustrating the preparation method of a single-atom ruthenium-modified blue-black titanium dioxide film electrode according to an embodiment of the present invention;

[0039] Figure 2 This is a graph showing the treatment time versus chemical oxygen demand removal rate for batch treatment of saline wastewater using membrane electrodes in Examples 1, 1, 2, 3, and 4 of this invention.

[0040] Figure 3 The graphs show the treatment time versus chemical oxygen demand removal rate of the membrane electrode half-batch treatment of saline wastewater in Examples 1, 5, and 6 of this invention.

[0041] Figure 4 This is a schematic diagram illustrating the principle of electrocatalytic treatment of saline waste liquid using a single-atom ruthenium-modified blue-black titanium dioxide film electrode according to an embodiment of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0043] The preparation method of the single-atom ruthenium-modified blue-black titanium dioxide film electrode according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0044] It should be noted that the sources of raw materials not mentioned in this invention may be commercially available or prepared by conventional methods, and this invention does not limit them.

[0045] Figure 1 The present invention illustrates a method for preparing a single-atom ruthenium-modified blue-black titanium dioxide film electrode, which may include the following steps:

[0046] Step S1: 3D printing a three-dimensional ordered porous titanium dioxide film electrode;

[0047] Step S2: The three-dimensional ordered porous titanium dioxide film electrode is subjected to electrochemical reduction treatment to obtain a blue-black titanium dioxide film electrode.

[0048] Step S3: Place the blue-black titanium dioxide film electrode in a ruthenium precursor dispersion and subject it to ultraviolet light irradiation to obtain a single-atom ruthenium-modified blue-black titanium dioxide film electrode.

[0049] Specifically, according to the method for preparing a single-atom ruthenium-modified blue-black titanium dioxide film electrode according to embodiments of the present invention, 3D printing can construct a three-dimensional ordered porous film electrode, followed by electrochemical reduction to increase oxygen vacancies on the surface of the film electrode. Subsequently, the film electrode immersed in a ruthenium precursor dispersion is subjected to ultraviolet irradiation treatment to obtain a single-atom ruthenium-modified blue-black titanium dioxide film electrode. The single-atom ruthenium-modified blue-black titanium dioxide film electrode prepared according to embodiments of the present invention, by constructing a three-dimensional ordered porous structure, can enhance the electron transport and mass transfer performance of the film electrode; the introduction of oxygen vacancies on the electrode surface is beneficial to improving the electron transport performance and exciting production. · OH activity; single-atom ruthenium can not only excite the chlorine evolution ability of the membrane electrode, but also regulate the oxygen vacancies on the membrane electrode surface. · OH excitation activity and stability, thus enabling the membrane electrode to possess both high chlorine evolution and high efficiency. · OH activation enhances the performance of membrane electrodes by comprehensively improving electrode mass transfer, electron transport, electrocatalytic activity, and stability, providing a more efficient, economical, and green technology option for the enhanced removal of organic pollutants from saline wastewater.

[0050] In some embodiments, commercially available three-dimensionally ordered porous titanium dioxide film electrodes can be used directly, or they can be prepared according to the following method, i.e., step S1 may include the following steps:

[0051] Step S11: Weigh titanium and titanium dioxide powder with a particle size of 50-200nm in a ratio of 9:1 to 1:9, and put them into a ball mill for thorough mixing.

[0052] Step S12: Place the titanium and titanium dioxide mixed powder in a vacuum drying oven at 40-60℃ and dry for 4-7 hours.

[0053] Step S13: The dried titanium and titanium dioxide mixed powder is spread on the printing platform and 3D printed under an inert gas atmosphere to obtain a titanium dioxide film electrode sample.

[0054] Specifically, 3D printing uses selective laser melting, with a laser power range of 100-200W, a scanning speed of 100-300mm / s, a scanning distance of 30-100μm, a powder layer thickness of 20-50μm, and a scanning method from the inside out.

[0055] The inert gas includes either argon or nitrogen.

[0056] Step S14: Sinter the titanium dioxide film electrode sample at 350-500℃ for 1-3 hours to obtain the three-dimensional ordered porous titanium dioxide film electrode.

[0057] In other words, selective laser melting 3D printing utilizes the thermal effect of a laser beam to form equiaxed crystals, enabling rapid, precise, and integrated molding of complex porous structures. This allows for precise control over parameters such as the pore shape, spatial distribution, and size of porous titanium, thereby constructing a three-dimensional ordered porous titanium dioxide film electrode.

[0058] The three-dimensional ordered porous titanium dioxide film electrode obtained as described above is then subjected to electrochemical reduction treatment. In some embodiments of the present invention, the electrochemical reduction treatment (i.e., step S2) may specifically include:

[0059] Step S21: The titanium dioxide film electrode sample is cleaned and etched to remove impurities, oil stains, oxide film, etc. on the electrode surface, while increasing the electrode exposure area and modification sites.

[0060] Step S22: Place the cleaned and etched titanium dioxide film electrode in a 0.5-2M sodium perchlorate electrolyte at 3-10 mA / cm². 2 Under current density conditions, electrochemical reduction is performed for 10-30 minutes to obtain the blue-black titanium dioxide film electrode. In some embodiments, the anode material includes any one of titanium plate, titanium plated with platinum, titanium plated with ruthenium-iridium, and stainless steel electrode.

[0061] In other embodiments, step S21 specifically includes:

[0062] S211, Place the titanium dioxide film electrode sample in anhydrous ethanol and ultrasonically wash it for 10 minutes.

[0063] Specifically, ultrasonic alcohol washing can remove impurities from the surface of titanium dioxide film electrode samples.

[0064] S212, the alcohol-washed titanium dioxide film electrode sample was placed in a 4.0 wt% sodium hydroxide solution and treated with alkali at 90°C for 30 minutes.

[0065] Specifically, the alkaline treatment is mainly to remove oil stains from the surface of the titanium dioxide film electrode sample.

[0066] S213, the alkali-treated titanium dioxide film electrode sample was placed in a 10.0wt% oxalic acid solution and etched at 90°C for 2 hours.

[0067] Specifically, oxalic acid etching can remove the oxide film on the surface of the titanium dioxide film electrode sample and increase the specific surface area of ​​the film electrode, exposing more sites, which helps with subsequent surface modification of the film electrode and anchoring of metal single atoms.

[0068] S214, the etched titanium dioxide film electrode sample is placed in pure water and ultrasonically cleaned for 10 minutes to obtain the cleaned and etched titanium dioxide film electrode sample.

[0069] Specifically, electrochemical reduction treatment can modify the surface of titanium dioxide electrodes by introducing oxygen vacancies into the metal oxide, generating blue-black titanium dioxide with localized electrons. Oxygen vacancies play a crucial role in determining the surface and electrochemical properties of titanium dioxide. On the one hand, oxygen vacancies can expand the lattice space and increase the density of states below the Fermi level, thereby reducing charge transfer resistance and promoting electron transport. On the other hand, oxygen vacancies with localized electrons can serve as active sites for water molecule adsorption and catalysis, reducing the adsorption binding energy of water molecules on the electrode surface and decreasing the amount of water produced during electrolysis. · The overpotential of OH enhances the electrode excitation process. · The activity of OH. In addition, compared with other modification methods such as vacuum annealing and ionothermal reduction, electrochemical reduction can achieve precise control of electrode surface modification by controlling current density and processing time.

[0070] As described above, a blue-black titanium dioxide film electrode is obtained, and then a single-atom ruthenium anchor is performed on it to obtain a single-atom ruthenium modified blue-black titanium dioxide film electrode. In some embodiments of the present invention, the single-atom ruthenium anchoring step (i.e., step S3) may include:

[0071] Step S31: Disperse the ruthenium precursor in an organic solvent to obtain a ruthenium precursor dispersion.

[0072] The ruthenium precursor dispersion contains a ruthenium precursor selected from at least one of ruthenium trichloride, ruthenium acetate, ruthenium bromide, ruthenium iodide, and their hydrates. These ruthenium precursors exhibit good stability and high solubility.

[0073] The organic solvent is selected from acetonitrile, phenylacetonitrile, and propionitrile. For better single-atom ruthenium anchoring, the organic solvent molecule must contain functional groups such as cyano or alkyl groups.

[0074] Step S32: Immerse the blue-black titanium dioxide film electrode in a ruthenium precursor dispersion to adsorb the ruthenium precursor and organic solvent on the surface of the blue-black titanium dioxide film electrode.

[0075] Step S33: Irradiate the blue-black titanium dioxide film electrode, which has adsorbed ruthenium precursor and organic solvent, under ultraviolet light for 20-60 minutes.

[0076] Specifically, nitrogen in the organic solvent is first adsorbed onto the oxygen vacancies of the blue-black titanium dioxide and forms nitrogen anchoring sites TiO2-N under ultraviolet irradiation. Then, the organic solvent is irradiated with ultraviolet light to generate active groups such as alkyl radicals and superoxide radicals. Under the action of alkyl radicals, nitrogen atoms and lattice oxygen on TiO2-N anchor ruthenium atoms. In addition, alkyl radicals and superoxide radicals in the reaction system can inhibit the formation of ruthenium atoms into clusters or nanoparticles, thereby anchoring ruthenium atoms on the surface of the blue-black titanium dioxide electrode in the form of single-atom ruthenium.

[0077] Step S34: The blue-black titanium dioxide film electrode after ultraviolet irradiation is washed and dried to remove organic solvents, ruthenium precursors, and unanchored ruthenium from the electrode surface, thereby obtaining the single-atom ruthenium modified blue-black titanium dioxide film electrode.

[0078] It should be noted that the anchoring of single-atom ruthenium relies on oxygen vacancies on the surface of the blue-black titanium dioxide film electrode, which does not affect the film electrode's... · OH activation can actually regulate the oxygen vacancy concentration on the membrane electrode surface, thereby improving the stability of the membrane electrode, because an oxygen vacancy concentration exceeding a certain level will affect the stability of the crystal lattice structure. Furthermore, single-atom ruthenium can also act as an active site, reducing the binding energy of chloride ions on the membrane electrode surface, thus lowering the chloride evolution overpotential of the membrane electrode, thereby ensuring the stability of the membrane electrode. · Under the premise of OH activation activity and stability, the chlorine evolution capacity of the membrane electrode is improved. Therefore, the ruthenium-modified blue-black titanium dioxide membrane electrode can fully utilize the ions in the saline waste liquid to generate chlorine in the electrocatalytic oxidation system. · It contains multiple active species such as OH and free chlorine to enhance the oxidative removal of recalcitrant organic matter in saline wastewater.

[0079] By using the above preparation method and adjusting the proportions of each raw material and the processing parameters, a single-atom ruthenium-modified blue-black titanium dioxide film electrode can be obtained. The film electrode has a pore size of 200-500 μm, a porosity of 75%-90%, and a ruthenium loading of 0.2-1.0 wt%.

[0080] The following examples further illustrate the preparation method of the single-atom ruthenium-modified blue-black titanium dioxide film electrode of the present invention.

[0081] Example 1

[0082] 1) Fabrication of three-dimensional ordered porous titanium dioxide film electrodes

[0083] 1.1) Weigh 40g of titanium powder with a particle size of 50nm and 60g of titanium dioxide powder, put them into a vacuum ball mill jar, and ball mill them for 15 minutes to mix them thoroughly.

[0084] 1.2) Place the material obtained in step 1.1) in a vacuum drying oven at 60°C and dry for 5 hours.

[0085] 1.3) Take the material obtained in step 1.2) and spread it on the printing platform. Under the protection of argon atmosphere, perform selective laser melting 3D printing. The laser power is 100W, the scanning speed is 100mm / s, the scanning interval is 30μm, the powder layer thickness is 30μm, and the scanning method is from the inside to the outside.

[0086] 1.4) The material obtained in step 1.3) is sintered at 450°C for 2 hours to obtain a three-dimensional ordered porous titanium dioxide film electrode.

[0087] 2) Preparation of blue-black titanium dioxide film electrode

[0088] 2.1) Place the material obtained in step 1.4) in anhydrous ethanol and ultrasonically wash for 10 minutes;

[0089] The alcohol-washed material was placed in a 4.0 wt% sodium hydroxide solution and treated with alkali at 90°C for 30 minutes.

[0090] The material treated with the above alkali was placed in a 10.0 wt% oxalic acid solution and etched at 90°C for 2 hours.

[0091] Place the etched material in pure water and ultrasonically clean it for 10 minutes.

[0092] 2.2) Using the material obtained in step 2.1) as the cathode and the titanium plate as the anode, place it in 300 mL of 1 M sodium perchlorate electrolyte at 5 mA / cm². 2 Under current density conditions, electrochemical reduction for 20 minutes yielded a blue-black titanium dioxide film electrode.

[0093] 3) Preparation of single-atom ruthenium-modified blue-black titanium dioxide film electrodes

[0094] 3.1) Weigh 0.7 g of ruthenium trichloride and dissolve and disperse it completely in 100 mL of acetonitrile to form a ruthenium precursor dispersion;

[0095] 3.2) The material obtained in step 2) is immersed in the ruthenium precursor dispersion prepared in step 3.1);

[0096] 3.3) Irradiate the material impregnated in the ruthenium precursor dispersion described in step 3.2) with ultraviolet light for 30 minutes;

[0097] 3.4) The material obtained in step 3.3) is washed and dried to obtain a single-atom ruthenium-modified blue-black titanium dioxide film electrode.

[0098] Comparative Example 1:

[0099] Except for 1) not performing 3D printing but directly using commercially available, equal-area, non-porous titanium plates for 2) and 3), the rest is the same as in Example 1 above, to obtain a single-atom ruthenium-modified blue-black titanium dioxide flat plate electrode.

[0100] Comparative Example 2:

[0101] Except for not performing the single-atom ruthenium modification after 2), the rest is the same as in Example 1 above, and a blue-black titanium dioxide film electrode is obtained.

[0102] Comparative Example 3:

[0103] Except for the fact that after 1), the electrochemical reduction treatment was not performed in step 2) but instead the treatment in step 3) was performed directly, the rest was the same as in Example 1 above, and a single-atom ruthenium-modified titanium dioxide film electrode was obtained.

[0104] Comparative Example 4:

[0105] Referring to Example 1 above, in step 3), an equal volume of deionized water was used instead of acetonitrile, and the rest was the same as in the above example, to obtain a nano-ruthenium modified blue-black titanium dioxide film electrode.

[0106] Comparative Example 5:

[0107] Referring to Example 1 above, in step 3), chloroplatinic acid hexahydrate was used instead of ruthenium trichloride, and the rest was the same as in the above example, to obtain a single-atom platinum-modified blue-black titanium dioxide film electrode.

[0108] Comparative Example 6:

[0109] Referring to Example 1 above, in step 3), palladium chloride of the same molar mass is used instead of ruthenium trichloride, and the rest is the same as in the above example, to obtain a single-atom palladium-modified blue-black titanium dioxide film electrode.

[0110] Performance test experiment A: Treatment effect on saline wastewater

[0111] The water sample to be treated was a saline waste liquid with an initial chemical oxygen demand (COD) of 150 mg / L, a chloride ion concentration of 9000 mg / L, a pH of 7.8, and a treatment sample volume of 50 mL.

[0112] The cathode is a nickel foam electrode, and the anodes are the electrodes prepared in Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4, respectively. The electrode area is 3×3cm. 2 The current applied to the anode and cathode is 270 mA, which is equivalent to a current density of 30 mA / cm². 2 The water samples to be treated were subjected to batch electrochemical treatment.

[0113] like Figure 2 As shown, when the single-atom ruthenium-modified blue-black titanium dioxide film electrode prepared according to Example 1 is used for electrocatalytic treatment, the COD removal rate of the salt-containing waste liquid can reach more than 90% when the treatment time is 45 minutes.

[0114] Compared with the experimental results of using a nickel foam electrode and a single-atom ruthenium-modified blue-black titanium dioxide plate electrode as the cathode and anode respectively (Comparative Example 1), with other experimental conditions remaining unchanged, the COD removal rate increased by about 40% after 45 minutes; compared with the experimental results of using a nickel foam electrode and a single-atom ruthenium-modified titanium dioxide film electrode as the cathode and anode respectively (Comparative Example 2), with other experimental conditions remaining unchanged, the COD removal rate increased by about 30% after 45 minutes; compared with the experimental results of using a nickel foam electrode and a single-atom ruthenium-modified titanium dioxide film electrode as the cathode and anode respectively (Comparative Example 3), with other experimental conditions remaining unchanged, the COD removal rate increased by about 50% after 45 minutes; compared with the experimental results of using a nickel foam electrode and a single-atom ruthenium-modified blue-black titanium dioxide film electrode as the cathode and anode respectively (Comparative Example 4), with other experimental conditions remaining unchanged, the COD removal rate increased by about 25% after 45 minutes.

[0115] Performance test experiment B: Treatment effect on saline wastewater

[0116] The water sample to be treated was a saline waste liquid with an initial chemical oxygen demand (COD) of 100 mg / L, a chloride ion concentration of 6000 mg / L, a pH of 7.5, and a treatment sample volume of 50 mL.

[0117] The cathode is a nickel foam electrode, and the anodes are the electrodes prepared in Example 1, Comparative Example 5, and Comparative Example 6, respectively. The electrode area is 3×3cm. 2 The current applied to the anode and cathode is 270 mA, which is equivalent to a current density of 30 mA / cm². 2 .

[0118] The water sample to be treated is pumped into the reactor from the bottom, and after passing through the anode and cathode, it flows out of the reactor from the top. The water sample flow rate is 20 mL / min. The water sample is subjected to semi-batch electrochemical treatment under continuous circulation conditions.

[0119] like Figure 3 As shown, when the single-atom ruthenium-modified blue-black titanium dioxide film electrode prepared according to Example 1 is used for electrocatalytic treatment, the COD removal rate of the saline waste liquid can reach over 90% after 30 minutes of treatment. Compared with the experimental results of foamed nickel electrode and single-atom platinum-modified blue-black titanium dioxide film electrode (Comparative Example 5) with the cathode and anode respectively, and other experimental conditions remaining unchanged, the COD removal rate increased by about 35% after 30 minutes; compared with the experimental results of foamed nickel electrode and single-atom palladium-modified blue-black titanium dioxide film electrode (Comparative Example 6) with the cathode and anode respectively, and other experimental conditions remaining unchanged, the COD removal rate increased by about 26% after 30 minutes.

[0120] Example 2

[0121] Except for the following differences, it is the same as in Example 1: 90g of titanium powder with a particle size of 100nm and 10g of titanium dioxide powder are weighed in step 1.1); the resulting ruthenium monoatomic modified blue-black titanium dioxide film electrode is obtained.

[0122] When the saline wastewater was treated according to the operating method in the above performance evaluation experiment A, the COD removal rate was 88.9% after 45 minutes.

[0123] Example 3

[0124] Except for the following differences, it is the same as in Example 1: the 3D printing scanning speed in step 1.3) is 260 mm / s and the scanning spacing is 80 μm; the resulting single-atom ruthenium-modified blue-black titanium dioxide film electrode.

[0125] When the saline wastewater was treated according to the operating method in the above performance evaluation experiment A, the COD removal rate was 93.1% after 45 minutes.

[0126] Example 4

[0127] Except for the following differences, it is the same as in Example 1: In step 2), at 10 mA / cm 2 Under current density conditions, the titanium dioxide film electrode was electrochemically reduced for 10 minutes; the resulting ruthenium-modified blue-black titanium dioxide film electrode was obtained.

[0128] When the saline wastewater was treated according to the operating method in the above performance evaluation experiment A, the COD removal rate was 91.6% after 45 minutes.

[0129] Example 5

[0130] Except for the following differences, it is the same as in Example 1: In step 3.1), 0.7 g of ruthenium acetate is weighed and fully dissolved and dispersed in 100 mL of acetonitrile; the resulting ruthenium monoatomic modified blue-black titanium dioxide film electrode.

[0131] When the saline wastewater was treated according to the operating method in the above performance evaluation experiment A, the COD removal rate was 92.7% after 45 minutes.

[0132] Example 6

[0133] Except for the following differences, it is the same as in Example 1: In step 3.1), ruthenium trichloride is fully dissolved and dispersed in 100 mL of phenylacetonitrile; the resulting ruthenium-modified blue-black titanium dioxide film electrode is obtained.

[0134] When the saline wastewater was treated according to the operating method in the above performance evaluation experiment A, the COD removal rate was 90.4% after 45 minutes.

[0135] Example 7

[0136] Except for the following differences, it is the same as in Example 1: in step 3.3), the blue-black titanium dioxide film electrode immersed in the ruthenium precursor dispersion is subjected to ultraviolet irradiation for 60 minutes; the resulting single-atom ruthenium modified blue-black titanium dioxide film electrode.

[0137] When the saline wastewater was treated according to the operating method in the above performance evaluation experiment A, the COD removal rate was 92.0% after 45 minutes.

[0138] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a single-atom ruthenium-modified blue-black titanium dioxide film electrode, characterized in that, Includes the following steps: Step S1 involves 3D printing a three-dimensional ordered porous titanium dioxide film electrode. The 3D printing employs a selective laser melting method. Step S1 includes: Step S11: Weigh titanium and titanium dioxide powder with a particle size of 50-200 nm in a ratio of 9:1 to 1:9, and put them into a ball mill for thorough mixing; Step S12: Place the titanium and titanium dioxide mixed powder in a vacuum drying oven at 40-60 ℃ and dry for 4-7 hours; Step S13: The dried titanium and titanium dioxide mixed powder is spread on the platform and 3D printed under an inert gas atmosphere to obtain a titanium dioxide film electrode sample. Step S14: Sinter the titanium dioxide film electrode sample at 350-500 °C for 1-3 hours to obtain the three-dimensional ordered porous titanium dioxide film electrode. Step S2 involves electrochemically reducing the three-dimensional ordered porous titanium dioxide film electrode to obtain a blue-black titanium dioxide film electrode. Step S2 includes: Step S21: The titanium dioxide film electrode sample is cleaned and etched to remove impurities, oil stains, and oxide film from the electrode surface, while increasing the exposed area and modification sites of the electrode. Step S22: Place the cleaned and etched titanium dioxide film electrode in a 0.5-2 M sodium perchlorate electrolyte at 3-10 mA / cm². 2 Under current density conditions, electrochemical reduction was performed for 10-30 minutes to obtain the blue-black titanium dioxide film electrode. Step S3: The blue-black titanium dioxide film electrode is placed in a ruthenium precursor dispersion and subjected to ultraviolet light irradiation to obtain a single-atom ruthenium-modified blue-black titanium dioxide film electrode. The single-atom ruthenium-modified blue-black titanium dioxide film electrode has a pore size of 200-500 μm, a porosity of 75%-90%, and a ruthenium loading of 0.2-1.0 wt%. Step S3 includes: Step S31: Disperse the ruthenium precursor in an organic solvent to obtain a ruthenium precursor dispersion, wherein the organic solvent includes any one of acetonitrile, phenylacetonitrile, and propionitrile; Step S32: Immerse the blue-black titanium dioxide film electrode in the ruthenium precursor dispersion to adsorb the ruthenium precursor and organic solvent on the surface of the blue-black titanium dioxide film electrode. Step S33: Irradiate the blue-black titanium dioxide film electrode, which has adsorbed the ruthenium precursor and organic solvent, with ultraviolet light for 20-60 minutes. Step S34: Wash and dry the ultraviolet-irradiated blue-black titanium dioxide film electrode to obtain the single-atom ruthenium-modified blue-black titanium dioxide film electrode.

2. The preparation method according to claim 1, characterized in that, The selective laser melting method comprises a laser power range of 100-200 W, a scanning speed of 100-300 mm / s, a scanning interval of 30-100 μm, a powder layer thickness of 20-50 μm, and a scanning pattern from the inside out. The inert gas includes either argon or nitrogen.

3. The preparation method according to claim 1, characterized in that, In step S2, the cathode material of the electrochemical reduction process is the titanium dioxide film electrode, and the anode material includes any one of titanium plate, titanium plating platinum, titanium plating ruthenium-iridium, and stainless steel electrode.

4. The preparation method according to claim 3, characterized in that, Step S21 includes: S211, The titanium dioxide film electrode is placed in anhydrous ethanol and ultrasonically washed for 10 minutes; S212, the alcohol-washed titanium dioxide film electrode is placed in a 4.0 wt% sodium hydroxide solution and treated with alkali at 90 °C for 30 minutes; S213, the alkali-treated titanium dioxide film electrode is placed in a 10.0 wt% oxalic acid solution and etched at 90 °C for 2 hours; S214, the etched titanium dioxide film electrode sample is placed in pure water and ultrasonically cleaned for 10 minutes to obtain the cleaned and etched titanium dioxide film electrode.

5. The preparation method according to claim 4, characterized in that, The ruthenium precursor includes one or more of ruthenium trichloride, ruthenium acetate, ruthenium bromide, ruthenium iodide, and their hydrates. The ruthenium precursor is added to the organic solvent at a ratio of 0.5-1.0 wt%.

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