Sulfur-mediated copper oxide (S-CuO) catalyst as well as preparation method and application thereof

Abstract

The invention discloses a sulfur-mediated copper oxide (S-CuO) catalyst and a preparation method and application thereof.The preparation method comprises the steps that copper sulfate pentahydrate is dissolved in a mixed solvent of N, N-dimethylformamide and absolute ethyl alcohol, and stirring is conducted to obtain a solution A; adding 2-aminoterephthalic acid into the solution A, and stirring to obtain a solution B; under vigorous stirring, 4, 5-imidazole dicarboxylic acid is rapidly added into the solution B to obtain a mixed solution, and the mixed solution is centrifuged, precipitated, washed and dried to obtain precursor powder; and calcining the precursor powder in an air or inert atmosphere, and washing and drying after calcining to obtain the sulfur-mediated copper oxide (S-CuO) catalyst. The catalyst has high-dispersion active sites, a stable Cu-O-S structure and an active local coordination structure, the conversion efficiency of the chlorine-containing volatile organic compounds can be effectively improved, and high purification efficiency and long-term stability are kept while the cost of the catalyst is reduced.

Description

Technical Field

[0001] This invention belongs to the field of air pollution control technology, and specifically relates to a sulfur-mediated copper oxide (S-CuO) catalyst, its preparation method, and its application. Background Technology

[0002] With the accelerating pace of industrialization, air pollution control has become a top priority in ecological and environmental protection. Among these efforts, the control of volatile organic compounds (VOCs, which are organic chemical substances with high vapor pressure and high volatility at normal temperature and pressure) emissions is particularly crucial. VOCs not only directly irritate the human respiratory tract and skin mucous membranes, but some substances also possess carcinogenic, teratogenic, and mutagenic properties, seriously endangering human health. Furthermore, they are core precursors to near-surface ozone and fine particulate matter (PM2.5) pollution, significantly impacting regional air quality and climate change. Among the many VOCs, chlorinated volatile organic compounds (CVOCs), due to their high toxicity and poor biodegradability, readily generate highly toxic byproducts such as dioxins and hydrogen chloride during traditional treatment processes, causing secondary pollution. The development and application of efficient and deep purification technologies for CVOCs have become a pressing challenge in the environmental protection field. Currently, catalytic oxidation is the mainstream end-of-pipe treatment technology for treating low-concentration VOCs in industry. It is widely used in waste gas treatment scenarios in many industries such as petrochemicals, pharmaceuticals, coating, and electronics manufacturing. This technology uses the action of a catalyst to oxidize and decompose VOCs into harmless substances such as carbon dioxide and water under relatively mild conditions. It has advantages such as high treatment efficiency, low energy consumption, and no secondary pollution, and occupies an important position in the field of waste gas purification.

[0003] In the application of catalytic oxidation, the performance of the catalyst directly determines the efficiency of waste gas treatment, operating energy consumption, and overall treatment cost, making it a core key to the practical application and promotion of this technology. Currently, the supported precious metal catalysts widely used in industry mainly use platinum (Pt) and palladium (Pd) as active components. While they exhibit excellent catalytic activity at relatively low temperatures, achieving rapid oxidation and decomposition of VOCs, they have significant limitations. On the one hand, the scarcity and high price of precious metals such as platinum and palladium significantly increase the preparation cost of catalysts and the threshold for industrial application, limiting their widespread adoption in small and medium-sized enterprises and large-scale waste gas treatment scenarios. On the other hand, these catalysts are extremely sensitive to chlorine-containing atmospheres; chlorine species generated during CVOCs decomposition are easily adsorbed onto the catalyst surface, leading to poisoning and deactivation of the precious metal active sites, significantly shortening the catalyst's lifespan and further increasing overall operating costs. Among transition metal oxide catalysts that replace precious metals, copper oxide (CuO) shows promising application prospects in the catalytic elimination of CVOCs due to its abundant reserves, low preparation cost, tunable redox properties, and potential activation ability for carbon-chlorine (C-Cl) bonds in CVOCs. However, unmodified copper oxide catalysts still cannot meet the needs of industrial applications. Not only is the active temperature window too high, requiring higher temperatures to achieve the ideal catalytic effect, increasing energy consumption, but it is also prone to deactivation of active sites due to chlorine species adsorption in water-rich conditions or during the reaction process, resulting in insufficient stability and inability to operate stably for a long time.

[0004] To address the technical shortcomings of existing catalysts, researchers and industry practitioners have conducted extensive studies dedicated to developing superior and lower-cost alternatives. To solve the problems of high cost and susceptibility to poisoning of precious metal catalysts, researchers have turned their attention to transition metal oxides, improving their catalytic performance through optimizing preparation processes and adjusting the proportions of active components. Copper oxide, in particular, has become a key research focus due to its inherent advantages. Simultaneously, to overcome the bottlenecks of insufficient activity and poor stability in ordinary copper oxide catalysts, researchers have explored various catalyst modification strategies, including metal doping, support modification, and morphology control. By precisely controlling the electronic structure and surface properties of the catalyst, their catalytic activity and stability can be optimized. In recent years, anion doping modification has proven to be an efficient and feasible strategy, with the introduction of sulfur species to modify copper oxide gradually becoming a research hotspot. This modification method mainly improves catalyst performance through three pathways: First, sulfur species react with copper oxide to form surface sulfate species or introduce lattice sulfur, significantly enhancing the acidity of the catalyst surface. The increase in acidic sites helps promote the adsorption of polar pollutants such as CVOCs and accelerates the breaking of C-Cl bonds, creating conditions for subsequent oxidative decomposition reactions. Second, strong interactions are formed between sulfur species and copper active centers, regulating the electronic state of copper, optimizing the catalyst's redox cycle capacity, promoting the generation and conversion of reactive oxygen species, and improving catalytic reaction efficiency. Third, the stable surface sulfur structure can isolate and protect the copper active centers, reducing the adsorption and deposition of chlorine species at the active centers, alleviating chlorine poisoning and high-temperature sintering deactivation problems of the catalyst, and extending the catalyst's service life.

[0005] Although the modification strategy of sulfur-modified copper oxide offers a new direction for addressing the shortcomings of existing catalysts, this technology is still in the laboratory research stage and has not yet been industrialized, with many problems remaining to be overcome. From the perspective of modification effects, the amount, mode of introduction, and form of sulfur species significantly affect catalyst performance. Currently, the optimal preparation process parameters are not clearly defined, making it difficult to precisely control the interaction between sulfur species and copper oxide, resulting in an unclear structure-activity relationship and hindering targeted optimization of catalytic performance. Furthermore, the reaction conditions in the laboratory environment are relatively simple, while industrial waste gas is complex, often containing moisture, other VOCs, dust, and other impurities. The adaptability and stability of sulfur-modified copper oxide catalysts in actual industrial conditions still need to be fully verified, and their anti-interference ability and long-term operating performance have not yet met industrial application standards. In addition, existing research has not sufficiently elucidated the reaction mechanism and the migration and transformation pathways of chlorine species in the catalytic oxidation of CVOCs by sulfur-modified copper oxide catalysts, thus restricting further optimization of the catalyst structure. In summary, current technologies have not yet completely solved the core defects of precious metal catalysts, such as high cost and susceptibility to poisoning, as well as the insufficient activity and poor stability of ordinary copper oxide catalysts. There is an urgent need to develop a highly efficient, stable, and low-cost catalytic oxidation solution for CVOCs, clarify the optimal structure and preparation process of sulfur-mediated copper oxide (S-CuO) catalysts, elucidate their structure-activity relationship and reaction mechanism, provide technical support for the industrial promotion of this type of catalyst, and help achieve the strategic goals of pollution prevention and green development. Summary of the Invention

[0006] This invention provides a sulfur-mediated copper oxide (S-CuO) catalyst, its preparation method, and its applications. It aims to address the challenge of balancing cost, purification performance, and stability in existing catalysts, specifically considering the emission characteristics and molecular features of chlorinated volatile alkane pollutants. This catalyst possesses highly dispersed active sites, a stable Cu-OS structure, and an active local coordination structure, effectively improving the conversion efficiency of chlorinated volatile organic compounds. This achieves reduced catalyst costs while maintaining high purification efficiency and long-term stability.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a sulfur-mediated copper oxide (S-CuO) catalyst, the specific steps of which are as follows: Copper sulfate pentahydrate was dissolved in a mixed solvent of N,N-dimethylformamide and anhydrous ethanol and stirred to obtain solution A; 2-Aminoterephthalic acid was added to solution A and stirred to obtain solution B; Under vigorous stirring, 4,5-imidazolium dicarboxylic acid was rapidly added to solution B to obtain a mixture. The mixture was centrifuged, precipitated, washed, and dried to obtain the precursor powder. The precursor powder was calcined in air or an inert atmosphere, and after calcination, it was washed and dried to obtain a sulfur-mediated copper oxide (S-CuO) catalyst.

[0008] Furthermore, the specific steps for preparing solution A are as follows: Dissolve 0.01 mol to 0.03 mol of copper sulfate pentahydrate in a mixed solvent consisting of 80 mL to 120 mL of N,N-dimethylformamide and 30 mL of anhydrous ethanol, and stir at 400 rpm to 600 rpm for 10 to 20 minutes to obtain solution A.

[0009] Furthermore, 0.02 mol to 0.06 mol of 2-aminoterephthalic acid is added to solution A.

[0010] Furthermore, in the step of obtaining the mixture, 0.03 mol to 0.05 mol of 4,5-imidazolium dicarboxylic acid is rapidly added to solution B at 800 rpm to 1000 rpm, and the stirring speed is increased to 1000 rpm to 1200 rpm. The reaction is continued at room temperature for 2 to 4 hours to obtain the mixture.

[0011] Furthermore, in the step of obtaining the precursor powder, the mixture is centrifuged at 4000rpm-6000rpm for 5min-10min, the supernatant is discarded, and the resulting precipitate is washed 3-5 times with N,N-dimethylformamide and anhydrous ethanol respectively; the washed precipitate is dried at 70℃-90℃ for 8h-12h to obtain the precursor powder.

[0012] Furthermore, in the step of calcining the precursor powder, the temperature is increased to 400℃-500℃ in air or an inert atmosphere at a heating rate of 1℃ / min-3℃ / min, and the precursor powder is calcined at this temperature for 1h-2h.

[0013] Furthermore, in the washing and drying steps after calcination, the calcined precursor powder is thoroughly washed with deionized water 4-6 times and dried overnight at 80℃-100℃.

[0014] The present invention also provides a sulfur-mediated copper oxide S-CuO catalyst, which is prepared by the above preparation method.

[0015] This invention also provides the application of a sulfur-mediated copper oxide (S-CuO) catalyst in the treatment of chlorine-containing volatile organic pollutants, at approximately 420℃~450℃, an oxygen concentration of 20%, and a space velocity of 36000 mL. h -1 g -1Under certain conditions, sulfur-mediated copper oxide S-CuO catalyst can achieve complete oxidation of 1,2-dichloroethane at 1000 ppm.

[0016] This invention also provides a method for purifying chlorine-containing volatile organic pollutants, wherein the aforementioned sulfur-mediated copper oxide (S-CuO) catalyst is used at approximately 420°C to 450°C, with an oxygen concentration of 20% and a space velocity of 36,000 mL. h -1 g -1 Under these conditions, complete oxidation of 1,2-dichloroethane to 1000 ppm can be achieved.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects: This invention provides a method for preparing a sulfur-mediated copper oxide (S-CuO) catalyst. Using copper sulfate pentahydrate as a raw material, the method combines MOF derivatization with a sulfur-mediated strategy, offering advantages in both process and cost. This approach requires only conventional chemical raw materials and can be completed through core steps such as precursor synthesis and calcination. It eliminates the need for sophisticated equipment, making the process simple and easy to implement, significantly reducing catalyst preparation costs. Compared to precious metal catalysts, it is more economical, providing crucial support for subsequent large-scale industrial production and breaking the cost limitation imposed on industrial applications.

[0018] The sulfur-mediated effect precisely breaks the original perfect lattice of copper oxide, directionally forming a stable Cu-OS structure. This structure also creates highly dispersed active sites, low-coordination Cu sites, and lattice distortion, directly enhancing the catalyst's catalytic activity and stability. Compared to traditional CuO catalysts, it performs better in treating chlorine-containing volatile organic pollutants, effectively reducing the activity temperature window and energy consumption. Furthermore, it avoids the drawbacks of precious metal catalysts, such as high cost, susceptibility to chlorine poisoning, and short lifespan, achieving a balance between purification efficiency, stability, and economy. This lays the foundation for subsequent parameter refinement and optimization.

[0019] This invention also clarifies and controls key process parameters in the preparation process, bringing significant industrial adaptability value. Precise parameter design ensures complete precursor conversion and maintains a stable and consistent catalyst microstructure, improving the repeatability and controllability of the preparation process from the source. This provides reliable technical support for mass production and avoids product performance differences caused by parameter fluctuations. This parameterized design can precisely control the catalyst microstructure, ensuring uniform dispersion of active sites and stable Cu-OS structure, while effectively reducing the production scrap rate and ensuring that each batch of product achieves the expected catalytic effect. This significantly enhances the industrial application potential of the catalyst and lays a solid foundation for large-scale mass production.

[0020] The S-CuO catalyst prepared using the above-mentioned method exhibits superior performance in the treatment of chlorinated volatile organic pollutants due to its core advantages of highly dispersed active sites, stable Cu-OS structure, and active local coordination structure. Under suitable conditions, it can achieve complete oxidative decomposition of 1000 ppm 1,2-dichloroethane, with a purification efficiency far exceeding that of traditional CuO catalysts, while consuming less energy. This meets the practical needs of long-term continuous industrial operation and resolves the contradiction between treatment efficiency and energy consumption in traditional catalysts.

[0021] The catalyst of this invention avoids the drawbacks of high cost and susceptibility to poisoning associated with precious metal catalysts, while also overcoming the performance limitations of traditional copper oxide catalysts. This method is suitable for industrial exhaust gas treatment scenarios, meets environmental protection requirements, and offers advantages such as stable operation and controllable cost. It provides a feasible solution for the efficient purification of chlorine-containing volatile organic pollutants and has broad prospects for large-scale industrial application. Attached Figure Description

[0022] Figure 1 This is a scanning electron microscope (SEM) image of the sulfur-mediated copper oxide S-CuO catalyst in this invention; Figure 2 The activity test curve of the sulfur-mediated copper oxide S-CuO catalyst for the catalytic degradation of 1,2-dichloroethane in this invention is shown. Figure 3 This is the Raman spectrum of the sulfur-mediated copper oxide S-CuO catalyst in this invention; Figure 4 This is the fine Cu 2p X-ray photoelectron spectroscopy spectrum of the sulfur-mediated copper oxide S-CuO catalyst in this invention; Figure 5 This is the fine X-ray photoelectron spectroscopy (XPS) 1s spectrum of the sulfur-mediated copper oxide S-CuO catalyst in this invention. Figure 6 The X-ray photoelectron spectroscopy (XPS) fine spectra of the sulfur-mediated copper oxide (S-CuO) catalyst in this invention are shown in the S 2p and N 1s fine spectra. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] This invention provides a method for preparing a sulfur-mediated copper oxide (S-CuO) catalyst, the specific steps of which are as follows: Dissolve 0.01-0.03 mol of copper sulfate pentahydrate completely in a mixed solvent consisting of 80-120 mL of N,N-dimethylformamide and 30 mL of anhydrous ethanol, and stir at 400-600 rpm for 10-20 min to form a clear, transparent blue solution A. Add 0.02-0.06 mol of 2-aminoterephthalic acid to solution A and stir continuously until completely dissolved to obtain solution B; Under vigorous stirring (800-1000 rpm), 0.03-0.05 mol of 4,5-imidazolium dicarboxylic acid was rapidly added to solution B, and the stirring speed was increased to 1000-1200 rpm. The reaction was continued at room temperature for 2-4 hours until a large amount of precipitate was formed.

[0025] Centrifuge the above mixture at 4000-6000 rpm for 5-10 min, discard the supernatant, and wash the resulting precipitate 3-5 times with N,N-dimethylformamide and anhydrous ethanol respectively. The washed precipitate was dried in a vacuum drying oven at 70-90℃ for 8-12 hours to obtain precursor powder.

[0026] The obtained precursor powder was placed in a tube furnace or muffle furnace and heated to 400-500 °C at a rate of 1-3 °C / min under air or an inert atmosphere, and calcined at this temperature for 1-2 h. After calcination, the system was allowed to cool naturally to room temperature, and the sample was removed. The calcined sample was washed thoroughly with deionized water 4-6 times to remove any possible soluble byproducts. Finally, the sample was dried overnight at 80-100 °C to obtain the sulfur-mediated copper oxide (S-CuO) catalyst.

[0027] This invention promotes sulfur-mediated modulation of the original perfect structure of copper oxide by adding a chelating agent. Sulfur affects the acidity, redox capacity, and oxygen migration ability of the catalyst surface, causing lattice distortion of copper oxide (CuO) and the formation of low-coordination copper (Cu) sites and lattice distortion structure. The resulting copper oxide nanoparticles not only have a uniform particle morphology but also possess highly dispersed and uniformly distributed active sites, a stable copper-oxygen-sulfur (Cu-OS) structure, and an active local coordination environment. These structural advantages significantly promote the degradation efficiency of 1,2-dichloroethane. This sulfur-modified copper oxide (S-CuO) catalyst exhibits excellent oxidation performance of chlorinated volatile hydrocarbons at a reaction temperature of around 450℃ and a space velocity of 36000 mL·h. -1 ·g -1 Under conditions of 20% oxygen concentration, complete oxidative decomposition of 1,2-dichloroethane at a concentration of 1000 ppm can be achieved.

[0028] This invention synthesizes a sulfur-mediated copper oxide S-CuO catalyst via MOF derivatization. The sulfur-mediated strategy disrupts the intact structure of copper oxide, forming stable Cu-OS sites with highly dispersed and uniform active sites and active local coordination structures. The catalyst obtained in this invention exhibits highly dispersed active sites and demonstrates excellent degradation ability for chlorinated volatile organic compounds. Specific implementation schemes are as follows: Example 1: Sulfur-mediated copper oxide S-CuO catalyst (S-CuO) prepared by MOF derivatization method 0.02 mol of copper sulfate pentahydrate was completely dissolved in a mixed solvent consisting of 100 mL of N,N-dimethylformamide and 30 mL of anhydrous ethanol, and stirred at 500 rpm for 15 min to form a clear and transparent blue solution A. 0.05 mol of 2-aminoterephthalic acid was added to solution A and stirred continuously until completely dissolved to obtain solution B; Under vigorous stirring (900 rpm), 0.04 mol of 4,5-imidazolium dicarboxylic acid was rapidly added to solution B, and the stirring speed was increased to 1100 rpm. The reaction was continued at room temperature for 3 hours until a large amount of precipitate was formed.

[0029] The above mixture was centrifuged at 5000 rpm for 8 min, the supernatant was discarded, and the resulting precipitate was washed 5 times each with N,N-dimethylformamide and anhydrous ethanol. The washed precipitate was dried in a vacuum drying oven at 80 °C for 10 h to obtain precursor powder.

[0030] The obtained precursor powder was placed in a tube furnace or muffle furnace and heated to 450 °C at a programmed heating rate of 2 °C / min under air atmosphere, and calcined at this temperature for 1.5 h. After calcination, the system was allowed to cool naturally to room temperature, and the sample was removed. The calcined sample was washed thoroughly with deionized water five times to remove any possible soluble byproducts. Finally, the sample was dried overnight at 90 °C to obtain the sulfur-mediated copper oxide (S-CuO) catalyst.

[0031] Example 2: Sulfur-mediated copper oxide S-CuO catalyst (S-CuO) prepared by MOF derivatization method 0.01 mol of copper sulfate pentahydrate was completely dissolved in a mixed solvent consisting of 80 mL of N,N-dimethylformamide and 30 mL of anhydrous ethanol, and stirred at 400 rpm for 10 min to form a clear, transparent blue solution A. 0.02 mol of 2-aminoterephthalic acid was added to solution A and stirred continuously until completely dissolved to obtain solution B; Under vigorous stirring (800 rpm), 0.03 mol of 4,5-imidazolium dicarboxylic acid was rapidly added to solution B, and the stirring speed was increased to 1000 rpm. The reaction was continued at room temperature for 2 hours until a large amount of precipitate was formed.

[0032] The above mixture was centrifuged at 4000 rpm for 10 min, the supernatant was discarded, and the resulting precipitate was washed 5 times each with N,N-dimethylformamide and anhydrous ethanol. The washed precipitate was dried in a vacuum drying oven at 70 °C for 12 h to obtain precursor powder.

[0033] The obtained precursor powder was placed in a tube furnace or muffle furnace and heated to 400 °C at a rate of 1 °C / min under an inert atmosphere, and calcined at this temperature for 1 h. After calcination, the system was allowed to cool naturally to room temperature, and the sample was removed. The calcined sample was washed thoroughly with deionized water five times to remove any possible soluble byproducts. Finally, the sample was dried overnight at 80 °C to obtain the sulfur-mediated copper oxide S-CuO catalyst.

[0034] Example 3: Sulfur-mediated copper oxide S-CuO catalyst (S-CuO) prepared by MOF derivatization method 0.03 mol of copper sulfate pentahydrate was completely dissolved in a mixed solvent consisting of 120 mL of N,N-dimethylformamide and 30 mL of anhydrous ethanol, and stirred at 600 rpm for 20 min to form a clear and transparent blue solution A. Add 0.06 mol of 2-aminoterephthalic acid to solution A and stir continuously until completely dissolved to obtain solution B; Under vigorous stirring (1000 rpm), 0.05 mol of 4,5-imidazolium dicarboxylic acid was rapidly added to solution B, and the stirring speed was increased to 1200 rpm. The reaction was continued at room temperature for 4 hours until a large amount of precipitate was formed.

[0035] The above mixture was centrifuged at 6000 rpm for 5 min, the supernatant was discarded, and the resulting precipitate was washed 5 times each with N,N-dimethylformamide and anhydrous ethanol. The washed precipitate was dried in a vacuum drying oven at 90 °C for 8 hours to obtain precursor powder.

[0036] The obtained precursor powder was placed in a tube furnace or muffle furnace and heated to 500℃ at a programmed heating rate of 3℃ / min under air atmosphere, and calcined at this temperature for 2 hours. After calcination, the system was allowed to cool naturally to room temperature, and the sample was removed. The calcined sample was washed thoroughly with deionized water 5 times to remove possible soluble byproducts. Finally, the sample was dried overnight at 100℃ to obtain the sulfur-mediated copper oxide S-CuO catalyst.

[0037] Example 4 Activity test and evaluation of sulfur-mediated copper oxide S-CuO catalyst (S-CuO) for the catalytic degradation of 1,2-dichloroethane The solid powder obtained in Example 1 was compressed into tablets and sieved (40-60 mesh). 0.5 g of the sieved catalyst was accurately weighed. Using 1,2-dichloroethane as the probe gas, the concentration of the reactants was controlled at 1000 ppm, and the reaction space velocity was 36000 mL·h. -1 ·g -1 With an oxygen concentration of 20%, the catalytic activity of the catalyst was tested at different temperatures (90, 150, 200, 250, 300, 350, 400 and 450°C), and the reaction products were monitored and analyzed by gas chromatography.

[0038] Figure 2 The figure shows the activity test curves for the catalytic degradation of 1,2-dichloroethane on a sulfur-mediated copper oxide (S-CuO) catalyst. As can be seen from the figure, the sulfur-mediated copper oxide (S-CuO) catalyst exhibits excellent low-temperature degradation ability of 1,2-dichloroethane. A removal rate of 50% of 1,2-dichloroethane can be achieved at approximately 360℃, 90% at approximately 420℃, and 100% at approximately 450℃. The CuO / Cu catalyst prepared from copper acetate achieved removal rates of 50% and 90% of 1,2-dichloroethane at approximately 417℃ and approximately 447℃, respectively. 50 and T 90 The T values ​​were approximately 57 °C and 27 °C higher than those of the sulfur-mediated copper oxide S-CuO catalyst, respectively. The CuO-N catalyst prepared from copper nitrate achieved a 50% removal rate of 1,2-dichloroethane at approximately 450 °C. 50 The temperature is approximately 90°C higher than that of the sulfur-mediated copper oxide S-CuO catalyst. Neither the CuO / Cu catalyst nor the CuO-N catalyst can achieve 100% removal of 1,2-dichloroethane at 450°C.

[0039] Example 5: Microstructure analysis of sulfur-mediated copper oxide S-CuO catalyst (S-CuO) A small amount of the catalyst powder obtained in Example 1 was uniformly dispersed on the surface of the conductive adhesive and then sputtered with gold to enhance the conductivity of the sample. Using a scanning electron microscope, at accelerating voltages of 5-15 kV and magnifications of 5,000-100,000, the surface morphology and particle size distribution of the catalyst were observed and acquired to analyze its overall microstructure, particle morphology, and agglomeration state.

[0040] Figure 1 The image shows a scanning electron microscope (SEM) image of the sulfur-mediated copper oxide (S-CuO) catalyst. As can be seen from the image, the sulfur-mediated copper oxide (S-CuO) catalyst exhibits a porous, regular particulate structure and is highly dispersed. The highly dispersed active sites contribute to improving the reaction efficiency of 1,2-dichloroethane on the sulfur-mediated copper oxide (S-CuO) catalyst. The porous, regular particulate structure typically has a large specific surface area, which can, to some extent, increase the contact area between the active sites on the catalyst and the target pollutant. Therefore, the prepared sulfur-mediated copper oxide (S-CuO) catalyst has significant advantages in heterogeneous catalysis, especially in the catalytic degradation of volatile organic pollutants, and has potential advantages in the highly efficient catalysis of 1,2-dichloroethane.

[0041] Example 6 Molecular structure analysis of sulfur-mediated copper oxide S-CuO catalyst (S-CuO) Take a small amount of the catalyst powder obtained in Example 1 and press it firmly onto a glass slide. Use a confocal micro Raman spectrometer, selecting a laser with a wavelength of 532 nm or 785 nm as the excitation source, and set the laser power to 0.5-5 mW to avoid sample damage. Set the spectral acquisition range to 200 cm⁻¹. -1 -1000 cm -1 Exposure time is 10-30 seconds, with 2-4 exposures. The standard peak (520 cm⁻¹) of a single-crystal silicon wafer is used for both pre- and post-test measurements. -1 Perform instrument calibration.

[0042] Figure 3 The image shows the Raman spectrum of the sulfur-mediated copper oxide (S-CuO) catalyst. As can be seen from the image, the sulfur-mediated copper oxide (S-CuO) catalyst exhibits high Raman performance at 300 cm⁻¹. -1 Nearby A g Raman Peak, 340 cm -1 Nearby B g Raman Peak and 630 cm -1 Nearby B gThree characteristic Raman peaks were observed. Compared with CuO / Cu and CuO-N, the three Raman peaks of the sulfur-mediated copper oxide S-CuO catalyst all showed different degrees of blue shift, confirming that sulfur has a significant impact on the Cu-O structure in copper oxide, forming a stable Cu-OS structure. In addition, the Raman peak intensity of the sulfur-mediated copper oxide S-CuO catalyst decreased, indicating that some CuO exists in an amorphous and non-crystalline state, confirming that sulfur doping disrupts the original structure of copper oxide and forms a Cu-OS structure.

[0043] Example 7 Elemental and chemical state analysis of sulfur-mediated copper oxide S-CuO catalyst (S-CuO) The catalyst powder obtained in Example 1 was uniformly spread onto the double-sided conductive adhesive of a dedicated sample stage. Analysis was performed using an X-ray photoelectron spectroscopy (XPS) instrument equipped with a monochromatic Al Kα X-ray source (1486.6 eV). The tests were conducted under ultra-high vacuum conditions (better than 5 × 10⁻⁶ eV). -8 The process involves collecting the full spectrum (scanning range 0-1200 eV, pass energy 100 eV) to determine all elements on the surface; then, high-resolution narrow-spectrum scans (pass energy 20-30 eV) are performed on the core energy level regions such as C 1s, O 1s, Cu 2p, S 2p, and N 1s.

[0044] Figure 4 The X-ray photoelectron spectroscopy (XPS) of sulfur-mediated copper oxide (S-CuO) catalyst is shown in the fine Cu 2p spectrum. As can be seen from the figure, the valence state of Cu in the sulfur-mediated copper oxide (S-CuO) catalyst is similar to that of Cu-OS structure formed by sulfur, and the original valence state of Cu is not changed.

[0045] Figure 5 The image shows the fine 1s X-ray photoelectron spectroscopy (XPS) spectrum of the sulfur-mediated copper oxide (S-CuO) catalyst. As can be seen from the figure, the sulfur-mediated copper oxide (S-CuO) catalyst has the highest surface adsorbed oxygen content. Surface adsorbed oxygen is one of the most reactive oxygen species on the catalyst surface to CVOCs, and can react with and degrade CVOCs efficiently. The highest surface adsorbed oxygen content of the sulfur-mediated copper oxide (S-CuO) catalyst indicates that it has the strongest ability to activate oxygen, and thus has the best catalytic activity for 1,2-dichloroethane.

[0046] Figure 6 The image shows the fine S 2p X-ray photoelectron spectroscopy (XPS) spectrum of the sulfur-mediated copper oxide (S-CuO) catalyst. As can be seen from the image, sulfur in the sulfur-mediated copper oxide (S-CuO) catalyst successfully bonds with oxygen and copper to form a Cu-OS structure.

[0047] In summary, this invention successfully prepared a sulfur-mediated copper oxide (S-CuO) catalyst with a particulate Cu-OS structure via a metal-organic framework derivatization method, providing a novel technical route for the purification of chlorine-containing volatile organic compounds. Leveraging the structural advantages brought by sulfur doping, this catalyst breaks the original perfect lattice of copper oxide, forming a stable Cu-OS structure, highly dispersed and uniform active sites, an active local coordination structure, and structural defects such as low-coordination Cu sites and lattice distortion. These characteristics synergistically enhance the catalytic activity, enabling it to maintain its catalytic activity at approximately 450 °C and a space velocity of 36,000 mL·h⁻¹. -1 ·g -1 Under conditions of 20% oxygen concentration, complete oxidation of 1000 ppm 1,2-dichloroethane can be achieved, demonstrating excellent oxidation performance of chlorinated volatile hydrocarbons. The raw materials used in this invention are inexpensive, and the synthesis method and conditions are simple and easy to implement, requiring no complex equipment or harsh reaction environment. It balances purification efficiency, catalytic stability, and economy, while possessing strong industrial adaptability and promotion potential. This provides practical technical support for the low-cost and efficient treatment of chlorinated volatile alkane pollutants, and is of great significance for promoting technological upgrading and industrial application in the field of environmental governance.

Claims

1. A method for preparing a sulfur-mediated copper oxide (S-CuO) catalyst, characterized in that, The specific steps are as follows: Copper sulfate pentahydrate was dissolved in a mixed solvent of N,N-dimethylformamide and anhydrous ethanol and stirred to obtain solution A; 2-Aminoterephthalic acid was added to solution A and stirred to obtain solution B; Under vigorous stirring, 4,5-imidazolium dicarboxylic acid was rapidly added to solution B to obtain a mixture. The mixture was centrifuged, precipitated, washed, and dried to obtain the precursor powder. The precursor powder was calcined in air or an inert atmosphere, and after calcination, it was washed and dried to obtain a sulfur-mediated copper oxide (S-CuO) catalyst.

2. The method for preparing a sulfur-mediated copper oxide (S-CuO) catalyst according to claim 1, characterized in that, The specific steps for preparing solution A are as follows: Dissolve 0.01 mol to 0.03 mol of copper sulfate pentahydrate in a mixed solvent consisting of 80 mL to 120 mL of N,N-dimethylformamide and 30 mL of anhydrous ethanol, and stir at 400 rpm to 600 rpm for 10 to 20 minutes to obtain solution A.

3. The method for preparing a sulfur-mediated copper oxide (S-CuO) catalyst according to claim 1, characterized in that, 0.02 mol to 0.06 mol of 2-aminoterephthalic acid was added to solution A.

4. The method for preparing a sulfur-mediated copper oxide (S-CuO) catalyst according to claim 1, characterized in that, In the step of obtaining the mixture, 0.03 mol to 0.05 mol of 4,5-imidazolium dicarboxylic acid is rapidly added to solution B at 800 rpm to 1000 rpm, and the stirring speed is increased to 1000 rpm to 1200 rpm. The reaction is continued at room temperature for 2 to 4 hours to obtain the mixture.

5. The method for preparing a sulfur-mediated copper oxide (S-CuO) catalyst according to claim 1, characterized in that, In the process of obtaining the precursor powder, the mixture is centrifuged at 4000rpm-6000rpm for 5min-10min, the supernatant is discarded, and the precipitate is washed 3-5 times with N,N-dimethylformamide and anhydrous ethanol respectively. The washed precipitate is then dried at 70℃-90℃ for 8h-12h to obtain the precursor powder.

6. The method for preparing a sulfur-mediated copper oxide (S-CuO) catalyst according to claim 1, characterized in that, In the calcination step of the precursor powder, the temperature is raised to 400℃-500℃ at a heating rate of 1℃ / min-3℃ / min under air or an inert atmosphere, and the precursor powder is calcined at this temperature for 1h-2h.

7. The method for preparing a sulfur-mediated copper oxide (S-CuO) catalyst according to claim 1, characterized in that, After calcination, during the washing and drying steps, the calcined precursor powder is thoroughly washed with deionized water 4-6 times and dried overnight at 80℃-100℃.

8. A sulfur-mediated copper oxide S-CuO catalyst, characterized in that, It is prepared by any one of claims 1 to 7.

9. The application of the sulfur-mediated copper oxide (S-CuO) catalyst according to claim 8 in the treatment of chlorine-containing volatile organic pollutants, characterized in that, At approximately 420℃~450℃, with an oxygen concentration of 20% and a space velocity of 36000 mL... h -1 g -1 Under certain conditions, sulfur-mediated copper oxide S-CuO catalyst can achieve complete oxidation of 1,2-dichloroethane at 1000 ppm.

10. A method for purifying chlorine-containing volatile organic pollutants, characterized in that, The sulfur-mediated copper oxide (S-CuO) catalyst of claim 8 operates at approximately 420°C to 450°C, with an oxygen concentration of 20% and a space velocity of 36,000 mL. h -1 g -1 Under these conditions, complete oxidation of 1,2-dichloroethane to 1000 ppm can be achieved.

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