A manganese-ruthenium bimetallic mesoporous polystyrene microsphere photocatalyst, a preparation method thereof and application thereof in selective reduction of acetophenone to phenethyl alcohol

Abstract

The application discloses a manganese-ruthenium bimetallic mesoporous polystyrene microsphere photocatalyst, a preparation method thereof and application of the photocatalyst in selective reduction of acetophenone to prepare phenethyl alcohol. The catalyst takes mesoporous polystyrene microspheres as a carrier, has uniform etching holes distributed on the surface, uniformly loads manganese and ruthenium bimetallic active components on the surface through an in-situ oxidation-reduction deposition method, and forms a manganese-ruthenium heterostructure. Compared with a single metal loading system, the catalyst has significantly improved catalytic activity, reaction rate and stability, and has a wide application prospect in the fields of green organic synthesis, environmental pollutant detection and photoenergy-driven chemical conversion.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, specifically to a supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere photocatalyst, its preparation method, and its application in the selective reduction of acetophenone to phenylethanol. Background Technology

[0002] Phenylacetyl alcohol, with its mild rose aroma, is an important intermediate in the fragrance, food additive, pharmaceutical, and liquid crystal material industries. With the continued growth in related market demand, its green synthesis process has attracted increasing attention. Currently, industrially, phenylethanol is mainly produced using styrene oxidation or acetophenone chemical reduction methods. However, these methods often require high-pressure hydrogen, precious metal catalysts, or equivalent amounts of sodium borohydride as reducing agents, resulting in harsh reaction conditions, significant safety hazards, low atom economy, and large amounts of waste. Therefore, achieving efficient and highly selective catalytic synthesis of phenylethanol under mild conditions has significant industrial value and environmental implications.

[0003] Mesoporous polystyrene microspheres are a high-performance polymer carrier with advantages such as large specific surface area, tunable pore size, abundant surface functional groups, and good chemical stability. Mesoporous structures can be controllably introduced into their surface through solvent-induced swelling etching, forming open channels and high surface roughness, which is beneficial for the uniform loading of metal nanoparticles and facilitates the diffusion and mass transfer of reactant molecules. Conversely, non-open-pore dense microspheres, lacking interconnected mesoporous channels, have a significantly reduced specific surface area and fewer surface active sites, making noble metal nanoparticles prone to aggregation and resulting in poor loading uniformity, ultimately leading to weak electrochemical response signals and a significant decrease in enzyme-like catalytic activity. Building upon this, constructing a manganese-ruthenium bimetallic heterostructure in situ on the microsphere surface can further leverage the synergistic effect between the carrier and the bimetallic interface. Related inventions often use solid microspheres, and only a single active material can be assembled in a single surface layer, resulting in low metal loading and substrate mass transfer efficiency due to the lack of internal channels. Simultaneously, the detection modes only possess single-signal detection capabilities such as fluorescence, colorimetry / UV-Vis spectrophotometry, and separation immunoassay, lacking electrochemical response capabilities and the presence of bimetallic electronic synergy, making them susceptible to quantitative errors due to interference from biological matrices. In contrast, the mesoporous polystyrene microspheres obtained by solvent-induced etching in this invention possess interconnected channels, allowing for the in-situ loading of manganese and ruthenium bimetals on both the inner and outer surfaces to construct heterogeneous interfaces. Through metal synergy, differential pulsed voltammetric electrochemical signals and highly efficient peroxidase-like catalytic colorimetric signals are simultaneously generated, forming an electrochemical-UV dual-mode detection system. The two sets of signals can mutually calibrate to eliminate food matrix interference, significantly improving substrate contact efficiency and detection sensitivity, and solving problems related to structure, composition, detection modes, and application limitations. Summary of the Invention

[0004] To address the above technical problems, this invention provides a photocatalyst supported on manganese-ruthenium bimetallic mesoporous polystyrene microspheres, its preparation method, and its application in the selective reduction of acetophenone to phenethyl alcohol. The catalyst of this invention uses mesoporous polystyrene microspheres as a support and employs an in-situ redox growth strategy to support Mn... 2+ and Ru 3+ Bimetallic active sites are uniformly loaded on the surface and within the pores of the carrier, forming a stable heterogeneous interface.

[0005] The first objective of this invention is to provide a supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst, wherein the catalyst uses mesoporous polystyrene microspheres as a support and a manganese-ruthenium bimetallic heterojunction composite active layer supported on the surface of the support and inside the mesopores.

[0006] In some embodiments of the present invention, the molar ratio of manganese to ruthenium in the manganese-ruthenium bimetallic heterojunction composite active layer is 0.25:1 to 4:1.

[0007] A second objective of this invention is to provide a method for preparing the aforementioned supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst, comprising the following steps: Preparation of polystyrene microsphere suspension; An inert porogen is used to penetrate into the interior of polystyrene microspheres and induce polymer chain rearrangement, promoting the formation of mesoporous structures. Mesoporous polystyrene microspheres are obtained by static reaction. Mesoporous polystyrene microspheres were dispersed in a solvent, and manganese salt solution and ruthenium salt solution were added. The mixture was stirred continuously to allow the metal ions to diffuse and adsorb onto the surface and pores of the mesoporous polystyrene microspheres, thus obtaining a mixed solution. An oxidant was added to the resulting mixed solution to carry out a reduction reaction and obtain the supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst.

[0008] In some embodiments of the present invention, the ratio of polystyrene microspheres to toluene is 1:20 to 1:23; The concentration of the polystyrene microsphere suspension is 12–30 µg / mL; The solvent of the polystyrene microsphere suspension includes deionized water and ethanol, and the volume ratio of deionized water to ethanol is 5:0.8 to 8:0.8. The temperature for static reaction is 25–30 °C, and the reaction time is 8–12 h. The inert porogen includes one or more of toluene, dibutyl phthalate, toluene, cyclohexane, and n-heptane.

[0009] In some embodiments of the present invention, the mass ratio of mesoporous polystyrene microspheres, manganese salt, and ruthenium salt is 0.02:(0.0075-0.03):(0.01-0.04). The concentration ratio of the manganese salt solution to the ruthenium salt solution is (0.25~4):1.

[0010] In some embodiments of the present invention, the manganese salt is selected from manganese sulfate and / or manganese chloride; the ruthenium salt is selected from one or more of ruthenium chloride, ruthenium nitrite nitrate and ruthenium ammonium chloride.

[0011] In some embodiments of the present invention, the oxidant is selected from one or more of potassium permanganate, sodium borohydride, and sodium citrate; The final concentration of the oxidant is 0.1~1.0 mM.

[0012] In some embodiments of the present invention, the conditions for carrying out the redox reaction are: time of 30 to 120 min and temperature of 30 to 35 °C.

[0013] A third objective of this invention is to provide the application of the aforementioned supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst in the photocatalytic selective reduction of acetophenone to phenylethanol.

[0014] In some embodiments of the present invention, the wavelength of the light source for photocatalysis is 400–470 nm; The amount of the supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst is 10–20 mg / mL; The concentration of acetophenone in the photocatalytic reaction system is 0.1–1.0 mM.

[0015] The beneficial effects of this invention are as follows: Under visible light irradiation, the manganese-ruthenium bimetallic heterostructure is photoexcited to generate photogenerated electrons and holes. The built-in electric field formed by the bimetallic interface can effectively promote carrier separation. The pores of the mesoporous polystyrene can disperse active metal particles and enrich acetophenone substrate, shortening the molecular diffusion path. After the alcohol sacrificial agent in the system is oxidized by valence band holes, it releases protons and reducing equivalents to provide hydrogen source for the reaction. The carbonyl group of the acetophenone molecule diffuses to the surface of the active site preferentially accepts photogenerated electrons and undergoes single electron transfer to generate a ketone radical anion intermediate. Then, through a proton-coupled electron transfer process, hydrogen is gradually added, and the carbonyl group is selectively reduced to a secondary hydroxyl group to generate phenethyl alcohol.

[0016] The catalyst obtained in this invention uses mesoporous polystyrene microspheres as a support, with uniformly etched pores distributed on the surface. Manganese and ruthenium bimetallic active components are uniformly loaded onto the surface via in-situ redox deposition, forming a manganese-ruthenium heterostructure. This invention also discloses a method for preparing this catalyst, comprising three steps: mesoporous microsphere preparation, metal ion adsorption, and redox deposition. The conditions are mild and the operation is simple. This catalyst exhibits excellent synergistic catalytic effects in photocatalytic reactions. Compared with single-metal supported systems, the catalyst of this invention significantly improves catalytic activity, reaction rate, and stability, and has broad application prospects in green organic synthesis, environmental pollutant detection, and photo-driven chemical conversion.

[0017] This invention prepares a mesoporous polystyrene microsphere catalyst with a surface-supported manganese-ruthenium bimetallic heterostructure for the photocatalytic reduction of acetophenone. The significance of this work lies in three aspects: first, by studying the interfacial synergistic mechanism between the support and the bimetal, it provides a theoretical reference for the design of novel photocatalytic materials; second, it achieves a simple preparation of a high-performance heterogeneous photocatalyst using a mild in-situ redox deposition method; and third, under ambient temperature and pressure and ultraviolet light irradiation, this catalyst can achieve a yield of over 95% in the reduction of acetophenone to phenylethanol, and it is easy to recycle and reuse, aligning with the direction of green chemistry, and is also expected to be applied to other aromatic ketone reduction and phenol-containing wastewater treatment scenarios. Attached Figure Description

[0018] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein... Figure 1 The images show electron microscope (EM) images of the polystyrene microspheres and the mesoporous polystyrene microsphere-supported manganese-ruthenium bimetallic heterostructure catalyst MesPS@Mn-Ru obtained in Example 1 of this invention.

[0019] Figure 2 The X-ray photoelectron spectroscopy (XPS) spectrum of the mesoporous polystyrene microsphere-supported manganese-ruthenium bimetallic heterostructure catalyst MesPS@Mn-Ru obtained in Example 1 of this invention is shown.

[0020] Figure 3 Comparison of UV detection values ​​of catalysts prepared under different optimized conditions; sub-figures (A), (B), and (C) correspond to different Mn values, respectively. 2+ / Ru 3+ UV detection data of samples under different feeding ratios, different final concentrations of potassium permanganate, and different reduction reaction times.

[0021] Figure 4 Lineweaver-Burk double inverse plots for different metals with different ratio loads.

[0022] Figure 5The results are liquid chromatography results for different light source wavelengths, where sub-graphs (A), (B), and (C) correspond to wavelengths of 400 nm, 470 nm, and simulated sunlight, respectively.

[0023] Figure 6 This is a fitted curve of peak area and concentration of acetophenone in liquid chromatography. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0025] Example 1 This embodiment provides a supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst, its preparation method, and its application. I. The preparation method of the supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst is as follows: 1. Preparation of polystyrene microspheres S11. The initiator azobisisobutyronitrile, the dispersant polyvinylpyrrolidone and styrene monomer are dispersed in a dispersion medium (a mixed solvent of ethylene glycol methyl ether and ethanol) and mixed to obtain a mixed solution; wherein the mass ratio of the styrene monomer, dispersant, initiator and dispersion medium is 10:2:0.14:51.56, and the mass ratio of ethylene glycol methyl ether and ethanol is 23.16:28.4.

[0026] S12. Pour the mixed solution into a single-necked flask, stir well, and introduce nitrogen gas into it for 30 min (connect the nitrogen gas delivery tube to the 1 mL pipette tip, insert it to the bottom of the liquid surface, and the gas flow rate is 50 mL / min). Then, tighten the stopper and seal the flask with plastic film to prevent air from entering.

[0027] S13. Heat to 70 °C, maintain stirring speed at 300 r / min, react for 24 h to obtain polystyrene microsphere solution. Wash with ethanol by centrifugation at 3000 r / min for 5 minutes, and finally dry under vacuum at 40 °C to obtain polystyrene microsphere powder.

[0028] 2. Preparation of polymesoporous styrene microspheres S21: Weigh 0.2 g of polystyrene microsphere powder and disperse it evenly in a mixed solvent system consisting of 5.0 mL of deionized water and 8.0 mL of ethanol.

[0029] S22: Slowly add 500 µL of toluene under continuous stirring, and let it stand at 35 °C for 1 h to allow the toluene to penetrate into the interior of the polystyrene microspheres and perform pore etching to form a mesoporous structure.

[0030] S23: After the reaction is complete, the mixture is dried in an isothermal environment and washed repeatedly with alternating ethanol and deionized water to remove residual organic solvents and unreacted substances, thereby obtaining structurally stable and surface-clean mesoporous polystyrene microspheres.

[0031] 3. Metal ion adsorption S31: The 0.2 g mesoporous polystyrene microspheres prepared in step 2 were redispersed in 10 mL of deionized water and a uniform and stable suspension was obtained by ultrasonic treatment.

[0032] S32: Add 0.2 mM manganese sulfate solution and 0.2 mM ruthenium chloride solution to the system, controlling the volume ratio of the two to be 1:1. Stir continuously at 200 rpm for 1 h at 35 °C to allow Mn to form. 2+ and Ru 3+ It diffuses and adsorbs fully onto the surface and inside the pores of mesoporous polystyrene microspheres.

[0033] 4. Redox Deposition S41: After the adsorption of metal ions reaches equilibrium, potassium permanganate solution is slowly added dropwise to the system, and the final concentration of potassium permanganate in the system after the addition is controlled to be 0.50 mM.

[0034] S42: An isothermal redox reaction was carried out at 35 °C for 60 min to allow manganese and ruthenium components to be synergistically deposited on the surface of mesoporous polystyrene microspheres, gradually forming a stable manganese-ruthenium composite active layer.

[0035] S43: After the reaction was completed, the product was collected by centrifugation and repeatedly washed with deionized water to remove unbound metal ions and byproducts. After purification, the mesoporous polystyrene microsphere-supported manganese-ruthenium bimetallic heterostructure catalyst MesPS@Mn-Ru was obtained.

[0036] II. Application: Photocatalytic selective reduction of acetophenone to phenylethanol S1 Weigh 10 mg of the prepared mesoporous polystyrene microsphere-supported manganese-ruthenium bimetallic heterostructure catalyst, add it to a methanol / water mixed solution (v:v=35:65) containing 0.1 mmol acetophenone, disperse it evenly by ultrasonication, and then place it in a light-protected reactor.

[0037] S2 was reacted at room temperature and atmospheric pressure under 400 nm ultraviolet light for 10 min. After the reaction, the catalyst was separated by centrifugation, and the supernatant was filtered and analyzed by liquid chromatography.

[0038] In the S3 liquid chromatography detection procedure, a C18 reversed-phase column (250 mm × 4.6 mm, 5 μm) was used with an acetonitrile-water mixture as the mobile phase, and separation was performed in isocratic elution mode. The detection wavelength was 254 nm. The mobile phase volume ratio was methanol:water = 35:65, the flow rate was 1.0 mL / min, the column temperature was 25 ℃, and the injection volume was 10 μL. The retention time of phenylethanol was 7 min. Samples were filtered through a 0.45 μm filter membrane before testing, and the column was flushed with a high proportion of organic phase for maintenance after testing. Experimental results are shown below. Figure 6 , Figure 6 The figure shows the fitting curve of phenylethanol concentration versus liquid chromatography peak area. As can be seen from the figure, the peak area of ​​phenylethanol exhibits a good linear relationship with the product concentration. Based on this fitting equation, the phenylethanol content can be accurately calculated from the sample peak area. This also shows that the complete set of chromatographic parameters, such as methanol-water isocratic elution and 254 nm detection wavelength, are suitable for the separation and quantification of phenylethanol. The stable retention time of 7 min proves that the target analyte is well separated with little interference from extraneous peaks, and can be stably used for the batch quantitative analysis of phenylethanol products in photocatalytic reactions.

[0039] Example 2 The preparation method of the supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst in this embodiment is similar to that in Example 1, the difference is that: in step 3, S32 for metal ion adsorption, manganese sulfate and ruthenium chloride solutions with different concentration ratios are added to the system, wherein the concentration ratios are 2:1, 0.25:1, and 4:1, respectively.

[0040] Example 3 The preparation method of the supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst in this embodiment is similar to that in Example 1, except that: different concentrations of potassium permanganate solution are added to the S41 redox deposition in step 4 of the first part, with concentrations of 0.1, 0.25, 0.5, 0.75, and 1.0 mM.

[0041] Example 4 The preparation method of the supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst in this embodiment is similar to that in Example 1, the difference is that the isothermal redox reaction time of S42 in step 4 of the first part is 30, 90 and 120 min respectively.

[0042] Example 5 This embodiment provides an experiment to optimize the catalytic performance of different light sources. It is the same as Example 1, except that in the second part of the application, step S2 is replaced with ultraviolet light irradiation reaction with different wavelengths (470 nm and simulated sunlight).

[0043] Comparative Example 1 The preparation method of the supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst in this comparative example is similar to that in Example 1, except that steps 3 and 4 are omitted, and mesoporous polystyrene microspheres PS MPs are finally obtained.

[0044] Comparative Example 2 The preparation method of the supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst in this comparative example is similar to that in Example 1, except that ruthenium chloride solution is not added to S32 during metal ion adsorption in step 3; finally, MesPS@Mn is obtained.

[0045] Comparative Example 3 The preparation method of the supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst in this comparative example is similar to that in Example 1, except that manganese sulfate solution is not added to S32 during metal ion adsorption in step 3; finally, MesPS@Ru is obtained.

[0046] Comparative Example 4 The preparation method of the supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst in this comparative example is similar to that in Example 2, except that the concentration ratio of manganese sulfate to ruthenium chloride solution is 0.5:1.0.

[0047] Characterization and performance testing 1. The MesPS@Mn-Ru catalyst obtained in Example 1 was structurally characterized, as detailed in the following figures. Figure 1 and Figure 2 ,Depend on Figure 1 The SEM images show that the prepared PS MPs and MesPS@Mn-Ru are spherical, uniform in size, and have a large number of interconnected mesopores on their surfaces. Figure 2 The XPS spectra show that the Mn 2p spectrum appears at 642 eV and 654 eV. 3+ Corresponding 2p 3 / 2 2p 1 / 2 Characteristic peaks; Ru 3p spectrum shows at 462 eV and 484 eV. 4+ Corresponding 3p 3 / 2 3p 1 / 2 Characteristic peaks confirmed that the active components Mn and Ru were successfully loaded onto the surface of mesoporous polystyrene microspheres, with Mn mainly present as Mn. 3+ Ru mainly uses Ru 4+ Oxidized state exists. The oxidation of the manganese-ruthenium bimetallic components onto the surface of the mesoporous microspheres was successfully confirmed. The two figures together fully demonstrate that this method can stably synthesize mesoporous polystyrene composite microspheres loaded with Mn-Ru bimetals.

[0048] 2. The MesPS@Mn-Ru catalysts obtained in Examples 1-4 and the catalyst obtained in Comparative Example 1 were subjected to ultraviolet spectroscopy. The experimental results are shown in [Figure 1]. Figure 3The effects of Mn / Ru molar ratio, potassium permanganate dosage, and reduction reaction time on the catalytic performance of the material for generating peroxidase were investigated, with the intensity of the oxTMB characteristic UV absorption peak near 652 nm used as the evaluation index. As shown in the figure, a Mn:Ru ratio of 2:1 is the optimal metal ratio, where the bimetallic heterogeneous synergistic effect is strongest. The UV absorbance reaches its peak when the concentration of KMnO4 added is 0.50 mM. The absorbance reaches its highest value at a reaction time of 120 min, indicating that a longer reduction time allows for sufficient in-situ metal reduction and the construction of a complete and compact Mn-Ru heterostructure, significantly improving the substrate catalytic conversion efficiency. The results of these three sets of variables jointly determine the optimal preparation process: a Mn / Ru molar ratio of 2:1, a KMnO4 dosage of 0.50 mM, and a reaction time of 120 min. Under these conditions, the material exhibits the strongest catalytic ability to generate oxTMB, corresponding to the highest UV absorption signal.

[0049] 3. The MesPS@Mn-Ru catalyst obtained in Example 1 and Comparative Examples 1-3 were subjected to catalytic testing using actual samples. The experimental results are shown in [Figure 1]. Figure 4 Figure 1 shows the Lineweaver-Burk double reciprocal curves for mesoporous microspheres loaded with different metals. As can be seen from the figure, the slope and intercept of the line for pure polystyrene microspheres (PSMPs) without metal loading are the largest, corresponding to the weakest catalytic activity. The catalytic activity of mesoporous microspheres loaded with single manganese (MesPS@Mn) and single ruthenium (MesPS@Ru) are significantly improved, and the catalytic performance of the single ruthenium system is better than that of the single manganese system. The slope and intercept of the line for the manganese-ruthenium bimetallic loaded MesPS@Mn-Ru are the smallest among the four groups, corresponding to the highest maximum reaction rate Vmax, the smallest Michaelis constant Km, and the strongest affinity for the substrate. This fully demonstrates that the Mn-Ru bimetallic heterostructure produces a significant synergistic catalytic effect, and the optimal peroxidase-like catalytic performance is achieved by combining the mass transfer advantages of the mesoporous support.

[0050] 4. The MesPS@Mn-Ru catalyst obtained in Example 1 was subjected to catalytic testing on actual samples. The experimental results are shown in [Figure 1]. Figure 5 The figures show the liquid chromatograms catalyzed by three different light sources. As can be seen from the figures, the yield of phenylethanol reached over 95% under irradiation with 400 nm and 470 nm light, while the yield was only 15% under simulated sunlight. This indicates that the photocatalytic reduction performance of this manganese-ruthenium bimetallic mesoporous polystyrene catalyst has a significant wavelength dependence. It has excellent photoresponse activity under visible light in the blue-violet band and can efficiently drive the selective reduction reaction of acetophenone.

[0051] 5. Construction of fitting curves for peak area and phenylethanol concentration in liquid chromatography. Accurately weigh 1222 mg of phenylethanol standard, dissolve it completely in chromatographically pure methanol, and dilute to 100 mL in a volumetric flask. Shake well to prepare a 100 mM standard stock solution. Seal and store at 4 °C protected from light.

[0052] A series of working solutions of different concentrations were prepared using a stepwise dilution method: different volumes of standard stock solutions were transferred and diluted to volume with methanol-water solution (consistent with the mobile phase, methanol:water = 35:65), setting up 7 concentration gradients (10, 20, 30, 40, 50, 60, 70 mM); all working solutions were filtered through a 0.45 µm organic filter membrane and then transferred to liquid chromatography vials for analysis.

[0053] Liquid chromatography was used for detection. A C18 reversed-phase column with a specification of 250 mm × 4.6 mm and a packing particle size of 5 µm was used. Isocratic elution was performed using a methanol-water mixture with a volume ratio of 35:65 as the mobile phase. The detection wavelength was set at 254 nm, the mobile phase flow rate was 1.0 mL / min, the column temperature was 25 ℃, and the single injection volume was 10 μL. After the baseline of the chromatographic system stabilized, the standard working solutions were injected sequentially in order of increasing concentration. Each concentration level was injected in parallel three times, and the peak area of ​​the corresponding phenylethanol chromatographic peak was recorded.

[0054] Standard curve plotting and data processing. Using the concentration of the standard working solution as the x-axis and the average peak area as the y-axis, a linear regression was performed, yielding the linear equation y = 38082x – 277781, with a correlation coefficient R0. 2 A value ≥0.99 indicates that the method exhibits good linearity within the set concentration range, providing a basis for subsequent calculation of the corresponding phenylethanol concentration by substituting the sample peak area.

[0055] The embodiments described above are merely preferred embodiments for fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A catalyst supported on manganese-ruthenium bimetallic mesoporous polystyrene microspheres, characterized in that, The catalyst uses mesoporous polystyrene microspheres as a carrier and a manganese-ruthenium bimetallic heterojunction composite active layer loaded on the surface of the carrier and inside the mesopores.

2. The supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst according to claim 1, characterized in that, The molar ratio of manganese to ruthenium in the manganese-ruthenium bimetallic heterojunction composite active layer is 0.25:1 to 4:

1.

3. A method for preparing a supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst as described in claim 1 or 2, characterized in that, Includes the following steps: Preparation of polystyrene microsphere suspension; An inert porogen is used to penetrate into the interior of polystyrene microspheres and induce polymer chain rearrangement, promoting the formation of mesoporous structures. Mesoporous polystyrene microspheres are obtained by static reaction. Mesoporous polystyrene microspheres were dispersed in a solvent, and manganese salt solution and ruthenium salt solution were added. The mixture was stirred continuously to allow the metal ions to diffuse and adsorb onto the surface and pores of the mesoporous polystyrene microspheres, thus obtaining a mixed solution. An oxidant was added to the resulting mixed solution to carry out a reduction reaction and obtain the supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst.

4. The preparation method according to claim 3, characterized in that, The ratio of polystyrene microspheres to toluene is 1:20 to 1:23; The concentration of the polystyrene microsphere suspension is 12–30 mg / mL; The solvent of the polystyrene microsphere suspension includes deionized water and ethanol, and the volume ratio of deionized water to ethanol is 5:0.8 to 8:0.

8.

5. The preparation method according to claim 3, characterized in that, The temperature for static reaction is 25–30 °C, and the static reaction time is 8–12 h. The inert porogen includes one or more of toluene, dibutyl phthalate, toluene, cyclohexane, and n-heptane.

6. The preparation method according to claim 3, characterized in that, The mass ratio of mesoporous polystyrene microspheres, manganese salt, and ruthenium salt is 0.02:(0.0075–0.03):(0.01–0.04). The concentration ratio of the manganese salt solution to the ruthenium salt solution is (0.25~4):1; Manganese salts are selected from manganese sulfate and / or manganese chloride; The ruthenium salt is selected from one or more of ruthenium chloride, ruthenium nitrite nitrate, and ruthenium ammonium chloride.

7. The preparation method according to claim 3, characterized in that, The oxidant is selected from one or more of potassium permanganate, sodium borohydride and sodium citrate; The final concentration of the oxidant is 0.1–1.0 mM; Conditions for redox reactions: time 30–120 min, temperature 30–35 ℃.

8. The application of the supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst according to claim 1 or 2 in the photocatalytic selective reduction of acetophenone to phenethyl alcohol.

9. The application according to claim 7, characterized in that, The light source wavelength for photocatalysis is 400–470 nm; The amount of the supported manganese-ruthenium bimetallic mesoporous polystyrene microsphere catalyst is 10–20 mg / mL; The concentration of acetophenone in the photocatalytic reaction system is 0.1–1.0 mM.

Images