Bimetal alkene catalyst and application thereof
By using bimetalene catalysts, the electronic structure of the Pd-based alloy surface and the multi-layer nanosheet structure is constructed, the problem of poor catalyst stability is solved, and high-efficiency and low-energy consumption sulfur-rich wastewater treatment is achieved.
Patent Information
- Application Number
- CN202510341322.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-21
- Publication Date
- 2025-07-11
AI Technical Summary
In the prior art, when treating sulfur-rich wastewater, the catalyst stability is poor, resulting in excessive energy consumption of electrolytic water, and the existing methods are costly and inefficient.
Bimetalene catalyst is used, which contains oxygen on the surface of the Pd-based alloy, and regulates the electronic structure to make it in a positive charge state, enhancing the adsorption strength to the intermediate. The catalyst is composed of a multi-layer nanosheet layer and has high electrocatalytic activity and stability.
The electrocatalytic activity and stability of the catalyst are improved, the energy consumption of electrolyzed water is reduced, and the possibility of treatment scale is expanded.
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Figure CN120285985A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical fields of nanomaterials and electrocatalysis, and particularly relates to a bimetallicene catalyst and its application.
Background Art
[0002] Sulfur-rich wastewater is generated by absorbing a large amount of H2S waste gas with an alkaline solution, and it is highly toxic. Although there are currently many methods such as chemical precipitation, oxidation, and biochemical methods to treat sulfur wastewater, the above methods have the disadvantages of high cost, high energy consumption, and low efficiency. The electrochemical method can treat sulfur-containing wastewater at room temperature, and this method is simple and easy to control, so it is conducive to large-scale expansion. At the same time, the potential of the sulfur oxidation reaction (SOR) under the reversible hydrogen electrode is as low as 0.142V, which is much lower than the potential of the anodic oxygen evolution reaction (1.23V) in water electrolysis. Therefore, SOR can replace the anodic oxygen evolution reaction and then be coupled with the cathodic hydrogen evolution reaction to solve the problem of excessive energy consumption in water electrolysis caused by the slow reaction kinetics of the oxygen evolution reaction. However, due to the strong binding characteristics of sulfides to metal electrodes, the metal electrodes are prone to passivation and corrosion during the SOR process, resulting in poor catalyst stability. Therefore, there is an urgent need to develop catalysts with high activity and high stability.
Summary of the Invention
[0003] The purpose of the present application is to provide a bimetallicene catalyst with good catalytic activity and stability.
[0004] To achieve the above purpose, an embodiment of the present application adopts the following technical solution:
[0005] A bimetallicene catalyst, the composition of the bimetallicene catalyst includes a Pd-based alloy, and the surface of the Pd-based alloy contains oxygen.
[0006] In the above technical solution, the composition of the bimetallicene catalyst includes a Pd-based alloy, and the surface of the Pd-based alloy contains oxygen. The oxygen contained on the surface can regulate the electronic structure of the Pd-based alloy surface, making its surface in a positively charged state, thereby increasing the position of the d-band center of the Pd-based alloy and enhancing the adsorption strength of the Pd-based alloy for intermediates during the electrocatalytic reaction process, making the bimetallicene catalyst have high electrocatalytic activity and stability.
[0007] An application of a bimetallicene catalyst, the bimetallicene catalyst is applied to the anodic sulfur oxidation reaction.
[0008] In the above technical solution, the composition of the bimetallene catalyst includes a Pd-based alloy. The surface of the Pd-based alloy contains oxygen, and the oxygen contained on the surface can regulate the electronic structure of the surface of the Pd-based alloy, making the surface of the Pd-based alloy in a positively charged state. Furthermore, the position of the d-band center of the Pd-based alloy is increased, and the adsorption of intermediates during the sulfur oxidation catalytic reaction of the Pd-based alloy is enhanced, making the bimetallene catalyst have high electrocatalytic activity and stability.
Description of the Drawings
[0009] Figure 1 It is the XRD pattern of p-PdMo obtained in Example 1 of this application and PdMo obtained in Comparative Example 1;
[0010] Figure 2 It is the XPS pattern of p-PdMo obtained in Example 1 of this application;
[0011] Figure 3 It is the schematic structural diagram of the surface of p-PdMo obtained in Example 1 of this application containing oxygen;
[0012] Figure 4 It is the AFM pattern of p-PdMo obtained in Example 1 of this application;
[0013] Figure 5 It is the TEM pattern of p-PdMo obtained in Example 1 of this application;
[0014] Figure 6 It is the linear sweep voltammetry (LSV) pattern of p-PdMo obtained in Example 1 of this application and PdMo obtained in Comparative Example 1 in 1M NaOH + 3M Na2S electrolyte;
[0015] Figure 7 It is the Tafel pattern of p-PdMo obtained in Example 1 of this application and PdMo obtained in Comparative Example 1;
[0016] Figure 8 It is the LSV pattern of p-PdMo obtained in Example 1 of this application in solutions with different concentrations of Na2S;
[0017] Figure 9 It is the relationship diagram of reaction time and current density of p-PdMo obtained in Example 1 of this application at different voltages;
[0018] Figure 10 It is the UV-vis pattern of the solution of p-PdMo obtained in Example 1 of this application after reacting for one hour at different voltages;
[0019] Figure 11 It is the double-layer capacitance (C dl ) pattern of p-PdMo obtained in Example 1 of this application and PdMo obtained in Comparative Example 1;
[0020] Figure 12 It is the comparison diagram of the anodic LSV of p-PdMo obtained in Example 1 of this application before and after 5000 cycles of CV;
[0021] Figure 13 It is the anodic stability test diagram of p-PdMo obtained in Example 1 of this application.
Specific Embodiments
[0022] The present application will be further described below in conjunction with the accompanying drawings and specific embodiments:
[0023] In order to enable those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present application.
[0024] A bimetallicene catalyst, the composition of the bimetallicene catalyst includes a Pd-based alloy, the surface of the Pd-based alloy contains oxygen, and the oxygen contained on the surface can regulate the electronic structure of the surface of the Pd-based alloy, making the surface of the Pd-based alloy in a positively charged state, thereby increasing the position of the d-band center of the Pd-based alloy and enhancing the adsorption of intermediates by the Pd-based alloy during the electrocatalytic reaction, so that the bimetallicene catalyst has high electrocatalytic activity and stability. The above Pd-based alloy includes one of PdMo alloy, PdFe alloy, PdMn alloy, PdCu alloy, PdZn alloy, PdW alloy and PdNi alloy.
[0025] The morphological structure of the bimetallic catalyst includes at least two layers of nanosheet layers 1, and there is a spacing between adjacent nanosheet layers 1. When the bimetallic catalyst is applied to an electrocatalytic reaction, the electrocatalytic reaction solution can be localized between adjacent nanosheet layers 1, increasing the concentration of the electrocatalytic reaction solution at the local sites and enhancing the kinetics of the electrocatalytic reaction, thereby enhancing the electrocatalytic activity of the bimetallicene catalyst. The layer spacings of at least two nanosheet layers are not equal, the layer spacing is 1-10 nanometers, the capacity of the electrocatalytic reaction solution localized between the two nanosheet layers is different, and thus there is concentration polarization, which promotes the directional migration of the reaction solution under the action of an electric field and is beneficial to the catalytic activity.
[0026] The thickness of nanosheet layer 1 is 1.2 - 2.4 nm. The small thickness of nanosheet layer 1 is beneficial to increasing the number of exposed atoms of the Pd-based alloy, thereby increasing the number of reactive sites and endowing the bimetallicene catalyst with good electrocatalytic activity. The surface of nanosheet layer 1 has pores, which further increase the number of exposed atoms of the Pd-based alloy, thereby increasing the number of reactive sites and endowing the bimetallicene catalyst with good electrocatalytic activity. Secondly, the pores reduce the coordination number of the atoms of the Pd-based alloy and enhance the ability of the atoms to adsorb reactants and intermediates, thus improving the electrocatalytic activity. The diameter of the pores is 3 - 10 nm, enabling the Pd-based alloy to expose an appropriate amount of low-coordination atoms. On the one hand, it endows the bimetallicene catalyst with good ability to adsorb intermediates and reactants; on the other hand, it ensures the mass activity of the bimetallicene catalyst.
[0027] Nanosheet layer 1 is in a wrinkled or curled shape, which can prevent the aggregation or overlap between nanosheet layers 1 and is beneficial to the exposure of the reactive sites of the Pd-based alloy. The strain of the bimetallicene catalyst is 0.2% - 2%. The overlap of the electron clouds of the Pd-based alloy atoms is weakened, the d-band center position is increased, the adsorption of intermediates during the electrocatalytic reaction process is enhanced, and high electrocatalytic activity is achieved.
[0028] Example 1
[0029] The preparation method of the bimetallicene catalyst includes:
[0030] Mix 0.033 mmol of palladium acetylacetonate, 0.02 mmol of molybdenum hexacarbonyl, 0.185 mmol of ascorbic acid and 5 ml of oleylamine, stir evenly to obtain a mixed solution, place it in a reaction kettle and hydrothermally heat at 80 °C for 12 h to obtain PdMo. Cool PdMo to room temperature, wash it 3 times alternately with ethanol and water, and dry it in an oven at 50 °C for 4 hours;
[0031] Disperse the obtained PdMo and 0.03 mmol of ammonium bromide in 5 ml of cyclohexane, then expose the solution to air and heat it at 45 °C for 20 h to obtain p-PdMo.
[0032] Comparative Example 1
[0033] Mix 0.033 mmol of palladium acetylacetonate, 0.02 mmol of molybdenum hexacarbonyl, 0.185 mmol of ascorbic acid and 5 ml of oleylamine, stir evenly to obtain a mixed solution, place it in a reaction kettle and hydrothermally heat at 80 °C for 12 h to obtain a sample PdMo. Cool the sample to room temperature, wash it 3 times alternately with ethanol and water, and dry it in an oven at 50 °C for 4 hours to obtain PdMo;
[0034] The specifications and manufacturers of the above reagents are as follows:
[0035]
[0036] Figure 1 This is the X-ray diffraction (XRD) pattern of p-PdMo obtained in Example 1 of the present invention. Figure 1 In the figure, the horizontal axis represents the X-ray diffraction angle, and the vertical axis represents the X-ray diffraction intensity. PdMo metalene exhibits three characteristic XRD peaks at 39.97°, 46.48°, and 67.93°, slightly lower than those of pure Pd crystals, respectively pointing to the (111), (200), and (220) crystal planes of the typical face-centered cubic Pd structure (Joint Committee on Powder Diffraction Standards (JCPDS) No. 46-1043). The diffraction peaks of PdMo metalene are shifted to the left compared to those of the standard Pd, indicating that the lattice expands after alloying, causing the peaks to shift to the left. In addition, after heat treatment with ammonium bromide, the obtained porous PdMo shows a further left shift of the peaks compared to PdMo, indicating that the introduction of porous defects increases the interatomic distance, generates tensile strain, and leads to the left shift of the diffraction peaks. This confirms the successful preparation of p-PdMo.
[0037] Figure 2 These are the X-ray photoelectron spectroscopy (XPS) diagrams of p-PdMo obtained in Example 1 of the present invention. It can be seen from the figure that in addition to Pd and Mo elements, there is also O element on the surface of p-PdMo. This is mainly because oxygen in the air also participates in the reaction during the etching process. While holes are formed on the surface of PdMo metalene, some oxygen atoms remain in the atomic gaps or hollow sites, as Figure 3 shown. The remaining oxygen atoms will attract electrons from the Pd sites, causing Pd to be in an electron-deficient state and the d-band center to shift upward, thereby enhancing the strength of the intermediate during the SOR process adsorbed on the metalene surface and ultimately improving the catalytic activity of PdMo for SOR.
[0038] Figure 4 and Figure 5 These are the atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM) diagrams of p-PdMo obtained in Example 1 of the present invention. It can be seen from Figure 5 that the morphological structure of p-PdMo is a flaky structure, and the thickness of the nanosheet layer 1 is about 1.2 - 2.4 nanometers ( Figure 4) The thickness of the nanosheets 1 is small, which is conducive to increasing the number of exposed atoms of the Pd-based alloy, thereby increasing the number of reactive sites and endowing the bimetallicene catalyst with good electrocatalytic activity. The surface of the nanosheets 1 has pores, which further increases the number of exposed atoms of the Pd-based alloy, thereby increasing the number of reactive sites and making the bimetallicene catalyst have good electrocatalytic activity. Secondly, it reduces the coordination number of the atoms of the Pd-based alloy and enhances the ability of the atoms to adsorb reactants and intermediates, thus improving the electrocatalytic activity. The diameter of the pores is 3-10 nanometers, which exposes an appropriate amount of low-coordination atoms of the Pd-based alloy. On the one hand, it enables the bimetallicene catalyst to have good ability to adsorb intermediates and reactants; on the other hand, it ensures the mass activity of the bimetallicene catalyst. The nanosheets 1 are wrinkled or curled, which can prevent the aggregation or overlap between the nanosheets 1 and is conducive to the exposure of the reactive sites of the Pd-based alloy. The strain of the bimetallicene catalyst is 0.2%-2%, the overlap of the electron clouds of the Pd-based alloy atoms is weakened, the d-band center position is increased, the adsorption of intermediates during the electrocatalytic reaction is enhanced, and high electrocatalytic activity is achieved.
[0039] From Figure 6 It can be seen that the overpotential of PdMo obtained in Comparative Example 1 at 10 mA cm -2 is 367 mV. After ammonium bromide etching, the overpotential of p-PdMo at 10 mA cm -2 is 325 mV. The overpotential of p-PdMo is less than that of PdMo because the etched nanosheets have a larger specific surface area and more exposed active sites. This indicates that etching the PdMo bimetallicene has a positive effect on improving the SOR performance.
[0040] From Figure 7 It can be seen that the Tafel slope of p-PdMo obtained in Example 1 is 97.58 mV dec -1 , which is lower than 116.9 mV dec of PdMo obtained in Comparative Example 1 -1 . The Tafel of p-PdMo is less than that of PdMo because the d-band center of Pd in p-PdMo shifts upward, enhancing the adsorption of intermediates during the electrocatalytic reaction and accelerating the electron transfer rate of the catalyst. This shows that the reaction kinetics of the etched PdMo bimetallicene is higher, and etching PdMo is beneficial to improving the SOR kinetics.
[0041] In addition, to understand its catalytic ability more deeply, the magnitude of the SOR overpotential at different sodium sulfide concentrations was also studied. As Figure 8 shown, when the solution is sodium sulfide with a concentration of 1 M / L, at 10 mA cm -2The overpotential is 403 mV. When the solution is sodium sulfide with a concentration of 3 M / L, at 10 mA cm -2 The overpotential is 325 mV. The reason is that when the electrolyte concentration increases, the diffusion resistance of the electrochemical reaction decreases, which is beneficial to the catalytic reaction, thus accelerating the SOR process. This indicates that as the concentration of sulfide ions increases, the reaction kinetics is enhanced, and the overpotential further decreases. To further study its reaction mechanism, the stability of the reaction for one hour at different voltages was also tested, and the solution was collected and tested by UV-vis. From Figure 9 it can be seen that at multiple different voltages, the response current density can remain constant with time, so the catalytic activity of the p-PdMo catalyst is very stable, while Figure 10 it shows that as the voltage increases, the peak intensity at 370 nm of the reaction solution after the reaction increases, indicating that the concentration of short-chain sulfide ions in the reaction solution increases, thus indicating an increase in the amount of sulfur elemental reaction products of SOR.
[0042] In addition, the double-layer capacitance (C dl ) was also measured, which proves the relatively large electrochemically active area of Example 1. As can be seen from Figure 11 it. The C dl value of p-PdMo is 55.49 mF cm -2 , exceeding 35.41 mF cm -2 of PdMo, thus highlighting the abundance of its active sites. In addition, a stability test was carried out on p-PdMo. As Figure 12 shown, after 5000 CV cycles, the LSV curves almost coincide, indicating its good stability. At the same time, as Figure 13 shown, p-PdMo can also maintain a stable potential at 10 mA cm -2 for 25 hours, further indicating its good stability.
[0043] It should be noted that the above embodiments are only used to illustrate the present application and do not limit the technical solutions described in the present application. Although this specification has described the present application in detail with reference to the above embodiments, those of ordinary skill in the art should understand that those skilled in the art can still modify the present application or make equivalent substitutions, and all technical solutions and their improvements that do not depart from the spirit and scope of the present application should be covered within the scope of the claims of the present application.
Claims
1. A bimetallene catalyst, characterized in that, The composition of the bimetallicene catalyst includes a Pd-based alloy, and the surface of the Pd-based alloy contains oxygen.
2. The bimetallicene catalyst according to claim 1, wherein The Pd-based alloy includes one of PdMo alloy, PdFe alloy, PdMn alloy, PdCu alloy, PdZn alloy, PdW alloy, and PdNi alloy.
3. The bimetalene catalyst according to claim 1 or 2, wherein The morphological structure of the bimetallic catalyst includes at least two layers of nanosheets (1), and there is a layer spacing (d) between adjacent nanosheets (1).
4. The double metalene catalyst according to claim 3, wherein The layer spacings of at least two of the nanosheets (1) are not equal, and the layer spacing (d) is 1 to 10 nanometers.
5. The bimetallene catalyst according to claim 3 or 4, wherein The thickness of the nanosheet (1) is 1.2 to 2.4 nanometers.
6. The bimetalene catalyst according to claim 3 or 4, wherein The surface of the nanosheet (1) has pores, and the diameter of the pores is 3 to 10 nanometers.
7. The bimetallic ene catalyst according to any one of claims 3-6, characterized in that, The nanosheet (1) is in a wrinkled or curled shape.
8. The bimetallic ene catalyst according to any one of claims 3-6, characterized in that The strain of the bimetallicene catalyst is 0.2% to 2%.
9. The application of a bimetallene catalyst, characterized in that, The composition of the bimetallicene catalyst includes a Pd-based alloy, the surface of the Pd-based alloy contains oxygen, and the bimetallicene catalyst is applied to the anodic sulfur oxidation reaction.
10. Use of the two-dimensional metalene catalyst according to claim 9, characterized in that, The anodic sulfur oxidation reaction includes hydrogen sulfide oxidation reaction, lithium sulfide oxidation reaction, or sodium sulfide oxidation reaction.