Preparation method and application of S vacancy anchoring Pd monatomic material
By constructing S vacancy-anchored Pd single-atom materials, the problems of low selectivity and Faraday efficiency of Ni3S2 catalysts in the electrocatalytic oxidation of PET were solved, and the efficient conversion of PET waste plastics into high-value chemicals was achieved, which has significant economic benefits and environmental protection significance.
Patent Information
- Application Number
- CN202510626538.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-15
- Publication Date
- 2025-10-10
AI Technical Summary
Existing Ni3S2 catalysts have low selectivity and Faradaic efficiency in the electrocatalytic oxidation of PET, and the random distribution of single atoms on the support leads to a lack of synergistic effect on active sites, which limits its electrocatalytic activity.
The Pd single-atom material is anchored by constructing an S vacancy structure. The preparation method includes immersing nickel foam in a thiourea solution, and after hydrothermal treatment, contacting it with a PdCl2 solution under a xenon lamp to form an S vacancy-anchored Pd single-atom material.
The electro-oxidation catalytic performance of PET is improved, and the efficient conversion of PET waste plastics into high-value chemicals is achieved, which has economic benefits and environmental protection significance.
Smart Images
Figure CN120758915A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of new material preparation, and particularly relates to a preparation method and application of an S vacancy-anchored Pd single-atom material. Background Art
[0002] To date, the global plastic waste recycling rate is less than 10%, and large amounts of untreated plastic waste enter ecosystems, posing a serious threat to the environment and biodiversity. Polyethylene terephthalate (PET), one of the most widely used plastics, is extremely difficult to degrade in the natural environment, necessitating appropriate recycling strategies to minimize its environmental impact. Electrocatalytic oxidation of PET offers an effective route for efficient PET recycling, converting the PET hydrolysis product, ethylene glycol (EG), into high-value chemicals.
[0003] Ni3S2 is considered a promising catalyst for the electrocatalytic oxidation of PET due to its low synthesis cost, stable chemical properties, and high electrical conductivity. However, its low selectivity and Faraday efficiency during the electrocatalytic oxidation of PET limit its large-scale application. Modification of Ni3S2 by single-atom doping can enhance its electrocatalytic performance in PET oxidation. However, the weak interaction between Ni3S2 and single atoms is a major obstacle to the design of PET electrocatalysts with abundant active sites and high stability. Furthermore, the dispersed single atoms are randomly distributed on the support, and the lack of synergistic interaction between active sites limits the optimization of electrocatalytic activity. Anchoring single atoms by constructing defect structures such as vacancies not only achieves controlled dispersion of single atoms on the support but also overcomes the weak interaction between the substrate and single atoms, which is of great significance for improving the performance of catalysts for the electrocatalytic oxidation of PET waste plastics. Summary of the Invention
[0004] In view of the problems existing in the prior art, the present invention aims to provide a method for preparing an S vacancy-anchored Pd single-atom material and its application, which is specifically achieved through the following technical solutions:
[0005] A method for preparing an S vacancy-anchored Pd single-atom material, the method comprising the following steps:
[0006] 1) dissolving thiourea in deionized water and uniformly dispersing the thiourea by ultrasonic oscillation, and then immersing the nickel foam in the thiourea solution to prepare a solution containing the nickel foam;
[0007] 2) preparing Ni3S2 by a one-step hydrothermal method using the solution prepared in step 1);
[0008] 3) The Ni3S2 prepared in step 2) is immersed in a PdCl2 solution for 6-10 hours, irradiated under a xenon lamp, and then washed and dried to obtain a S vacancy-anchored Pd single-atom material.
[0009] Furthermore, in step 1), the amount of deionized water and thiourea added is: the amount of thiourea in 10 mL of deionized water is 0.2-0.8 mmol, and the added volume of the nickel foam is 2.5×2 cm.
[0010] Furthermore, in step 1), the frequency of ultrasonic oscillation is 60-100W, and the ultrasonic time is 10-20 minutes.
[0011] Furthermore, the specific steps of step 2) are: transferring the solution containing nickel foam to a 100 mL high-pressure reactor with a polytetrafluoroethylene liner for hydrothermal reaction, naturally cooling to room temperature after the reaction is completed, filtering the product, and then washing it with anhydrous ethanol and deionized water for 2 to 4 times respectively, and drying it in an oven to obtain Ni3S2.
[0012] Furthermore, the temperature of the hydrothermal reaction is 100-140° C., the time of the hydrothermal reaction is 6-14 hours, and the drying temperature of the oven is 40-60° C.
[0013] Furthermore, in step 3), the irradiation time under the xenon lamp is 0.5-2 hours, and the specific steps of washing and drying are: washing with deionized water and anhydrous ethanol 3-6 times and drying in a vacuum oven at 80°C.
[0014] Among them, the material prepared by irradiation for 1 hour is Pd / d-Ni3S2, and the material directly irradiated under a xenon lamp for 1 hour without being immersed in PdCl2 solution is d-Ni3S2.
[0015] The S vacancy-anchored Pd single-atom material prepared by the above preparation method is used as an electrocatalytic material.
[0016] Furthermore, the S vacancy-anchored Pd single-atom material has a sheet-like structure and can electrocatalytically oxidize ethylene glycol, a derivative of PET waste plastic, into formic acid.
[0017] At room temperature, when the electrolyte is 1M KOH + 0.16M ethylene glycol (PET is hydrolyzed by KOH, and it is determined that 1M KOH solution contains 0.16M ethylene glycol), when the current density is 100mA / cm 2 When , the potential of the Pd / d-Ni3S2 material described in the present invention is 1.34V.
[0018] At room temperature, when the electrolyte is 1M KOH and the current density is 100mA / cm 2 When , the potential of the Pd / d-Ni3S2 material described in the present invention is 1.59V.
[0019] At room temperature, when the electrolyte is 1M KOH+0.16M ethylene glycol and the working electrode is Pd / d-Ni3S2 material, the NMR spectra of the electrodes are obtained during the electrolysis at 1.45V for 12h. 1 H and 13 In the C NMR spectrum, it can be seen that the peak of ethylene glycol gradually becomes smaller, and the peak of formic acid gradually becomes larger, indicating that the product generated by the electrocatalytic oxidation of ethylene glycol is formic acid.
[0020] The synthesis method of the present invention is simple, low-cost, suitable for large-scale production, and has broad application prospects. The S-vacancy-anchored Pd single-atom material prepared by the present invention can convert PET waste plastic into high-value formic acid under mild conditions, with significant economic benefits and important environmental protection implications. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 This is the XRD pattern of the S vacancy-anchored Pd single-atom material Pd / d-Ni3S2 prepared by irradiation for 1 h in Example 1;
[0022] Figure 2 The SEM and mapping images of the S vacancy-anchored Pd single-atom material Pd / d-Ni3S2 prepared by irradiation for 1 h in Example 1;
[0023] Figure 3 TEM image of the S vacancy-anchored Pd single-atom material Pd / d-Ni3S2 prepared by irradiation for 1 h in Example 1;
[0024] Figure 4 This is a spherical aberration-corrected transmission electron microscopy (AC-TEM) image of the S vacancy-anchored Pd single-atom material Pd / d-Ni3S2 prepared by irradiation for 1 h in Example 1;
[0025] Figure 5 The EPR patterns of the S-vacancy-anchored Pd single-atom materials Pd / d-Ni3S2 and d-Ni3S2 prepared by irradiation for 1 h in Example 1;
[0026] Figure 6 This is the synchrotron radiation pattern of the S vacancy-anchored Pd single-atom material Pd / d-Ni3S2 prepared by irradiation for 1 h in Example 1;
[0027] Figure 7 This is the LSV diagram of the S vacancy-anchored Pd single-atom material Pd / d-Ni3S2 in 1M KOH prepared by irradiation for 1 h in Example 1;
[0028] Figure 8This is the LSV plot of the S-vacancy-anchored Pd single-atom material Pd / d-Ni3S2 in 1M KOH + 0.16M ethylene glycol prepared by irradiation for 1 h in Example 1;
[0029] Figure 9 The NMR images of the electrolyte solution of Example 1 are 1M KOH + 0.16M ethylene glycol and the working electrode is Pd / d-Ni3S2 material during electrolysis at 1.45V vs. RHE for 12h. 1 H NMR spectrum;
[0030] Figure 10 The NMR images of the electrolyte solution of Example 1 are 1M KOH + 0.16M ethylene glycol and the working electrode is Pd / d-Ni3S2 material during electrolysis at 1.45V vs. RHE for 12h. 13 C NMR spectrum. DETAILED DESCRIPTION
[0031] The present invention is further described below in conjunction with specific embodiments to facilitate a better understanding of the present technical solution.
[0032] Example 1
[0033] 0.5 mmol of thiourea was added to 10 mL of deionized water and evenly dispersed by ultrasonic oscillation at a frequency of 60-100 W for 10-20 minutes. A 2.5 x 2 cm nickel foam was then immersed in the thiourea solution.
[0034] The nickel foam solution was transferred to a 100 mL polytetrafluoroethylene-lined autoclave. The autoclave was subjected to a hydrothermal reaction at 120°C for 12 hours, followed by natural cooling to room temperature. The product was filtered, washed 2-4 times with anhydrous ethanol and then with deionized water, and then dried in an oven at 40-60°C to obtain Ni3S2.
[0035] The prepared Ni3S2 was immersed in PdCl2 solution for 6-10 hours, irradiated under a xenon lamp for 1 hour, and then the sample was washed with deionized water and anhydrous ethanol 3-6 times, and dried in a vacuum oven at 80°C to obtain the S vacancy-anchored Pd single atom material Pd / d-Ni3S2. The material that was not immersed in PdCl2 solution and directly irradiated under a xenon lamp for 1 hour was d-Ni3S2.
[0036] Example 2
[0037] 0.2 mmol of thiourea was added to 10 mL of deionized water. Ultrasonic oscillation was used to evenly disperse the thiourea in the deionized water at a frequency of 60-100 W for 10-20 minutes. A 2.5 x 2 cm nickel foam was then immersed in the thiourea solution.
[0038] The nickel foam solution was transferred to a 100 mL polytetrafluoroethylene-lined autoclave. The autoclave was subjected to a hydrothermal reaction at 100°C for 6 hours, followed by natural cooling to room temperature. The product was filtered, washed 2-4 times with anhydrous ethanol and deionized water, respectively, and dried in an oven at 40-60°C to yield NiS.
[0039] The prepared Ni3S2 was immersed in a PdCl2 solution for 6-10 hours, irradiated under a xenon lamp for 0.5 hours, and then the sample was washed with deionized water and anhydrous ethanol 3-6 times, and dried in a vacuum oven at 80°C to obtain the S vacancy-anchored Pd single atom material.
[0040] Example 3
[0041] 0.8 mmol of thiourea was added to 10 mL of deionized water and evenly dispersed by ultrasonication at a frequency of 60-100 W for 10-20 minutes. A 2.5 x 2 cm nickel foam was then immersed in the thiourea solution.
[0042] The nickel foam solution was transferred to a 100 mL polytetrafluoroethylene-lined autoclave. The autoclave was subjected to a hydrothermal reaction at 140°C for 14 hours, followed by natural cooling to room temperature. The product was filtered, washed 2-4 times with anhydrous ethanol and deionized water, respectively, and dried in an oven at 40-60°C to yield Ni3S2.
[0043] The prepared Ni3S2 was immersed in a PdCl2 solution for 6-10 hours, irradiated under a xenon lamp for 2 hours, and then the sample was washed with deionized water and anhydrous ethanol 3-6 times, and dried in a vacuum oven at 80°C to obtain the S vacancy-anchored Pd single atom material.
[0044] like Figure 1 As shown, the Pd / d-Ni3S2 and d-Ni3S2 prepared in Example 1 match the standard card of Ni3S2 (JCPDS No.44-1418) and have no impurity peaks, proving that the synthesized materials have high purity.
[0045] The SEM and Mapping images of Pd / d-Ni3S2 prepared in Example 1 are as follows: Figure 2 As shown by Figure 2 It can be seen that the Pd / d-Ni3S2 material has a flaky structure and the Pd, Ni and S elements are evenly distributed.
[0046] The TEM image of Pd / d-Ni3S2 prepared in Example 1 is as follows: Figure 3 As shown, it is further confirmed that the Pd / d-Ni3S2 material prepared in the embodiment has a flaky structure.
[0047] The spherical aberration corrected transmission electron microscope (AC-TEM) image of Pd / d-Ni3S2 prepared in Example 1 is as follows: Figure 4 As shown, the lattice spacing of 0.12 nm corresponds to the (401) crystal plane of Ni3S2, and Pd single atoms (yellow circles) can be observed dispersed on Ni3S2.
[0048] The EPR patterns of Pd / d-Ni3S2 and d-Ni3S2 prepared in Example 1 are as follows: Figure 5 As shown, it can be seen that the EPR peak at g = 2.003 is the characteristic peak of the S vacancy in Ni3S2 containing S vacancy, while the characteristic peak of the S vacancy in Pd / d-Ni3S2 disappears, indicating that the Pd single atom is anchored on the S vacancy.
[0049] The synchrotron radiation pattern of Pd / d-Ni3S2 prepared in Example 1 is as follows: Figure 6 As shown, it can be observed that there are no Pd-Pd and Pd-O peaks in Pd / d-Ni3S2, indicating that Pd exists in the form of single atoms. The existence of Pd-Ni bonds in Pd / d-Ni3S2 further proves that the Pd single atom is anchored on the S vacancy of d-Ni3S2.
[0050] Example 4
[0051] The performance of the S-vacancy-anchored Pd single-atom material was tested using a conventional three-electrode electrochemical workstation (CHI 760E). The counter electrode was a C rod, the S-vacancy-anchored Pd single-atom material was used as the working electrode, Hg / HgO was used as the reference electrode, and the electrolyte was 1 M KOH + 0.16 M ethylene glycol. All potentials were calibrated relative to the reversible hydrogen electrode (RHE) using the following calculation: E RHE =E Hg / HgO +0.098V+0.059pH, all polarization curves were corrected with 90% iR compensation.
[0052] like Figure 7 As shown, at room temperature, the electrolyte is 1M KOH + 0.16M ethylene glycol, when the current density is 100mA / cm 2 The potential of the S vacancy-anchored Pd single-atom material of the present invention is 1.35V.
[0053] Example 5
[0054] The performance of the S-vacancy anchored Pd single atom material was tested using a conventional three-electrode electrochemical workstation (CHI 760E). The counter electrode was a C rod, the S-vacancy anchored Pd single atom was used as the working electrode, the Hg / HgO electrode was used as the reference electrode, and the electrolyte was 1 M KOH. All potentials were calibrated relative to the reversible hydrogen electrode (RHE) by the following calculation: E RHE =E Hg / HgO +0.098V+0.059pH, all polarization curves were corrected with 90% iR compensation.
[0055] like Figure 8 As shown, at room temperature, the electrolyte is 1M KOH solution, when the current density is 100mA / cm 2 When , the potential of the S vacancy anchored Pd single atom material of the present invention is 1.59V.
[0056] Example 6
[0057] The electrolytic performance of the S-vacancy-anchored Pd single atom material was tested using a traditional three-electrode electrochemical workstation (CHI 760E). The counter electrode was a C rod, the S-vacancy-anchored Pd single atom was used as the working electrode, the Hg / HgO electrode was used as the reference electrode, and the electrolyte was 1M KOH + 0.16M ethylene glycol. The electrolysis was carried out at a voltage of 1.45V vs. RHE for 12h.
[0058] like Figure 9 and Figure 10 As shown in FIG5 , after electrolysis, the intensity of the ethylene glycol peak becomes weaker, and the intensity of the formic acid peak gradually becomes stronger, indicating that the product of the electrocatalytic oxidation of ethylene glycol is formic acid.
Claims
1. A method for preparing a S vacancy anchored Pd single atom material, characterized in that: The preparation method comprises the following steps: 1) dissolving thiourea in deionized water and uniformly dispersing the thiourea by ultrasonic oscillation, and then immersing the nickel foam in the thiourea solution to prepare a solution containing nickel foam; 2) preparing Ni3S2 by a one-step hydrothermal method using the solution prepared in step 1); 3) The Ni3S2 prepared in step 2) is immersed in a PdCl2 solution for 6-10 h, irradiated under a xenon lamp, and then washed and dried to obtain a S vacancy-anchored Pd single atom material.
2. The method for preparing a S vacancy-anchored Pd single-atom material according to claim 1, wherein: In step 1), the amount of deionized water and thiourea added is: the amount of thiourea in 10 mL of deionized water is 0.2-0.8 mmol, and the added volume of nickel foam is 2.5×2 cm.
3. The method for preparing a S vacancy-anchored Pd single-atom material according to claim 1, wherein: In step 1), the frequency of ultrasonic oscillation is 60-100W, and the ultrasonic time is 10-20 minutes.
4. The method for preparing a S vacancy-anchored Pd single-atom material according to claim 1, wherein: The specific steps of step 2) are as follows: the solution containing nickel foam is transferred to a 100 mL high-pressure reactor with a polytetrafluoroethylene liner for hydrothermal reaction. After the reaction is completed, it is naturally cooled to room temperature, the product is filtered, and then washed with anhydrous ethanol and deionized water 2 to 4 times respectively, and dried in an oven to obtain Ni3S2.
5. The method for preparing a S vacancy-anchored Pd single-atom material according to claim 4, wherein: The temperature of the hydrothermal reaction is 100-140° C., the time of the hydrothermal reaction is 6-14 hours, and the drying temperature of the oven is 40-60° C.
6. The method for preparing a S vacancy-anchored Pd single-atom material according to claim 1, wherein: In step 3), the irradiation time under the xenon lamp is 0.5-2 hours. The specific steps of washing and drying are: washing with deionized water and anhydrous ethanol 3-6 times and drying in a vacuum oven at 80°C.
7. Use of the S vacancy-anchored Pd single-atom material prepared by the preparation method according to any one of claims 1 to 6 as an electrocatalytic material.
8. The use according to claim 7, characterized in that The S vacancy-anchored Pd single-atom material has a sheet structure and can electrocatalytically oxidize ethylene glycol, a derivative of PET waste plastic, into formic acid.