Low-antimony palladium-based catalyst for electrocatalytic reduction of carbon dioxide, preparation method and application
By doping Pd-based catalysts with trace amounts of antimony and regulating their electronic structure, the problem of excessive adsorption of CO intermediates in the electrocatalytic reduction of carbon dioxide by palladium-based catalysts was solved, achieving a highly selective and stable CO2 reduction reaction and improving the catalyst's resistance to poisoning and electrocatalytic performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WUHAN UNIV OF SCI & TECH
- Filing Date
- 2026-03-23
- Publication Date
- 2026-05-12
AI Technical Summary
In the electrocatalytic carbon dioxide reduction reaction, palladium-based catalysts suffer from excessive adsorption of CO intermediates, which prevents timely desorption of products, occupies active sites, and causes catalyst poisoning, resulting in rapid activity decay and decreased stability.
By finely controlling the electronic structure of Pd-based catalysts doped with trace amounts of antimony, optimizing the adsorption behavior of reaction intermediates, and preparing PdxSb catalytic materials using a hydrothermal synthesis method, the palladium lattice structure is kept unchanged, thereby enhancing the catalyst's resistance to poisoning.
It significantly improves the CO selectivity and stability of the catalyst, achieving a CO Faraday efficiency of 80%. It maintains high catalytic performance during long-term electrolysis, which is superior to undoped pure palladium catalysts.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrocatalytic carbon dioxide reduction reaction technology under alkaline conditions, and relates to a palladium-based catalytic material doped with trace amounts of antimony, its preparation method, and its application in the efficient and stable electrocatalytic carbon dioxide reduction reaction under alkaline conditions. Technical Background
[0002] Electrocatalytic carbon dioxide reduction (CO2RR) can utilize renewable energy to convert CO2 into high-value-added fuels and chemicals, and is an important pathway to achieve carbon resource recycling. Among them, carbon monoxide (CO) is a key component of syngas, and its highly selective preparation has significant industrial value (Liu Z, Qian J, Zhang G, et al. Electrochemical CO2-to-CO conversion: A comprehensive review of recent developments and emerging trends[J]. Separation and Purification Technology, 2024, 330:125-177.).
[0003] Palladium (Pd)-based catalysts have attracted much attention due to their unique electronic structure and product tunability, and can selectively generate formic acid or CO in different potential ranges. However, Pd-based catalysts face a key bottleneck when used for CO preparation: the adsorption of CO intermediates on the Pd surface is too strong, which leads to the inability of the product to desorb in time, the occupation of active sites, and catalyst poisoning, resulting in rapid activity decay and decreased stability (Wu P, Zaffran J, Xu D, et al. First-principles-based microkinetic simulations of CO2 hydrogenation to methanol over intermetallicGaPd2: method development to include complex interactions between surface adsorbates[J]. The Journal of Physical Chemistry C, 2020, 124(29): 15977-15987.). Therefore, how to regulate the adsorption strength of Pd for CO intermediates and improve its resistance to poisoning is the core problem in this field.
[0004] In recent years, the introduction of heteroelemental elements to regulate the electronic structure of Pd has proven to be a feasible approach. Studies have shown that in the CO2 reduction reaction (CORR) field, antimony (Sb) exhibits the potential to regulate the selectivity of catalyst products due to its unique electronic effects and atomic size. This provides important insights for optimizing the surface adsorption behavior of Pd-based catalysts through Sb (Xue J, Dong X, Liu C, et al. Turning copper into an efficient and stable CO evolution catalyst beyond noble metals[J]. Nature Communications, 2024, 15(1): 5998.). Based on this, this invention proposes a modification strategy of palladium doping with trace amounts of antimony: finely regulating the electronic structure of Pd at the atomic scale, while maintaining its bulk lattice unchanged, effectively weakens the adsorption energy for CO intermediates, thereby significantly enhancing the catalyst's resistance to poisoning. This strategy has a simple preparation method and stable product structure, achieving an effective balance between high CO selectivity, ease of preparation, and excellent operational stability, providing a practical new solution for the application of Pd-based catalysts in the CO2 reduction to CO field. Summary of the Invention
[0005] To address the aforementioned problems, this invention provides a Pd-based catalytic material and its preparation method, as well as its application in electrocatalytic carbon dioxide reduction. By employing a micro-Sb doping strategy, the electronic structure of Pd is modulated without altering the bulk crystal structure, effectively weakening the adsorption energy of Pd for CO intermediates. This results in a Pd material exhibiting structural stability and good CO selectivity during long-term electrolysis. x Among Sb catalysts, Pd exhibits the best performance. 50 Sb exhibits a CO Faradaic efficiency of 80% in a 0.5 M KHCO3 electrolyte and can continuously and stably catalyze the carbon dioxide reduction reaction for about 10 hours, providing a new design idea for developing efficient and stable CO2 electroreduction catalysts.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows:
[0007] A trace Sb-doped Pd-based catalytic material for electrocatalytic carbon dioxide reduction, wherein the Pd-based catalytic material has a nano-aggregate structure and its chemical formula is Pd. x Sb, wherein the doping amount of Sb remains constant, x is the relative content of Pd, and the value of x ranges from 30 to 70; the catalytic material uses Pd as the main active component, and the electronic structure of Pd is regulated by introducing Sb, thereby optimizing the adsorption behavior of reaction intermediates and obtaining a catalyst with excellent catalytic performance.
[0008] Furthermore, the trace Sb-doped Pd-based catalyst Pd x In Sb, the preferred structure is: Pd 50 Sb.
[0009] Furthermore, the trace Sb-doped Pd-based catalyst is in the form of a black powder.
[0010] Furthermore, the nanoclusters of the trace Sb-doped Pd-based catalyst are 20–80 nm in size.
[0011] A method for preparing a trace Sb-doped Pd catalyst for electrocatalytic carbon dioxide reduction includes the following steps:
[0012] The first step involves mixing palladium precursor, antimony precursor, and an alkaline solution prepared with KOH, N,N dimethylformamide (DMF), and ethylene glycol, adding a structure-directing agent, and stirring until a homogeneous solution is obtained.
[0013] The palladium precursor is selected from at least one of sodium chloropalladium, chloropalladic acid, palladium nitrate, and palladium acetate; the antimony precursor is selected from at least one of antimony trichloride, antimony acetate, and antimony oxide.
[0014] The molar ratio of the palladium precursor to the antimony precursor is 30 to 70:1, and the optimal molar ratio of the palladium precursor to the antimony precursor is 50:1.
[0015] The second step involves transferring the mixed solution obtained in the first step to a hydrothermal reactor and carrying out a hydrothermal reaction at 120-250°C for 6-12 hours.
[0016] The third step involves centrifuging the reaction product, washing it several times with deionized water and ethanol alternately, and then drying it in a vacuum drying phase to obtain a trace amount of Sb-doped Pd-based catalytic material.
[0017] The vacuum drying temperature is 50-80 ℃, and the time is 6-10 hours.
[0018] The application of a trace Sb-doped Pd catalyst for electrocatalytic carbon dioxide reduction involves loading the powdered catalyst onto hydrophobic carbon paper for electrocatalytic reduction of carbon dioxide to carbon monoxide.
[0019] The innovation of this invention lies in the successful construction of Pd using a simple hydrothermal synthesis method. xBy precisely controlling the amount of antimony doped in the Sb-doped catalyst system, the electronic structure of palladium can be finely tuned. This micro-doping strategy induces changes in the electronic state density on the catalyst surface without altering the palladium crystal structure, thereby optimizing the adsorption behavior of intermediates in the electrocatalytic carbon dioxide reduction reaction and significantly improving catalytic performance.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] (1) A strategy of doping with trace amounts of antimony and regulating the electronic structure of palladium is proposed. By introducing trace amounts of antimony into palladium, the electronic structure of the catalyst can be effectively regulated, thereby optimizing its activity and selectivity in the electrocatalytic carbon dioxide reduction reaction. This synthesis method is simple and controllable, providing a new technical route for the design of high-performance catalysts.
[0022] (2) The catalyst exhibits excellent electrocatalytic performance. The incorporation of antimony alters the electronic environment on the palladium surface, optimizes the adsorption free energy of the reaction intermediate, significantly improves the Faraday efficiency and current density of the target product carbon monoxide, and effectively inhibits the competitive hydrogen evolution reaction. Its catalytic performance is superior to that of undoped pure palladium catalysts.
[0023] (3) The catalyst has a simple preparation process, excellent electrochemical performance, and shows good application potential in carbon dioxide conversion and utilization. In addition, this approach of using trace metal doping to regulate the electronic structure of noble metals can provide a reference for the performance optimization of other noble metal-based catalysts. Attached Figure Description
[0024] Figure 1 This is a flowchart illustrating the technical process of the present invention.
[0025] Figure 2 SEM image of the catalytic material obtained in Example 2 of this invention.
[0026] Figure 3 EDS diagram of the catalytic material obtained in Example 2 of this invention.
[0027] Figure 4 Powder diffraction (PXRD) images of the catalytic material and its comparative sample obtained in Example 2 of this invention.
[0028] Figure 5 XPS images of the catalytic material and its comparative sample obtained in Example 2 of this invention.
[0029] Figure 6 The stability test diagram of the catalytic material obtained in Example 2 of this invention.
[0030] Figure 7The Faraday efficiency diagrams of CO products obtained from the catalytic materials of Examples 1-3 and the control group of this invention are shown in the figure. Detailed Implementation
[0031] To better understand the technical solution of the present invention, specific examples are provided for further detailed explanation, but the solution is not limited thereto.
[0032] Implementation 1: Pd 30 Sb
[0033] At room temperature, 0.1 M Na₂PdCl₄ and 0.1 M SbCl₃ solutions were prepared using DMF as the solvent and set aside. Then, 3.0 g KOH was dissolved in a mixed solvent of 16.8 mL DMF and 12 mL ethylene glycol. After stirring and dissolving, 3 mL of the prepared Na₂PdCl₄ solution, 0.1 mL of SbCl₃ solution, and 15 mL of diethylenetriamine were added sequentially. After thorough mixing, the mixture was transferred to a 100 mL high-pressure reactor and reacted in an oven at 200 °C for 8 hours, followed by natural cooling. Finally, the product was washed three times alternately with anhydrous ethanol and deionized water, and dried under vacuum at 60 °C for 8 hours to obtain Pd. 30 Sb catalytic materials.
[0034] The catalyst Pd obtained in this embodiment 30 When Sb is used in the efficient and stable electrocatalytic carbon dioxide reduction reaction under alkaline conditions, its CO Faradaic efficiency is about 60%.
[0035] Example 2: Pd 50 Sb
[0036] (a) The preparation method includes the following steps:
[0037] At room temperature, 0.1 M Na₂PdCl₄ and 0.1 M SbCl₃ solutions were prepared using DMF as solvent and set aside. Then, 3.0 g KOH was dissolved in a mixed solvent of 16.8 mL DMF and 12 mL ethylene glycol. After stirring and dissolving, 5 mL of the prepared Na₂PdCl₄ solution, 0.1 mL of SbCl₃ solution, and 15 mL of diethylenetriamine were added sequentially. After thorough mixing, the mixture was transferred to a 100 mL high-pressure reactor and reacted in an oven at 200 °C for 8 hours, followed by natural cooling. Finally, the product was washed three times alternately with anhydrous ethanol and deionized water, and dried under vacuum at 60 °C for 8 hours to obtain Pd. 50 Sb catalytic materials.
[0038] The catalyst Pd obtained in this embodiment 50Sb is used in the efficient and stable electrocatalytic reduction of carbon dioxide under alkaline conditions, with a CO Faradaic efficiency of approximately 80%.
[0039] Example 3: Pd 70 Sb
[0040] At room temperature, 0.1 M Na₂PdCl₄ and 0.1 M SbCl₃ solutions were prepared using DMF as the solvent and set aside. Then, 3.0 g KOH was dissolved in a mixed solvent of 16.8 mL DMF and 12 mL ethylene glycol. After stirring and dissolving, 7 mL of the prepared Na₂PdCl₄ solution, 0.1 mL of SbCl₃ solution, and 15 mL of diethylenetriamine were added sequentially. After thorough mixing, the mixture was transferred to a 100 mL high-pressure reactor and placed in an oven. The reactor was reacted at 200 °C for 8 hours and then allowed to cool naturally. Finally, the product was washed three times alternately with anhydrous ethanol and deionized water and dried under vacuum at 60 °C for 8 hours to obtain Pd. 70 Sb catalytic materials.
[0041] The catalyst Pd obtained in this embodiment 70 Sb is used in the efficient and stable electrocatalytic reduction of carbon dioxide under alkaline conditions, with a CO Faradaic efficiency of approximately 40%.
[0042] Comparative Example 1: Pd
[0043] At room temperature, a 0.1 M Na₂PdCl₄ solution was prepared using DMF as the solvent. Then, 3.0 g of KOH was dissolved in a mixed solvent of 16.8 mL DMF and 12 mL ethylene glycol. After stirring and dissolving, 5 mL of the prepared Na₂PdCl₄ solution and 15 mL of diethylenetriamine (without adding SbCl₃ solution) were added sequentially. After thorough mixing, the mixture was transferred to a 100 mL high-pressure reactor and reacted in an oven at 200 °C for 8 hours, followed by natural cooling. Finally, the product was washed three times alternately with anhydrous ethanol and deionized water, and then dried under vacuum at 60 °C for 8 hours to obtain pure Pd catalyst.
[0044] The pure Pd catalyst obtained in this embodiment, when applied to the highly efficient and stable electrocatalytic carbon dioxide reduction reaction under alkaline conditions, has a CO Faradaic efficiency of approximately 40%, which is significantly lower than the performance of the catalysts in Examples 1-2 of this application, but comparable to the catalytic performance of Example 3.
[0045] (II) Testing
[0046] Figure 1 A schematic diagram of the entire synthesis method.
[0047] Figure 2 Pd obtained in Example 250 The SEM image of the Sb catalyst material shows that it consists of particle agglomerates with a morphology of about 50 nm.
[0048] Figure 3 Pd obtained in Example 2 50 The EDS spectrum of the Sb catalyst material shows that Sb elements are uniformly distributed in Pd particles, indicating that uniform Sb doping was successfully achieved by the hydrothermal method, and no obvious elemental segregation or agglomeration was observed.
[0049] Figure 4 Pd obtained in Example 2 50 Powder diffraction (PXRD) comparison of Sb catalyst and pure Pd catalyst obtained in Comparative Example 1. Figure 3 It can be seen that, compared with pure Pd, Pd 50 The slight shift in the diffraction peaks of the Sb material indicates that Sb has been successfully doped into the Pd lattice, causing a small change in the lattice parameters.
[0050] Figure 5 Pd obtained in Example 2 50 XPS comparison images of the Sb catalyst and the pure Pd catalyst obtained in Comparative Example 1 show that, compared with pure Pd, Pd... 50 The shift in the binding energy of the Pd 3d orbitals in Sb materials indicates that Sb doping induces changes in the electronic structure of Pd, optimizing its adsorption energy for CO intermediates.
[0051] Figure 6 Pd obtained in Example 2 50 The stability test results of the Sb catalyst at −0.9 V vs. RHE potential. As can be seen from the figure, after 10 hours of continuous electrolysis, the CO Faraday efficiency decays by less than 5%, indicating that the catalyst has excellent catalytic stability.
[0052] Figure 7 Example Pd 30 The Faraday efficiency diagrams of Sb, Pd50Sb, Pd70Sb, and pure Pd at different potentials for the electrocatalytic reduction of CO2 to CO show that appropriate Sb doping can significantly improve the CO selectivity of Pd-based catalysts. Among them, Pd:Sb=50:1 is the optimal doping ratio; insufficient doping (70:1) or excessive doping (30:1) cannot achieve the best catalytic effect.
[0053] The embodiments and comparative examples described above are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.
Claims
1. A trace antimony (Sb)-doped palladium (Pd)-based catalytic material for electrocatalytic carbon dioxide reduction, characterized in that, The Pd-based catalytic material described above has a nano-agglomerated structure and its chemical formula is Pd. x Sb, wherein the doping amount of Sb remains constant, x is the relative content of Pd, and the value of x ranges from 30 to 70; the catalytic material uses Pd as the main active component, and the electronic structure of Pd is regulated by introducing Sb, thereby optimizing the adsorption behavior of reaction intermediates and obtaining a catalyst with excellent catalytic performance.
2. The trace Sb-doped Pd-based catalyst for electrocatalytic carbon dioxide reduction according to claim 1, characterized in that, The Sb-doped Pd-based catalyst Pd x The preferred structure in Sb is: Pd 50 Sb.
3. The trace Sb-doped Pd-based catalyst for electrocatalytic carbon dioxide reduction according to claim 1, characterized in that, The Sb-doped Pd-based catalyst is in the form of a black powder; the nanoclusters of the Sb-doped Pd-based catalyst have a particle size of 20-80 nm.
4. A method for preparing a trace Sb-doped Pd-based catalyst for electrocatalytic carbon dioxide reduction as described in any one of claims 1-3, characterized in that, Includes the following steps: The first step involves mixing the palladium precursor, the antimony precursor, and an alkaline solution prepared with KOH, N,N dimethylformamide (DMF), and ethylene glycol. Then, a structure-directing agent is added, and the mixture is stirred until homogeneous to obtain a mixed solution. The molar ratio of the palladium precursor to the antimony precursor is 30-70:1, and the amount of antimony precursor added remains constant. The second step involves transferring the mixed solution obtained in the first step to a hydrothermal reactor and carrying out a hydrothermal reaction at 120-250°C for 6-12 hours. The third step involves centrifuging the product obtained from the reaction, washing it several times alternately with deionized water and ethanol, and then drying it in a vacuum drying oven to obtain a trace amount of Sb-doped Pd-based catalytic material.
5. The method for preparing a trace Sb-doped Pd-based catalyst for electrocatalytic carbon dioxide reduction as described in claim 4, characterized in that, In the first step, the Pd precursor is selected from at least one of sodium chloropalladium, chloropalladium acid, palladium nitrate, and palladium acetate; the Sb precursor is selected from at least one of antimony trichloride, antimony acetate, and antimony oxide.
6. The method for preparing a trace Sb-doped Pd-based catalyst for electrocatalytic carbon dioxide reduction as described in claim 4, characterized in that, In the first step, the molar ratio of the palladium precursor to the antimony precursor is 50:
1.
7. The method for preparing a trace Sb-doped Pd-based catalyst for electrocatalytic carbon dioxide reduction as described in claim 4, characterized in that, In the third step, the drying temperature is 50-80℃ and the drying time is 6-10 hours.
8. The application of the trace Sb-doped Pd-based catalyst for electrocatalytic carbon dioxide reduction according to any one of claims 1-3, characterized in that, It is applied to the electrocatalytic reduction of carbon dioxide to carbon monoxide.