High-entropy prussian blue material and preparation method and application thereof
By preparing a high-entropy Prussian blue material Cu0.2Ni0.2Co0.2Mn0.2Zn0.2(Fe(CN)6) as an electrocatalyst, the problems of high cost and low efficiency in nitrate treatment were solved, and the effect of efficient and selective reduction of nitrate to ammonia was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LIAONING UNIVERSITY
- Filing Date
- 2026-03-17
- Publication Date
- 2026-06-09
Smart Images
Figure CN122166798A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of high-entropy transition metal coordination polymer technology, specifically relating to a high-entropy Prussian blue material, its preparation method, and its application as an electrocatalyst. Background Technology
[0002] With rapid industrialization and increasing environmental pollution, the problem of excessive nitrate levels in industrial wastewater and polluted groundwater is becoming increasingly prominent. This not only leads to eutrophication and damages ecosystems but also threatens human health due to excessive nitrate accumulation in drinking water. Traditional methods such as anaerobic bacterial denitrification and physicochemical treatment suffer from drawbacks such as high cost, high energy consumption, and large land area requirements, making it difficult to meet the demand for efficient and low-cost treatment. Electrochemical reduction technology offers a promising solution for nitrate treatment, converting nitrate into ammonia with high utilization value. However, the nitrate electrocatalytic reduction reaction (NO3RR) involves a slow-kinetic 8-electron transfer process and a 9-proton transfer mechanism, and it competes fiercely with the hydrogen evolution reaction (HER), easily generating byproducts such as NO and N2H4, resulting in a significant reduction in reaction selectivity and efficiency. Therefore, there is an urgent need to develop catalysts with both high activity and high selectivity. To address the technical problems of high cost, low efficiency, and poor selectivity in existing nitrate treatment methods, this invention aims to provide a high-entropy Prussian blue material with readily available raw materials, a simple preparation method, high catalytic efficiency, and excellent NH3 selectivity, along with its preparation method and applications. High-entropy Prussian blue (HEPBA) materials have attracted widespread attention as a new generation of electrocatalysts. Their key characteristic is the uniform distribution of multiple transition metal cations within the crystal lattice, without significant phase separation, forming a homogeneous solid solution. This unique composition endows HEPBA with two advantages: 1) the high-entropy effect can precisely tune the spin state of transition metal ions, optimizing the catalyst's electron transport efficiency; 2) the lattice distortion caused by the coordination of multiple metal ions generates abundant surface active sites, providing ample reaction sites for nitrate reduction. Summary of the Invention
[0003] In order to solve the technical problems existing in the prior art, the purpose of this invention is to provide a high-entropy Prussian blue material with readily available raw materials, simple preparation method, and high catalytic efficiency, as well as its preparation method and application.
[0004] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:
[0005] A high-entropy Prussian blue material is Cu 0.2 Ni 0.2 Co 0.2 Mn 0.2 Zn 0.2 (Fe(CN)6) 0.667 .
[0006] The above-mentioned method for preparing high-entropy Prussian blue includes the following steps:
[0007] 1) Dissolve MnCl2•4H2O, CoCl2•6H2O, CuCl2•2H2O, ZnCl2, and NiCl2•6H2O in 50 mL of deionized water, and add sodium citrate complexing agent; this solution is labeled A. Dissolve potassium ferricyanide in 50 mL of deionized water; this solution is labeled B. Slowly add solution B dropwise to solution A while stirring.
[0008] 2) The stirred solution was allowed to settle at room temperature, washed three times with deionized water by centrifugation, then washed three times with ethanol, and dried to obtain the high-entropy Prussian blue material.
[0009] Furthermore, in the above-mentioned method for preparing a high-entropy Prussian blue material, in step 1), the total amount of MnCl2•4H2O, CoCl2•6H2O, CuCl2•2H2O, ZnCl2 and NiCl2•6H2O and potassium ferricyanide are added in an equimolar ratio.
[0010] Furthermore, in the above-mentioned method for preparing a high-entropy Prussian blue material, in step 1), the molar ratio of MnCl2•4H2O, CoCl2•6H2O, CuCl2•2H2O, ZnCl2 and NiCl2•6H2O is 1:1:1:1:1.
[0011] Furthermore, in the above-mentioned method for preparing a high-entropy Prussian blue material, in step 1), the molar ratio of sodium citrate complexing agent to potassium ferricyanide is 2.25:2.
[0012] Furthermore, in the above-mentioned method for preparing a high-entropy Prussian blue material, in step 1), the stirring time is 30 min.
[0013] Furthermore, in the above-mentioned method for preparing a high-entropy Prussian blue material, step 2) involves a settling time of 24 h.
[0014] Furthermore, in the above-mentioned method for preparing a high-entropy Prussian blue material, step 2) involves a drying temperature of 60 °C.
[0015] The above-mentioned high-entropy Prussian blue material is used as an electrocatalyst in the neutral electrocatalytic reduction of nitrate.
[0016] Furthermore, the above application method is as follows: high-entropy Prussian blue material is loaded on carbon cloth as the working electrode, Ag / AgCl is the reference electrode, platinum sheet is the counter electrode, and 0.1 M potassium sulfate solution and 0.1 M potassium nitrate solution are used as the electrolyte to electrocatalyze the reduction of nitrate to synthesize NH3.
[0017] The beneficial effects of this invention are:
[0018] 1. The high-entropy Prussian blue material provided by this invention has high catalytic efficiency. Specifically, at -0.8 (V vs. RHE), the FE of NH3 reaches 98.3%, which is higher than that of Cu(Fe(CN)6). 0.667 It increased by 16.05% while suppressing side reactions (NO2). - (FE is lower).
[0019] 2. The high-entropy Prussian blue material prepared by the method of this invention lays the foundation for the preparation of sustainable nitrogen fixation electrocatalysts for practical water treatment applications. Attached Figure Description
[0020] Figure 1 These are the XRD spectra of the Prussian blue analogue and the high-entropy Prussian blue material prepared in Example 1.
[0021] Figure 2 This is the refined XRD pattern of the high-entropy Prussian blue material prepared in Example 1.
[0022] Figure 3 These are SEM images of the Prussian blue analogue and high-entropy Prussian blue material prepared in Example 1, where a is the SEM image of CPBA, b is the SEM image of CN PBA, c is the SEM image of CNC PBA, d is the SEM image of CNCM PBA, and e is the SEM image of CNCMZ PBA.
[0023] Figure 4 These are the infrared spectra of the Prussian blue analogue and the high-entropy Prussian blue material prepared in Example 1.
[0024] Figure 5 This is the LSV diagram of the high-entropy Prussian blue material prepared in Example 1.
[0025] Figure 6 The table shows the CV curves and corresponding Cdl values for different scan rates of the Prussian blue analogues and high-entropy Prussian blue materials prepared in Example 1. Specifically, a represents the CV curve for C PBA as an electrocatalyst at different scan rates, b represents the CV curve for CN PBA as an electrocatalyst at different scan rates, c represents the CV curve for CNC PBA as an electrocatalyst at different scan rates, d represents the CV curve for CNCM PBA as an electrocatalyst at different scan rates, e represents the CV curve for CNCMZ PBA as an electrocatalyst at different scan rates, and f represents the Cdl values for the five materials.
[0026] Figure 7 This is a comparison chart of the Faraday efficiency of the high-entropy Prussian blue material prepared in Example 1.
[0027] Figure 8The graph shows the ammonia yield and Faraday efficiency of C PBA (a) and CNCMZ PBA (b) prepared in Example 1.
[0028] Figure 9 These are the electrochemical impedance spectra of the Prussian blue analogue and the high-entropy Prussian blue material prepared in Example 1.
[0029] Figure 10 This is a schematic diagram of the structure of the high-entropy Prussian blue material prepared in Example 1. Detailed Implementation
[0030] Example 1: High-entropy Prussian Blue Material
[0031] (a) Prussian blue analogues (Cu(Fe(CN)6)) 0.667 )
[0032] The preparation method is as follows:
[0033] 1) Dissolve 2 mmol CuCl2·2H2O and 2.25 mmol sodium citrate complexing agent in 50 mL deionized water, and denote this as solution A; dissolve 2 mmol potassium ferricyanide in 50 mL deionized water, and denote this as solution B; slowly add solution B dropwise to solution A and stir for 30 min.
[0034] 2) The stirred solution was allowed to settle at room temperature for 24 h, washed three times with deionized water by centrifugation, then washed three times with ethanol, and dried at 60 °C to obtain the Prussian blue analog Cu(Fe(CN)6). 0.667 , denoted as C PBA.
[0035] (ii) Prussian blue analogues (Cu 0.5 Ni 0.5 (Fe(CN)6) 0.667 )
[0036] The preparation method is as follows:
[0037] 1) Dissolve 1 mmol CuCl2·2H2O, 1 mmol NiCl2·H2O and 2.25 mmol sodium citrate complexing agent in 50 mL of deionized water, and denote it as solution A; dissolve 2 mmol potassium ferricyanide in 50 mL of deionized water, and denote it as solution B; slowly add solution B dropwise to solution A and stir for 30 min.
[0038] 2) The stirred solution was allowed to settle at room temperature for 24 hours, then washed three times with deionized water by centrifugation, followed by three washes with ethanol. The solution was then dried at 60 °C to obtain the Prussian blue analogue Cu. 0.5 Ni 0.5 (Fe(CN)6) 0.667 , denoted as CN PBA.
[0039] (iii) Prussian blue analogues (Cu 0.333 Ni 0.333 Co 0.333 (Fe(CN)6) 0.667 )
[0040] The preparation method is as follows:
[0041] 1) Dissolve 0.67 mmol CuCl2·2H2O, 0.67 mmol NiCl2·6H2O, 0.67 mmol CoCl2·6H2O and 2.25 mmol sodium citrate complexing agent in 50 mL of deionized water, and denote this as solution A. Dissolve 2 mmol potassium ferricyanide in 50 mL of deionized water, and denote this as solution B. Slowly add solution B dropwise to solution A and stir for 30 min.
[0042] 2) The stirred solution was allowed to settle at room temperature for 24 hours, then washed three times with deionized water by centrifugation, followed by three washes with ethanol. The solution was then dried at 60°C to obtain the Prussian blue analogue Cu. 0.333 Ni 0.333 Co 0.333 (Fe(CN)6) 0.667 This is denoted as CNC PBA.
[0043] (iv) Prussian blue analogues (Cu 0.25 Ni 0.25 Co 0.25 Mn 0.25 (Fe(CN)6) 0.667 )
[0044] The preparation method is as follows:
[0045] 1) Dissolve 0.5 mmol CuCl2·2H2O, 0.5 mmol NiCl2·6H2O, 0.5 mmol CoCl2·6H2O, 0.5 mmol MnCl2·4H2O and 2.25 mmol sodium citrate complexing agent in 50 mL of deionized water, and denote this as solution A. Dissolve 2 mmol potassium ferricyanide in 50 mL of deionized water, and denote this as solution B. Slowly add solution B dropwise to solution A and stir for 30 min.
[0046] 2) The stirred solution was allowed to settle at room temperature for 24 h, washed three times with deionized water by centrifugation, then washed three times with ethanol, and dried at 60 °C to obtain the Prussian blue analogue Cu. 0.25 Ni 0.25 Co 0.25 Mn 0.25 (Fe(CN)6) 0.667 , denoted as CNCM PBA.
[0047] (v) High-entropy Prussian blue materials (Cu 0.2 Ni 0.2 Co 0.2 Mn 0.2 Zn 0.2 (Fe(CN)6) 0.667 )
[0048] The preparation method is as follows:
[0049] 1) Dissolve 0.4 mmol CuCl2·2H2O, 0.4 mmol NiCl2·6H2O, 0.4 mmol CoCl2·6H2O, 0.4 mmol MnCl2·4H2O, 0.4 mmol ZnCl2 and 2.25 mmol sodium citrate complexing agent in 50 mL of deionized water, and denote this as solution A. Dissolve 2 mmol potassium ferricyanide in 50 mL of deionized water, and denote this as solution B. Slowly add solution B dropwise to solution A and stir for 30 min.
[0050] 2) The stirred solution was allowed to settle at room temperature for 24 h, washed three times with deionized water by centrifugation, then washed three times with ethanol, and dried at 60 °C to obtain the high-entropy Prussian blue material Cu. 0.2 Ni 0.2 Co 0.2 Mn 0.2 Zn 0.2 (Fe(CN)6) 0.667 It is denoted as CNCMZPBA.
[0051] (vi) Test results
[0052] Figure 1 These are the XRD patterns of the Prussian blue analogue and high-entropy Prussian blue material prepared in this embodiment. Powder X-ray diffraction (XRD) analysis confirmed that the characteristic diffraction peaks of all samples are consistent with Cu(Fe(CN)6). 0.667 The results are consistent with the standard card (PDF#86-0513), indicating that the products all exhibit a typical Prussian blue cubic crystal structure. The diffraction peaks broaden gradually with increasing dopant metal types, suggesting that the introduction of multi-metal ions induces lattice distortion, which confirms the successful preparation of high-entropy Prussian blue.
[0053] Figure 2 This is the refined XRD pattern of the high-entropy Prussian blue material prepared in this embodiment. The experimental curve and the calculated curve are in high agreement, the difference curve is flat, and the refinement reliability factor Rp=5.71%, indicating that the established cubic phase model can accurately describe the crystal structure of the sample, confirming the successful synthesis of high-entropy Prussian blue and its typical Prussian blue framework characteristics.
[0054] Figure 3 These are SEM images of the Prussian blue analogue and high-entropy Prussian blue material prepared in Example 1. All samples exhibit a typical cubic morphology.
[0055] Figure 4 The images show the infrared absorption spectra of the Prussian blue analogues and high-entropy Prussian blue materials prepared in this embodiment, confirming that the synthesized materials contain key Prussian blue groups such as OH, C≡N, and MC / MN.
[0056] Example 2: Application of high-entropy Prussian blue material as an electrocatalyst in the electrocatalytic reduction of nitrate.
[0057] (a) The application method is as follows:
[0058] The high-entropy Prussian blue material prepared in Example 1 was used as an electrocatalyst supported on carbon cloth as the working electrode. The reference electrode was Ag / AgCl, the counter electrode was a platinum sheet, and the electrolyte was 0.1M potassium sulfate solution and 0.1M potassium nitrate solution. The electrocatalytic reduction of nitrate ions to NH3 was achieved.
[0059] (II) Test Results
[0060] Figure 5 The image shows the LSV (Laser-to-Volume Value) of the high-entropy Prussian blue material prepared in Example 1 as an electrocatalyst. Comparison of LSV values in potassium sulfate electrolytes containing and without nitrate within a potential window of -1.4 to 0.2 V relative to the reversible hydrogen electrode shows that the current density increases in the nitrate-containing electrolyte, indicating that the material is active for the electrocatalytic reduction of nitrate to ammonia.
[0061] Figure 6 The table shows the CV curves and corresponding Cdl values for the Prussian blue analogue and high-entropy Prussian blue material prepared in Example 1 as electrocatalysts at different scan rates. The Cdl value calculated from the CV curves reaches 0.534 mF cm⁻¹. -2 It is much higher than that of copper-based PBA and other samples.
[0062] Figure 7 This is a comparison chart of the Faradaic efficiency of the high-entropy Prussian blue material prepared in Example 1 as an electrocatalyst. The Faradaic efficiency (FE) first increases and then decreases slightly, reaching a peak of 98.3% at -0.8V (V vs. RHE). Analysis of nitrogen-containing byproducts shows that NO2 is the most abundant nitrogen-containing byproduct at all tested potentials. - The FE is low.
[0063] Figure 8 This is a graph showing the ammonia yield and Faradaic efficiency of the high-entropy Prussian blue material prepared in Example 1 as an electrocatalyst. The yield of the high-entropy Prussian blue material increases with increasing potential negativity, reaching 6.002 mgh at -1.0 V (V vs. RHE).-1 mg cat. -1 At the same potential, it is 3.327 mg h higher than copper-based PBA. -1 mg cat. -1 Its Faraday efficiency reaches 98.3% at -0.8 V (V vs. RHE), which is significantly higher than the 82.25% of copper-based PBA.
[0064] Figure 9 The image shows the electrochemical impedance spectroscopy (EIS) of the high-entropy Prussian blue material prepared in Example 1 as an electrocatalyst. The high-entropy Prussian blue material exhibits the lowest charge transfer resistance, higher ion transport efficiency, and faster electrochemical reaction kinetics.
Claims
1. A high-entropy Prussian blue material, characterized in that, The high-entropy Prussian blue material is Cu. 0.2 Ni 0.2 Co 0.2 Mn 0.2 Zn 0.2 (Fe(CN)6) 0.667 .
2. The method for preparing high-entropy Prussian blue according to claim 1, characterized in that, Includes the following steps: 1) Dissolve MnCl2•4H2O, CoCl2•6H2O, CuCl2•2H2O, ZnCl2, and NiCl2•6H2O in 50 mL of deionized water, and add sodium citrate complexing agent; this solution is labeled A. Dissolve potassium ferricyanide in 50 mL of deionized water; this solution is labeled B. Slowly add solution B dropwise to solution A while stirring. 2) The stirred solution was allowed to settle at room temperature, washed three times with deionized water by centrifugation, then washed three times with ethanol, and dried to obtain the high-entropy Prussian blue material.
3. The method for preparing a high-entropy Prussian blue material according to claim 2, characterized in that, In step 1), the total amount of MnCl2•4H2O, CoCl2•6H2O, CuCl2•2H2O, ZnCl2 and NiCl2•6H2O and potassium ferricyanide are added in an equimolar ratio.
4. The method for preparing a high-entropy Prussian blue material according to claim 3, characterized in that, In step 1), the molar ratio of MnCl2•4H2O, CoCl2•6H2O, CuCl2•2H2O, ZnCl2 and NiCl2•6H2O is 1:1:1:1:
1.
5. The method for preparing a high-entropy Prussian blue material according to claim 2, characterized in that, In step 1), the molar ratio of sodium citrate complexing agent to potassium ferricyanide is 2.25:
2.
6. The method for preparing a high-entropy Prussian blue material according to claim 2, characterized in that, In step 1), the stirring time is 30 min.
7. The method for preparing a high-entropy Prussian blue material according to claim 2, characterized in that, In step 2), the settling time is 24 hours.
8. The method for preparing a high-entropy Prussian blue material according to claim 2, characterized in that, In step 2), the drying temperature is 60 °C.
9. The application of the high-entropy Prussian blue material as described in claim 1 as an electrocatalyst in the neutral electrocatalytic reduction of nitrate.
10. The application according to claim 9, characterized in that, The application method is as follows: High-entropy Prussian blue material is loaded on carbon cloth as the working electrode, Ag / AgCl is the reference electrode, platinum sheet is the counter electrode, and 0.1 M potassium sulfate solution and 0.1 M potassium nitrate solution are used as the electrolyte to electrocatalyze the reduction of nitrate to NH3.