Tetranuclear heterometallic cluster compounds modified with dimethylamine, methods of making and using the same
By preparing dimethylamine-modified tetranuclear heterometallic cluster compounds, the stability and conductivity issues of the catalyst in the oxygen evolution reaction were solved, achieving low overpotential and high-efficiency electrocatalytic oxygen evolution performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HARBIN UNIV OF SCI & TECH
- Filing Date
- 2024-10-21
- Publication Date
- 2026-06-05
AI Technical Summary
Existing catalysts exhibit poor cycle stability and electronic conductivity in the oxygen evolution reaction, hindering the practical application of hydrogen energy.
A dimethylamine-modified tetranuclear heterometallic cluster compound [(CH3)2NH2][Ni(H2O)6][{NaNiSbW(OH)4(H2O)6}{SbW8O30}] was developed, which forms a stable structure through unique tetranuclear heterometallic units and hydrogen bonding, and is used for alkaline electrocatalytic oxygen production.
A low overpotential of 39.7 mV, a Tafel slope of 19.75 mV/dec, and an electrochemical transfer resistance of 1.9 Ω were achieved, demonstrating significant stability and high efficiency in electrocatalytic oxygen evolution.
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Figure CN119350400B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrocatalytic oxygen evolution, and specifically to a compound, its preparation method, and its applications. Background Technology
[0002] With environmental degradation and the depletion of carbon-based fuels, exploring an environmentally friendly energy source to replace traditional fuels has become increasingly urgent. Hydrogen is considered a fossil fuel alternative due to its high energy density, renewability, and environmental friendliness. Water electrolysis has attracted significant attention due to its stable yield, high energy conversion efficiency, and high product purity. Water electrolysis involves two half-reactions: hydrogen evolution reaction (OER) and oxygen evolution reaction (OER), with OER being the anodic reaction in water splitting. However, OER is a multi-electron, multi-proton reaction process with slow kinetics, typically requiring high overpotentials. Despite considerable efforts, the cycling stability and poor electronic conductivity of these catalysts still hinder their practical application in the future hydrogen economy. Therefore, the development of catalysts with excellent and stable OER catalytic performance is urgently needed. Summary of the Invention
[0003] The purpose of this invention is to address the problem of hydrogen energy shortage by providing a dimethylamine-modified tetranuclear heterometallic cluster compound, its preparation method, and its applications.
[0004] The dimethylamine-modified tetranuclear heterometallic cluster compound has the molecular formula [(CH3)2NH2][Ni(H2O)6][{NaNiSbW(OH)4(H2O)6}{SbW8O 30}]·2H2O, with a molecular weight of 2861.62.
[0005] The preparation method of the dimethylamine-modified tetranuclear heterometallic cluster compound is as follows:
[0006] I. Na9[SbW9O 33 Preparation of precursor: Dissolve 40.0 g of sodium tungstate in 80 mL of deionized water, stir and heat to 90 °C to obtain solution A;
[0007] Dissolve 1.96 g of antimony oxide in 13 mL of hydrochloric acid to obtain solution B;
[0008] Solution A was heated to 90°C, and solution B was added to solution A and reacted for 1 hour. After cooling, the solution was filtered to obtain a clear and transparent solution. After seven days, transparent crystals were obtained, which yielded Na₂[SbW₁₉O₂]. 33 Precursor;
[0009] II. Na9[SbW9O 33 The precursor dissolves in deionized water, {NaSbW9O 33The mass ratio of the precursor to the volume of deionized water was 0.68–0.69 g: 20–40 mL. 0.29–0.3 g of nickel nitrate was added, and the mixture was stirred for 15 minutes. Then, 0.11–0.12 g of terephthalic acid was added, and the mixture was stirred for 10 minutes. Finally, a 1 mol / L NaOH solution was added dropwise until the terephthalic acid was completely dissolved. This process continued for 30 minutes. The reaction was carried out for 2 hours at a pH of 6–7 and a temperature of 85–95°C. After cooling, the mixture was filtered, and 0.25 g of dimethylamine hydrochloride was added. The mixture was evaporated and crystallized at room temperature. After three days, hexagonal yellow crystals appeared, yielding the dimethylamine-modified tetranuclear heterometallic cluster compound.
[0010] The dimethylamine-modified tetranuclear heterometallic cluster compound is used for alkaline electrocatalytic oxygen production.
[0011] The dimethylamine-modified tetranuclear heterometallic cluster compound mainly consists of {B-β-SbW8}, a unique tetranuclear heterometallic unit {NaNiSbW(OH)4(H2O)6}, and free (CH3)2NH2 and Ni(H2O)6. The unique tetranuclear heterometallic unit is composed of sodium, nickel, antimony, and tungsten metal ions, with two symmetrical tetranuclear heterometals forming a parallelogram structure at the sandwich position. The two polymeric anions {SbW8O... 30} 9- A β-type sandwich structure is formed by the connection of Sb(1), W(1), and Ni(2) in the tetranuclear heterometallic unit. The Sb(2) in the polyacid anion {B-β-SbW8} is bonded to surrounding oxygen atoms to form a tetrahedral structure, which is further surrounded by eight WO6 octahedra. Each structural unit is connected by Na(1) to form a one-dimensional chain structure. The one-dimensional chain structure forms a two-dimensional planar structure through hydrogen bonding supramolecular interactions. The faces are connected by hydrogen bonds between Ni(1) and {B-β-SbW8}.
[0012] The overpotential of the dimethylamine-modified tetranuclear heterometallic cluster compound of this invention reaches 39.7 mV. The Tafel slope is 19.75 mV / dec. The slope of the fitted straight line is 4.51 mF / cm. 2 The electrochemical transfer resistance is 1.9 Ω. The curve remains constant over 15 hours, demonstrating the significant stability of the electrocatalytic oxygen evolution material under alkaline conditions. Attached Figure Description
[0013] Figure 1 This is the monomer structure diagram of the tetranuclear heterometallic cluster compound modified with dimethylamine in Experiment 1;
[0014] Figure 2 Polyhedral diagram of the dimethylamine-modified tetranuclear heterometallic cluster compound in Experiment 1;
[0015] Figure 3One-dimensional structural diagram of the dimethylamine-modified tetranuclear heterometallic cluster compound in Experiment 1;
[0016] Figure 4 Two-dimensional structural diagram of the tetranuclear heterometallic cluster compound modified with dimethylamine in Experiment 1;
[0017] Figure 5 Three-dimensional structural diagram of the tetranuclear heterometallic cluster compound modified with dimethylamine in Experiment 1;
[0018] Figure 6 Infrared spectrum of the dimethylamine-modified tetranuclear heterometallic cluster compound in Experiment 1;
[0019] Figure 7 The UV-Vis absorption spectrum of the dimethylamine-modified tetranuclear heterometallic cluster compound in Experiment 1;
[0020] Figure 8 Linear sweep voltammetry (LSV) chromatogram of the dimethylamine-modified tetranuclear heterometallic cluster compound in Experiment 1;
[0021] Figure 9 Tafel slope curves of the dimethylamine-modified tetranuclear heterometallic cluster compounds in Experiment 1;
[0022] Figure 10 Cyclic voltammetry curves of the dimethylamine-modified tetranuclear heterometallic cluster compound in Experiment 1;
[0023] Figure 11 Impedance (EIS) spectra of the dimethylamine-modified tetranuclear heterometallic cluster compound in Experiment 1;
[0024] Figure 12 Current-time curves of the 15-hour electrolysis of the dimethylamine-modified tetranuclear heterometallic cluster compound in Experiment 1. Detailed Implementation
[0025] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.
[0026] Specific Implementation Method 1: The dimethylamine-modified tetranuclear heterometallic cluster compound in this implementation method has the molecular formula [(CH3)2NH2][Ni(H2O)6][{NaNiSbW(OH)4(H2O)6}{SbW8O] 30}]·2H2O, with a molecular weight of 2861.62.
[0027] Specific Implementation Method Two: The preparation method of the dimethylamine-modified tetranuclear heterometallic cluster compound described in Specific Implementation Method One is as follows:
[0028] I. Na9[SbW9O 33Preparation of precursor: Dissolve 40.0 g of sodium tungstate in 80 mL of deionized water, stir and heat to 90 °C to obtain solution A;
[0029] Dissolve 1.96 g of antimony oxide in 13 mL of hydrochloric acid to obtain solution B;
[0030] Solution A was heated to 90°C, and solution B was added to solution A and reacted for 1 hour. After cooling, the solution was filtered to obtain a clear and transparent solution. After seven days, transparent crystals were obtained, which yielded Na₂[SbW₁₉O₂]. 33 Precursor;
[0031] II. Na9[SbW9O 33 The precursor dissolves in deionized water, {NaSbW9O 33 The mass ratio of the precursor to the volume of deionized water was 0.68–0.69 g: 20–40 mL. 0.29–0.3 g of nickel nitrate was added, and the mixture was stirred for 15 minutes. Then, 0.11–0.12 g of terephthalic acid was added, and the mixture was stirred for 10 minutes. Finally, a 1 mol / L NaOH solution was added dropwise until the terephthalic acid was completely dissolved, a process that lasted 30 minutes. The reaction was carried out for 2 hours at a pH of 6–7 and a temperature of 85–95°C. After cooling, the mixture was filtered, and 0.25 g of dimethylamine hydrochloride was added. The mixture was evaporated and crystallized at room temperature. After three days, hexagonal yellow crystals appeared, yielding the dimethylamine-modified tetranuclear heterometallic cluster compound.
[0032] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method Two in that in step two, {NaSbW9O} 33 The mass ratio of the precursor to the volume of deionized water is 0.6888 g: 40 mL. Everything else is the same as in Specific Implementation Method Two.
[0033] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods Two to Three in that the amount of nickel nitrate added in step two is 0.2928g, and the amount of terephthalic acid added is 0.1166g. Everything else is the same as in Specific Implementation Methods Two to Three.
[0034] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods Two to Four in that in step two, the pH value is maintained at 6.4 while heating to 90°C. Everything else is the same as in Specific Implementation Methods Two to Four.
[0035] Specific Implementation Method Six: The dimethylamine-modified tetranuclear heterometallic cluster compound described in this implementation method and in one of the specific implementation methods one to four is used for alkaline electrocatalytic oxygen production.
[0036] The following experiments were used to verify the effectiveness of the invention:
[0037] Experiment 1:
[0038] The preparation method of dimethylamine-modified tetranuclear heterometallic cluster compounds is as follows:
[0039] I. Na9[SbW9O 33 Preparation of precursor: Dissolve 40.0 g of sodium tungstate in 80 mL of deionized water, stir and heat to 90 °C to obtain solution A;
[0040] Dissolve 1.96 g of antimony oxide in 13 mL of hydrochloric acid to obtain solution B;
[0041] Solution A was heated to 90°C, and solution B was added to solution A and reacted for 1 hour. After cooling, the solution was filtered to obtain a clear and transparent solution. After seven days, transparent crystals were obtained, which yielded Na₂[SbW₁₉O₂]. 33 Precursor;
[0042] II. Na9[SbW9O 33 The precursor dissolves in deionized water, {NaSbW9O 33 The mass ratio of the precursor to the volume of deionized water was 0.68–0.69 g: 20–40 mL. 0.2928 g of nickel nitrate was added, and the mixture was stirred for 15 minutes. Then, 0.1166 g of terephthalic acid was added, and the mixture was stirred for 10 minutes. A 1 mol / L NaOH solution was then added dropwise until the terephthalic acid was completely dissolved. This process continued for 30 minutes. The reaction was carried out for 2 hours at a pH of 6.4 and a temperature of 90°C. After cooling, the mixture was filtered, and 0.25 g of dimethylamine hydrochloride was added. The mixture was evaporated and crystallized at room temperature. After three days, hexagonal yellow crystals appeared, yielding the dimethylamine-modified tetranuclear heterometallic cluster compound.
[0043] The compound is mainly composed of {B-β-SbW8}, a unique tetranuclear heterometallic unit {NaNiSbW(OH)4(H2O)6}, and free (CH3)2NH2 and Ni(H2O)6. The unique tetranuclear heterometallic unit is composed of sodium, nickel, antimony, and tungsten metal ions, with two symmetrical tetranuclear heterometals forming a parallelogram structure in the sandwich position. The two polymeric anions {SbW8O}... 30} 9- A β-type sandwich structure is formed by the connection of Sb(1), W(1), and Ni(2) in the tetranuclear heterometallic unit. The Sb(2) in the polyacid anion {B-β-SbW8} is bonded to surrounding oxygen atoms to form a tetrahedral structure, which is further surrounded by eight WO6 octahedra. Each structural unit is connected by Na(1) to form a one-dimensional chain structure. The one-dimensional chain structure forms a two-dimensional planar structure through hydrogen bonding. The faces are connected by hydrogen bonds between Ni(1) and {B-β-SbW8}.
[0044] The electrochemical performance of the dimethylamine-modified tetranuclear heterometallic cluster catalytic oxygen evolution material prepared above was tested:
[0045] Electrode fabrication:
[0046] Grind the sample and carbon black at a mass ratio of 2:1 for 30 minutes. Weigh 0.005g of the ground sample into a centrifuge tube, add 150μL of anhydrous ethanol and 50μL of deionized water, and sonicate for 30 minutes. Spread the resulting slurry evenly on a 1*1cm... 2 After drying at room temperature on the carbon cloth, a thin film is evenly coated on it. After drying, the electrocatalytic performance can be tested.
[0047] 1. Overpotential testing of electrocatalytic oxygen evolution materials
[0048] The oxygen evolution linear sweep voltammetry (LSV) curves of the dimethylamine-modified tetranuclear heterometallic cluster compounds of this invention are shown below. Figure 8 As shown. The electrochemical oxygen production activity of the electrode in alkaline solution was studied using a standard three-electrode electrochemical apparatus (0.5 mol / L KOH solution), with a standard mercury electrode as the reference electrode, a platinum sheet electrode as the negative electrode, and the working electrode as the positive electrode.
[0049] The electrolyte was a 0.5 mol / L KOH solution, the voltage measurement range was 0–0.65 V, and the scan rate was 0.005 V / s. An initial oxidation peak was observed at 16 mV, which can be attributed to Ni oxidation. The overpotential of this oxygen evolution material was 39.7 mV.
[0050] 2. Tafel slope test of electrocatalytic oxygen evolution material
[0051] The Tafel slope curve of the dimethylamine-modified tetranuclear heterometallic cluster compound of this invention is shown in the figure. Figure 9 As shown. The polarization curves were obtained at a scan rate of 5 mV / s. The Tafel slope obtained from the kinetic analysis of the OER is 19.75 mV / dec.
[0052] 3. Electrochemical active surface area test of electrocatalytic oxygen evolution materials
[0053] The cyclic voltammetry curves of the dimethylamine-modified tetranuclear heterometallic cluster compounds of this invention are as follows: Figure 10 As shown in (a), the test conditions were as follows: the electrolyte solution was 0.5 mol / L KOH solution, and the scan rate was 10–80 mV / s. The figure shows that the test curves at different scan rates were all parallelograms, and there was no significant change with increasing scan rate. Figure 10 (b) represents the sample's Δj / 2 (Δj = j a -j c Linear fitting of the scan rate at a potential of 0.1V, where J a Where j is the anode current density cLet be the cathode current density. The slope of the fitted straight line is 4.51 mF / cm. 2 .
[0054] 4. Impedance of electrocatalytic oxygen evolution materials
[0055] The impedance (EIS) spectrum of the dimethylamine-modified tetranuclear heterometallic cluster compound of this invention is shown below. Figure 11 As shown, the electrochemical transfer resistance of the electrode material is 1.9 Ω.
[0056] 5. Electrochemical stability testing of electrocatalytic oxygen evolution materials
[0057] The current-time curve of the dimethylamine-modified tetranuclear heterometallic cluster compound of this invention after 15 hours of electrolysis is shown below. Figure 12 As shown. Under given operating conditions (E = 0.83 V, 0.5 mol / L KOH solution), the chronoamperometry was used. The curve remained constant over 15 hours, highlighting the significant stability of the electrocatalytic oxygen evolution material of this invention under alkaline conditions.
[0058] The crystallographic data of the dimethylamine-modified tetranuclear heterometallic cluster compounds described in this experiment are shown in Table 1:
[0059] Table 1 Crystallographic Parameters
[0060]
[0061]
[0062] Table 2 shows a partial bond length table of the dimethylamine-modified tetranuclear heterometallic cluster compounds described in this experiment:
[0063] Table 2 Bond Length Table
[0064]
[0065]
[0066] The bond angles of the dimethylamine-modified tetranuclear heterometallic cluster compounds described in this experiment are shown in Table 3.
[0067] Table 3 Key Angle Table
[0068]
[0069]
[0070]
[0071] The hydrogen bond table of the dimethylamine-modified tetranuclear heterometallic cluster compounds described in this experiment is shown in Table 4:
[0072] Table 4
[0073]
[0074]
[0075] The infrared absorption spectrum of the dimethylamine-modified tetranuclear heterometallic cluster compound in this experiment is shown below. Figure 6 As shown. From Figure 6 As can be seen from this, 3227.771cm -1 and 1627.626cm -1 The peak at 3130.61 cm⁻¹ is attributed to the H₂O vibration absorption peak in water molecules. -1 and 1412.12cm -1 The peaks at these locations are attributed to the NH and CN vibrational absorption peaks of dimethylamine. (1020.641, 932.8958, 863.471, 679.7845 cm⁻¹) -1 The peaks at that location belong to the polyacids υ(W=Ot) and υ(WO) b -W), υ(WO) c Vibrational absorption peaks of -W) and υ(Sb-O).
[0076] The UV-Vis absorption spectra of the dimethylamine-modified tetranuclear heterometallic cluster compound as a function of light exposure time are shown below. Figure 7 As shown. From Figure 7 As the illumination time increases, a new broad absorption band is observed starting from 454 nm, with the strongest absorption intensity near 410 nm.
Claims
1. A dimethylamine-modified tetranuclear heterometallic cluster compound, characterized in that... The dimethylamine-modified tetranuclear heterometallic cluster compound has the molecular formula [(CH3)2NH2][Ni(H2O)6][{NaNiSbW(OH)4(H2O)6}{SbW8O] 30 }]·2H2O.
2. The method for preparing the dimethylamine-modified tetranuclear heterometallic cluster compound according to claim 1, characterized in that... The preparation method of the dimethylamine-modified tetranuclear heterometallic cluster compound is as follows: I. Na9[SbW9O 33 Preparation of the precursor: 40.0 g of sodium tungstate was dissolved in 80 mL of deionized water, stirred, and heated to 90 °C to obtain solution A; 1.96 g of antimony oxide was dissolved in 13 mL of hydrochloric acid to obtain solution B; Solution A was heated to 90 °C, and solution B was added to solution A and reacted for 1 hour. After cooling, the solution was filtered to obtain a clear and transparent solution. After seven days, transparent crystals were obtained, which is Na₂[SbW₁₉O₂]. 33 Precursor; II. Na9[SbW9O 33 The precursor dissolves in deionized water, {NaSbW9O 33 The mass ratio of the precursor to the volume of deionized water was 0.68–0.69 g: 20–40 mL. 0.29–0.3 g of nickel nitrate was added, and the mixture was stirred for 15 minutes. Then, 0.11–0.12 g of terephthalic acid was added, and the mixture was stirred for 10 minutes. Finally, a 1 mol / L NaOH solution was added dropwise until the terephthalic acid was completely dissolved. This process continued for 30 minutes. The reaction was carried out for 2 hours at a pH of 6–7 and a temperature of 85–95°C. After cooling, the mixture was filtered, and 0.25 g of dimethylamine hydrochloride was added. The mixture was evaporated and crystallized at room temperature. After three days, hexagonal yellow crystals appeared, yielding the dimethylamine-modified tetranuclear heterometallic cluster compound.
3. The method for preparing the dimethylamine-modified tetranuclear heterometallic cluster compound according to claim 2, characterized in that... In step two, {NaSbW9O} 33 The mass ratio of the precursor to the volume of deionized water was 0.6888 g: 40 mL.
4. The method for preparing the dimethylamine-modified tetranuclear heterometallic cluster compound according to claim 2, characterized in that... In step two, the amount of nickel nitrate added is 0.2928 g, and the amount of terephthalic acid added is 0.1166 g.
5. The method for preparing the dimethylamine-modified tetranuclear heterometallic cluster compound according to claim 2, characterized in that... In step two, the pH value is maintained at 6.4, and the temperature is heated to 90 °C.
6. The application of the dimethylamine-modified tetranuclear heterometallic cluster compound of claim 1, characterized in that... The dimethylamine-modified tetranuclear heterometallic cluster compound is used for alkaline electrocatalytic oxygen production.