Co-ni-c composite material, preparation method thereof and application of the composite material in electrocatalytic oxygen reduction for preparing hydrogen peroxide
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TIANJIN UNIV
- Filing Date
- 2022-01-27
- Publication Date
- 2026-06-19
Smart Images
Figure CN116555813B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrocatalysis technology, and in particular to a Co-Ni-C composite material, its preparation method, and its application in the electrocatalytic oxygen reduction to produce hydrogen peroxide. Background Technology
[0002] Hydrogen peroxide is an indispensable chemical in our lives and a green oxidant with a wide range of applications, primarily in pharmaceutical disinfection, paper bleaching, chemical preparation, and semiconductor cleaning. To meet global demand, over 3.5 million metric tons of hydrogen peroxide are produced annually globally using the traditional anthraquinone process. However, the traditional anthraquinone process requires large-scale, centralized production, resulting in high energy consumption. It also generates significant amounts of organic byproducts, necessitating complex impurity separation processes, which are costly. Furthermore, the hydrogen peroxide produced by this method is often stored and transported at a high concentration (around 70%), and its instability poses significant safety risks during storage and transportation. Compared to high-concentration hydrogen peroxide, low-concentration hydrogen peroxide can already meet most industrial and domestic needs. Therefore, developing a miniaturized, efficient, convenient, and economical method to overcome the drawbacks of the traditional anthraquinone process, while directly and in-situ preparing hydrogen peroxide, has greater market application value.
[0003] Electrocatalytic oxygen reduction (OOR) via a two-electron pathway enables the in-situ, small-scale production of hydrogen peroxide in various solution environments at room temperature and pressure. This not only effectively addresses the problems associated with the anthraquinone process but also allows for the full utilization of clean and renewable energy sources such as solar and wind power. Currently, OOR production of hydrogen peroxide primarily occurs in alkaline solutions. However, the high instability of hydrogen peroxide in alkaline environments significantly limits its application. Therefore, developing methods for producing hydrogen peroxide in other pH environments is urgently needed. This process requires catalysts that combine high activity and low cost to achieve highly selective electrocatalytic reduction of oxygen to hydrogen peroxide. Currently, noble metal-based amalgam alloys are effective catalysts for the two-electron OOR production of hydrogen peroxide under acidic conditions, but their high cost severely limits their application. Summary of the Invention
[0004] The purpose of this invention is to address the problems of high catalyst costs in existing technologies by providing a Co-Ni-C composite material.
[0005] Another object of the present invention is to provide a method for preparing Co-Ni-C composite materials.
[0006] Another objective of this invention is to provide an application of Co-Ni-C composite material in the electrocatalytic oxygen reduction to prepare hydrogen peroxide.
[0007] The technical solution adopted to achieve the purpose of this invention is:
[0008] A Co-Ni-C composite material comprising two-dimensional graphene nanosheets and Co and Ni bimetallic elements uniformly dispersed in single-atom form and loaded on the two-dimensional graphene nanosheets.
[0009] In the above technical solution, the Co-Ni-C composite material is prepared through the following steps:
[0010] Step 1: Dissolve cobalt salt, zinc salt and nickel salt in a solvent in a predetermined ratio to prepare a metal salt solution;
[0011] Step 2: Add the metal salt solution from Step 1 to a predetermined amount of hard template, stir until uniformly mixed, and dry to obtain the mixture;
[0012] Step 3: Add the organic ligand to a mixed solvent of anhydrous methanol and anhydrous ethanol, and stir magnetically until the organic ligand is completely dissolved to obtain an organic ligand alcohol solution.
[0013] Step 4: Add the organic ligand alcohol solution prepared in Step 3 to the mixture obtained in Step 2, stir to allow the metal salt and organic ligand to react uniformly and completely, and then dry to obtain the precursor.
[0014] Step 5: Pyrolyze the precursor obtained in Step 4 to obtain the carbonized precursor;
[0015] Step 6: Wash and filter the carbonized precursor obtained in step 5 to remove the hard template, and then wash, dry, clean and calcine to obtain the Co-Ni-C composite material.
[0016] The mass ratio of Ni to Co in the Co-Ni-C composite material is 7.5:1 to 8.5:1.
[0017] In the above technical solution, the cobalt salt in step 1 is cobalt nitrate, the zinc salt is zinc nitrate, the nickel salt is nickel acetylacetone, and the solvent is a mixed solvent of anhydrous methanol and anhydrous ethanol.
[0018] The organic ligand is 2,5-dihydroxyterephthalic acid, terephthalic acid, or dimethylimidazole.
[0019] In the above technical solution, the mass ratio of cobalt nitrate to zinc nitrate is (1-3):(25-30), the mass ratio of nickel acetylacetonate to the sum of the masses of cobalt nitrate and zinc nitrate is (1-7):1300, and the mass ratio of anhydrous methanol to anhydrous ethanol is (3-4):(1-0).
[0020] In the above technical solution, the hard template in step 2 is sodium chloride, and the mass ratio of the hard template to the metal salt solution is (10-15):1.
[0021] In the above technical solution, the ratio of the mass of the organic ligand to the sum of the masses of cobalt nitrate and zinc nitrate in step 3 is (9-10):13, and the mass ratio of anhydrous methanol to anhydrous ethanol is (3-4):(1-0).
[0022] In the above technical solution, the drying method in step 4 is to place the item in an electric heating drying oven for drying at a temperature of 80-90℃ for a time of 6-48 hours.
[0023] The washing method in step 6 is to wash the substance obtained after filtration with hydrochloric acid aqueous solution and deionized water of a predetermined concentration in sequence.
[0024] The drying method in step 6 is to place the container in an electric drying oven at a temperature of 80-90°C for 6-48 hours. The concentration of the hydrochloric acid aqueous solution in step 6 is 1-2M, and the container is calcined at a temperature greater than or equal to 800°C for 30-60 minutes.
[0025] In step 5, the pyrolysis temperature is greater than or equal to 550℃, and the heating rate is 5-10℃ / min. -1 The heat preservation time is 1 to 2 hours.
[0026] In another aspect, the present invention provides the application of the Co-Ni-C composite material as a catalyst in the electrocatalytic oxygen reduction to prepare hydrogen peroxide.
[0027] In the above technical solution, the Co-Ni-C composite material is uniformly dispersed in a mixed solution of Nafion and water to obtain a slurry with a concentration of 1-3 mg / mL. This slurry is then drop-coated onto a glassy carbon electrode portion on a rotating disk electrode and dried at room temperature to obtain a glassy carbon electrode loaded with the Co-Ni-C composite material. An aqueous solution of 0.05-0.15 M HClO4 is prepared as the electrolyte. The glassy carbon electrode loaded with the Co-Ni-C composite material is used as the working electrode, and a graphite rod is used as the counter electrode. H2O2 is prepared by electrolysis at a voltage less than 0.70 V (RHE).
[0028] The volume ratio of the nafion to water is 1:(80-115).
[0029] In another aspect, the present invention provides a method for preparing a Co-Ni-C composite material, comprising the following steps:
[0030] Step 1: Dissolve cobalt salt, zinc salt and nickel salt in a predetermined ratio to prepare a metal salt solution;
[0031] Step 2: Add a predetermined amount of hard template to the metal salt solution described in Step 1, stir until uniformly mixed, and dry to obtain the mixture;
[0032] Step 3: Prepare an organic ligand alcohol solution by adding dimethylimidazole to a mixed solvent of anhydrous methanol and anhydrous ethanol and stirring magnetically until the dimethylimidazole is completely dissolved.
[0033] Step 4: Add the organic ligand alcohol solution prepared in Step 3 to the mixture obtained in Step 2, stir to allow the metal salt and organic ligand to react uniformly and completely, and then dry to obtain the precursor.
[0034] Step 5: Pyrolyze the precursor obtained in Step 4 to obtain the carbonized precursor;
[0035] Step 6: Wash and filter the carbonized precursor obtained in Step 5 to remove the hard template. Then wash the filtered material with hydrochloric acid aqueous solution and deionized water of a predetermined concentration in sequence. After drying and washing again, the Co-Ni-C composite material can be obtained.
[0036] Compared with the prior art, the beneficial effects of the present invention are:
[0037] 1. The Co-Ni-C composite material of the present invention, as a catalyst, has a greater atom utilization rate and lower cost compared with traditional catalysts, showing great potential in the rational utilization of metal resources and atom economy.
[0038] 2. Compared with noble metal-based amalgam catalysts, the Co-Ni-C composite material of the present invention, which is uniformly dispersed and supported on two-dimensional (2D) graphene nanosheets by the hard template method, has a larger specific surface area and hierarchical porous structure, and has both high activity and selectivity. It can be used for economical, efficient, in-situ, and small-scale dispersion preparation of hydrogen peroxide.
[0039] 3. The Co-Ni-C composite material of the present invention is uniformly loaded with a large number of bimetallic Co and Ni active sites distributed in single-atom form. The addition of a small number of single-atom Ni sites efficiently modulates the electrocatalytic oxygen reduction of the Co-Ni-C material into a two-electron pathway. At the same time, it has good conductivity, large specific surface area and hierarchical porous structure, which enables it to exhibit excellent reactivity, selectivity and stability in the electrocatalytic two-electron oxygen reduction to prepare hydrogen peroxide.
[0040] 4. This invention utilizes a hard template method and a subsequent pyrolysis process to obtain Co-Ni-C composite materials. The preparation method of this invention is simple, has low equipment cost, strong process controllability, and good applicability.
[0041] 5. The Co-Ni-C composite material of this invention can electrocatalytically reduce oxygen to produce hydrogen peroxide in a wide pH range (pH = 1–7). Compared with traditional carbon-based metal nanoparticle catalysts, this material exhibits superior selectivity (pH = 1, ~90%; pH = 3.5, ~85%; pH = 7.4, ~93%) and long-term stability (pH = 1, selectivity ~95%, continuous reaction time > 10 h) for the electrocatalytic reduction of oxygen to produce hydrogen peroxide in a liquid-phase system at room temperature and pressure under a wide pH range. The produced hydrogen peroxide has wide applications in medicine, industry, and environmental protection, and therefore has significant market potential. Attached Figure Description
[0042] Figure 1 This is a surface SEM image of the Co-Ni-C catalytic material prepared in Example 1.
[0043] Figure 2 This is a magnified SEM image of the Co-Ni-C catalytic material prepared in Example 1.
[0044] Figure 3 This is a TEM image of the surface of the Co-Ni-C catalytic material prepared in Example 1.
[0045] Figure 4 This is a TEM magnified image of the Co-Ni-C catalytic material prepared in Example 1.
[0046] Figure 5 This is a HAADF-STEM image of the Co-Ni-C catalytic material prepared in Example 1.
[0047] Figure 6 The linear sweep voltage (LSV) curves of hydrogen peroxide prepared by electrocatalytic oxygen reduction in an electrolyte at pH=1 using the Co-Ni-C material prepared in Example 1 as a catalyst are shown.
[0048] Figure 7 The linear sweep voltage (LSV) curves of the preparation of hydrogen peroxide by electrocatalytic oxygen reduction in an electrolyte at pH 3.5 using the Co-Ni-C material prepared in Example 1 as a catalyst are shown.
[0049] Figure 8 The linear sweep voltage (LSV) curves of hydrogen peroxide prepared by electrocatalytic oxygen reduction in an electrolyte at pH 7.4 using the Co-Ni-C material prepared in Example 1 as a catalyst are shown.
[0050] Figure 9The time-current (It) curves for preparing hydrogen peroxide by long-term electrocatalytic oxygen reduction using the Co-Ni-C material prepared in Example 1 as a catalyst in an electrolyte with pH=1 are shown.
[0051] Figure 10 This is a surface SEM image of the Co-Ni-C catalytic material prepared in Example 3.
[0052] Figure 11 This is a magnified SEM image of the Co-Ni-C catalytic material prepared in Example 3.
[0053] Figure 12 This is a TEM image of the surface of the Co-Ni-C catalytic material prepared in Example 3. Detailed Implementation
[0054] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
[0055] Example 1:
[0056] A Co-Ni-C composite material is prepared by the following steps:
[0057] Step 1: Add 0.6g of zinc nitrate, 0.072g of cobalt nitrate, and 0.1mg of nickel acetylacetone to a 50mL beaker, and then add 35g of anhydrous methanol and anhydrous ethanol as a metal salt solution. Stir on a magnetic stirrer until the metal salt is completely dissolved to obtain a metal salt solution.
[0058] Step 2: Add the above metal salt solution to 350g of NaCl hard template, and then stir to mix the metal salt solution and NaCl hard template evenly to obtain a mixture.
[0059] Step 3: Take another 50mL beaker, add 0.45g of dimethylimidazole to a metal salt solution of 35g of anhydrous methanol and anhydrous ethanol, and stir on a magnetic stirrer until the organic ligand is completely dissolved to obtain a dimethylimidazole alcohol solution.
[0060] Step 4: Pour the above dimethylimidazol solution into the mixture and stir until the metal salt and organic ligand react completely and uniformly. Then place it in an electric drying oven and dry at 80°C for 6 hours to dry the alcohol solvent and obtain the precursor.
[0061] Step 5: Pyrolyze the above precursor in a tube furnace at a temperature of 650°C and a heating rate of 5°C / min. -1 The heat treatment time was 1 hour to obtain the carbonized precursor.
[0062] Step 6: The obtained carbonized precursor was washed with deionized water and filtered to remove the NaCl hard template. The filtered material was then washed successively with 1M hydrochloric acid aqueous solution and deionized water. The resulting material was then placed in an electric drying oven and dried at 80℃ for 6 hours to remove moisture. Finally, it was calcined at 950℃ for 30 minutes to obtain the Co-Ni-C composite material.
[0063] The surface morphology of the prepared Co-Ni-C catalytic material was observed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). Figures 1-4 As shown, this material is composed of stacked sheets with a size of μm. Its surface is relatively smooth with some wrinkles, and it possesses a hierarchical porous structure due to the overlapping of the nanosheets. Figure 3 As shown in the box, after pickling and high-temperature calcination, the metal particles are removed, leaving a large number of pore structures of varying sizes on the surface of the 2D carbon material. For example... Figure 5 As shown, Co and Ni are loaded onto two-dimensional graphene nanosheets in the form of single atoms.
[0064] Example 2
[0065] The catalytic performance of the Co-Ni-C composite material prepared in Example 1 was tested. Specifically, a 0.1M HClO4 aqueous solution was prepared as the electrolyte for the catalytic performance test. The Co-Ni-C composite material was uniformly dispersed in a 1:80 mixture of Nafion and water to obtain a slurry with a concentration of 3 mg / mL. This slurry was then drop-coated onto a glassy carbon electrode portion of a rotating disk electrode and dried at room temperature to obtain a glassy carbon electrode loaded with the Co-Ni-C composite material. This glassy carbon electrode loaded with the Co-Ni-C composite material was used as the working electrode, and a graphite rod as the counter electrode. The activity, selectivity, and long-term stability of its electrocatalytic oxygen reduction to hydrogen peroxide production were tested.
[0066] like Figure 6 As shown, when the pH of the electrolyte is adjusted to 1.5, the Co-Ni-C composite material can reach an initial reaction potential of 0.70V vs. RHE in 0.1M HClO4 electrolyte. It can achieve a selectivity of >80% in an ultra-long voltage range of >0.7V, and achieve a selectivity of nearly 100% near the voltage range of ~0.7V, indicating that Co-Ni-C has excellent activity and selectivity in 0.1M HClO4.
[0067] In addition, such as Figure 7-8As shown, when the pH of the electrolyte was adjusted to 3.5 and 7.4, the Co-Ni-C composite material started to react at 0.40V vs. RHE and 0.80V vs. RHE, respectively, and achieved selectivity of 85% and 93% near voltages of ~0.2V and ~0.6V, respectively. This indicates that the material has excellent electrocatalytic activity and selectivity for the reduction of two electrons of oxygen to hydrogen peroxide in a wide range of pH = 1 to 7.
[0068] like Figure 9 As shown, when the pH of the electrolyte is adjusted to 1.5, the Co-Ni-C composite material can continuously operate for more than 10 hours at a voltage of 0.5V vs. RHE in 0.1M HClO4 while maintaining selectivity of ~95%, indicating that the material also has good stability.
[0069] Example 3
[0070] Based on Example 1, the pyrolysis temperature in this example is controlled at 550℃, the pyrolysis time is 2h, and all other conditions are the same as in Example 1. The final Co-Ni-C composite material has surface morphology SEM and TEM images as shown below. Figures 10-12 As shown in the figure, the Co-Ni-C composite material is still composed of stacked sheets with a size of μm. Its surface is relatively smooth with some wrinkles, and it possesses a hierarchical porous structure due to the overlapping of the nanosheets. Testing revealed that the electrocatalytic oxygen reduction to hydrogen peroxide production performance of this Co-Ni-C composite material is similar to that of Example 1.
[0071] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A Co-Ni-C composite material, characterized by, It includes two-dimensional graphene nanosheets and Co and Ni bimetallic elements uniformly dispersed in single-atom form and loaded on the two-dimensional graphene nanosheets; The Co-Ni-C composite material is prepared by the following steps: Step 1: Dissolve cobalt salt, zinc salt and nickel salt in a solvent in a predetermined ratio to prepare a metal salt solution; Step 2: Add the metal salt solution from Step 1 to a predetermined amount of hard template, stir until uniformly mixed, and dry to obtain the mixture; Step 3: Add the organic ligand to a mixed solvent of anhydrous methanol and anhydrous ethanol, and stir magnetically until the organic ligand is completely dissolved to obtain an organic ligand alcohol solution. Step 4: Add the organic ligand alcohol solution prepared in Step 3 to the mixture obtained in Step 2, stir to allow the metal salt and organic ligand to react uniformly and completely, and then dry to obtain the precursor. Step 5: Pyrolyze the precursor obtained in Step 4 to obtain the carbonized precursor; Step 6: Wash and filter the carbonized precursor obtained in step 5 to remove the hard template, and then wash, dry, clean and calcine to obtain the Co-Ni-C composite material. The mass ratio of Ni to Co in the Co-Ni-C composite material is 7.5:1 to 8.5:
1. In step 1, the cobalt salt is cobalt nitrate, the zinc salt is zinc nitrate, the nickel salt is nickel acetylacetone, and the solvent is a mixture of anhydrous methanol and anhydrous ethanol. The organic ligand is 2,5-dihydroxyterephthalic acid, terephthalic acid, or dimethylimidazole; The mass ratio of cobalt nitrate to zinc nitrate is (1-3):(25-30), the mass ratio of nickel acetylacetonate to the sum of the masses of cobalt nitrate and zinc nitrate is (1-7):1300; the mass ratio of anhydrous methanol to anhydrous ethanol is (3-4):(1-0). In step 2, the hard template is sodium chloride, and the mass ratio of the hard template to the metal salt solution is (10-15):
1.
2. The Co-Ni-C composite material of claim 1, wherein In step 3, the mass ratio of the organic ligand to the sum of the masses of cobalt nitrate and zinc nitrate is (9-10):13, and the mass ratio of anhydrous methanol to anhydrous ethanol is (3-4):(1-0).
3. The Co-Ni-C composite material as described in claim 1, characterized in that, The drying method in step 4 is to place the item in an electric drying oven at a temperature of 80-90℃ for 6-48 hours. The washing method in step 6 is to wash the substance obtained after filtration with hydrochloric acid aqueous solution and deionized water of a predetermined concentration in sequence. The drying method in step 6 is to place the container in an electric drying oven at a temperature of 80-90°C for 6-48 hours. The concentration of the hydrochloric acid aqueous solution in step 6 is 1-2M, and the container is calcined at a temperature greater than or equal to 800°C for 30-60 minutes. In step 5, the pyrolysis temperature is greater than or equal to 550℃, the heating rate is 5-10℃min⁻¹, and the holding time is 1-2h.
4. The application of the Co-Ni-C composite material as described in any one of claims 1-3 as a catalyst in the electrocatalytic oxygen reduction to prepare hydrogen peroxide.
5. The application as described in claim 4, characterized in that, Co-Ni-C composite material was uniformly dispersed in a mixed solution of nafion and water to obtain a slurry with a concentration of 1-3 mg / mL. This slurry was then drop-coated onto a glassy carbon electrode portion of a rotating disk electrode and dried at room temperature to obtain a glassy carbon electrode loaded with Co-Ni-C composite material. A 0.05-0.15 M aqueous solution of HClO4 was prepared as the electrolyte. Using the glassy carbon electrode loaded with Co-Ni-C composite material as the working electrode and a graphite rod as the counter electrode, H2O2 was prepared by electrolysis at a voltage less than 0.70 V (RHE). The volume ratio of nafion to water was 1:(80-115).