Carbon nanotube supported nickel-iron phytate oer catalysts and methods of making same
A simple and efficient one-step co-precipitation method was used to prepare nickel-iron phytate catalysts supported on carbon nanotubes, which solved the problems of long preparation time and high cost of existing OER catalysts, and achieved high OER activity and low cost catalyst application.
Patent Information
- Application Number
- CN202510101552.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-22
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2045-01-22
AI Technical Summary
Existing OER catalysts are time-consuming, costly, and have low catalytic activity, which limits their widespread application. In particular, the scarcity and high cost of Ru and Ir-based materials further hinder their application.
A simple and efficient one-step co-precipitation method was used to prepare a nickel-iron phytate catalyst supported on carbon nanotubes. The catalyst was prepared by stirring and mixing a mixture of soluble nickel salt, iron salt and carbon nanotubes with an aqueous solution of sodium phytate at room temperature, thereby generating nickel-iron phytate nanoparticles supported on carbon nanotubes. The conductivity of carbon nanotubes and the photothermal response characteristics of nickel-iron phytate were utilized to accelerate the reaction kinetics and enhance the catalytic activity under near-infrared irradiation.
A low-cost and simple catalyst preparation method was achieved, which has high OER activity and significantly improves catalytic activity under near-infrared light irradiation. This method solves the problem of the effectiveness of the preparation method, reduces the activation energy of OER, and improves the energy conversion efficiency of electrochemical water splitting.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of catalysts, and particularly relates to a carbon nanotube-loaded nickel-iron phytate OER catalyst and a preparation method thereof. BACKGROUND
[0002] Hydrogen energy is an energy carrier with great development prospects, and electrocatalytic water splitting is one of the effective strategies to obtain sustainable green hydrogen energy, including cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER). However, OER involves a four-electron transfer process, which requires a higher energy to overcome the slow reaction kinetics, greatly limiting the energy conversion efficiency of electrochemical water splitting. At present, Ru and Ir-based materials have very high OER activity, but their scarcity and excessively high cost hinder their wide application. Therefore, it is imperative to design and manufacture OER electrocatalysts with cost-effectiveness and high performance.
[0003] Transition metal phosphates have flexible coordination characteristics, which can effectively stabilize the intermediate state of the active center, and the phosphate group can also act as a proton acceptor to accelerate proton conductivity, and are one of the OER catalysts with great development prospects. However, the long preparation time and high-temperature treatment cause excessive consumption of energy, and the low catalytic activity limits its application. SUMMARY
[0004] In order to solve the above problems, the application provides a carbon nanotube-loaded nickel-iron phytate OER catalyst and a preparation method thereof. The carbon nanotube-loaded nickel-iron phytate OER catalyst is prepared by a simple and efficient one-step co-precipitation method, and the preparation method is simple and can be prepared at room temperature. The prepared catalyst has high OER activity, and due to the characteristics of photo-thermal response of the catalyst, the OER activity can be further significantly improved under near-infrared light.
[0005] The application is implemented by the following technical solutions.
[0006] The application provides a preparation method of a carbon nanotube-loaded nickel-iron phytate OER catalyst, comprising the following steps:
[0007] A mixed solution of soluble nickel salt, soluble iron salt and carbon nanotubes is prepared with water as the dispersion medium.
[0008] The sodium phytate aqueous solution is mixed with the mixed solution, and complexation is stirred at room temperature. Nickel-iron phytate nanoparticles generated in the complexation process are loaded on the carbon nanotubes to obtain the carbon nanotube-loaded nickel-iron phytate OER catalyst. Both phytic acid and its sodium salt have strong metal chelating ability, but the acid-base properties of their aqueous solutions are quite different. The phytic acid aqueous solution is acidic, while the sodium phytate aqueous solution is alkaline. The application uses sodium phytate.
[0009] Preferably, the amount of Ni element is 70% to 90% of the total moles of Ni and Fe, more preferably 80%.
[0010] Preferably, the total amount of the soluble nickel salt and the soluble iron salt and the amount of the carbon nanotubes in the mixed solution are in a ratio of 0.01 g to 0.02 g: 1 mg to 2 mg. More preferably, the soluble nickel salt and the soluble iron salt are dissolved in water to obtain a mixed salt solution, and the mixed salt solution is mixed with the aqueous dispersion of the carbon nanotubes under stirring to obtain the mixed solution. The solid-liquid ratio of the total amount of the soluble nickel salt and the soluble iron salt and water is 0.02 g to 0.04 g: 1 mL, more preferably 0.03 g: 1 mL; the concentration of the aqueous dispersion of the carbon nanotubes is 1 mg / mL to 2 mg / mL, more preferably 1.5 mg / mL; and the volume ratio of the mixed salt solution and the aqueous dispersion of the carbon nanotubes is 1:2.
[0011] Preferably, the molar ratio of sodium phytate to the total amount of Ni and Fe is 1:2 to 3, more preferably 1:2.5.
[0012] Preferably, the stirring time for complexation is 0.5 h to 1.5 h, more preferably 1 h.
[0013] Preferably, the soluble nickel salt and the soluble iron salt are corresponding nitrate salts.
[0014] Preferably, the stirring time for preparation of the mixed solution is 5 min.
[0015] Preferably, after the complexation reaction is completed, centrifugal separation, washing, and drying are performed, and the drying temperature is 60°C, and the drying time is 12 h.
[0016] The application provides a carbon nanotube-supported nickel-iron phytate OER catalyst prepared by the above preparation method. The carbon nanotubes are connected and intertwined with each other, and the surface of the carbon nanotubes is loaded with nickel-iron phytate nanoparticles, and the average diameter of the nickel-iron phytate nanoparticles is 30 nm. The carbon nanotubes provide more growth space for the particles and expose more active sites, and at the same time, the carbon nanotubes can enhance the electrical conductivity of the nanomaterials. The abundant functional groups on the surface of the carbon nanotubes adsorb metal ions through electrostatic attraction, and then the multiple complexation sites of the phytate enable it to bind different metal ions in one or more ligands, further strengthening the intermetallic synergistic effect.
[0017] The application provides an oxygen evolution reaction (OER) electrocatalyst, which is a carbon nanotube supported nickel-iron phytate OER catalyst.
[0018] Compared with the prior art, the application has the following beneficial effects:
[0019] The application first prepares a mixed solution containing soluble nickel salt, soluble iron salt and carbon nanotube in an aqueous dispersion medium, then mixes a sodium phytate aqueous solution with the mixed solution, and complexes under stirring at room temperature. Nickel-iron phytate nanoparticles generated in the complexing process are loaded on the carbon nanotube to obtain the carbon nanotube supported nickel-iron phytate OER catalyst. The preparation method of the application adopts a simple one-step co-precipitation method at room temperature, does not require special equipment, has low cost, can be scaled up, has high repeatability, and has a broad industrial application prospect.
[0020] The carbon nanotube supported nickel-iron phytate nanomaterial prepared by the application has excellent OER performance, and the catalyst has a photothermal response feature, which can further significantly improve the OER activity under near-infrared light. For example, under near-infrared light irradiation, a current density of 1000 mA cm-2 is only required at 285 mV. Near-infrared light irradiation offsets the endothermic enthalpy change and reduces the activation energy of OER, significantly improving the OER performance. -2 BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 The figure is an XRD pattern of the catalyst sample prepared in Example 1 of the application.
[0022] Figure 2 The figure is an SEM pattern of the catalyst sample prepared in Example 1 of the application.
[0023] Figure 3 The figure is a TEM pattern of the catalyst sample prepared in Example 1 of the application.
[0024] Figure 4 The figure is a linear sweep voltammetry curve of the OER of the catalyst sample prepared in Example 1 of the application in 1M KOH solution.
[0025] Figure 5 Linear sweep voltammogram of the catalyst sample prepared for the embodiment 1 of the present application under near-infrared light irradiation, wherein (a) to (e) the near-infrared light intensity gradually increases.
[0026] Figure 6 SEM image of the catalyst sample prepared for the comparative example 1 of the present application.
[0027] Figure 7 Linear sweep voltammogram of the catalyst sample prepared for the comparative example 1 of the present application in 1M KOH solution.
[0028] Figure 8 SEM image of the catalyst sample prepared for the comparative example 2 of the present application.
[0029] Figure 9 Linear sweep voltammogram of the catalyst sample prepared for the comparative example 2 of the present application in 1M KOH solution.
[0030] Figure 10 Linear sweep voltammogram of the catalyst sample prepared for different nickel-iron metal ratio ranges in 1M KOH solution.
[0031] Figure 11 Linear sweep voltammogram of the catalyst sample prepared for different concentration ranges of the aqueous dispersion of carbon nanotubes in 1M KOH solution.
[0032] Figure 12 Linear sweep voltammogram of the catalyst sample prepared for different ratio ranges of phytate and metal salt in 1M KOH solution.
[0033] Figure 13 Linear sweep voltammogram of the catalyst sample prepared for different time ranges of stirring complexation in 1M KOH solution. DETAILED DESCRIPTION
[0034] In order for those skilled in the art to better understand the technical solutions of the present application and to implement them, the present application will be further described below in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present application. The experimental methods and detection methods described in the following embodiments are all conventional methods unless otherwise specified; and the reagents and materials described are all commercially available unless otherwise specified.
[0035] In order to solve the problems that the preparation of the current OER catalyst is time-consuming and the high-temperature treatment causes excessive consumption of energy, and the poor conductivity and low catalytic activity limit its application, the present application provides a preparation method of carbon nanotube loaded nickel-iron phytate nanomaterial, comprising the following steps:
[0036] Dissolve soluble nickel salt and soluble iron salt in water to obtain a mixed salt solution, and mix the mixed salt solution with a water dispersion of carbon nanotubes under stirring to obtain a mixed solution.
[0037] Dissolve sodium phytate in water and add to the mixed solution, and complex under stirring at room temperature. The nickel-iron phytate nanoparticles generated in the complexing process are loaded on the carbon nanotubes to obtain carbon nanotube-loaded nickel-iron phytate nanomaterial. The structure of the carbon nanotube-loaded nickel-iron phytate nanomaterial is that the carbon nanotubes are connected and intertwined with each other, and the nickel-iron phytate nanoparticles with an average diameter of about 30 nm are modified on the surface of the carbon nanotubes; the carbon nanotubes provide more growth space for the particles and expose more active sites, and meanwhile the carbon nanotubes can enhance the electrical conductivity of the nanomaterial. The abundant functional groups on the surface of the carbon nanotubes adsorb metal ions through electrostatic attraction, and then the multiple complexing sites of the phytate enable it to bind different metal ions within one or more ligands, further strengthening the intermetallic synergistic effect.
[0038] The present application is specifically illustrated below by the following examples and comparative examples.
[0039] Example 1
[0040] (1) 30 mg of carbon nanotubes were added to 20 mL of deionized water, and ultrasonic dispersion was performed to form a uniform carbon nanotube dispersion.
[0041] (2) 0.8 mM of nickel nitrate hexahydrate and 0.2 mM of iron nitrate nonahydrate were dissolved in 10 mL of deionized water, and stirring was performed to form a uniform solution.
[0042] (3) The metal salt solution was added to the carbon nanotube dispersion, and stirring was performed for 5 min.
[0043] (4) 0.4 mM of sodium phytate was dissolved in 10 mL of deionized water, and stirring was performed to form a uniform solution;
[0044] (5) The sodium phytate solution was added to the mixed solution in (3), and complexing was performed under stirring for 1 h.
[0045] (6) Centrifugal separation was performed, and washing was performed with deionized water and ethanol for multiple times, and vacuum drying was performed at 60°C for 12 h to obtain the final sample.
[0046] The carbon nanotube-loaded nickel-iron phytate nanomaterial prepared in Example 1 was subjected to OER reaction performance test, and the details are as follows:
[0047] Weigh 2.5 mg of the catalyst sample (the catalyst prepared in Example 1 of this invention, hereinafter referred to as the catalyst sample) and add it to a solution containing 480 μL of isopropanol and 20 μL of Naifon solution (5 wt%). Sonicate the solution for 30 min to ensure uniform dispersion. Apply 5 μL of the uniformly dispersed sample solution to the surface of a glassy carbon electrode. After drying, perform testing using a standard three-electrode system, with a graphite rod as the counter electrode, mercury / mercuric oxide as the reference electrode, and 1 M KOH as the electrolyte. The scan rate for the linear voltammetry curve is 5 mV / s.
[0048] Test results: such as Figure 4 As shown, when 20 mA·cm -2 At a current density of , the overpotential is 245mV.
[0049] Considering the excellent photothermal effects of both nickel phytate and carbon nanotubes, the OER performance of the carbon nanotube-supported nickel-iron phytate nanomaterials prepared in this embodiment was further tested under near-infrared light irradiation. As the intensity of near-infrared light increased, i.e., from (a) to (e) gradually increased, the carbon nanotube-supported nickel-iron phytate nanomaterials prepared in this embodiment exhibited a gradually decreasing overpotential, such as... Figure 5 As shown, the maximum light intensity reaches 1000 mA·cm. -2 The required current density is only 285mV. This is attributed to the fact that under near-infrared irradiation, light energy is directly converted into heat energy, promoting interfacial charge transfer and accelerating reaction kinetics, thereby improving OER performance.
[0050] Comparative Example 1
[0051] (1) Add 30 mg of carbon nanotubes to 20 mL of deionized water and ultrasonically disperse to form a uniform carbon nanotube dispersion.
[0052] (2) Dissolve 1 mM nickel nitrate hexahydrate in 10 mL of deionized water and stir to form a homogeneous solution.
[0053] (3) Add the metal salt solution to the carbon nanotube dispersion and stir for 5 minutes.
[0054] (4) Dissolve 0.4 mM sodium phytate in 10 mL of deionized water and stir to form a homogeneous solution.
[0055] (5) Add the sodium phytate solution to the mixed solution in (3) and stir to complex for 1 hour.
[0056] (6) Centrifuge, wash with deionized water and ethanol multiple times, and vacuum dry at 60°C for 12 hours to obtain the final sample.
[0057] The OER reaction performance of the carbon nanotube-supported nickel-iron phytate nanomaterial prepared in Comparative Example 1 was tested, and the specific implementation method is as in Example 1.
[0058] Test results: such as Figure 7 As shown, when 20 mA·cm -2 At a current density of [value missing], the overpotential was 377 mV. Compared to Example 1, Comparative Example 1 did not introduce iron, resulting in an increased overpotential.
[0059] Comparative Example 2
[0060] (1) Add 30 mg of carbon nanotubes to 20 mL of deionized water and ultrasonically disperse to form a uniform carbon nanotube dispersion.
[0061] (2) Dissolve 1 mM ferric nitrate nonahydrate in 10 mL of deionized water and stir to form a homogeneous solution.
[0062] (3) Add the metal salt solution to the carbon nanotube dispersion and stir for 5 minutes.
[0063] (4) Dissolve 0.4 mM sodium phytate in 10 mL of deionized water and stir to form a homogeneous solution.
[0064] (5) Add the sodium phytate solution to the mixed solution in (3) and stir to complex for 1 hour.
[0065] (6) Centrifuge, wash with deionized water and ethanol multiple times, and vacuum dry at 60°C for 12 hours to obtain the final sample.
[0066] The OER reaction performance of the carbon nanotube-supported nickel-iron phytate nanomaterials prepared in Comparative Example 2 was tested, and the specific implementation method is as in Example 1.
[0067] Test results: such as Figure 9 As shown, when 20 mA·cm -2 At a current density of [value missing], the overpotential was 452 mV. Compared to Example 1, Comparative Example 2 did not introduce nickel, resulting in an increased overpotential.
[0068] Figure 1 This is the XRD pattern of the catalyst sample prepared in Example 1 of this invention. Figure 1 As can be seen, no obvious diffraction peaks were observed, indicating that the prepared nanomaterials have an amorphous configuration; the broad diffraction peaks at around 26° are attributed to the presence of carbon nanotubes.
[0069] Figure 2 This is a SEM image of the catalyst sample prepared in Example 1 of this invention. Figure 2 It can be seen that the structure of the prepared nanomaterial consists of interconnected and entangled carbon nanotubes, with nickel-iron phytate nanoparticles generated by complexation loaded on the carbon nanotubes.
[0070] Figure 3 TEM image of the catalyst sample prepared for Example 1 of the present application. It can be seen that the structure of the prepared nanomaterial is that carbon nanotubes are connected and intertwined with each other, and the nickel-iron phytate nanoparticles with an average diameter of about 30 nm are decorated on the surface of the carbon nanotubes. Figure 3
[0071] SEM image of the catalyst sample prepared for Comparative Example 1 of the present application. It can be seen that the structure of the prepared nanomaterial is that carbon nanotubes are connected and intertwined with each other, and the nickel phytate nanoparticles complexed and generated are loaded on the carbon nanotubes. The number of nickel phytate nanoparticles is small, which may be attributed to the relatively weak complexing ability of phytate for nickel ions. Figure 6 Figure 6 SEM image of the catalyst sample prepared for Comparative Example 2 of the present application. It can be seen that the structure of the prepared nanomaterial is that carbon nanotubes are connected and intertwined with each other, and the iron phytate nanoparticles complexed and generated are loaded on the carbon nanotubes.
[0072] Figure 8 Figure 8 Example 2
[0073] Compared with Example 1, the molar ratio of nickel-iron metal is 9:1. The specific steps are as follows:
[0074] Compared with Example 1, the molar ratio of nickel-iron metal is 7:3. The specific steps are as follows:
[0075] (1) 30 mg of carbon nanotubes were added to 20 mL of deionized water to form a uniform carbon nanotube dispersion by ultrasonic dispersion.
[0076] (2) 0.9 mM of nickel nitrate hexahydrate and 0.1 mM of iron nitrate nonahydrate were dissolved in 10 mL of deionized water to form a uniform solution by stirring.
[0077] (3) The metal salt solution was added to the carbon nanotube dispersion, and stirred for 5 min.
[0078] (4) 0.4 mM of sodium phytate was dissolved in 10 mL of deionized water to form a uniform solution by stirring;
[0079] (5) The sodium phytate solution was added to the mixed solution in (3), and stirred for 1 h for complexation.
[0080] (6) Centrifugal separation, washed with deionized water and ethanol for several times, and vacuum dried at 60°C for 12 h to obtain the final sample.
[0081] Example 3
[0082] Compared with Example 1, the molar ratio of nickel-iron metal is 7:3. The specific steps are as follows:
[0083] (1) 30 mg of carbon nanotubes were added to 20 mL of deionized water, and ultrasonic dispersion was performed to form a uniform carbon nanotube dispersion liquid.
[0084] (2) 0.7 mM of nickel nitrate hexahydrate and 0.3 mM of iron nitrate nonahydrate were dissolved in 10 mL of deionized water, and stirring was performed to form a uniform solution.
[0085] (3) The metal salt solution was added to the carbon nanotube dispersion liquid, and stirring was performed for 5 min.
[0086] (4) 0.4 mM of sodium phytate was dissolved in 10 mL of deionized water, and stirring was performed to form a uniform solution.
[0087] (5) The sodium phytate solution was added to the mixed solution in (3), and complexation was performed by stirring for 1 h.
[0088] (6) Centrifugal separation was performed, deionized water and ethanol were used for multiple washing, and vacuum drying was performed at 60°C for 12 h to obtain the final sample.
[0089] Example 4
[0090] Compared with Example 1, the concentration of the water dispersion liquid of carbon nanotubes was 1 mg / mL. The specific steps were as follows:
[0091] (1) 20 mg of carbon nanotubes were added to 20 mL of deionized water, and ultrasonic dispersion was performed to form a uniform carbon nanotube dispersion liquid.
[0092] (2) 0.8 mM of nickel nitrate hexahydrate and 0.2 mM of iron nitrate nonahydrate were dissolved in 10 mL of deionized water, and stirring was performed to form a uniform solution.
[0093] (3) The metal salt solution was added to the carbon nanotube dispersion liquid, and stirring was performed for 5 min.
[0094] (4) 0.4 mM of sodium phytate was dissolved in 10 mL of deionized water, and stirring was performed to form a uniform solution.
[0095] (5) The sodium phytate solution was added to the mixed solution in (3), and complexation was performed by stirring for 1 h.
[0096] (6) Centrifugal separation was performed, deionized water and ethanol were used for multiple washing, and vacuum drying was performed at 60°C for 12 h to obtain the final sample.
[0097] Example 5
[0098] Compared with Example 1, the concentration of the water dispersion liquid of carbon nanotubes was 2 mg / mL. The specific steps were as follows:
[0099] (1) 40 mg of carbon nanotubes were added to 20 mL of deionized water, and ultrasonic dispersion was performed to form a uniform carbon nanotube dispersion liquid.
[0100] (2) Dissolve 0.8 mM nickel nitrate hexahydrate and 0.2 mM iron nitrate nonahydrate in 10 mL of deionized water, and stir to form a uniform solution.
[0101] (3) Add the metal salt solution into the carbon nanotube dispersion, and stir for 5 min.
[0102] (4) Dissolve 0.4 mM sodium phytate in 10 mL of deionized water, and stir to form a uniform solution;
[0103] (5) Add the sodium phytate solution into the mixed solution in (3), and stir to complex for 1 h.
[0104] (6) Centrifugal separation, wash with deionized water and ethanol for several times, and vacuum dry at 60 °C for 12 h to obtain the final sample.
[0105] Example 6
[0106] Compared with Example 1, the molar ratio of phytate to metal salt is 1:2. The specific steps are as follows:
[0107] (1) Add 30 mg of carbon nanotubes into 20 mL of deionized water, and ultrasonically disperse to form a uniform carbon nanotube dispersion.
[0108] (2) Dissolve 0.8 mM nickel nitrate hexahydrate and 0.2 mM iron nitrate nonahydrate in 10 mL of deionized water, and stir to form a uniform solution.
[0109] (3) Add the metal salt solution into the carbon nanotube dispersion, and stir for 5 min.
[0110] (4) Dissolve 0.5 mM sodium phytate in 10 mL of deionized water, and stir to form a uniform solution;
[0111] (5) Add the sodium phytate solution into the mixed solution in (3), and stir to complex for 1 h.
[0112] (6) Centrifugal separation, wash with deionized water and ethanol for several times, and vacuum dry at 60 °C for 12 h to obtain the final sample.
[0113] Example 7
[0114] Compared with Example 1, the molar ratio of phytate to metal salt is 1:3. The specific steps are as follows:
[0115] (1) Add 30 mg of carbon nanotubes into 20 mL of deionized water, and ultrasonically disperse to form a uniform carbon nanotube dispersion.
[0116] (2) Dissolve 0.8 mM nickel nitrate hexahydrate and 0.2 mM iron nitrate nonahydrate in 10 mL of deionized water, and stir to form a uniform solution.
[0117] (3) Add the metal salt solution into the carbon nanotube dispersion solution, and stir for 5 min.
[0118] (4) Dissolve 0.3 mM sodium phytate into 10 mL deionized water, and stir to form a uniform solution;
[0119] (5) Add the sodium phytate solution into the mixed solution in (3), and stir to complex for 1 h.
[0120] (6) Centrifugal separation, wash with deionized water and ethanol for several times, and vacuum dry at 60°C for 12 h to obtain the final sample.
[0121] Example 8
[0122] Compared with Example 1, the stirring complexation is 0.5 h. The specific steps are as follows:
[0123] (1) Add 30 mg of carbon nanotubes into 20 mL of deionized water, and ultrasonically disperse to form a uniform carbon nanotube dispersion solution.
[0124] (2) Dissolve 0.8 mM nickel nitrate hexahydrate and 0.2 mM iron nitrate nonahydrate into 10 mL of deionized water, and stir to form a uniform solution.
[0125] (3) Add the metal salt solution into the carbon nanotube dispersion solution, and stir for 5 min.
[0126] (4) Dissolve 0.4 mM sodium phytate into 10 mL of deionized water, and stir to form a uniform solution;
[0127] (5) Add the sodium phytate solution into the mixed solution in (3), and stir to complex for 0.5 h.
[0128] (6) Centrifugal separation, wash with deionized water and ethanol for several times, and vacuum dry at 60°C for 12 h to obtain the final sample.
[0129] Example 9
[0130] Compared with Example 1, the stirring complexation is 1.5 h. The specific steps are as follows:
[0131] (1) Add 30 mg of carbon nanotubes into 20 mL of deionized water, and ultrasonically disperse to form a uniform carbon nanotube dispersion solution.
[0132] (2) Dissolve 0.8 mM nickel nitrate hexahydrate and 0.2 mM iron nitrate nonahydrate into 10 mL of deionized water, and stir to form a uniform solution.
[0133] (3) Add the metal salt solution into the carbon nanotube dispersion solution, and stir for 5 min.
[0134] (4) Dissolve 0.4 mM sodium phytate salt in 10 mL of deionized water, and stir to form a uniform solution;
[0135] (5) Add the sodium phytate salt solution to the mixed solution in (3), and stir to complex for 1.5 h.
[0136] (6) Centrifugalize, wash with deionized water and ethanol multiple times, and vacuum dry at 60°C for 12 h to obtain the final sample.
[0137] Figure 10 Linear sweep voltammograms of the OER of catalyst samples prepared for different ranges of nickel-iron metal ratios in 1M KOH solution. It can be seen that the catalytic performance is similar in the above ratio range, but is best when the nickel-iron metal molar ratio is 8:2.
[0138] Figure 11 Linear sweep voltammograms of the OER of catalyst samples prepared for different ranges of concentrations of carbon nanotube aqueous dispersion in 1M KOH solution. It can be seen that the catalytic performance is similar in the above ratio range, but is best when the concentration of the carbon nanotube aqueous dispersion is 1.5 mg / mL.
[0139] Figure 12 Linear sweep voltammograms of the OER of catalyst samples prepared for different ranges of ratios of phytate salt to metal salt in 1M KOH solution. It can be seen that the catalytic performance is similar in the above ratio range, but is best when the phytate salt to metal salt molar ratio is 1:2.5.
[0140] Figure 13 Linear sweep voltammograms of the OER of catalyst samples prepared for different ranges of complexing times in 1M KOH solution. It can be seen that the catalytic performance is similar in the above ratio range, but is best when the complexing time is 1 h.
[0141] It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit and scope of the application. Thus, it is intended that the present application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.
Claims
1. A method for preparing a carbon nanotube-supported nickel-iron phytate OER catalyst, characterized by, The method comprises the following steps: Preparation of a mixed solution of soluble nickel salt, soluble iron salt and carbon nanotubes with water as the dispersion medium; Mixing of a sodium phytate aqueous solution with the mixed solution and stirring for complexation at room temperature, the nickel-iron phytate nanoparticles generated during the complexation process being loaded on the carbon nanotubes to obtain a carbon nanotube-loaded nickel-iron phytate OER catalyst; The amount of Ni element is 70% to 90% of the total moles of Ni and Fe; in the carbon nanotube-loaded nickel-iron phytate OER catalyst, the carbon nanotubes are connected and intertwined with each other, the surface of the carbon nanotubes is loaded with nickel-iron phytate nanoparticles, and the average diameter of the nickel-iron phytate nanoparticles is 30 nm; the carbon nanotube-loaded nickel-iron phytate OER catalyst catalyzes the anode oxygen evolution reaction under near-infrared light irradiation; In the mixed solution, the total amount of soluble nickel salt and soluble iron salt and the amount of carbon nanotubes are in a ratio of 0.01 g to 0.02 g to 1 mg to 2 mg; The molar ratio of the total amount of Ni and Fe in the sodium phytate is 1:2 to 3; The stirring time for complexation is 0.5 h to 1.5 h.
2. The production method according to claim 1, characterized by, The soluble nickel salt and the soluble iron salt are dissolved in water to obtain a mixed salt solution, and the mixed salt solution is mixed with the water dispersion of carbon nanotubes under stirring to obtain a mixed solution.
3. The production method according to claim 2, characterized by, In the mixed salt solution, the total amount of soluble nickel salt and soluble iron salt and the solid-liquid ratio of water are 0.02 g to 0.04 g to 1 mL; the concentration of the water dispersion of carbon nanotubes is 1 mg / mL to 2 mg / mL, and the volume ratio of the mixed salt solution to the water dispersion of carbon nanotubes is 1:
2.
4. The carbon nanotube-loaded nickel-iron phytate OER catalyst prepared by the preparation method according to any one of claims 1 to 3.
5. The carbon nanotube supported nickel-iron phytate OER catalyst of claim 4, wherein, In the carbon nanotube-loaded nickel-iron phytate OER catalyst, the carbon nanotubes are connected and intertwined with each other, the surface of the carbon nanotubes is loaded with nickel-iron phytate nanoparticles, and the average diameter of the nickel-iron phytate nanoparticles is 30 nm.
6. The carbon nanotube supported nickel-iron phytate OER catalyst of claim 4, wherein, The carbon nanotube-loaded nickel-iron phytate OER catalyst catalyzes the anode oxygen evolution reaction under near-infrared light irradiation.