A preparation method of a nickel-cobalt-aluminum layered double hydroxide combined with a two-dimensional transition metal carbide oxygen reduction catalyst

Abstract

This invention discloses a method for preparing an oxygen reduction catalyst composed of a nickel-cobalt-aluminum layered double hydroxide and a two-dimensional transition metal carbide, comprising the following steps: preparing a nickel-cobalt-aluminum layered double hydroxide and a two-dimensional transition metal carbide; attaching the nickel-cobalt-aluminum layered double hydroxide to the two-dimensional transition metal carbide, thereby successfully preparing the nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide, and disclosing its application as a cathode catalyst for microbial fuel cells. The material prepared by this invention has high porosity, numerous reaction sites, good electrochemical stability, and high conductivity. Therefore, as a cathode catalyst for microbial fuel cells, it improves the efficiency of ion flow, ensures the stability of electrode cycling and power generation efficiency, thereby improving the performance of microbial fuel cells.

Description

Background Technology

[0001] Microbial fuel cells (MFCs) are a technology based on microbial electrochemical systems that provides energy and treats wastewater, and are now widely used in various fields. Their low energy consumption, environmental friendliness, and high efficiency have attracted much research attention. However, low power density, long cycle time, high material costs, and low cathode reaction efficiency have hindered their further development. To address these issues, many researchers have focused on optimizing materials for the structurally simple air cathode. Extensive research has found that layered double hydroxides and two-dimensional transition metal carbides, due to their large specific surface area, numerous active sites, and stable electrochemical properties, have become hot topics in MFC research.

[0002] Layered double hydroxides (LDHs) are a class of two-dimensional nanoflower-like materials that are inexpensive, highly reactive in reduction, and environmentally friendly, with their performance significantly improved upon combination with metal ions. However, they still suffer from problems such as self-stacking and low ion transport efficiency. To address these issues, many researchers have combined them with porous materials such as carbon nanotubes and graphene. MXene, a two-dimensional transition metal carbon nanomaterial, has attracted considerable attention due to its excellent electrical conductivity, hydrophilic surface, and structural stability. Its numerous surface-active groups also make MXene an ideal substrate material, and its large specific surface area simplifies electron transport and surface modification. However, its self-stacking and low mass density hinder its use as an electrode material. Therefore, it is necessary to explore new strategies to enhance its inherent electrocatalytic performance. Many scholars have focused on modifying MXene by combining it with metal-doped layered double hydroxides to improve its activity, but related research is limited, and the synthesized composite materials also present some problems. Therefore, further solutions are needed to address these issues. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing an oxygen reduction catalyst composed of nickel-cobalt-aluminum layered double hydroxides and two-dimensional transition metal carbides. The prepared microbial fuel cell cathode catalyst can effectively improve the power generation performance of MFC.

[0004] This invention is achieved through the following technical solution:

[0005] A method for preparing an oxygen reduction catalyst composed of a nickel-cobalt-aluminum layered double hydroxide and a two-dimensional transition metal carbide, the method comprising the following steps:

[0006] Step 1: Take 4 g of Ti3AlC2 and put it into 80 mL of HF solution, stir magnetically; centrifuge, freeze dry, and obtain Ti3C2MXene.

[0007] Step 2: Dissolve 0.9 g NiCl2·H2O, 0.45 g CoCl2·H2O, 0.46 g AlCl3·H2O, and 1.5 g urea in 70 mL of deionized water and stir thoroughly; then put it into a reaction vessel, heat it, centrifuge and dry it to obtain nickel cobalt aluminum layered double hydroxide.

[0008] Step 3: Dissolve 0.9 g NiCl2·H2O, 0.45 g CoCl2·H2O, 0.46 g AlCl3·H2O, and 1.5 g urea in 70 mL of deionized water and stir at room temperature for 30 minutes. After stirring, add 100 mg C6H8O. 10 · H2O and 350 mg of Ti3C2 MXene prepared in step one were stirred thoroughly; the solution was transferred to a 100 mL polytetrafluoroethylene sampling tube and placed in a stainless steel autoclave for heating; after cooling to room temperature, it was centrifuged and dried to obtain nickel cobalt aluminum layered double hydroxide combined with two-dimensional transition metal carbide.

[0009] Furthermore, the stirring described in step one is performed at room temperature for 20 hours.

[0010] Furthermore, the stirring described in step two is stirring at room temperature for 30 minutes.

[0011] Furthermore, the heating described in step two is heating at 120 °C for 10 h.

[0012] Furthermore, the drying process described in step two involves drying at 60°C for 8 hours.

[0013] Furthermore, the thorough stirring described in step three is stirring at room temperature for 4 hours.

[0014] Furthermore, the heating described in step three is heating at 120 °C for 10 h.

[0015] Furthermore, the drying process described in step three involves drying at 60°C for 8 hours.

[0016] This invention provides a method for preparing an oxygen reduction catalyst of nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbides. A simple one-step hydrothermal method was used to successfully prepare the multi-metal composite material of nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbides. First, the Al layer in Ti3AlC2 MXene was removed by etching to obtain Ti3C2 MXene. Then, NiCoAl-LDH was uniformly grown on the surface of Ti3C2 MXene using a one-step hydrothermal method. A unique nanostructure was thus created, which significantly improved the performance of the nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbides as a cathode for microbial fuel cells by providing a large number of ion transport channels and active sites. Finally, a titanium dioxide / bimetallic organic framework compound combined with zinc-aluminum layered double hydroxide microbial fuel cell cathode was prepared using a two-layer polytetrafluoroethylene (PTEF) method on a stainless steel wire mesh (SS) substrate, and its effect on improving the performance of microbial fuel cells was investigated. Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of the preparation method of the oxygen reduction catalyst of nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide of the present invention.

[0018] Figure 2 This is a SEM image of the preparation method of the oxygen reduction catalyst of nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide according to the present invention. Figure 2 a is a scanning electron microscope image of a two-dimensional transition metal carbide. Figure 2 b is a scanning electron microscope image of nickel-cobalt-aluminum layered double hydroxide. Figure 2 c is a scanning electron microscope image of a nickel-cobalt-aluminum layered double hydroxide combined with a two-dimensional transition metal carbide. Figure 2 d is a scanning electron microscope image of a nickel-cobalt-aluminum layered double hydroxide combined with a two-dimensional transition metal carbide;

[0019] Figure 3 The FT-IR and XRD patterns of the two-dimensional transition metal carbide, the nickel-cobalt-aluminum layered double hydroxide, and the nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide are shown in the preparation method of the oxygen reduction catalyst of the present invention.

[0020] Figure 4 XPS images of two-dimensional transition metal carbides, nickel-cobalt-aluminum layered double hydroxides, and nickel-cobalt-aluminum layered double hydroxides combined with two-dimensional transition metal carbides in the preparation method of the oxygen reduction catalyst of the present invention.

[0021] Figure 5In the preparation method of the oxygen reduction catalyst of nickel cobalt aluminum layered double hydroxide combined with two-dimensional transition metal carbide of the present invention, the CV curve and LSV curve of two-dimensional transition metal carbide, nickel cobalt aluminum layered double hydroxide, and nickel cobalt aluminum layered double hydroxide combined with two-dimensional transition metal carbide as nano-microbial fuel electrocathode catalyst are shown.

[0022] Figure 6 The CV curves of the nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide nano-microbial fuel electrocathode catalyst at different scan rates are shown in the preparation method of the oxygen reduction catalyst of the present invention.

[0023] Figure 7 The power density curves of the two-dimensional transition metal carbide, the nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide nano-microbial fuel electrocathode catalyst in the preparation method of the present invention are shown when the voltage is stable. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to specific embodiments.

[0025] Example 1

[0026] Please see Figure 1 , Figure 1 This is a schematic flowchart of the preparation method of the oxygen reduction catalyst of nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide according to the present invention.

[0027] like Figure 1 As shown, this invention provides a method for preparing an oxygen reduction catalyst composed of a nickel-cobalt-aluminum layered double hydroxide and a two-dimensional transition metal carbide, comprising the following steps:

[0028] Step 1: Take 4 g of Ti3AlC2 and put it into 80 mL of HF solution, stir magnetically; centrifuge, freeze dry, and obtain Ti3C2MXene.

[0029] Step 2: Dissolve 0.9 g NiCl2·H2O, 0.45 g CoCl2·H2O, 0.46 g AlCl3·H2O, and 1.5 g urea in 70 mL of deionized water and stir thoroughly. Then, transfer the solution to a reaction vessel, heat, centrifuge, and dry to obtain nickel-cobalt-aluminum layered double hydroxide.

[0030] Step 3: Dissolve 0.9 g NiCl2·H2O, 0.45 g CoCl2·H2O, 0.46 g AlCl3·H2O, and 1.5 g urea in 70 mL of deionized water and stir at room temperature for 30 minutes. After stirring, add 100 mg C6H8O. 10 · H2O and 350 mg of Ti3C2 MXene prepared in step one were stirred thoroughly; the solution was transferred to a 100 mL polytetrafluoroethylene sampling tube and placed in a stainless steel autoclave for heating; after cooling to room temperature, it was centrifuged and dried to obtain nickel cobalt aluminum layered double hydroxide combined with two-dimensional transition metal carbide.

[0031] Following the three steps described above, the prepared nickel-cobalt-aluminum layered double hydroxide combined two-dimensional transition metal carbide oxygen reduction catalyst is complete. After these three steps, the structure can be tested, for example, by using the sample as a cathode to test the performance of a microbial fuel cell.

[0032] Step 4: Electrochemical performance testing was conducted on an electrochemical workstation using a three-electrode system. The performance of the microbial fuel cell was tested using a composite material of nickel-cobalt-aluminum layered double hydroxides combined with two-dimensional transition metal carbides as the cathode catalyst.

[0033] The abbreviations used in this invention are all fixed abbreviations in the field, and some of the letters are explained as follows: SEM: Scanning Electron Microscope; FTIR: Fourier Transform Infrared Spectroscopy; XRD: X-ray Diffraction Pattern; XPS: X-ray Photoelectron Spectroscopy.

[0034] Example 3

[0035] This implementation case demonstrates an implementation scheme for an oxygen reduction catalyst combining nickel-cobalt-aluminum layered double hydroxides and two-dimensional transition metal carbides, as follows:

[0036] This invention aims to investigate the electrochemical performance of oxygen reduction catalysts composed of nickel-cobalt-aluminum layered double hydroxides and two-dimensional transition metal carbides. Two-dimensional transition metal carbides, nickel-cobalt-aluminum layered double hydroxides, and nickel-cobalt-aluminum layered double hydroxides combined with two-dimensional transition metal carbides were used as MFC cathode catalysts. CV and LSV experiments were conducted in 50 mM PBS solution.

[0037] Please see Figure 4Comparison of cyclic voltammetry curves reveals that, at the same scan rate, the cyclic voltammetric integral area of ​​the nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide is significantly larger than that of other catalysts. The results indicate that the synthesized nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide nanostructure possesses excellent redox performance. The high specific surface area of ​​the nickel-cobalt-aluminum layered double hydroxide and the stable two-dimensional transition metal carbide synergistically increase ion transport channels and enhance redox activity. As shown in the figure, the composite material of nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide exhibits a distinct redox peak in PBS solution, indicating the valence state transition of nickel and cobalt ions within the composite material. This further demonstrates the redox activity of the nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide as a cathode catalyst.

[0038] To further investigate the electrocatalytic activity of the composite catalyst, the LSV curves of different catalysts were examined. The results showed that the order of catalyst slope was: nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide > nickel-cobalt-aluminum layered double hydroxide > two-dimensional transition metal carbide. The slope of the voltammetric curves indicated that, at the same cathode potential, the nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide exhibited a larger current and higher conductivity. Overall, the oxygen reduction catalyst of nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide possesses good redox performance and high catalytic efficiency.

[0039] Example 3

[0040] This implementation case demonstrates an implementation scheme for a nickel-cobalt-aluminum layered double hydroxide combined with a two-dimensional transition metal carbide oxygen reduction catalyst, as shown below:

[0041] To investigate the electrochemical performance of the nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide oxygen reduction catalyst, two-dimensional transition metal carbide, nickel-cobalt-aluminum layered double hydroxide, and nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide oxygen reduction catalysts were used as MFC cathode catalysts, respectively. CV experiments were conducted in 50 mM PBS solution.

[0042] Please see Figure 6 , Figure 5Cyclic voltammetry (CV) curves of the nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide oxygen reduction catalyst at different scan rates are shown. The scan rates ranged from 10 to 100 mV / s, and the potential ranged from -1.0 to 1.0 V. As the current varied, the CV curves maintained a consistent shape; even with increasing current, the CV curves remained smooth and stable, indicating the stability and reversibility of the composite material. Within a certain range, as the scan rate increased, the composite material exhibited more pronounced redox peaks and more stable redox reaction activity. The cyclic voltammetry curves at different scan rates demonstrate that the nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide oxygen reduction catalyst can significantly improve the electrocatalytic performance of the MFC air cathode.

[0043] Example 4

[0044] This implementation case demonstrates an implementation scheme for an oxygen reduction catalyst combining nickel-cobalt-aluminum layered double hydroxides and two-dimensional transition metal carbides, as follows:

[0045] Please see Figure 7 Two-dimensional transition metal carbides, nickel-cobalt-aluminum layered double hydroxides, and a combination of nickel-cobalt-aluminum layered double hydroxides and two-dimensional transition metal carbides were used as cathode catalysts for single-chamber MFCs, respectively, while maintaining a consistent anolyte state, to evaluate the impact of different cathode catalysts on the power generation capacity of the MFC. The power density curves and voltage at stable voltage were evaluated by gradually reducing the external resistance of the MFC (from 2000 Ω to 20 Ω).

[0046] Please see Figure 7 The maximum power density of nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide-MFC can reach 362.404 mW / m³. 2 It is 1.54 times that of two-dimensional transition metal carbides-MFC (234.256 mW / m). 2 It is 1.71 times that of nickel-cobalt-aluminum layered double hydroxides (211.56 mW / m). 2 The results show that the cathode modified with nickel-cobalt-aluminum layered double hydroxides combined with two-dimensional transition metal carbides exhibits good power generation performance and redox activity.

[0047] Please refer to Table 1. The continuous output voltage of the nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide-MFC is 452 mV, which is 2.1 times (214 mV) of the two-dimensional transition metal carbide-MFC and 3.5 times (130 mV) of the nickel-cobalt-aluminum layered double hydroxide. The higher voltage means faster glucose consumption, which further proves that the nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide is more effective as a cathode catalyst in the ORR reaction. In addition, the output voltage of the nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide MFC does not change much over 10 days, indicating that the catalyst has good durability and cycle stability.

[0048]

[0049] The specific conclusions of the oxygen reduction catalyst of nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide described in the above embodiments are as follows:

[0050] Please see Figure 2 , Figure 2 This is a SEM image of the preparation method of the oxygen reduction catalyst of nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide according to the present invention. Figure 2 a is a scanning electron microscope image of a two-dimensional transition metal carbide. Figure 2 b is a scanning electron microscope image of a two-dimensional transition metal carbide. Figure 2 Image c is a scanning electron microscope (SEM) image of a nickel-cobalt-aluminum layered double hydroxide combined with a two-dimensional transition metal carbide. The SEM image clearly shows the surface morphology of each element, further confirming the perfect preparation of the nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide. The two-dimensional transition metal carbide exhibits a distinct layered structure, indicating that the Al layer was successfully etched away in the HF solution. The nickel-cobalt-aluminum layered double hydroxide possesses a bouquet-shaped nanosheet structure, and its abundant spherical porous structure provides numerous active sites and ion channels. The nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide exhibits a very obvious 3D porous structure. The nickel-cobalt-aluminum layered double hydroxide is uniformly attached to the surface and interlayer of the two-dimensional transition metal carbide, roughening the material surface, providing more reactive sites, and improving structural stability. The nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide is a nanocomposite material with sheet-like two-dimensional transition metal carbide as the substrate and nickel-cobalt-aluminum layered double hydroxide attached to the surface. SEM testing further confirms that the composite material has been perfectly prepared and possesses great catalytic potential.

[0051] Please see Figure 3 , Figure 3In the preparation method of the oxygen reduction catalyst of nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide of the present invention, FT-IR and XRD patterns of two-dimensional transition metal carbide, nickel-cobalt-aluminum layered double hydroxide, and nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide are shown. The FT-IR pattern clearly shows the composition of functional groups on the surface of the composite material. In the pattern of nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide, 1373 cm⁻¹... -1 For Cl -1 The vibration peak is at 1684 cm. -1 The prominent peak at 1537 cm⁻¹ represents hydroxyl groups. -1 The peak at 2347 cm⁻¹ represents the torsional vibration of water molecules. -1 The vibrational peak of -OH (between hydroxyl and composite material) indicates the perfect bonding between the composite materials. At 3604 cm⁻¹ -1 The weakening peak indicates a reduction in free hydroxyl radicals, further demonstrating the successful adhesion of the nickel-cobalt-aluminum layered double hydroxide to the surface of the two-dimensional transition metal carbide. Some are less than 800 cm⁻¹. -1 The peak, for example, at 672 cm. -1 The values ​​represent the tensile vibrations of the metal-oxygen bond and the double hydroxide crystal structure. The XRD pattern clearly shows the diffraction planes of each component in the composite material. The two-dimensional transition metal carbide, nickel-cobalt-aluminum layered double hydroxide, and nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide all have obvious characteristic peaks, indicating that the plate-like zinc-aluminum layered double hydroxide substrate and the dual organic framework compound core have been successfully prepared. (002) and (004) are the diffraction planes of the two-dimensional transition metal carbide. The absence of a peak at 2θ=39° indicates the successful etching of the Al layer. (003), (006), (012), and (110) are the diffraction planes of the nickel-cobalt-aluminum layered double hydroxide. In the diffraction planes of the nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide, the peak at 2θ=8.94° is positioned further to the left than that of the two-dimensional transition metal carbide diffraction planes, indicating that the self-stacking effect of the two-dimensional transition metal carbide is significantly reduced after the attachment of the nickel-cobalt-aluminum layered double hydroxide. (012), (105), and (100) are the diffraction planes of the nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide. The diffraction planes of the nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide are not obvious because the addition of the nickel-cobalt-aluminum layered double hydroxide makes the material surface rougher and the crystallinity lower. However, the rough surface can provide more active sites, which is more conducive to catalysis.

[0052] XRD tests show that the nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbides has been perfectly synthesized.

[0053] Please see Figure 4 , Figure 4 XPS spectra of the two-dimensional transition metal carbide, nickel-cobalt-aluminum layered double hydroxide, and nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide in the preparation method of the oxygen reduction catalyst of the present invention are shown. The XPS spectra clearly show the content and valence state of each element in the composite material. By scanning each sample with XPS, it was found that the sample of nickel-cobalt-aluminum layered double hydroxide combined with two-dimensional transition metal carbide contains peaks of both nickel-cobalt-aluminum layered double hydroxide and two-dimensional transition metal carbide, indicating that the sample was perfectly prepared. In the figure, the significant signal peaks of Ni (856.32 eV), Co (781.47 eV), O (531.73 eV), Ti (455.24 eV), Cl (285.25 eV), and Al (68.4 eV) indicate the perfect synthesis of elements such as Ni, Co, O, Ti, and Cl in the sample. The O1 (531.8 eV) is a -OH bond, indicating the presence of M-OH (M=Ni, Mn, and Zn) bonds. The C 1s plot shows the successful synthesis of nickel-cobalt-aluminum layered double hydroxides and two-dimensional transition metal carbides. The signal peaks at 288.37 eV, 285.49 eV, 284.35 eV, and 280.76 eV correspond to OC=O, CO, CC / C=C, and C-Ti-Tx bonds, respectively. At 280.76 eV, all C-Ti-Tx bonds are converted to C-Ti bonds, indicating that the Tx groups on the MXene surface have been removed by the nickel-cobalt-aluminum layered double hydroxide. In Ni 2p 3 / 2 In the XPS plot, the signal peaks at 880 eV and 862.1 eV are two satellite peaks, and the signal peaks at 856.5 eV and 873.8 eV represent Ni2p. 3 / 2 and Ni 2p 1 / 2 This indicates the presence of layered double hydroxides in the composite material. In the XPS diagram of Co 2p, the signal peak of trivalent cobalt ions is significantly higher than that of divalent cobalt ions, indicating that the cobalt ion valence state in the nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide is mainly trivalent. In the XPS diagram of Ti 2p, the signal peaks at 464.41 eV, 463.45 eV, 461.09 eV, 458.5 eV, 457.6 eV, and 455.59 eV represent Ti-C bonds, Ti-O bonds, Ti-X bonds, and Ti... x O y The key further demonstrates the Ti3C2T x It exists in the composite material. The above results indicate that the nickel-cobalt-aluminum layered double hydroxide was successfully attached to the surface of the two-dimensional transition metal carbide and occupied a relatively large proportion, further demonstrating the successful synthesis of the nickel-cobalt-aluminum layered double hydroxide combined with the two-dimensional transition metal carbide.

[0054] Comparative Example 1

[0055] The other steps are the same as in Example 1, except that the HF solution in step 1 is replaced with a hydrochloric acid solution: sodium fluoride solution = 2:1. After testing, no obvious layered structure was found, indicating that etching was not successful in the hydrochloric acid and sodium fluoride solutions. No bouquet-shaped nanosheet structure was observed under field emission scanning electron microscopy.

[0056] Compared with existing technologies, the advantages of this invention are: the composite material uses a multilayer two-dimensional transition metal carbide as a substrate, with nickel-cobalt-aluminum layered double hydroxide uniformly attached to its surface. The composite material's large specific surface area and numerous active sites promote ion transport. This special structure of the composite material has high porosity, providing channels for ion transfer between the two-dimensional transition metal carbide and the nickel-cobalt-aluminum layered double hydroxide, thus improving its redox capacity. The combination of the nickel-cobalt-aluminum layered double hydroxide and the two-dimensional transition metal carbide increases the electron transport rate, reduces surface resistance, and enhances its electrochemical activity as a microbial fuel cell.

Claims

1. The application of a nickel-cobalt-aluminum layered double hydroxide combined with a two-dimensional transition metal carbide oxygen reduction catalyst in a microbial fuel cell, characterized in that, The preparation method includes the following steps: Step 1: Take 4 g of Ti3AlC2 and put it into 80 mL of HF solution. Stir magnetically at room temperature for 20 h. Centrifuge and freeze dry to obtain Ti3C2 MXene. Step 2: Dissolve 0.9 g NiCl2·H2O, 0.45 g CoCl2·H2O, 0.46 g AlCl3·H2O, and 1.5 g urea in 70 mL of deionized water and stir at room temperature for 30 minutes; after stirring, add 100 mg C6H8O. 10 • H2O and 350 mg of Ti3C2 MXene prepared in step one were stirred at room temperature for 4 h; the solution was transferred to a 100 mL polytetrafluoroethylene sampling tube and placed in a stainless steel autoclave, heated at 120 ℃ for 10 h; cooled to room temperature, centrifuged, and dried at 60 ℃ for 8 h to obtain an oxygen reduction catalyst of nickel cobalt aluminum layered double hydroxide combined with two-dimensional transition metal carbide.

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