Preparation method and application of yarn-like nickel-cobalt hydroxide modified electrode materials

Abstract

This invention discloses a method for preparing a tufted nickel-cobalt hydroxide nanomaterial modified electrode material. The tufted nickel-cobalt hydroxide is prepared on carbon paper using a constant potential method. The electrolyte is a solution of nickel sulfate and cobalt sulfate. The specific operation is as follows: S1. Carbon paper pretreatment; S2. Electrode preparation is a solution containing nickel sulfate and cobalt sulfate; S3. Electrode preparation finally obtains the tufted electrode material.

Description

Technical Field

[0001] This invention relates to the field of electrochemical technology, and in particular to the preparation method and application of tufted nickel-cobalt hydroxide modified electrode materials. Background Technology

[0002] Nickel hydroxide and transition metal hydroxides form layered hydroxides, which exhibit excellent electrochemical activity due to their unique layered structure and large surface area. Nickel-cobalt hydroxide-based electrode materials are widely used in supercapacitors, photocatalysis, and lithium-ion batteries. However, the tendency of nanomaterials to agglomerate and their low conductivity significantly affect their performance. The emergence of self-supporting electrodes can solve the problems of nanomaterial agglomeration and poor electrode conductivity. Currently, self-supporting electrodes are commonly prepared using hydrothermal methods and electrochemical deposition. Hydrothermal methods suffer from cumbersome post-processing, while electrochemical deposition offers advantages such as simple preparation methods, no need for precursor solutions, and no need for templates. Zhang Yu et al. constructed a three-dimensional CoxP@NiCo-LDH heterostructure nanosheet array on nickel foam using electrodeposition and high-temperature phosphating techniques, creating an enzyme-free glucose sensor (Yu Zhang, Zhiyuan He, Qiaoyan Dong, Xin Tang, Lu Yang, Ke Huang, Zhirong Zou, Xue Jiang, Xiaoli Xiong, Microchemical Journal, 2022, 172(Part A): 106923); Annalakshmi Muthaiah et al. successfully synthesized flower-like NiCo layered double hydroxide microspheres composed of three-dimensional ultrathin nanosheets using a hydrothermal method, and applied NiCo... LDH-modified glassy carbon electrodes serve as highly efficient bifunctional electrocatalysts for non-enzymatic glucose and hydrogen peroxide biosensors. These electrodes exhibit enhanced electrocatalytic sensing performance with rapid response times (<3 s), wide linear ranges (50 nM-18.95 mM and 20 nM-11.5 mM), and limits of detection (S / N = 3) (10.6 and 4.4 nm), along with good stability, selectivity, and reproducibility (Annalakshmi Muthaiah; Kumaravel Sakthivel; Chen Tse Wei; Chen Shen Ming; Lou Bih Show, ACS Applied Bio Materials, 2021, 4(4): 3203-3213). Song Dandan successfully synthesized three-dimensional (3D) hierarchical layered double hydroxide (LDH) nanomaterials with high specific surface area and more active sites on carbon cloth via a simple hydrothermal method. This electrode material exhibits excellent electrochemical catalytic oxidation performance (Song Dandan, International Journal of Electrochemical...). Science, 2020, 15(3): 1949-1963). On the other hand, the structure of nanomaterials on the electrode has a significant impact on the electrode's performance.Among them, three-dimensional structural materials have unique structures and large specific surface areas, which can provide sufficient catalytic active sites. Non-enzymatic glucose sensors based on these materials exhibit many advantages such as fast response speed, high sensitivity, and strong stability. The coiled structure can help increase the surface area and the number of active sites, thereby helping to improve the relevant performance of the material. Xu Bin et al. prepared coiled MnO2 and found that it showed good stability as a lithium-ion cathode material (Xu Shan, Lu Lin, Liu Lian, Luo Yiwen, Wang Shiquan, Liu Jianwen, Li Guohua, Feng Chuanqi. Journal of Inorganic Chemistry, 2016, 32(01):124-130.). Zhang Hua et al. synthesized a coiled C / BiOCl catalyst that responds to visible light using a hydrothermal method and found that it has good photocatalytic performance and cycle stability (Zhang Hua, Li Dongya, Cai Yujie, Sun Lei, Cheng Gong, Xu Haiming, Xia Dongsheng. Modern Chemical Industry, 2018, 47(06):1119-1123). Zhang Yahui et al. successfully synthesized coiled cobalt sulfide nanochains with significant magnetic anisotropy using wet chemical methods and low-temperature sulfidation methods (Zhang Yahui, Guo Lin, Liu Kang, He Lin, Chen Jinping. Rare Metal Materials and Engineering, 2009, 38(S2):1003-1006.). Ma Shaofeng et al. synthesized spherical nickel hydroxide with good catalytic performance using a hydrothermal method (Ma Shaofeng, Peng Shujing, Zhang Yuhao, Liu Dongfang, Gao Jianhui. Shandong Chemical Industry, 2021, 50(03):20-21.). However, nickel-cobalt layered hydroxides are prone to agglomeration, which reduces their conductivity and affects their catalytic performance. At the same time, the morphology of nanomaterials has a significant impact on their performance, and there is currently little research on spherical or coiled cobalt-nickel hydroxides. Summary of the Invention

[0003] (I) Technical Issues

[0004] This application aims to address the problem that nickel-cobalt layered hydroxides are prone to agglomeration, which reduces their conductivity and affects their catalytic performance.

[0005] (II) Technical Solution

[0006] This invention provides an electrode material modified with a yarn-like nickel-cobalt hydroxide nanomaterial, and characterizes the morphology and elements of the material. An enzyme-free glucose sensor is constructed using this material, which exhibits a wide linear range, high sensitivity, significant stability and repeatability, excellent anti-interference ability, and good experimental results.

[0007] This invention provides a method for preparing a tufted electrode material, which involves preparing tufted nickel-cobalt hydroxide on carbon paper using a potentiostatic method. The electrolyte is a solution of nickel sulfate and cobalt sulfate. The specific operation is as follows:

[0008] S1. Carbon paper pretreatment: Cut the hydrophilic carbon paper into strips of 1cm×2cm, then ultrasonically clean it 2-3 times with anhydrous ethanol and distilled water respectively, and dry it in an oven at 60℃ for later use.

[0009] S2. The electrolyte is a solution containing nickel sulfate and cobalt sulfate, wherein the molar ratio of cobalt ions to nickel ions is 0.1:4 to 0.3:4.

[0010] S3. Electrode Preparation: A three-electrode system was formed by using treated carbon paper as the working electrode, a platinum sheet electrode as the auxiliary electrode, and a calomel electrode as the reference electrode. 20 ml of electrolyte was added to a beaker. Using a CHI660D electrochemical workstation, an amperometric current-time program was selected, setting the working potential to -0.75V to -1.1V and the time to 180 to 300 seconds, respectively. After the run, the electrodes were removed, washed with distilled water, and dried under an infrared lamp, ultimately yielding a tufted electrode material.

[0011] In another aspect, the present invention provides a NiCo hydroxide with a three-dimensional structure, wherein the three-dimensional NiCo hydroxide has a "fluffy" structure, wherein the "fluffy" structure is composed of nanofibers and contains C, O, Co and Ni elements.

[0012] (III) Beneficial Effects

[0013] This invention addresses the issue of existing electrodes being susceptible to agglomeration and low conductivity due to nanomaterials. It constructs a self-supporting nickel-cobalt hydroxide / carbon paper electrode by depositing a three-dimensional, tufted nickel-cobalt hydroxide on conductive carbon paper, thus preventing nickel-cobalt hydroxide agglomeration and improving its conductivity. Simultaneously, this tufted three-dimensional structure effectively increases its specific surface area and enhances the number of active sites, contributing to improved electrocatalytic oxidation performance.

[0014] The enzyme-free glucose sensor constructed using this electrode has a wide detection range, high sensitivity, good stability and repeatability, as well as excellent anti-interference ability and experimental results. Attached Figure Description

[0015] Figure 1 Ampere current-time response to glucose solutions of different concentrations under different concentrations of cobalt ions (a), synthesis potential (b), and synthesis time (c).

[0016] Figure 2 SEM images of nickel-cobalt hydroxide at different resolutions.

[0017] Figure 3 EDS diagram of nickel-cobalt hydroxide / carbon paper electrode material.

[0018] Figure 4 The current-time curve (a) of the NiCo hydroxide / carbon paper electrode at 0.60 V and the linear fit of the current intensity with glucose concentration (b). Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figure 1-4 As shown, this invention provides a three-electrode system consisting of a treated carbon paper as the working electrode, a platinum sheet electrode as the auxiliary electrode, and a calomel electrode as the reference electrode. A nickel-cobalt hydroxide / carbon paper self-supporting electrode was synthesized using a CHI660D electrochemical workstation with a cobalt sulfate and nickel sulfate solution in a molar ratio of 0.2:4 at a working potential of -1.0V and a working time of 240s, selected by an amperometric current-time program. After the reaction, the electrode was rinsed clean and dried under an infrared lamp for 10 minutes before use. Furthermore, by adjusting and controlling the concentration ratio of cobalt sulfate to nickel sulfate, the synthesis potential, and the synthesis time, its response to different concentrations of glucose was studied, as shown in [reference needed]. Figure 1 As shown in the figure, the synthesized electrode exhibited the most significant continuous detection signal for glucose under the conditions of a cobalt ion concentration of 5.00 mM, a synthesis potential of -1.0 V, and a synthesis time of 240 seconds. The morphology and elemental composition of the electrode material prepared under these conditions are shown in the figures. Figure 2 and Figure 3 As shown in the figure, a three-dimensional material with a diameter of about 2 μm is uniformly distributed on the carbon paper fiber in the form of a tuft of yarn. This electrode material mainly contains C, O, Co and Ni elements.

[0021] The prepared nickel-cobalt hydroxide / carbon paper self-supported electrode, platinum sheet electrode, and calomel electrode were used as the working electrode, counter electrode, and reference electrode of a three-electrode system, respectively. 20 ml of 0.1 mol / L NaOH solution was used as the electrolyte. Using the Ampere current-time response method in a CHI660D electrochemical workstation, the response signal of the electrode to the continuous droplet addition of glucose solution was recorded at the optimal potential of 0.6 V. Figure 4The electrode exhibited good linearity in glucose concentrations of 0–0.84 mmol / L and 0.84–3.04 mmol / L, demonstrating high sensitivity (5430 μA·mmol⁻¹·L·cm⁻²). Furthermore, it displayed excellent reproducibility and stability, significant anti-interference capabilities, and strong experimental performance.

[0022] It should be noted that, in this document, terms such as "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0023] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing electrode materials modified with tufted nickel-cobalt hydroxide nanomaterials, characterized in that: A tufted nickel-cobalt hydroxide was prepared on carbon paper using a potentiostatic method. The electrolyte was a solution of nickel sulfate and cobalt sulfate. The specific operation is as follows: S1. Carbon paper pretreatment: Cut the hydrophilic carbon paper into strips of 1cm×2cm, then ultrasonically clean it 2-3 times with anhydrous ethanol and distilled water respectively, and dry it in an oven at 60℃ for later use. S2. The electrolyte is a solution containing nickel sulfate and cobalt sulfate, wherein the molar ratio of cobalt ions to nickel ions is 0.1:4 to 0.3:4; S3. Electrode preparation: The treated carbon paper was used as the working electrode, the platinum sheet electrode as the auxiliary electrode, and the calomel electrode as the reference electrode to form a three-electrode system; 20 ml of electrolyte was added to the beaker, and the amperometric current-time program was selected in the CHI660D electrochemical workstation. The working potential and time were set to -0.75V to -1.1V and 180 to 300 seconds, respectively. After the operation was completed, the electrode was removed, washed with distilled water, and dried under an infrared lamp to finally obtain a tufted electrode material to construct an enzyme-free glucose sensor. The nickel-cobalt hydroxide has a three-dimensional structure with a "fluffy" structure containing C, O, Co and Ni elements.

2. The tufted nickel-cobalt hydroxide prepared by the preparation method described in claim 1 is used as a nanomaterial-modified electrode material to construct an enzyme-free glucose sensor.

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