阅读说明：本技术 超薄纳米花状的钴/六氨基苯导电聚合物及其应用 (Ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer and application thereof ) 是由 付永胜 李春 高艳婷 施玲玲 陈鹏 朱俊武 汪信 欧阳晓平 于 2019-11-13 设计创作，主要内容包括：本发明公开了一种超薄纳米花状的钴/六氨基苯导电聚合物及其在电催化析氧反应中的应用。所述的超薄纳米花状的钴/六氨基苯导电聚合物通过先将六氨基苯三盐酸盐加入到N,N-二甲基甲酰胺-去氧超纯水体系中在冰浴下搅拌溶解,再与钴盐溶液混合均匀后加入氨水,搅拌反应制得。本发明以六氨基苯三盐酸盐为前驱体材料,采用液相法制备了超薄纳米花状钴/六氨基苯导电聚合物,所述的聚合物对析氧反应具有优异的催化性能,其过电位达到310mV,适用于电催化析氧反应。(The invention discloses an ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer and application thereof in electrocatalytic oxygen evolution reaction. The ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer is prepared by adding hexa-aminobenzene trihydrochloride into an N, N-dimethylformamide-deoxidized ultrapure water system, stirring and dissolving in an ice bath, uniformly mixing with a cobalt salt solution, adding ammonia water, and stirring and reacting. The invention takes hexa-aminobenzene tri-hydrochloride as a precursor material, and adopts a liquid phase method to prepare the ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer, the polymer has excellent catalytic performance on oxygen evolution reaction, the overpotential of the polymer reaches 310mV, and the polymer is suitable for electrocatalytic oxygen evolution reaction.)

1. The preparation method of the ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer is characterized by comprising the following specific steps of:

dropwise adding N, N-dimethylformamide-deoxidized ultrapure water solution of hexaminobenzenetrihydrochloride into a cobalt salt solution according to the molar ratio of hexaminobenzenetrihydrochloride to cobalt salt of 1:2: 8-1: 3:15, stirring uniformly, dropwise adding ammonia water, stirring at 60-75 ℃ for reaction, after the reaction is finished, washing with water and absolute ethyl alcohol, drying in vacuum, and grinding to obtain the ultrathin nanometer flower-shaped cobalt/hexaminobenzene conductive polymer.

2. The method according to claim 1, wherein the N, N-dimethylformamide-deoxygenated ultrapure aqueous solution of hexaminobenzenetrihydrochloride is prepared by dissolving hexaminobenzenetrihydrochloride in N, N-dimethylformamide and deoxygenated ultrapure water under ice bath.

3. The method of claim 1, wherein the cobalt salt is selected from the group consisting of cobalt acetate, cobalt nitrate, and cobalt chloride.

4. The method according to claim 1, wherein the molar ratio of hexa-aminobenzene trihydrochloride, ammonia water and cobalt salt is 1:2: 10.

5. The preparation method according to claim 1, wherein the stirring reaction time is 2-4 h.

6. The method according to claim 1, wherein the drying temperature is 60 to 70 ℃.

7. The ultra-thin nano flower-like cobalt/hexa-aminobenzene conductive polymer prepared by the preparation method according to any one of claims 1 to 6.

8. The ultra-thin nanoflower cobalt/hexa-aminobenzene conductive polymer of claim 7, wherein the average thickness of the ultra-thin nanoflower sheet is 4.5 nm.

9. The use of the ultra-thin nanoflower-like cobalt/hexa-aminobenzene conductive polymer according to claim 7 or 8 as a catalyst in electrocatalytic oxygen evolution reactions.

Technical Field

The invention relates to an ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer and application thereof in electrocatalytic oxygen evolution reaction, belonging to the technical field of electrocatalytic oxygen evolution catalysts.

Background

The electrocatalytic water decomposition technology can extract hydrogen from non-fossil fuel, which is a clean energy source, and has attracted extensive attention in various industries related to energy sources (electric vehicles, satellites, aerospace and the like). The water electrolysis process comprises an anodic Oxygen Evolution Reaction (OER) and a cathodic Hydrogen Evolution Reaction (HER), and the oxygen evolution reaction process is a four electron transfer process, requires a higher overpotential and thus becomes a bottleneck for electrocatalytic water decomposition. The oxygen evolution reaction requires a noble metal catalyst such as ruthenium oxide, RuO₂IrO (iridium oxide)₂The scarcity and high cost of noble metals limits the utility of electrocatalytic water splitting in practical production.

The conductive polymer formed by the transition metal central ions and the organic ligand can achieve the catalytic activity equivalent to that of a noble metal catalyst, but the stability and the conductivity are poor, and high-temperature sintering is needed to be used for electrocatalysis in most cases. Wang et al synthesized Co-loaded Co by using cobalt salt and dimethyl imidazole as raw materials through liquid phase method and high temperature pyrolysis method₃O₄The MOF material has an over potential of 384mV in electrocatalytic oxygen evolution reaction, but the preparation process is complex, the material needs to be pyrolyzed at a high temperature of 800 ℃ under the condition of nitrogen, the energy consumption is high, and the yield is low [ DOU S, LI X, TAO L, et al].Chemical Communications,2016,52(62):9727-30.]。

The coordination polymer formed by the pi-d conjugated organic ligand and the transition metal has higher conductivity and electrochemical activity, forms a unique conductive polymer and has unique advantages in catalyzing oxygen reduction reaction. In particular, in recent years, researchers have promoted their related properties by controlling the synthesis of pi-d conjugated conductive polymers with different structures and morphologies through different methods. Bao et al synthesized cobalt/hexa-aminobenzene Conductive MOF by a liquid phase method, which was a rod-like nanocrystal used for energy Storage and conversion in Sodium ion batteries, but could not be used as a catalyst in an electro-catalytic oxygen evolution reaction [ PARK J, LEE M, FENG D, et al.Stabilization of Hexaminobenzazene in a 2D Conductive Metal-Organic Framework for High Power Sodium Storage [ J ]. J.Am Chem Soc,2018,140(32):10315-23 ].

Disclosure of Invention

The invention aims to provide an ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer with high electrocatalytic activity and application thereof in electrocatalytic oxygen evolution reaction.

The technical solution for realizing the purpose of the invention is as follows:

the preparation method of the ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer comprises the following specific steps of:

dropwise adding N, N-dimethylformamide-deoxidized ultrapure water solution of hexaminobenzenetrihydrochloride into a cobalt salt solution according to the molar ratio of hexaminobenzenetrihydrochloride to cobalt salt of 1:2: 8-1: 3:15, stirring uniformly, dropwise adding ammonia water, stirring at 60-75 ℃ for reaction, after the reaction is finished, washing with water and absolute ethyl alcohol, drying in vacuum, and grinding to obtain the ultrathin nanometer flower-shaped cobalt/hexaminobenzene conductive polymer.

Preferably, the N, N-dimethylformamide-deoxygenated ultrapure water solution of hexa-aminobenzene trihydrochloride is prepared by dissolving hexa-aminobenzene trihydrochloride in N, N-dimethylformamide and deoxygenated ultrapure water under an ice bath.

Preferably, the cobalt salt is soluble cobalt salt selected from cobalt acetate, cobalt nitrate or cobalt chloride.

Preferably, the molar ratio of the hexa-aminobenzene trihydrochloride to the ammonia water to the cobalt salt is 1:2: 10.

Preferably, the stirring reaction time is 2-4 h.

Preferably, the drying temperature is 60-70 ℃.

The invention also provides the ultrathin nanometer flower-shaped cobalt/hexaamino benzene conductive polymer prepared by the preparation method.

Further, the invention provides application of the ultrathin nanometer flower-shaped cobalt/hexaamino benzene conductive polymer as a catalyst in an electrocatalytic oxygen evolution reaction.

Compared with the prior art, the invention has the advantages that:

(1) the ultrathin nanometer flower-like cobalt/hexa-aminobenzene conductive polymer is prepared through a simple synthesis process;

(2) the ultrathin nanometer flower-like cobalt/hexa-aminobenzene conductive polymer is prepared by adopting the smallest organic conjugated ligand hexa-aminobenzene, has excellent catalytic performance on oxygen evolution reaction, has an overpotential of 310mV, and is suitable for the field of electrocatalytic water decomposition.

Drawings

FIG. 1 is a schematic diagram of a preparation method of an ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer.

FIG. 2 is an SEM photograph of the cobalt/hexa-aminobenzene conductive polymers obtained in example 1(a), comparative example 1(b), comparative example 2(c), comparative example 3(d), comparative example 4(e), and comparative example 5 (f).

FIG. 3 is a TEM image of cobalt/hexa-aminobenzene conductive polymers prepared in example 1(a), comparative example 1(b), comparative example 2(c), comparative example 3(d), comparative example 4(e), and comparative example 5 (f).

FIG. 4 is an AFM image of the ultrathin nanoflower cobalt/hexa-aminobenzene conductive polymer prepared in example 1.

FIG. 5 is a graph comparing the linear sweep voltammograms of the cobalt/hexa-aminobenzene conductive polymers prepared in examples 1-4 and comparative examples 1-5.

Detailed Description

The present invention will be described in more detail with reference to the following examples and the accompanying drawings.

As shown in fig. 1, the ultra-thin nano flower-like cobalt/hexa-aminobenzene conductive polymer of the present invention is prepared by the following steps:

dropwise adding N, N-dimethylformamide-deoxidized ultrapure water solution of hexaminobenzenetrihydrochloride into a cobalt salt solution according to the molar ratio of the hexaminobenzenetrihydrochloride to the cobalt salt solution of 1:2: 8-1: 3:15, stirring uniformly, dropwise adding ammonia water, stirring at 60-75 ℃ for reaction, washing with water and absolute ethyl alcohol after the reaction is finished, drying in vacuum, and grinding to obtain the ultrathin nanometer flower-shaped cobalt/hexaminobenzene conductive polymer.

Example1

Dissolving 58.2mg of cobalt nitrate in 10mL of deoxidized ultrapure water, stirring for 10 minutes, dissolving 27.8mg of hexa-aminobenzene trihydrochloride in 10mL of N, N-dimethylformamide and 5mL of deoxidized ultrapure water, stirring for 5 minutes in an ice bath, dropwise adding the N, N-dimethylformamide-deoxidized ultrapure water solution of hexa-aminobenzene trihydrochloride into the cobalt nitrate solution, stirring uniformly, dropwise adding 0.072mL of ammonia water (25-28%), stirring continuously for 2 hours at 60 ℃, wherein the molar ratio of the hexa-aminobenzene trihydrochloride, the cobalt salt and the ammonia water is 1:2:10, after the reaction is finished, washing with water and absolute ethyl alcohol, drying in vacuum at 60 ℃, and grinding to obtain the ultrathin nano-flower-shaped cobalt/hexa-aminobenzene conductive polymer.

The scanning electron microscope of the prepared ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer is shown in figure 2(a), the transmission electron microscope is shown in figure 3(a), and the conductive polymer sheet layer is in a flower cluster shape; FIG. 4 is an atomic force microscope image of an ultrathin nanoflower cobalt/hexa-aminobenzene conductive polymer with an average thickness of the conductive polymer sheet of 4.5 nm; electrochemical performance tests are carried out by taking the prepared ultrathin nano flower-shaped cobalt/hexaamino benzene conductive polymer as a working electrode, and the sample 1 in figure 5 shows that the catalytic initial potential of the ultrathin nano flower-shaped cobalt/hexaamino benzene conductive polymer on oxygen evolution reaction reaches 1.528V.

Example 2

Dissolving 58.2mg of cobalt nitrate in 10mL of deoxidized ultrapure water, stirring for 10 minutes, dissolving 27.8mg of hexa-aminobenzene trihydrochloride in 10mL of N, N-dimethylformamide and 5mL of deoxidized ultrapure water, stirring for 5 minutes in an ice bath, dropwise adding the N, N-dimethylformamide-deoxidized ultrapure water solution of hexa-aminobenzene trihydrochloride into the cobalt nitrate solution, stirring uniformly, dropwise adding 0.064mL of ammonia water (25-28%), stirring continuously for 2 hours at 60 ℃, wherein the molar ratio of the hexa-aminobenzene trihydrochloride, the cobalt salt and the ammonia water is 1:2:8, after the reaction is finished, washing with water and absolute ethyl alcohol, drying in vacuum at 60 ℃, and grinding to obtain the ultrathin nano-flower-shaped cobalt/hexa-aminobenzene conductive polymer.

The prepared cobalt/hexa-aminobenzene conductive polymer sheet layer is in a flower cluster shape, and the average thickness of the conductive polymer sheet layer is 4.5 nm; the prepared ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer is used as a working electrode to carry out electrochemical performance test, and the sample 2 in figure 5 shows that the catalytic initial potential of the polymer to the oxygen evolution reaction is 1.538V.

Example 3

Dissolving 87.3mg of cobalt nitrate in 10mL of deoxidized ultrapure water, stirring for 10 minutes, dissolving 27.8mg of hexa-aminobenzene trihydrochloride in 10mL of N, N-dimethylformamide and 5mL of deoxidized ultrapure water, stirring for 5 minutes in an ice bath, dropwise adding the N, N-dimethylformamide-deoxidized ultrapure water solution of hexa-aminobenzene trihydrochloride into the cobalt nitrate solution, stirring uniformly, dropwise adding 0.107mL of ammonia water (25-28%), stirring continuously for 2 hours at 60 ℃, wherein the molar ratio of the hexa-aminobenzene trihydrochloride, the cobalt salt and the ammonia water is 1:3:15, after the reaction is finished, washing with water and absolute ethyl alcohol, drying in vacuum at 60 ℃, and grinding to obtain the ultrathin nano flower-shaped cobalt/hexa-aminobenzene conductive polymer.

The prepared cobalt/hexa-aminobenzene conductive polymer sheet layer is in a flower cluster shape, and the average thickness of the conductive polymer sheet layer is 4.5 nm; the prepared ultrathin nanometer flower-like cobalt/hexa-aminobenzene conductive polymer is used as a working electrode to carry out electrochemical performance test, and the sample 3 in figure 5 shows that the catalytic initial potential of the polymer to the oxygen evolution reaction is 1.533V.

Example4

Dissolving 58.2mg of cobalt nitrate in 10mL of deoxidized ultrapure water, stirring for 10 minutes, dissolving 27.8mg of hexa-aminobenzene trihydrochloride in 10mL of N, N-dimethylformamide and 5mL of deoxidized ultrapure water, stirring for 5 minutes in an ice bath, dropwise adding the N, N-dimethylformamide-deoxidized ultrapure water solution of hexa-aminobenzene trihydrochloride into the cobalt nitrate solution, stirring uniformly, dropwise adding 0.072mL of ammonia water (25-28%), stirring continuously for 2 hours at 75 ℃, wherein the molar ratio of the hexa-aminobenzene trihydrochloride, the cobalt salt and the ammonia water is 1:2:10, after the reaction is finished, washing with water and absolute ethyl alcohol, drying in vacuum at 60 ℃, and grinding to obtain the ultrathin nano-flower-shaped cobalt/hexa-aminobenzene conductive polymer.

The prepared ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer sheet layer is in a flower cluster shape, and the average thickness of the conductive polymer sheet layer is 4.5 nm; the prepared ultrathin nano flower-like cobalt/hexa-aminobenzene conductive polymer is used as a working electrode to carry out electrochemical performance test, and the sample 4 in figure 5 shows that the catalytic initial potential of the conductive polymer on the oxygen evolution reaction reaches 1.525V.

Comparative example1

Dissolving 58.2mg of cobalt nitrate in 10mL of deoxidized ultrapure water, stirring for 10 minutes, dissolving 27.8mg of hexaminobenzenetrihydrochloride in 10mL of LN, N-dimethylformamide and 5mL of deoxidized ultrapure water, stirring for 5 minutes in an ice bath, dropwise adding the N, N-dimethylformamide-deoxidized ultrapure water solution of hexaminobenzenetrihydrochloride into the cobalt nitrate solution, stirring uniformly, dropwise adding 0.072mL of ammonia water (25-28%), stirring continuously at room temperature for 2 hours, wherein the molar ratio of the hexaminobenzenetrihydrochloride, the cobalt salt and the ammonia water is 1:2:10, after the reaction is finished, washing with water and absolute ethyl alcohol, drying in vacuum at 60 ℃, and grinding to obtain the cobalt/hexaminobenzene conductive polymer.

The scanning electron microscope of the prepared cobalt/hexa-aminobenzene conductive polymer is shown in figure 2(b), the transmission electron microscope is shown in figure 3(b), and the conductive polymer is in a blocky structure and is thicker than the product in example 1; electrochemical performance tests are carried out by taking the prepared cobalt/hexa-aminobenzene conducting polymer as a working electrode, and the sample 5 in figure 5 shows that the catalytic initial potential of the cobalt/hexa-aminobenzene conducting polymer on oxygen evolution reaction is 1.638V, and the initial potential is too high.

Comparative example 2

Dissolving 58.2mg of cobalt nitrate in 10mL of deoxidized ultrapure water, stirring for 10 minutes, dissolving 27.8mg of hexamine benzenetrihydrochloride in 10mL of LN, N-dimethylformamide and 5mL of deoxidized ultrapure water, stirring for 5 minutes in an ice bath, dropwise adding the N, N-dimethylformamide-deoxidized ultrapure water solution of hexamine benzenetrihydrochloride into the cobalt nitrate solution, stirring uniformly, dropwise adding 0.72mL of ammonia water (25-28%), stirring continuously for 2 hours at 60 ℃, wherein the molar ratio of the hexamine benzenetrihydrochloride, the cobalt salt and the ammonia water is 1:2:100, after the reaction is finished, washing with water and absolute ethyl alcohol, drying in vacuum at 60 ℃, and grinding to obtain the cobalt/hexamine benzeneconductive polymer.

The scanning electron microscope of the prepared cobalt/hexa-aminobenzene conductive polymer is shown in fig. 2(c), the transmission electron microscope is shown in fig. 3(c), the conductive polymer sheet layers are very few and are in a flower cluster shape, and the conductive polymer sheet layers are seriously stacked; the prepared ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer is used as a working electrode to carry out electrochemical performance test, and the sample 6 in figure 5 shows that the catalytic initial potential of the ultrathin nanometer flower-shaped cobalt/hexa-aminobenzene conductive polymer on oxygen evolution reaction reaches 1.584V and the initial potential is too high.

Comparative example 3

Dissolving 58.2mg of cobalt nitrate in 10mL of deoxidized ultrapure water, stirring for 10 minutes, dissolving 27.8mg of hexa-aminobenzene trihydrochloride in 10mL of LN, N-dimethylformamide and 5mL of deoxidized ultrapure water, stirring for 5 minutes in an ice bath, dropwise adding the N, N-dimethylformamide-deoxidized ultrapure water solution of hexa-aminobenzene trihydrochloride into the cobalt nitrate solution, stirring uniformly, dropwise adding 0.072mL of ammonia water (25-28%), stirring continuously for 2 hours at 100 ℃, wherein the molar ratio of the hexa-aminobenzene trihydrochloride, the cobalt salt and the ammonia water is 1:2:10, after the reaction is finished, washing with water and absolute ethyl alcohol, drying in vacuum at 60 ℃, and grinding to obtain the nano-particle-shaped cobalt/hexa-aminobenzene conductive polymer.

The scanning electron microscope of the prepared nano-particle-shaped cobalt/hexa-aminobenzene conductive polymer is shown in figure 2(d), the transmission electron microscope is shown in figure 3(d), and the conductive polymer is nano-particles and is seriously stacked; electrochemical performance tests are carried out by taking the prepared nano-particle-shaped cobalt/hexa-aminobenzene conductive polymer as a working electrode, and the sample 7 in figure 5 shows that the catalytic initial potential of the nano-particle-shaped cobalt/hexa-aminobenzene conductive polymer for oxygen evolution reaction reaches 1.578V and is too high.

Comparative example4

Dissolving 58.2mg of cobalt nitrate in 10mL of deoxidized ultrapure water, stirring for 10 minutes, dissolving 27.8mg of hexaminobenzenetrihydrochloride in 10mL of N, N-dimethylformamide and 5mL of deoxidized ultrapure water, stirring for 5 minutes in an ice bath, dropwise adding the N, N-dimethylformamide-deoxidized ultrapure water solution of hexaminobenzenetrihydrochloride into the cobalt nitrate solution, stirring uniformly, dropwise adding 0.072mL of ammonia water (25-28%), stirring continuously for 2 hours in an ice bath, wherein the molar ratio of the hexaminobenzenetrihydrochloride, the cobalt salt and the ammonia water is 1:2:10, after the reaction is finished, washing with water and absolute ethyl alcohol, drying in vacuum at 60 ℃, and grinding to obtain the cobalt/hexaminobenzene conductive polymer.

The scanning electron microscope of the prepared cobalt/hexa-aminobenzene conductive polymer is shown in fig. 2(e), the transmission electron microscope is shown in fig. 3(e), the conductive polymer has large lamellar area, is not regularly arranged and has disordered orientation, and the lamellar is thinner than the sample in the comparative example 5 and is thicker than the sample in the embodiment example 1; sample 8 in FIG. 5 shows that the catalytic onset potential for the oxygen evolution reaction reached 1.588V, which is too high.

Comparative example 5

Dissolving 58.2mg of cobalt nitrate in 10mL of deoxidized ultrapure water, stirring for 10 minutes, dissolving 27.8mg of hexaminobenzenetrihydrochloride in 10mL of N, N-dimethylformamide and 5mL of deoxidized ultrapure water, stirring for 5 minutes in an ice bath, dropwise adding the N, N-dimethylformamide-deoxidized ultrapure water solution of hexaminobenzenetrihydrochloride into the cobalt nitrate solution, stirring uniformly, dropwise adding 0.072mL of ammonia water (25-28%), stirring continuously for 2 hours at 150 ℃, wherein the molar ratio of the hexaminobenzenetrihydrochloride, the cobalt salt and the ammonia water is 1:2:10, after the reaction is finished, washing with water and absolute ethyl alcohol, drying in vacuum at 60 ℃, and grinding to obtain the cobalt/hexaminobenzene conductive polymer.

The scanning electron microscope of the prepared cobalt/hexa-aminobenzene conductive polymer is shown in figure 2(f), the transmission electron microscope is shown in figure 3(f), the conductive polymer lamella is hexagonal, the diameter is about 100nm, the conductive polymer lamella is not regularly arranged, and the orientation is disordered; sample 9 in FIG. 5 shows that the catalytic onset potential for oxygen evolution reached 1.564V, which is too high.