阅读说明：本技术 一种三苯胺基钴卟啉类催化剂及其制备方法和用途 (Triphenylamine-based cobalt porphyrin catalyst and preparation method and application thereof ) 是由 赵龙 徐庆祥 马雨涵 袁蕊 于 2021-05-12 设计创作，主要内容包括：本发明属于电催化氧还原生产过氧化氢技术领域,尤其涉及一种三苯胺基钴卟啉催化剂及其制备方法、三苯胺基钴卟啉修饰碳材料复合催化剂及其制备方法和应用。本发明提供了三苯胺基钴卟啉类催化剂,三苯胺与卟啉环之间可以插入不同的共轭链接基团,根据链接基团的供、吸电子特性,会使钴卟啉分子的界面电荷态发生改变。本发明提供的催化剂同时含有三苯胺基团和钴卟啉环,该结构的催化剂能够增强碳材料负载三苯胺基钴卟啉类复合催化剂的ORR性能,提高过氧化氢选择性。(The invention belongs to the technical field of hydrogen peroxide production by electrocatalytic oxygen reduction, and particularly relates to a triphenylamine-based cobalt porphyrin catalyst and a preparation method thereof, and a triphenylamine-based cobalt porphyrin modified carbon material composite catalyst and a preparation method and application thereof. The invention provides a triphenylamine-based cobalt porphyrin catalyst, wherein different conjugated linking groups can be inserted between triphenylamine and porphyrin rings, and the interface charge state of cobalt porphyrin molecules can be changed according to the electron supply and absorption characteristics of the linking groups. The catalyst provided by the invention simultaneously contains triphenylamine groups and cobalt porphyrin rings, and the catalyst with the structure can enhance the ORR performance of the carbon material loaded triphenylamine cobalt porphyrin composite catalyst and improve the hydrogen peroxide selectivity.)

1. A triphenylamine-based cobalt porphyrin catalyst is characterized by having a structure shown in formula I:

wherein R is₁、R₂And R₃Are each C_0～4An alkyl group; r₄Is an aromatic group or an aromatic alkylene group.

2. The triphenylamine-based cobalt porphyrin-based catalyst of claim 1, wherein C is_0～4Alkyl includes normal alkyl or isomeric alkyl; the R is₄Comprises phenyl, carbazolyl, thienyl, 2,1, 3-benzothiadiazolyl or the combination of a plurality of groups.

3. The method for preparing the triphenylamine-based cobalt porphyrin-based catalyst according to claim 1, wherein the method comprises the following steps:

(A1) reacting a compound IIMixing a compound IIIOHC-R4-Br, palladium tetrakis (triphenylphosphine), toluene and a sodium carbonate aqueous solution, and carrying out Suzuki coupling reaction to obtain a first intermediate;

(A2) compound IVMixing pyrrole and a hydrochloric acid aqueous solution, and carrying out condensation reaction to obtain a second intermediate;

(A3) mixing the first intermediate, the second intermediate, trifluoroacetic acid, chloranil and anhydrous dichloromethane, and carrying out condensation reaction to obtain a third intermediate porphyrin;

(A4) and dissolving the third intermediate and cobalt acetate in a trichloromethane and methanol system, and performing coordination reaction to obtain the triphenylamine cobalt porphyrin catalyst.

4. The method according to claim 3,

in the step A1, the use amount ratio of the compound II, the compound III, the palladium tetrakis (triphenylphosphine), the toluene and the sodium carbonate aqueous solution is 1-1.5 mmol: 1.2-2.0 mmol: 0.1-0.2 g: 30-40 mL: 5-8 mL of sodium carbonate aqueous solution with the concentration of 2M; the temperature of the Suzuki coupling reaction is 90-98 ℃, and the time is 40-50 h;

in the step A2, the dosage ratio of the compound IV to pyrrole is 0.5-1 mL: 1.5-2.5 mL, wherein the concentration of the hydrochloric acid aqueous solution is 0.18M, the temperature of the condensation reaction is room temperature, and the time is 8-12 h;

in the step A3, the dosage ratio of the first intermediate to the second intermediate to trifluoroacetic acid to chloranil and dichloromethane is 250-300 mg: 200-450 mg: 140-200 μ L: 200-300 mg: 100-150 mL; the condensation reaction is carried out at room temperature for 1-2.5 h;

in the step A4, the dosage ratio of the third intermediate to the cobalt acetate is 0.05-0.25 mmol: 0.25-1.5 mmol; the temperature of the coordination reaction is 65-75 ℃, and the time is 3-6 h.

5. The method according to claim 4,

in step A1, the use ratio of compound II, compound III, tetrakis (triphenylphosphine) palladium, toluene and aqueous sodium carbonate solution is 1.5 mmol: 2 mmol: 0.2 g: 35mL of: 5 mL;

in the step A2, the dosage ratio of the compound IV to pyrrole is 0.7-1 mL: 2-2.5 mL; the time is 8-10 h;

in the step A3, the dosage ratio of the first intermediate to the second intermediate to trifluoroacetic acid to chloranil and dichloromethane is 260-290 mg: 210-420 mg: 140-180 μ L: 200-300 mg: 100-130 mL; the time is 2 hours;

in the step A4, the dosage ratio of the third intermediate to the cobalt acetate is 0.05-0.25 mmol: 0.25-1.25 mmol; the time is preferably 5 hours.

6. The method for preparing the triphenylamine-based cobalt porphyrin-based catalyst according to claim 1, wherein the method comprises the following steps:

(B1) reacting a compound IIMixing a compound IIIOHC-R4-Br, palladium tetrakis (triphenylphosphine), toluene and a sodium carbonate aqueous solution, and carrying out Suzuki coupling reaction to obtain a first intermediate;

(B2) mixing the first intermediate, trifluoroacetic acid, chloranil and anhydrous dichloromethane, and carrying out condensation reaction to obtain a third intermediate porphyrin;

(B3) and dissolving the third intermediate and cobalt acetate in a trichloromethane and methanol system, and performing coordination reaction to obtain the triphenylamine cobalt porphyrin catalyst.

7. The method according to claim 6,

in the step B1, the dosage ratio of the compound II, the compound III, the palladium tetrakis (triphenylphosphine), the toluene and the sodium carbonate aqueous solution is 1-1.5 mmol: 1.2-2.0 mmol: 0.1-0.2 g: 30-40 mL: 5-8 mL of sodium carbonate aqueous solution, wherein the concentration of the sodium carbonate aqueous solution is 2 mol/L; the temperature of the Suzuki coupling reaction is 90-98 ℃, and the time is 40-50 h;

in the step B2, the dosage ratio of the first intermediate, trifluoroacetic acid, chloranil and dichloromethane is 250-300 mg: 140-200 μ L: 200-300 mg: 100-150 mL; the condensation reaction is carried out at room temperature for 1-2.5 h;

in the step B3, the dosage ratio of the third intermediate to the cobalt acetate is 0.05-0.25 mmol: 0.25-1.5 mmol; the temperature of the coordination reaction is 65-75 ℃, and the time is 3-6 h.

8. The method according to claim 7,

in step B1, the amount ratio of compound II, compound III, tetrakis (triphenylphosphine) palladium, toluene and aqueous sodium carbonate solution is 1.5 mmol: 2 mmol: 0.2 g: 35mL of: 5 mL;

in the step B2, the dosage ratio of the first intermediate, trifluoroacetic acid, chloranil and dichloromethane is 260-290 mg: 140-180 μ L: 200-300 mg: 100-130 mL; the condensation reaction time is 2 hours; in the step B3, the dosage ratio of the third intermediate to the cobalt acetate is 0.05-0.25 mmol: 0.25-1.25 mmol; the time is preferably 5 hours.

9. The application of the triphenylamine cobalt porphyrin catalyst of claim 1 in preparation of a carbon material-supported triphenylamine cobalt porphyrin composite catalyst, wherein the triphenylamine cobalt porphyrin catalyst is supported on a carbon material, the supporting amount of the triphenylamine cobalt porphyrin catalyst is 5-30 wt%, and the carbon material is a carbon nanotube, carbon black or graphene.

10. The use according to claim 9, characterized by the specific steps of: 1-4 mg of the dosage ratio: 5-15 mL: mixing the triphenylamine cobalt porphyrin catalyst, dichloromethane and the carbon material in 10mg, uniformly mixing under the ultrasonic action at room temperature, and removing the dichloromethane to obtain the carbon material-loaded triphenylamine cobalt porphyrin composite catalyst.

Technical Field

The invention belongs to the technical field of hydrogen peroxide production by electrocatalytic oxygen reduction, and particularly relates to a triphenylamine-based cobalt porphyrin catalyst and a preparation method thereof, and a triphenylamine-based cobalt porphyrin modified carbon material composite catalyst and a preparation method and application thereof.

Background

The hydrogen peroxide is used as a commercial chemical product and has wide application in the fields of organic synthesis, medical disinfection, paper pulp bleaching, wastewater treatment, novel clean energy and the like. Currently, industrial hydrogen peroxide is mainly produced by an anthraquinone method, and the production mode has the disadvantages of 1) large investment in infrastructure and high energy consumption, 2) continuous degradation of anthraquinone caused by over-hydrogenation in the production process, and 3) increased explosion risk due to coexistence of an organic solvent and high-concentration hydrogen peroxide. It is therefore highly desirable to develop a green, low cost hydrogen peroxide production technology.

As an alternative to the anthraquinone process for producing hydrogen peroxide, the 2-electron reduction of oxygen to produce hydrogen peroxide has received much attention. The Oxygen Reduction Reaction (ORR) produces hydrogen peroxide without any harmful by-products. ORR can be carried out in acidic or alkaline medium, with the limitation that hydrogen peroxide is generated by ORR in alkaline medium 1) H₂O₂(or HO)₂ ^-At pH>11.6) is easily decomposed in an alkaline medium; 2) presence of metal ions, e.g. K⁺、Na⁺Also, H is caused₂O₂Decomposition, which typically requires the use of chelating agents to chelate the metal ions, inhibits this from occurring, which increases operating costs. In contrast, H₂O₂Stable under acidic conditions, ORR produces hydrogen peroxide that tends to be acidic process media. Currently, the most efficient ORR catalysts for producing hydrogen peroxide are still noble metal based catalysts such as Pt-Hg or amalgam, and their high price and scarce reserves limit the large-scale industrial application of such catalysts. Some nitrogen-doped mesoporous carbon materials in recent years show good selectivity in catalytic hydrogen peroxide production, but have over-high overpotential and poor catalytic performance. People are eagerly looking for an ORR catalyst with high efficiency, green and low price.

In long-term studies, transition metal-based porphyrins, such as iron porphyrin and cobalt porphyrin, have been found to be highly potential non-noble metal ORR catalysts. Ferriporphyrin can be involved in the Fenton reaction when hydrogen peroxide is produced, deactivating the catalyst. In contrast, cobalt porphyrin has good stability and tends to generate hydrogen peroxide through a2 electron transfer path, which is related to factors such as adsorption binding energy between metallic cobalt and reaction intermediates. For the ORR mechanism of the cobalt porphyrin 2 electron transfer pathway, the first step of the catalytic reaction is the adsorption of oxygen by the metal in the porphyrin macrocycle; the second step is to form a transition state of Co (III) -OOH in the presence of protons and electrons, and there are usually two pathways in the second step, because the valence state of the transient metal changes to form two isomers, Co (III) has a stronger adsorption affinity for oxygen atoms than Co (II), so that the Co (II) -O bond and the Co (III) -O bond have different cleavage energies; the third step is based on intermediate Co (III) -OOH, an electron is obtained to form Co (II) -OOH transition state, and finally the transition state is protonated to generate hydrogen peroxide. The cobalt porphyrin substituent on the outside of the ring can influence the catalytic performance of ORR: 1) the electron supply and absorption effects of the substituent can change the electron cloud density of the central metal, and influence the adsorption of oxygen; 2) substituents that have a proton-managing effect will alter the proton concentration at the catalytic interface. Therefore, the structure of cobalt porphyrin is regulated and improved, the interface two-electron reaction is deeply known and optimized, and the catalyst plays an important role in developing the catalyst for producing hydrogen peroxide by an in-situ electrochemical method.

Disclosure of Invention

The invention aims to provide a triphenylamine cobalt porphyrin catalyst and a preparation method thereof, a carbon material-loaded triphenylamine cobalt porphyrin composite catalyst and a preparation method and application thereof. The carbon material loaded triphenylamine cobalt porphyrin composite catalyst has good ORR catalytic effect and higher hydrogen peroxide selectivity.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a triphenylamine-based cobalt porphyrin catalyst, which has a structure shown in a formula I:

wherein R is₁、R₂And R₃Are each C_0～4An alkyl group; r₄Is an aromatic group or an aromatic alkylene group.

Further, C_0～4Alkyl includes normal alkyl or isomeric alkyl; the R is₄Including phenyl, carbazolyl, thienyl, 2,1, 3-benzothiadiazolyl or several groupsThe combination between clusters.

The first preparation method of the triphenylamine-based cobalt porphyrin catalyst provided by the invention comprises the following steps:

(A1) reacting a compound IIMixing a compound IIIOHC-R4-Br, palladium tetrakis (triphenylphosphine), toluene and a sodium carbonate aqueous solution, and carrying out Suzuki coupling reaction to obtain a first intermediate;

(A2) compound IVMixing pyrrole and a hydrochloric acid aqueous solution, and carrying out condensation reaction to obtain a second intermediate;

(A3) mixing the first intermediate, the second intermediate, trifluoroacetic acid, chloranil and anhydrous dichloromethane, and carrying out condensation reaction to obtain a third intermediate porphyrin;

(A4) and dissolving the third intermediate and cobalt acetate in a trichloromethane and methanol system, and performing coordination reaction to obtain the triphenylamine cobalt porphyrin catalyst.

Wherein the content of the first and second substances,

in the step A1, the use amount ratio of the compound II, the compound III, the palladium tetrakis (triphenylphosphine), the toluene and the sodium carbonate aqueous solution is 1-1.5 mmol: 1.2-2.0 mmol: 0.1-0.2 g: 30-40 mL: 5-8 mL of sodium carbonate aqueous solution, wherein the concentration of the sodium carbonate aqueous solution is 2 mol/L; the temperature of the Suzuki coupling reaction is 90-98 ℃, and the time is 40-50 h;

in the step A2, the dosage ratio of the compound IV to pyrrole is 0.5-1 mL: 1.5-2.5 mL, wherein the concentration of the hydrochloric acid aqueous solution is 0.18mol/L, the temperature of the condensation reaction is room temperature, and the time is 8-12 h;

in the step A3, the dosage ratio of the first intermediate to the second intermediate to trifluoroacetic acid to chloranil and dichloromethane is 250-300 mg: 200-450 mg: 140-200 μ L: 200-300 mg: 100-150 mL; the condensation reaction is carried out at room temperature for 1-2.5 h;

in the step A4, the dosage ratio of the third intermediate to the cobalt acetate is 0.0.05-0.25 mmol: 0.25-1.5 mmol; the temperature of the coordination reaction is 65-75 ℃, and the time is 3-6 h.

Preferably, the first and second electrodes are formed of a metal,

in step A1, the use ratio of compound II, compound III, tetrakis (triphenylphosphine) palladium, toluene and aqueous sodium carbonate solution is 1.5 mmol: 2 mmol: 0.2 g: 35mL of: 5 mL;

in the step A2, the dosage ratio of the compound IV to pyrrole is 0.7-1 mL: 2-2.5 mL; the time is 8-10 h;

in the step A3, the dosage ratio of the first intermediate to the second intermediate to trifluoroacetic acid to chloranil and dichloromethane is 260-290 mg: 210-420 mg: 140-180 μ L: 200-300 mg: 100-130 mL; the time is 2 hours;

in the step A4, the dosage ratio of the third intermediate to the cobalt acetate is 0.05-0.25 mmol: 0.25-1.25 mmol; the time is preferably 5 hours.

The second preparation method of the triphenylamine-based cobalt porphyrin catalyst provided by the invention comprises the following steps:

(B1) reacting a compound IIMixing a compound IIIOHC-R4-Br, palladium tetrakis (triphenylphosphine), toluene and a sodium carbonate aqueous solution, and carrying out Suzuki coupling reaction to obtain a first intermediate;

(B2) mixing the first intermediate, trifluoroacetic acid, chloranil and anhydrous dichloromethane, and carrying out condensation reaction to obtain a third intermediate porphyrin;

(B3) and dissolving the third intermediate and cobalt acetate in a trichloromethane and methanol system, and performing coordination reaction to obtain the triphenylamine cobalt porphyrin catalyst.

Wherein the content of the first and second substances,

in the step B1, the dosage ratio of the compound II, the compound III, the palladium tetrakis (triphenylphosphine), the toluene and the sodium carbonate aqueous solution is 1-1.5 mmol: 1.2-2.0 mmol: 0.1-0.2 g: 30-40 mL: 5-8 mL of sodium carbonate aqueous solution, wherein the concentration of the sodium carbonate aqueous solution is 2 mol/L; the temperature of the Suzuki coupling reaction is 90-98 ℃, and the time is 40-50 h;

in the step B2, the dosage ratio of the first intermediate, trifluoroacetic acid, chloranil and dichloromethane is 250-300 mg: 140-200 μ L: 200-300 mg: 100-150 mL; the condensation reaction is carried out at room temperature for 1-2.5 h;

in the step B3, the dosage ratio of the third intermediate to the cobalt acetate is 0.05-0.25 mmol: 0.25-1.5 mmol; the temperature of the coordination reaction is 65-75 ℃, and the time is 3-6 h.

Preferably, the first and second electrodes are formed of a metal,

in step B1, the amount ratio of compound II, compound III, tetrakis (triphenylphosphine) palladium, toluene and aqueous sodium carbonate solution is 1.5 mmol: 2 mmol: 0.2 g: 35mL of: 5 mL;

in the step B2, the dosage ratio of the first intermediate, trifluoroacetic acid, chloranil and dichloromethane is 260-290 mg: 140-180 μ L: 200-300 mg: 100-130 mL; the condensation reaction time is 2 hours;

in the step B3, the dosage ratio of the third intermediate to the cobalt acetate is 0.05-0.25 mmol: 0.25-1.25 mmol; the time is preferably 5 hours.

The triphenylamine-based cobalt porphyrin catalyst prepared by the invention comprises:

the invention provides a carbon material loaded triphenylamine cobalt porphyrin composite catalyst, wherein the triphenylamine cobalt porphyrin catalyst prepared by the method is loaded on a carbon material carrier, the load capacity of the triphenylamine cobalt porphyrin catalyst is 5-30 wt%, and the carbon material carrier is a carbon nano tube, carbon black or graphene.

The invention also provides a preparation method of the carbon material loaded triphenylamine cobalt porphyrin composite catalyst, which comprises the following steps:

mixing the triphenylamine cobalt porphyrin catalyst, dichloromethane and the carbon material at room temperature, uniformly mixing under the action of ultrasound, and removing the dichloromethane to obtain the carbon material-loaded triphenylamine cobalt porphyrin composite catalyst.

Wherein the dosage ratio of the triphenylamine cobalt porphyrin catalyst, the dichloromethane and the carbon material is 1-4 mg: 5-15 mL:10mg, preferably 3mg:10mL:10 mg.

The ultrasonic mixing time is 0.5-1 h.

The mixing process is preferably to disperse cobalt porphyrin and the carbon material in dichloromethane, perform ultrasonic action for 20 minutes, and fully and uniformly disperse the cobalt porphyrin and the carbon material. After the dispersion was completed, dichloromethane was removed using a rotary evaporator, and vacuum-dried in a vacuum drying oven to obtain a dried porphyrin-doped carbon composite material.

The invention provides carbon material loaded triphenylamine cobalt porphyrin composite catalyst ink, which adopts the technical scheme that the carbon material loaded triphenylamine cobalt porphyrin composite catalyst ink, water, ethanol and a Nafion solution are uniformly mixed under the action of ultrasound.

The dosage ratio of the carbon material-loaded triphenylamine cobalt porphyrin composite catalyst to the water, the ethanol and the Nafion solution is 1-3 mg: 0-0.3 mL: 0-0.6 mL:0.024mL, and preferably 3mg:0.3mL:0.3mL:0.024 mL.

The compounding temperature is room temperature, and the ultrasonic mixing time is 0.5-1 h, preferably 0.5 h.

The invention provides a carbon material loaded triphenylamine cobalt porphyrin composite catalyst electrode, wherein triphenylamine cobalt porphyrin composite catalyst ink loaded by the carbon material is modified on the surface of the electrode by adopting a dripping method, and is naturally dried at room temperature.

Wherein the using amount of the carbon material loaded triphenylamine cobalt porphyrin composite catalyst ink is 24-72 mu L/cm²Preferably 24. mu.L/cm²。

The invention provides application of the carbon material loaded triphenylamine cobalt porphyrin composite catalyst in the technical scheme in production of hydrogen peroxide by electro-catalysis ORR. The process of using the carbon material-supported triphenylamine cobalt porphyrin composite catalyst for producing hydrogen peroxide by electro-catalysis ORR is not particularly limited, and the process known by the technical personnel in the field can be selected. In order to determine the electrocatalytic ORR performance of the carbon material loaded triphenylamine cobalt porphyrin composite catalyst, a three-electrode structure is adopted, an electrode modified by the carbon material loaded triphenylamine cobalt porphyrin composite catalyst is used as a Working Electrode (WE), a platinum wire is used as a Counter Electrode (CE), and a saturated silver/silver chloride electrode is used as a Reference Electrode (RE). The electrocatalytic ORR performance of the composite was tested using Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV).

All tests were performed at room temperature. A Rotating Disk Electrode (RDE) test was performed on a ring disk electrode set with a disk electrode diameter of 4 mm. And (4) carrying out experimental calibration and verification. Before each measurement, high purity O is used₂Or N₂Gas purifies the electrolyte for 30 minutes, and O is always kept in the experimental process₂Or N₂A gaseous environment.

The invention has the beneficial effects that:

(1) in the carbon material loaded triphenylamine cobalt porphyrin composite catalyst prepared by the invention, triphenylamine cobalt porphyrin is uniformly loaded on the carbon material, and the exposed metal active sites are utilized to ensure that the composite catalyst has good electrocatalytic oxygen reduction activity and higher hydrogen peroxide selectivity.

(2) The synthesis process of the triphenylamine cobalt porphyrin catalyst and the method for preparing the carbon material loaded triphenylamine cobalt porphyrin composite catalyst provided by the invention have the advantages of simple synthesis method and lower cost.

(3) The invention provides a triphenylamine cobalt porphyrin catalyst. At the catalytic interface, the cobalt porphyrin ring is in a position containing H⁺And providing e^-The triphenylamine outside the ring has a propeller-shaped three-dimensional structure, and the exposed polycation orbit can accelerate H⁺And e^-The collision frequency, during the reaction, strongly fluctuates close to the charge state of the porphyrin molecule, which, according to the macuss theory, promotes electron transfer due to the adaptation of the interface energy barrier. Different conjugated linking groups can be inserted between the triphenylamine and the porphyrin ring, and the interface electricity of the cobalt porphyrin molecule can be ensured according to the electron supply and absorption characteristics of the linking groupsThe charge state changes. The catalyst provided by the invention simultaneously contains triphenylamine groups and cobalt porphyrin rings, and the catalyst with the structure can enhance the ORR performance of the carbon material loaded triphenylamine cobalt porphyrin composite catalyst and improve the hydrogen peroxide selectivity.

Drawings

FIG. 1 shows that TPA-Cb-CoPor/C, TPA-Ph-CoPor/C and TPA-BTD-CoPor/C are 0.5mol/L H mol under saturated oxygen condition₂SO₄I-t curve of (1). Voltage 0.2V, electrode rotation speed 1600 RPM;

FIG. 2 is a graph of calculated energy consumption of TPA-Cb-CoPor/C, TPA-Ph-CoPor/C and TPA-BTD-CoPor/C versus production rate of hydrogen peroxide.

Detailed Description

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the present invention, unless otherwise specified, the starting materials for the preparation are commercially available or prepared by methods well known to those skilled in the art.

Example 1

(1) Synthesis of the first intermediate 6- (4- (diphenylamino) phenyl) -9-ethylcarbazole-3-carbaldehyde (Suzuki coupling reaction):

1.5mmol (455mg) 6-bromo-9-ethyl-9H-carbazole-3-carbaldehyde and 2mmol (579mg)4- (dianilino) phenylboronic acid were dissolved in 35mL toluene, 5mL sodium carbonate solution (2M) were added, stirring was continued for 1 min, and then 200mg tetrakis (triphenylphosphine) palladium (0) was added. The system is refluxed at 95 ℃ for 45 hours under the protection of nitrogen. Then the mixed solution is washed by saturated salt solution, diluted hydrochloric acid and dichloromethane for extraction. The organic phase was separated, dried over anhydrous sodium sulfate and spin-dried, and the crude product was purified by column chromatography on silica gel with dichloromethane/n-hexane (2:1) as eluent. 608.9mg of product was obtained as a yellow solid in 87% yield.

(2) Synthesis of the second intermediate 2, 2' - (2, 4, 6-trimethylphenylmethylene) dipyrrole (condensation reaction):

0.18M HCl (100mL) was added to a two-necked flask, and 30mmol (2.1mL) of pyrrole was added to the flask via syringe under nitrogen. After stirring for 2 minutes, 5mmol (0.735mL) of 2,4, 6-trimethylbenzaldehyde was added, and the mixture was stirred at room temperature overnight, followed by extraction of the aqueous phase with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, rotary evaporated and the crude product obtained was purified using silica gel column chromatography (eluent: dichloromethane ═ 1: 1). The product was dissolved with a small amount of methylene chloride, and recrystallized by adding a large amount of n-hexane to obtain 0.54g of a white solid product with a yield of 41%.

(3) Synthesis (condensation reaction) of a third intermediate, 5, 15-bis (3- (4- (dianilino) phenyl) - (9-ethylcarbazol-6-yl)) -10, 20-bis (2, 4, 6-trimethylphenyl) porphyrin:

to 100mL of dichloromethane (with water removed via molecular sieves) were added 1mmol of the first intermediate and 1mmol (264mg) of 2, 2' - (2, 4, 6-trimethylphenylmethylene) dipyrrole (second intermediate), and the mixture was stirred under nitrogen for 2 minutes, followed by slow dropwise addition of 180. mu.l of trifluoroacetic acid. The system was stirred at room temperature for 1 hour, then 1mmol (227mg) of tetrachlorobenzoquinone was added thereto, and further stirred for 1 hour. After the reaction, the system was neutralized with 0.337ml of triethylamine and the solvent was spin-dried. The crude product was purified using silica gel column chromatography eluting with dichloromethane/n-hexane (7:3) to give a violet solid in 4.4% yield.

(4) The compound TPA-Cb-CoPor: synthesis of 5, 15-bis (3- (4- (dianilino) phenyl) - (9-ethylcarbazole) -6-yl) -10, 20-bis (2, 4, 6-trimethylphenyl) cobalt (II) porphyrin (coordination reaction):

0.05mmol (71mg) of the third intermediate was dissolved in 6mL of chloroform under nitrogen and refluxed for 15 minutes. 0.25mmol (62mg) of cobalt (II) acetate was dissolved in 4ml of methanol and added to the system. After refluxing at 70 ℃ for 5 hours, it was washed with 3X 100ml of deionized water, extracted with dichloromethane, the lower organic phase was collected, dried over anhydrous sodium sulfate and the solvent was removed by rotary evaporation. The crude product was purified using silica gel column chromatography eluting with dichloromethane/n-hexane (3:1) to give a dark red solid in 94% yield.

The specific process is as follows:

preparing a carbon material loaded triphenylamine cobalt porphyrin composite catalyst: respectively dispersing a mixture of 3mg of compound TPA-Cb-CoPor and 10mg of carbon black in 15mL of ethanol, performing ultrasonic action for 20 minutes, fully and uniformly dispersing, removing the ethanol by using a rotary evaporator, and performing vacuum drying for 8 hours at 50 ℃ in a vacuum drying oven to obtain a dried porphyrin-doped carbon black composite material which is marked as TPA-Cb-CoPor/C.

Preparation of TPA-Cb-CoPor/C ink: 3mg of TPA-Cb-CoPor/C was added to a mixed solvent of ethanol (300. mu.L), water (300. mu.L) and 5% Nafion (24. mu.L), and the mixture was sonicated for 30 minutes to prepare a catalyst ink.

Preparation of TPA-Cb-CoPor/C modified electrode: 7.5 microliter of TPA-Cb-CoPor/C ink is dripped on the working electrode and naturally dried in the air to obtain the TPA-Cb-CoPor/C modified electrode.

Example 2

(1) A first intermediate: synthesis of 4- (4- (dianilino) phenyl) -benzaldehyde (Suzuki coupling reaction) the synthesis method was the same as in step (1) of example 1, with a yield of 90%.

(2) A third intermediate: synthesis (condensation reaction) of 5, 15-bis (1- (4- (diphenylamino) phenyl) - (phenyl-4-yl)) -10, 20-bis (2, 4, 6-trimethylphenyl) porphyrin the synthesis method was the same as in step (3) of example 1. Yield 8.0%, purple solid.

(3) The compound TPA-Ph-CoPor: synthesis (coordination reaction) of 5, 15-bis (1- (4- (dianilino) phenyl) - (phenyl-4-yl)) -10, 20-bis (2, 4, 6-trimethylphenyl) cobalt (II) porphyrin according to the same method as the compound TPA-Cb-CoPor of example 1, yield 94.0%, dark red solid.

The specific process is as follows:

preparing a carbon material loaded triphenylamine cobalt porphyrin composite catalyst: respectively dispersing a mixture of 3mg of compound TPA-Ph-CoPor and 10mg of carbon black in 15mL of ethanol, performing ultrasonic action for 20 minutes, fully and uniformly dispersing, removing the ethanol by using a rotary evaporator, and performing vacuum drying for 8 hours at 50 ℃ in a vacuum drying oven to obtain a dried porphyrin-doped carbon black composite material, which is marked as TPA-Ph-CoPor/C.

Preparation of TPA-Ph-CoPor/C ink: 3mg of TPA-Cb-CoPor/C was added to a mixed solvent of ethanol (300. mu.L), water (300. mu.L) and 5% Nafion (24. mu.L), and the mixture was sonicated for 30 minutes to prepare a catalyst ink.

Preparation of TPA-Ph-CoPor/C modified electrode: 7.5 microliter of TPA-Ph-CoPor/C ink is dripped on the working electrode and naturally dried in the air to obtain the TPA-Ph-CoPor/C modified electrode.

Example 3

(1) A first intermediate: 7- (4- (Dianilino) phenyl) benzo [ c ] [1,2,5] thiadiazole-4-carbaldehyde (g) was synthesized in the same manner as in step (1) of example 1 in a yield of 88%.

(2) A third intermediate: 5, 15-bis (3- (4- (dianilino) phenyl) - (2, 1, 3-benzothiadiazol-4-yl)) -10, 20-bis (2, 4, 6-trimethylphenyl) porphyrin (condensation reaction) was synthesized in the same manner as in step (3) of example 1. Yield 12.3%, purple solid.

(3) The compound TPA-BTD-CoPor: synthesis (coordination reaction) of 5, 15-bis (3- (4- (dianilino) phenyl) - (2, 1, 3-benzothiadiazol-4-yl)) -10, 20-bis (2, 4, 6-trimethylphenyl) cobalt (II) porphyrin by the same method as that of TPA-Cb-CoPor, a yield of 89%, a dark red solid,

the specific process is as follows:

preparing a carbon material loaded triphenylamine cobalt porphyrin composite catalyst: respectively dispersing a mixture of 3mg of compound TPA-BTD-CoPor and 10mg of carbon black in 15mL of ethanol, performing ultrasonic action for 20 minutes, fully and uniformly dispersing, removing the ethanol by using a rotary evaporator, and performing vacuum drying for 8 hours in a vacuum drying oven at 50 ℃ to obtain a dried porphyrin-doped carbon black composite material which is marked as TPA-BTD-CoPor/C.

Preparation of TPA-BTD-CoPor ink: 3mg of TPA-BTD-CoPor/C was added to a mixed solvent of ethanol (300. mu.L), water (300. mu.L) and 5% Nafion (24. mu.L), and the mixture was sonicated for 30 minutes to prepare a catalyst ink.

Preparation of TPA-BTD-CoPor/C modified electrode: 7.5 microliter of TPA-BTD-CoPor/C ink is dripped on the working electrode and naturally dried in the air to obtain the TPA-BTD-CoPorr/C modified electrode.

Performance testing

The hydrogen peroxide preparation capacities of the carbon material-supported triphenylamine cobalt porphyrin composite catalysts prepared in examples 1 to 3 were analyzed respectively:

the method adopts a three-electrode structure, an electrode modified by carbon material loaded triphenylamine cobalt porphyrin composite catalyst is used as a Working Electrode (WE), a platinum wire is used as a Counter Electrode (CE), and a saturated silver/silver chloride electrode is used as a Reference Electrode (RE).

The current magnitude tested by the electrochemical method is used for comparing the oxygen reduction kinetics of the composite material, and the test result is shown in the figure.

FIG. 1 shows that TPA-Cb-CoPor/C, TPA-Ph-CoPor/C and TPA-BTD-CoPor/C are 0.5mol/L H mol under saturated oxygen condition₂SO₄I-t curve of (1). From fig. 1, it can be seen that the three composite catalysts all show obvious reduction current curves within the test time range, indicating the catalytic activity of the three composite catalysts on ORR.

FIG. 2 is a graph of calculated energy consumption of TPA-Cb-CoPor/C, TPA-Ph-CoPor/C and TPA-BTD-CoPor/C and the production rate of hydrogen peroxide, the reduction selectivity of hydrogen peroxide is about 90%, and the Faraday efficiency is 95%. As can be seen from FIG. 2, the hydrogen peroxide preparation rate of the three composite catalysts in the test time range is about 10kg/h, the energy consumption is about 3.5 kilowatt-hour, wherein the hydrogen peroxide preparation rate of TPA-BTD-CoPor/C is the highest and reaches 11.21 kg/h.

The synthesis process of triphenylamine cobalt porphyrin and the method for preparing the carbon material loaded triphenylamine cobalt porphyrin composite catalyst provided by the invention have the advantages of simple synthesis method, low cost, simple equipment, low investment and the like, and have wide application prospect and important environmental protection significance.

From the above embodiments, a triphenylamine cobalt porphyrin catalyst and a preparation method thereof, a carbon material-supported triphenylamine cobalt porphyrin composite catalyst and a preparation method and application thereof are disclosed. The carbon material loaded triphenylamine cobalt porphyrin composite catalyst has good ORR catalytic effect and higher hydrogen peroxide selectivity.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.