阅读说明：本技术 电催化剂B-MnO/CNT的制备方法及其应用 (Preparation method and application of electrocatalyst B-MnO/CNT ) 是由 姜毅 王晓迪 夏立新 于 2021-01-05 设计创作，主要内容包括：本发明涉及电催化剂B-MnO/CNT的制备方法及其应用。包括如下步骤：将碳纳米管分散于去离子水中,超声得溶液A；取无水MnCl-2和柠檬酸,充分溶解于水中,超声后搅拌,得溶液B；将溶液A和溶液B混合均匀后,超声得混合溶液；在冰水浴条件下,将NaBH-4溶液逐滴加入到混合溶液中,并继续搅拌,离心收集黑色固体,依次用去离子水和无水乙醇洗涤后,烘干,研磨后放入管式炉,氮气保护下,300℃煅烧1h,得B-MnO/CNT。本发明以B-MnO/CNT电极为工作电极,将阳极苄胺氧化代替OER反应,实现苄胺的氧化协同阴极析氢,采用本发明的方法,相同电压下,加入苄胺的电流密度明显高于OER反应。(The invention relates to a preparation method and application of an electrocatalyst B-MnO/CNT. The method comprises the following steps: dispersing carbon nano tubes in deionized water, and performing ultrasonic treatment to obtain a solution A; taking anhydrous MnCl 2 And citric acid, fully dissolving in water, stirring after ultrasonic treatment to obtain a solution B; uniformly mixing the solution A and the solution B, and performing ultrasonic treatment to obtain a mixed solution; under the condition of ice-water bath, NaBH is added 4 And dropwise adding the solution into the mixed solution, continuously stirring, centrifugally collecting black solids, washing with deionized water and absolute ethyl alcohol in sequence, drying, grinding, putting into a tube furnace, and calcining at 300 ℃ for 1h under the protection of nitrogen to obtain the B-MnO/CNT. The method takes a B-MnO/CNT electrode as a working electrode, and oxidizes the anode benzylamine to replace an OER reaction, so that the oxidization of the benzylamine is cooperated with the cathodic hydrogen evolution.)

1. The preparation method of the electrocatalyst B-MnO/CNT is characterized by comprising the following steps: dispersing carbon nanotubes in deionized water, and performing ultrasonic dispersion uniformly to obtain a solution A; taking anhydrous MnCl₂And citric acid, fully dissolving in water, stirring after ultrasonic treatment to obtain a solution B; uniformly mixing the solution A and the solution B, and performing ultrasonic treatment for 30-40min to obtain a mixed solution; under the condition of ice-water bath, NaBH is added₄And dropwise adding the solution into the mixed solution, continuously stirring for 30-40min under the ice-water bath condition, centrifugally collecting black solids, washing with deionized water and absolute ethyl alcohol in sequence, drying, grinding, placing into a tubular furnace, and calcining for 1h at 300 ℃ under the protection of nitrogen to obtain the B-MnO/CNT.

2. The method of claim 1, comprising the steps of: dispersing 50mg of carbon nanotubes in 30mL of deionized water, and uniformly dispersing by ultrasonic for 15min to obtain a solution A; 0.132g of anhydrous MnCl is taken₂And 0.25g of citric acid, fully dissolving in 15mL of water, stirring for 30min after ultrasonic treatment to obtain a solution B; mixing solution A and solution B uniformly, and performing ultrasonic treatment for 30min to obtainMixing the solution; 20mL of 0.15M NaBH in an ice-water bath₄And dropwise adding the solution into the mixed solution, continuously stirring for 30min under the ice-water bath condition, centrifuging to collect black solids, sequentially washing with deionized water and absolute ethyl alcohol, drying in a 60 ℃ oven, grinding, then placing in a tubular furnace, and calcining for 1h at 300 ℃ under the protection of nitrogen to obtain the B-MnO/CNT.

3. Use of an electrocatalyst B-MnO/CNT prepared according to the method of claim 1 or 2 for the production of hydrogen by electrocatalytic water splitting.

4. Use according to claim 3, characterized in that the method is as follows: adding deionized water, absolute ethyl alcohol and Nafion into the B-MnO/CNT, after uniform ultrasonic dispersion, dropwise adding the mixture onto a glassy carbon electrode, and drying the glassy carbon electrode in a 40 ℃ oven to obtain a B-MnO/CNT electrode; and (3) adding benzylamine into the anode chamber by taking the B-MnO/CNT electrode as a working electrode, the reference electrode as an Ag/AgCl electrode, the counter electrode as a platinum electrode and 1M KOH as electrolyte, and performing electrocatalytic water cracking to prepare hydrogen.

5. The use according to claim 4, wherein the ratio of deionized water to absolute ethanol to Nafion is 495:500:5 by volume.

6. The use of claim 5, wherein 4mg of B-MnO/CNT is added to 1000. mu.L of the mixed solution of deionized water, absolute ethanol and Nafion.

7. The use according to claim 5, wherein benzylamine is added in an amount of 1mmol benzylamine to 20mL KOH electrolyte having a concentration of 1M.

Technical Field

The invention belongs to the field of electrochemistry, and particularly relates to a preparation method and application of an electrocatalyst B-MnO/CNT for hydrogen production by electrocatalytic water cracking.

Background

Electrocatalytic water cracking is an effective way to produce clean energy hydrogen, however the OER reaction is a four-electron process, kinetically not favored, limiting the rate of water decomposition. Although many advanced non-noble metal electrocatalysts have been developed to increase OER activity, OER reactions still require higher overpotentials to match the HER rate, resulting in lower energy conversion efficiency. Therefore, the strategy of replacing the anodic OER reaction with the electrooxidation of the thermodynamically more favorable species is of increasing importance for increasing the hydrogen generation rate.

Disclosure of Invention

The invention aims to provide a B-MnO/CNT electrode, wherein an anode benzylamine is oxidized to replace an OER reaction, so that the oxidization of benzylamine is cooperated with the cathodic hydrogen evolution.

The technical scheme adopted by the invention is as follows: the preparation method of the electrocatalyst B-MnO/CNT comprises the following steps: dispersing carbon nanotubes in deionized water, and performing ultrasonic dispersion uniformly to obtain a solution A; taking anhydrous MnCl₂And citric acid, fully dissolving in water, stirring after ultrasonic treatment to obtain a solution B; uniformly mixing the solution A and the solution B, and performing ultrasonic treatment for 30-40min to obtain a mixed solution; under the condition of ice-water bath, NaBH is added₄And dropwise adding the solution into the mixed solution, continuously stirring for 30-40min under the ice-water bath condition, centrifugally collecting black solids, washing with deionized water and absolute ethyl alcohol in sequence, drying, grinding, placing into a tubular furnace, and calcining for 1h at 300 ℃ under the protection of nitrogen to obtain the B-MnO/CNT.

Preferably, the method comprises the following steps: dispersing 50mg of carbon nanotubes in 30mL of deionized water, and uniformly dispersing by ultrasonic for 15min to obtain a solution A; 0.132g of anhydrous MnCl is taken₂And 0.25g of citric acid, fully dissolving in 15mL of water, stirring for 30min after ultrasonic treatment to obtain a solution B; uniformly mixing the solution A and the solution B, and performing ultrasonic treatment for 30min to obtain a mixed solution; 20mL of 0.15M NaBH in an ice-water bath₄And dropwise adding the solution into the mixed solution, continuously stirring for 30min under the ice-water bath condition, centrifuging to collect black solids, sequentially washing with deionized water and absolute ethyl alcohol, drying in a 60 ℃ oven, grinding, then placing in a tubular furnace, and calcining for 1h at 300 ℃ under the protection of nitrogen to obtain the B-MnO/CNT.

The invention provides an application of an electrocatalyst B-MnO/CNT in hydrogen production by electrocatalytic water cracking.

Preferably, the method is as follows: adding deionized water, absolute ethyl alcohol and Nafion into the B-MnO/CNT, after uniform ultrasonic dispersion, dropwise adding the mixture onto a glassy carbon electrode, and drying the glassy carbon electrode in a 40 ℃ oven to obtain a B-MnO/CNT electrode; and (3) adding benzylamine into the anode chamber by taking the B-MnO/CNT electrode as a working electrode, the reference electrode as an Ag/AgCl electrode, the counter electrode as a platinum electrode and 1M KOH as electrolyte, and performing electrocatalytic water cracking to prepare hydrogen.

Preferably, the volume ratio of the deionized water to the absolute ethyl alcohol to the Nafion is 495 to 500 to 5.

Preferably, 4mg of B-MnO/CNT is added to each 1000. mu.L of the mixed solution of deionized water, absolute ethanol and Nafion.

Preferably, the amount of benzylamine added is 20mL of 1M KOH electrolyte to which 1mmol of benzylamine is added.

The invention has the beneficial effects that: the prepared B-MnO/CNT composite electrode is used as a working electrode, and the oxidation of benzylamine at the anode replaces the OER reaction, so that the oxidation of benzylamine is cooperated with the cathodic hydrogen evolution. At 2.0V, the oxidation current of benzylamine reaches 71mA cm^-2And is 2 times higher than the oxidation current density of water.

Drawings

FIG. 1 is a scanning electron micrograph of B-MnO/CNT powder prepared in example 1.

FIG. 2 is an X-ray diffraction pattern (XRD) of the B-MnO/CNT powder prepared in example 1.

FIG. 3 is a linear sweep voltammogram of B-MnO/CNT for electrocatalytic oxidation of benzylamine and electrocatalytic water oxidation.

Detailed Description

Example 1

The preparation method of the electrocatalyst B-MnO/CNT comprises the following steps:

dispersing 50mg of carbon nanotubes in 30mL of deionized water, and uniformly dispersing by ultrasonic for 15min to obtain a solution A; 0.132g of anhydrous MnCl is taken₂And 0.25g of citric acid, fully dissolving in 15mL of water, stirring for 30min after ultrasonic treatment to obtain a solution B; uniformly mixing the solution A and the solution B, and performing ultrasonic treatment for 30min to obtain a mixed solution; 20mL of 0.15M NaBH in an ice-water bath₄Adding the solution dropwise into the mixed solution, stirring for 30min under ice-water bath condition, centrifuging to collect black solid, sequentially adding into the mixtureAnd washing the mixture with deionized water and absolute ethyl alcohol for 3 times respectively, then drying the mixture in a 60 ℃ drying oven, grinding the mixture, then putting the ground mixture into a tubular furnace, and calcining the mixture for 1h at 300 ℃ under the protection of nitrogen to obtain a black solid product B-MnO/CNT.

FIG. 1 is a scanning electron micrograph of the prepared B-MnO/CNT powder. As can be seen from FIG. 1, the B-MnO/CNT prepared by the present invention is a tubular shape.

FIG. 2 is an X-ray diffraction pattern (XRD) of the prepared B-MnO/CNT powder. As can be seen from FIG. 2, the diffraction peaks of CNT and MnO correspond to each other, thus proving that the B-MnO/CNT composite electrode is successfully prepared.

Example 2

Application of (I) electrocatalyst B-MnO/CNT in hydrogen production by electrocatalytic water cracking

The method comprises the following steps:

preparation of B-MnO/CNT electrode: adding 495 muL of deionized water, 500 muL of absolute ethyl alcohol and 5 muL of Nafion into 4mg of B-MnO/CNT, ultrasonically dispersing, and dripping 5 muL of the solution into a container with the area of 0.07cm²And putting the glassy carbon electrode on a drying oven at 40 ℃ for drying to obtain the B-MnO/CNT electrode.

The electrochemical performance of the composite electrode was tested using the CHI 760E electrochemical workstation. An H-shaped electrolytic cell and a three-electrode working system are adopted to carry out electrochemical performance test. With 1M KOH as electrolyte, 20mL of electrolyte was added to each of the anode and cathode chambers, and 1mmol of benzylamine was added to the anode chamber. And taking a B-MnO/CNT electrode as a working electrode, a platinum wire as a counter electrode and an Ag/AgCl electrode as a reference electrode. The electrolytic cell was sealed, and the solution was saturated with nitrogen by passing nitrogen gas through the liquid surface for 30min to remove oxygen from the solution, followed by electrochemical performance analysis. The linear sweep voltammetry scan parameter is a rotation rate of 1600rpm and a scan rate of 10mV s^-1. The voltage used is based on the standard hydrogen electrode potential. The results are shown in FIG. 3.

(II) comparative example

Preparation of B-MnO/CNT electrode: adding 495 muL of deionized water, 500 muL of absolute ethyl alcohol and 5 muL of Nafion into 4mg of B-MnO/CNT, ultrasonically dispersing, and dripping 5 muL of the solution into a container with the area of 0.07cm²And putting the glassy carbon electrode on a drying oven at 40 ℃ for drying to obtain the B-MnO/CNT electrode.

Electrochemical method using CHI 760EThe workstation tests the electrochemical performance of the composite electrode. An H-shaped electrolytic cell and a three-electrode working system are adopted to carry out electrochemical performance test. 1M KOH is used as electrolyte, and 20mL of electrolyte is respectively added into the anode chamber and the cathode chamber. And taking a B-MnO/CNT electrode as a working electrode, a platinum wire as a counter electrode and an Ag/AgCl electrode as a reference electrode. The electrolytic cell was sealed, and the solution was saturated with nitrogen by passing nitrogen gas through the liquid surface for 30min to remove oxygen from the solution, followed by electrochemical performance analysis. The linear sweep voltammetry scan parameter is a rotation rate of 1600rpm and a scan rate of 10mV s^-1. The voltage used is based on the standard hydrogen electrode potential. The results are shown in FIG. 3.

FIG. 3 is a linear sweep voltammogram of B-MnO/CNT for electrocatalytic oxidation of benzylamine and electrocatalytic water oxidation. As can be seen from FIG. 3, the current density increased significantly with the addition of benzylamine, indicating that benzylamine oxidizes more readily than water at the same voltage. At 2.0V, the oxidation current of benzylamine reaches 71mA cm^-2And is 2 times higher than the oxidation current density of water.