阅读说明：本技术 一种碳纳米管的氧化方法及其应用 (Oxidation method of carbon nano tube and application thereof ) 是由 逯一中 李长龙 姜媛媛 陈传霞 倪朋娟 王波 张成会 于 2020-12-15 设计创作，主要内容包括：本发明提供一种碳纳米管的氧化方法及其应用,将去离子水、CNTs与Na-2S-2O-8混合,超声分散后,加热搅拌,冷却、离心、洗涤、干燥,得到O-CNTs催化剂。该制备方法简单、无污染、成本低,制备得到的氧化碳纳米管在电催化还原氧气生产双氧水的过程中具有高选择性、稳定性和产量。(The invention provides an oxidation method of carbon nano-tube and application thereof, which comprises the steps of mixing deionized water, CNTs and Na 2 S 2 O 8 Mixing, ultrasonically dispersing, heating and stirring, cooling, centrifuging, washing and drying to obtain the O-CNTs catalyst. The preparation method is simple, pollution-free and low in cost, and the prepared carbon oxide nanotube has high selectivity, stability and yield in the process of producing hydrogen peroxide by electrocatalytic reduction of oxygen.)

1. The preparation method of the O-CNTs catalyst is characterized by mixing deionized water, CNTs and Na₂S₂O₈Mixing, ultrasonically dispersing, heating and stirring, cooling, centrifuging, washing and drying to obtain the O-CNTs catalyst.

2. The method of claim 1, wherein the deionized water, CNTs and Na are mixed₂S₂O₈The addition amount ratio of (A) to (B) is as follows: 500 ml: 50 mg: 1g of the total weight of the composition.

3. The preparation method according to claim 1, wherein the ultrasonic dispersion time is 60 minutes, the heating and stirring time is 3 to 9 hours, and the stirring speed is 300 r/min.

4. The method of claim 1, wherein the drying temperature is 60 ℃.

5. A catalyst O-CNTs-X, X =3, 6, 9, prepared by the preparation method according to one of claims 1 to 4.

6. Use of the catalyst of claim 5 for the electrocatalytic production of hydrogen peroxide.

Technical Field

The invention relates to an oxidation method of a carbon nano tube and application thereof, belonging to the technical field of carbon-based catalysts in electrocatalysis.

Background

The only by-product of hydrogen peroxide oxidation is water, one of the greenest oxidants considered, in papermakingAnd the industrial industries such as electronics, industrial wastewater treatment and oxidation play important roles. In 2015, the global hydrogen peroxide market demand is about 385 million tons/year, and by 2024, the value reaches 600 million tons/year, and the market value is $ 64 million. The main process for industrially producing hydrogen peroxide is the anthraquinone process, which is an indirect batch process requiring sequential hydrogenation, oxidation of anthraquinone molecules and extraction of H from organic solvents₂O₂. However, this multi-step process is energy intensive and it is difficult to produce H on site₂O₂. People have been working to develop efficient site H₂O₂Production process which not only can greatly reduce H₂O₂The cost of synthesis, transportation, storage and handling, and the subsequent application process can be promoted.

By the 2 e-pathway: o is₂+2H⁺+2e-→H₂O₂The method can be used for carrying out electrocatalytic reduction on oxygen and producing hydrogen peroxide in situ under the conditions of proper temperature and atmospheric pressure, and is an ideal way for producing hydrogen peroxide on a small scale. This requires a highly active, low cost electrocatalyst that reduces oxygen to hydrogen peroxide with high selectivity (2 e-route), avoiding reduction to water: o is₂+4H⁺+4e-→2H₂O (4 e-pathway). In recent years, many promising catalysts have been proposed, the most excellent catalyst is a noble metal catalyst, the wide application of which is limited due to its high price, and the carbon-based material has abundant reserves, low price, controllable surface and structural properties, and is a potential substitute for the noble metal catalyst.

Disclosure of Invention

Aiming at the problems of high price and limited resources of noble metal catalysts in the prior art, the invention aims to provide an oxidation method of a carbon nano tube and application thereof.

The invention is realized by the following technical scheme:

a preparation method of O-CNTs catalystIonized water, CNTs and Na₂S₂O₈Mixing, ultrasonically dispersing, heating and stirring, cooling, centrifuging, washing and drying to obtain the O-CNTs catalyst.

Preferably, the deionized water, CNTs and Na are adopted₂S₂O₈The addition amount ratio of (A) to (B) is as follows: 500 ml: 50 mg: 1g of the total weight of the composition.

Preferably, the ultrasonic dispersion time is 60 minutes, the heating and stirring time is 3-9 hours, and the stirring speed is 300 r/min.

Preferably, the drying temperature is 60 ℃.

The catalyst O-CNTs-X prepared by the preparation method is provided with X =3, 6 and 9.

The invention also provides application of the catalyst in producing hydrogen peroxide through electrocatalysis.

Advantageous effects

The invention discloses a preparation method of a carbon nano tube, and (1) the method has the advantages of simple preparation process, no pollution and low cost. (2) The electrocatalyst prepared by the method has the advantages of higher current density, higher hydrogen peroxide selectivity, stability and yield.

Drawings

FIG. 1 is (A) a TEM image of CNTs; (B) O-CNTs-6 TEM image;

FIG. 2 is a Raman spectrum image of (A) each catalyst; (B) XPS full spectrum analysis of CNTs and O-CNTs-6;

in FIG. 3 (A) CNTs and O-CNTs-6 are at O₂LSV curve of (d); (B) the hydrogen peroxide selectivity of CNTs and O-CNTs-6; (C) I-T curve of O-CNTs-6 catalyst; (D) time-yield curve for O-CNTs-6 catalyst.

Detailed Description

The following examples are given for the detailed implementation and specific operation of the present invention, but the scope of the present invention is not limited to the following examples.

Example 1

(1) Preparing and characterizing an O-CNTs catalyst: 50ml of deionized water and 50mg of CNTs are taken、1g Na₂S₂O₈2.5cm spindle magnetons were placed in a 100ml round bottom flask, continuously ultrasonically dispersed for 1h, and then placed in a magnetic oil bath stirrer at 85 ℃ for heating and stirring for X hours (X =3, 6, 9), with the stirring speed being 300 r/min. And taking out the round-bottom flask after heating and stirring are finished, cooling to room temperature, centrifuging and washing the obtained product to remove residual impurity ions, and drying in an oven at 60 ℃ for one night, wherein the products are marked as O-CNTs-3, O-CNTs-6 and O-CNTs-9 according to the heating time. We performed characterization using Transmission Electron Microscopy (TEM), Raman spectroscopy (Raman spectroscopy) and X-ray photoelectron spectroscopy (XPS).

FIG. 1 is (A) a TEM image of CNTs; (B) O-CNTs-6 TEM image; FIG. 2 is a Raman spectrum image of (A) each catalyst; (B) XPS full spectrum analysis of CNTs and O-CNTs-6; as seen from the SEM image, the shapes of the O-CNTs-6 after oxidation treatment and the untreated CNTs are basically not changed. I in Raman spectra_D/I_GThe value of (A) gradually increased with the increase in the treatment time, indicating that the increase in the treatment time increases the defects of the catalyst. XPS results show that the treated O-CNTs-6 contains a large number of oxygen-containing functional groups.

(2) Electrochemical oxygen reduction test: the carbon-based catalysts prepared above were subjected to a linear scanning test (LSV) and a stability test (I-T). And calculating the hydrogen peroxide selectivity of each catalyst according to the LSV experimental result, evaluating the stability of the catalyst according to the I-T experimental result, and calculating the hydrogen peroxide yield of the catalyst by combining with an ultraviolet-visible spectrophotometer (UV-8000).

All electrochemical tests were performed at room temperature, using a conventional three-electrode system CHI 660 electrochemical station for electrochemical oxygen reduction tests. A Rotating Disk Electrode (RDE), a Saturated Calomel Electrode (SCE) and a graphite rod were used as a working electrode, a reference electrode and a counter electrode, respectively. Both the Linear Scan test (LSV) and the stability test (I-T) are at saturation O₂In 0.1M KOH electrolyte. The scan rate of LSV is 20 mV s^-1。

In FIG. 3 (A) CNTs and O-CNTs-6 are at O₂LSV curve of (d); (B) CNTsAnd O-CNTs-6; (C) I-T curve of O-CNTs-6 catalyst; (D) time-yield curve for O-CNTs-6 catalyst.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.