Modified cobalt-manganese-oxide-doped carbon nanotube catalyst as well as preparation method and application thereof

A cobalt oxide manganese oxide catalyst, carbon nanotube technology, applied in electrical components, battery electrodes, circuits, etc., can solve the problems of low active site, small specific surface area, limited catalytic activity, etc., to increase solubility and dispersibility. Effect

Inactive Publication Date: 2016-05-04

SOUTH CHINA UNIV OF TECH

3 Cites 6 Cited by

AI-Extracted Technical Summary

Problems solved by technology

It has been reported that CoMn 2 o 4 It is used in supercapacitors because of its potential ORR performance, however due to ...

Method used

1, carbon nanotubes are further carried out functionalized treatment with PDDA to increase the solubility and dispersibility of carbon nanotubes, specifically for placing the weighed 0.1g carbon nanotubes in a 200mL beaker, add 2mL1wt% PDDA aqueous solution After ultrasonic dispersion for 1 hour, a stable black solution can be obtained.

[0064] The carbon nanotubes for preparing the catalyst provide support points for the CoMn2O4 particles, while enhancing the specific surface area of the catalyst and enhancing the catalytic performance and electrical conductivity of the catalyst. However, pure carbon nanotubes limit their catalytic performance due to their weak hydrophilicity. In this experiment, the method of PDDA is used to modify the carbon nanotubes, strengthen its hydrophilic properties, and promote the prepared CoMn2O4 to attach more to the surface of CNTs. At the same time, FT-IR and XPS analysis of the modified CNT found that the infrared spectrum of the modified carbon tube and the pure carbon tube, it can be seen from the figure that for the PDDA-CNT catalyst, the wavelength is 3431 and 2942cm Below, the corresponding functional groups are O-H and C-H. At the same time, due to the introduction of PDDA, there are characteristic C=C peaks at wavelengths of 1474 and 1634cm-1, which indicates that there is a π-π interaction between carbon tubes and PDDA. It can be seen from the figure that the nitrogen content of the PDDA-modified carbon tube is 6.7%, while the nitrogen content of the pure CNT is 0.05%, indicating that the PDDA functionalization introduces nitrogen-containing functional groups. In addition, the wavelength of 1327cm-1 corresponds to the C...

Abstract

The invention discloses a modified cobalt-manganese-oxide-doped carbon nanotube catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: (1), putting carbon nanotubes in a PDDA aqueous solution and carrying out ultrasonic dispersion, thereby obtaining a homogeneous solution; (2), firstly dispersing the obtained homogeneous solution in deionized water, adding a dimethylformamide solution and carrying out ultrasonic dispersion; then, dissolving Co2+ and Mn2+ in the mixed solution according to a molar ratio of 1 : (2-2.5), and slowly stirring till obtaining black precipitate; (3), washing the black precipitate by utilizing the deionized water, putting the washed precipitate in a polytetrafluoroethylene high-pressure reactor, heating for 8-10 hours at 160-180 DEG C, and finally drying the processed black precipitate, thereby obtaining the modified cobalt-manganese-oxide-doped carbon nanotube catalyst. The modified cobalt-manganese-oxide-doped carbon nanotube catalyst can successfully starts MFC and shortens a starting period of the MFC; compared with a comparison group Pt/C, the modified cobalt-manganese-oxide-doped carbon nanotube catalyst has better performance, and following the reduction of CoMn2O4 load, the performance of the MFC is also gradually improved.

Application Domain

Cell electrodes

Technology Topic

IonManganese oxide +10

Image

Examples

Experimental program(8)

Example Embodiment

[0050] Example 1 (CoMn 2 O 4 /PDDA-CNT catalyst preparation)

[0051] 1. Use PDDA to further functionalize the carbon nanotubes to increase the solubility and dispersibility of the carbon nanotubes. Specifically, the weighed 0.1g carbon nanotubes are placed in a 200mL beaker, and 2mL of 1wt% PDDA aqueous solution is added to ultrasonic dispersion for 1h. , You can get a stable black solution.

[0052] 2. Using the Hummer method to prepare, first disperse PDDA-CNT in 20 mL of deionized water, add 100 mL of dimethyl formamide (DMF) solution, and sonicate together for 0.5 h. Secondly, 3.792gCo(OAc) 2 ·6H 2 O and 7.477gMn(OAc) 2 ·6H 2 O was dissolved in the mixed solution at a molar ratio of 1:2, and stirred slowly for 0.5 hours to obtain a black precipitate.

[0053] 3. Wash the precipitated black solid 0.03g with deionized water, and put the precipitate into a polytetrafluoroethylene autoclave, heat it at 180℃ for 10h, and finally put the black precipitate in an oven at 80℃ for 24h to obtain 30 % CoMn 2 O 4 /PDDA-CNT.

[0054] Follow CoMn 2 O 4 : CNT mass ratio is 0.4:1, 0.5:1, weigh the corresponding mass of Co(OAc) 2 ·6H 2 O, Mn(OAc) 2 ·6H 2 O, according to the same experimental method, the CoMn corresponding to 40% and 50% are obtained 2 O 4 /PDDA-CNTT.

Example Embodiment

[0055] Example 2 (CoMn 2 O 4 / TEM characterization of PDDA-CNT)

[0056] The surface morphology of the catalyst was observed with a Transmission Electron Microscope (TEM) (HITACHIH-7650, Japan).

[0057] Use TEM analysis to observe as pure CNT and CoMn 2 O 4 /PDDA-CNT catalyst surface morphology, the test voltage is 80kV.

[0058] Through this example, pure CNT and CoMn 2 O 4 /PDDA-CNT catalyst TEM observation, it can be seen that the formed black nano-scale particles are uniformly attached to the CNT surface. And, as the load increases, the number of particles loaded on the surface of the carbon tube also increases. Nanostructure PDDA-CoMn 2 O 4 /CNT compound can effectively increase the specific surface area of the catalyst, thereby increasing oxygen adsorption and CoMn 2 O 4 The catalytic performance. That is, the reduction of the specific surface area will limit the interaction between oxygen and the catalyst, thereby limiting the ORR performance.

Example Embodiment

[0059] Example 3 (CoMn 2 O 4 /XRD characterization of PDDA-CNT and PDDA-CNT)

[0060] XRD analysis: used to analyze the elemental composition of NiO/CNT catalyst. The test process is realized on the D8ADVANCE instrument. The test condition is copper target, incident radiation λ = 0.15418nm, Ni filter, tube pressure 40KV, tube flow 40mA; scanning The step length is 0.02 degrees, the scanning speed is 0.1 second/step; the slit DS0.5°RS8mm (corresponding to the LynxExe array detector). Use the Scherer formula to estimate the average particle size of NiO. Where λ is the wavelength of X-ray, β 1/2 Is the half-width, and θ is the angle of the NiO(200) diffraction peak.

[0061] According to the Raman spectrum, the prepared compound has a tetragonal spinel crystal structure and the XRD peaks are obvious, indicating that the prepared compound has a significant crystal structure. In addition, with standard CoMn 2 O 4 Compared with the peaks, the peak positions of the prepared materials are consistent with the standard peaks, which are between 30° and 40°. For the carbon peak between materials (2θ=26°), the carbon peak in PDDA-CNTs material is weaker than the peak intensity of pure CNT carbon peak, which indicates that the introduction of PDDA weakens the intensity of the carbon peak. According to the Debye-Scherrer formula, CoMn 2 O 4 The diameter of the particles is about 80 nm. The nano-structured catalyst material can provide a larger specific surface area, enhance the diffusion of oxygen, and promote the ORR performance of the material.

PUM

Property	Measurement	Unit
Diameter	80.0	nm
Maximum power density	732.0	mW/m²

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