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A kind of preparation method of bifunctional co-n-c electrocatalyst

An electrocatalyst and dual function technology, applied in the field of electrocatalyst and its preparation, can solve the problems of high cost, scarcity of resources, hindering large-scale production and application, etc., and achieve excellent performance, simple preparation process, good electrochemical performance and reliability. repetitive effect

Active Publication Date: 2022-06-21
CHINA THREE GORGES UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Noble metals are the most efficient catalysts in terms of electrochemical activity and stability, but the high cost and scarcity of resources seriously hinder their large-scale production and application.

Method used

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  • A kind of preparation method of bifunctional co-n-c electrocatalyst
  • A kind of preparation method of bifunctional co-n-c electrocatalyst
  • A kind of preparation method of bifunctional co-n-c electrocatalyst

Examples

Experimental program
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Effect test

Embodiment 1

[0030] Dissolve 0.12 M cobalt chloride in 60 mL formamide solution at room temperature at 200 o C for hydrothermal reaction for 12 h; after cooling to room temperature, filter and wash with deionized water and ethanol repeatedly, and dry in a vacuum oven overnight to obtain a polymer containing cobalt and nitrogen. After grinding and mixing 0.1 g of polymer powder and 0.4 g of dicyandiamide together, they were put into a tube furnace and heated at 800 °C under Ar flow. o C reaction 4 h, heating rate 5 o C / min, take it out after naturally cooling to room temperature.

[0031] figure 1 It is the XRD pattern of the bifunctional Co-N-C electrocatalyst prepared in Example 1 before and after annealing. It can be seen from the figure that the powder after hydroheating basically has no characteristic peaks, indicating that after the crystallization water is removed, the polymer formed by formamide can coordinate a large amount of cobalt ions (the structure is as shown above), even ...

Embodiment 2

[0039] Dissolve 0.12 M cobalt chloride in 60 mL formamide solution at room temperature at 200 o C for hydrothermal reaction for 12 h; after cooling to room temperature, filter and wash with deionized water and ethanol repeatedly, and dry in a vacuum oven overnight to obtain a polymer containing cobalt and nitrogen. Put 0.1 g of polymer powder into a tube furnace, under Ar flow at 800 o C reaction 4 h, heating rate 5 o C / min, take it out after naturally cooling to room temperature.

[0040] Figure 9 It is the OER, ORR linear voltammetry sweep (LSV) diagram of the sample electrode prepared in Example 2. It can be seen from the figure that when the current density of the electrode is 10 mA / cm 2 , the potential corresponding to OER reaction oxygen production in alkaline aqueous solution is E 10 = 1.588 V, the half-wave potential corresponding to the ORR reaction in alkaline aqueous solution is E 1 / 2 = 0.861 V, the limiting current density can reach ~5.55 mA / cm at 1600 rpm r...

Embodiment 3

[0042] Dissolve 0.12 M cobalt chloride in 60 mL formamide solution at room temperature at 200 o C for hydrothermal reaction for 12 h; after cooling to room temperature, filter and wash with deionized water and ethanol repeatedly, and dry in a vacuum oven overnight to obtain a polymer containing cobalt and nitrogen. After grinding and mixing 0.1 g of polymer powder and 0.8 g of dicyandiamide together, they were put into a tube furnace and heated at 800 °C under Ar flow. o C reaction 4 h, heating rate 5 o C / min, take it out after naturally cooling to room temperature.

[0043] Figure 10 It is the OER, ORR linear voltammetry sweep (LSV) diagram of the sample electrode prepared in Example 3. It can be seen from the figure that when the current density of the electrode is 10 mA / cm 2 , the potential corresponding to OER reaction oxygen production in alkaline aqueous solution is E 10 = 1.578V, the half-wave potential corresponding to the ORR reaction in alkaline aqueous solutio...

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Abstract

The invention provides a method for preparing a bifunctional Co-N-C electrocatalyst, which uses hydrothermal reaction to prepare a granular high polymer containing cobalt and nitrogen, and then anneals the cyanamide and the high polymer under a protective atmosphere to obtain Co‑N‑C electrocatalysts. The polymer formed in the hydrothermal reaction is transformed into carbon during the annealing process under the protective atmosphere. The ammonia gas generated by cyanamide during the annealing process reduces the divalent cobalt to metal cobalt, and the nitrogen-carbon fragments generated by the decomposition of cyanamide are in the metal cobalt. Under the action of catalysis, carbon nanotubes with cobalt as the core and doped with nitrogen are generated. The product obtained by the technical solution of the present invention, due to the construction of a variety of high electrocatalytic active sites, including nitrogen-doped active sites in carbon materials and other lattice defects caused by this, the strong coupling interface between nitrogen-doped carbon materials and cobalt , e.g. generating Co‑N x ‑C bond, which makes it have excellent electrocatalytic oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) performance.

Description

technical field [0001] The invention relates to an electrocatalyst and its preparation, and belongs to the field of energy storage and conversion materials and devices. Background technique [0002] Faced with the severe challenge of the energy crisis, countries are committed to developing efficient new energy technologies. Due to the advantages of high energy density, low cost and environmental friendliness, metal-air batteries have become promising energy storage devices. Noble metals are the most efficient catalysts in terms of electrochemical activity and stability, but their high cost and scarcity of resources seriously hinder their large-scale production and application. Therefore, the present invention aims to prepare a cheap and efficient bifunctional electrocatalyst capable of catalyzing oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). [0003] In recent years, transition metals and their compounds (including oxides, sulfides, nitrides, etc.) h...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/88H01M4/90H01M12/06
CPCH01M4/8882H01M4/9008H01M12/06
Inventor 黄妞杨柳邵梅方闫术芳骆禅
Owner CHINA THREE GORGES UNIV