Preparation of a nitrogen-doped graphene airgel-supported non-noble metal oxygen reduction catalyst

Abstract

The invention provides a method for preparing a nitrogen-doped graphene airgel-loaded non-precious metal catalyst, comprising the following steps: stirring a mixed solution of an organic amine and an aldehyde at 50-90°C for 0.5-2h, and then adding graphite oxide Alkene and non-noble metal salt solution, continuously stirred at 60~99°C for 1~24h to obtain organic gel, after freezing or supercritical drying, heat up to 500~1000°C under the protection of inert gas, keep it warm for 1~6h, and cool naturally to At room temperature, a nitrogen-doped graphene airgel supported non-noble metal oxygen reduction catalyst was obtained. The nitrogen-doped graphene airgel-supported non-noble metal oxygen reduction catalyst of the present invention has a simple preparation method, is easy to scale up production, is low in cost, has high oxygen reduction catalytic activity, and is favorable for commercial promotion.

Description

technical field [0001] The invention belongs to the field of graphene catalytic materials, in particular to the preparation and application of a nitrogen-doped graphene airgel-loaded non-noble metal oxygen reduction catalyst. Background technique [0002] Oxygen reduction reaction, as the positive electrode reaction of fuel cells and metal-air batteries, has always been a hot spot in electrochemical research. Oxygen has a slow reaction rate, so catalysts are needed. Traditional catalysts are mainly Pt-based noble metals, which have poor stability and high production costs, and are not suitable for commercial promotion. Therefore, it is particularly important to develop a cheap, efficient, stable, and large-scale production of non-noble metal catalysts to replace Pt-based noble metal catalysts. [0003] Graphene is a two-dimensional honeycomb carbon material with a thickness of one atomic layer. It has the characteristics of high specific surface area and high conductivity. ...

AI Technical Summary

Problems solved by technology

[0004] Nitrogen-doped graphene-supported non-precious metal materials are used as oxygen reduction catalysts, which have good oxygen reduction catalytic performance. Chinese patents CN103599805A and CN103611555A mix graphene oxide solution, non-noble metal salt solution and nitrogen-containing organic small molecules, evaporate to dryness, and then The non-noble metal oxygen reduction catalyst supported by nitrogen-doped graphene was obtained by high-temperature heat treatment, which showed good oxygen reduction catalytic activity. However, the graphene layer has π-π interaction, which is easy to reunite during use. And positively charged non-noble metal ions can further promote the agglomeration of negatively charged graphene sheets, making the specific surface area of ​​the composite much smaller than the theoretical specific surface area of ​​graphene, resulting in low utilization of oxygen reduction active sites.

At present, the method to solve graphene aggregation is mainly to make graphene into a three-dimensional gel. Chinese patent CN102849731A uses a mixed solution of graphene oxide and organic amine as a hydrothermal reaction mother liquor to synthesize nitrogen-doped graphene hydrogel. Graphene and nitrogen-containing compounds were used as raw materials to hydrothermally synthesize nitrogen-doped graphene hydrogel, and then heat-treated under the protection of an inert atmosphere to obtain nitrogen-doped graphene airgel. CN103721736A mixed solution of graphene oxide and organic iron compound Transfer to a high-pressure reactor for hydrothermal reaction to obtain an iron-containing graphene hydrogel, and then treat it at a high temperature under an ammonia atmosphere to obtain a nitrogen-doped graphene-supported iron catalyst. The above-mentioned preparation of nitrogen-doped graphene gel involves to the hydrothermal method, and the hydrothermal reaction requires high equipment and low output, which is not conducive to large-scale industrial production

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