Graphene-based composite material with surface coated by mesoporous silica and loaded with noble metal nanoparticles, as well as preparation method and application of graphene-based composite material

Abstract

The invention discloses a graphene-based composite material with surface coated by mesoporous silica and loaded with noble metal nanoparticles, and a preparation method of the graphene-based composite material. The preparation method comprises the following steps of: loading noble metal precursors on the surface of oxidized graphene by the deposition-precipitation method, so as obtain the oxidized graphene loaded with the noble metal precursors; coating the surface of the oxidized graphene located with the noble metal precursors by a silica material with a mesoporous structure through the sol-gel method in the presence of a surface active agent and a silicon source, so as to obtain an original composite material; and reducing the original composite material to obtain the composite material. The preparation method is mild in condition and universal in application; products can be prepared as mass; the distance between laboratory investigation and industrial application can be effectively reduced; and the composite material can be used as a catalyst.

Description

technical field [0001] The invention belongs to the field of preparation of nanocomposite materials, and in particular relates to a graphene-based composite material whose surface is coated with mesoporous silicon dioxide and loaded with noble metal nanoparticles, as well as its preparation method and application. Background technique [0002] Graphene is a sp 2 Two-dimensional monoatomic layer materials formed by hexagonal arrangement of hybridized carbon atoms have attracted extensive attention due to their excellent electron mobility, thermal conductivity, and high specific surface area. Graphene is widely used as a catalyst carrier and has shown excellent performance in fields such as electrocatalysis, photocatalysis, and thermal catalysis, mainly due to its high electron mobility and high specific surface area. Especially in the field of thermal catalysis, both theoretical and experimental studies have demonstrated that graphene can greatly enhance the catalytic perfor...

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Problems solved by technology

[0003] However, in the actual thermal catalytic reaction system, the graphene / noble metal composite catalysts reported so far still have many limitations, such as: (1) Due to the π-π interaction, the van der Waals force between graphenes makes it easy to agglomerate, making the current The synthesized graphene / noble metal composite catalyst material always exists in the state of agglomeration or precipitation, which covers the catalytic reaction active sites and hinders the mass transfer process of substrates and products, which is not conducive to the occurrence and progress of catalytic reactions (see literature: P.V.Kamat, Phys.Chem.Lett.2009,1,520); (2) Noble metal nanoparticles have high catalytic activity because of their high proportion of surface atoms and many corner atoms, but these nanoparticles also have high surface energy As well as the weaker interaction with the graphene surface, during use, especially under high temperature reaction conditions, Ostwald ripening will occur between nanoparticles to generate larger particles, resulting in a reduction in its catalytic activity (reference : X.Chen, J.Am.Chem.Soc.2011,133,3693); (3) The general method of loading various noble metal ultrafine nanoparticles on the surface of graphene is still rarely reported

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