Preparation method for functionalized graphene loaded noble metal nano-crystalline composite catalyst

Abstract

The invention discloses a preparation method for a functionalized graphene loaded noble metal nano-crystalline composite catalyst, which synchronously realizes reduction of a noble metal precursor and graphite oxide to obtain the composite catalyst in a structure that grapheme with surface modified by sulfonic acid is uniformly loaded with noble metal nano-crystalline. The method comprises the following steps: 1, preparing the graphite oxide; 2, carrying out covalent modification on the graphite oxide by benzenesulfonic acid; and 3, synchronously reducing the noble metal precursor and the graphite oxide and stabilizing noble metal nano particles by utilizing a coordination effect between a sulfonic acid group and the noble metal. Meanwhile, the surface sulfonic acid group has the hydrophilcity so that the catalyst can be uniformly dispersed in a water solution. A result shows that the noble metal nano particles with narrow size distribution can be uniformly distributed on the surface of graphene to form the efficient catalyst which has good dispersion in the water solution. Catalytic reduction reaction of p-nitrophenol proves that the catalyst has a very excellent catalysis performance; the catalyst still keeps the previous activity after being recycled and reutilized for five times.

Description

technical field [0001] The invention relates to the technical field of chemical catalysis, in particular to a method for preparing a functionalized graphene-supported noble metal nanocrystal composite catalyst. Background technique [0002] Noble metal nanocrystalline homogeneous catalysts stabilized by ligands have important applications in catalytic organic reactions due to their fast reaction rate, good selectivity, and high catalytic yield. However, homogeneous catalysts are difficult to purify for recycling after catalysis, so their applications are greatly limited. The development of a highly dispersed noble metal nanocrystal composite catalytic system supported by a carrier can effectively solve the above-mentioned shortcomings of homogeneous catalysts, and has broad prospects in practical applications. [0003] Graphene is very suitable for the support of noble metal nanocatalysts due to its large specific surface area, high thermal and electrical conductivity, and ...

AI Technical Summary

Problems solved by technology

Most of the existing technologies use graphite oxide as a carrier, and use the oxygen-containing groups and defect positions on the surface of graphite oxide to bind and immobilize nanoparticles. However, due to the surface defects, graphite oxide completely loses its electrical conductivity compared with graphene. The electrons cannot move freely in the layer, and the thermal conductivity is also greatly affected.

Therefore, using this as a carrier to catalyze organic reactions only takes advantage of its large specific surface area. It is difficult to exert the excellent electron transport performance and thermal conductivity of graphene. At the same time, the defects and oxygen-containing groups caused by oxidation are distributed on the surface of graphite oxide. is uneven, which will inevitably cause uneven distribution of nanoparticles on its surface, which will also affect its catalytic efficiency

The reason why everyone uses graphite oxide as a carrier is that graphite oxide can form a homogeneous aqueous solution. In the prior art, graphene is prepared by chemical reduction of graphite oxide. However, after reduction, graphene loses the oxygen-containing groups on the surface. Due to the hydrophilic effect, it will quickly aggregate in the solution, and even re-accumulate into a graphite structure. Therefore, although pure graphene sheets have many advantages in physical and chemical properties, they are difficult to process in solution, thus limiting their applications.

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