Preparation Of Metal/Graphene And Its Catalytic Performance

As an important raw material of fine chemical, aniline has been widely used in the fields of medicine, agriculture, rubber chemicals etc. With the large specific surface area, good chemical stability, superior heat resistance, high intensity and other good characteristics, graphene is regarded as an ideal catalyst support.In this paper, graphene oxide was prepared from natural graphite by the method of secondary oxidation. Then Ni/graphene, Pt/graphene, Pd/graphene catalysts were prepared when graphene oxide as surport. The influences of metal precursor, reductant type and precursor percentages on the performance of nitrobenzene hydrogenation have been investigated. The optimum parameters of nitrobenzene hydrogenation were researched, and the life of the catalyst was investigated.The result shows that graphite oxide prepared via secondary oxidation method has more oxygen-containing functional groups. Ni/graphene, Pt/graphene, Pd/graphene catalysts were prepared when graphite oxide as support and different metals as precursors. The particle size of catalyst is small and uniform, mainly in the range of 4-5 nm. Ni/graphene, Pt/graphene, Pd/Graphene catalysts were successfully applied in nitrobenzene hydrogenation. Ni/graphene catalyst prepared when ethylene glycol as reductant agent and 30 wt% Ni used, has 96.63% of conversion and 90.23% of aniline selectivity in nitrobenzene hydrogenation. For Pt/graphene and Pd/graphene catalysts using ethylene glycol as reducing agent, as Pt, Pd percentage contents are 5 wt%, their conversions are 95.89%, 96.08%, while aniline selectivity are 89.55%, 91.15%, respectively,which are superior to other catalysts. When Pd/graphene catalyst was used as catalyst, the ideal parameters of nitrobenzene hydrogenation and catalyst life were investigated. The optimum parameters of nitrobenzene hydrogenation are as follows 110 mL ethanol, 125 mg catalyst, 150 oC of the reaction temperature, 1.5 MPa of reaction pressure, 6 h of reaction time, and 800 rpm of speed. After ten cycles, the conversion and aniline selectivity have been cut by 17.32, 20.42 percent point, respectively. This research provides a theoretical basis for the hydrogenation of nitrobenzene to aniline.