Preparation And Catalytic Properties Of Fe₃O₄/C Composite Supported Pt Catalysts

Pt/C catalysts have been widely used in multiphase-catalytic hydrogenation, multiphase-catalytic dehydrogenation and selective oxidation due to their high activity and selectivity. Pt nanopaticles on carbon supports exhibit higher catalytic activity than macroscopical Pt and the cost can be reduced due to the less dosage of Pt. In this paper we synthesised Fe3O4@C core-shell nanoparticles used as supports to prepare magnetic Pt/Fe3O4@C catalysts, these catalysts could be easily recycled by magnetic separation.Firstly, we prepared carbon nanospheres using glucose by hydrothermal method. The results showed that the morphology of carbon nanospheres was affected by the hydrothermal temperature and time. The carbon nanospheres processed high dispersion and uniform size distribution under 160℃ and 9 h. The Pt/carbon nanospheres had high catalytic activity and selectivity in o-CNB’s hydrogenation catalysis reaction. The conversion rate of o-CNB reached’100% in 30 min, and the selectivity of o-CAN increased by adding Ni2、Co2+、Fe3+.Secondly, Fe3O4@C core-shell nanopaticles were fabricated by one-step hydrothermal method. The Fe3O4 cores were formed via the reduction of Fe3+by glucose; the carbon shell derived from the carbonized glucose. Fe3O4@C core-shell nanopaticles were uniform size distribution and when the ratio of solvent (HbO:EG) was 9:1; the carbon shell on Fe3O4 cores were amorphous and the thickness of carbon shell increased as the reaction time prolonged; the Fe3O4 cores couldn’t be coated by carbon shell when glucose was replaced by starch.Finally, Pt/Fe3O4@C catalysts were used to catalyze the liquid phase hydrogenation of o-CNB. The results showed that, Pt/Fe3O4@C catalysts had higher selectivity of o-CAN than Pt/carbon nanospheres; the catalytical activity of Pt/Fe3O4@C increased when Fe3O4@C supports were treated under 300℃; prolonging Fe3O4@C supports’hydrothermal time also could increase the catalytical activity. The catalytical activity of Pt/Fe3O4@C catalysts showed excellent results in recycling.