Carbon microsphere supported Pd catalysts for the hydrogenation of ethylene

Carbon microspheres were prepared from acetylene at 800 °C. The microspheres were loaded with 2% Pd (impregnation method), both before and after acid treatment, and characterized and tested for ethylene hydrogenation. Transmission electron microscopy (TEM) confirmed that the carbon microspheres had a core-shell structure and that the shell was crystalline in nature. XPS studies on the fresh carbon microsphere supported Pd catalyst showed the presence of the Pd (3d5/2) in two different oxidation states. The influence of space velocity and C2H4/H2 mole ratio on the catalyst performance in the ethylene hydrogenation reaction was studied at 60 °C. The acid treated carbon microsphere supported Pd catalyst showed better ethylene hydrogenation activity than the non-acid treated catalyst, but TEM analysis revealed that the Pd metal sintered during catalysis.