Carbon microsphere supported Pd catalysts for the hydrogenation of ethylene

Carbon microspheres were prepared from acetylene at 800 degrees 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 (3d(5/2)) in two different oxidation states. The influence of space velocity and C2H4/H-2 mole ratio on the catalyst performance in the ethylene hydrogenation reaction was studied at 60 degrees 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. (C) 2007 Elsevier B.V. All rights reserved.