Prior to making catalysts, the zeta-potentials of prepared activated carbons were measured to Gnd out the most desirable conditions of active metal adsorption [4]. Because the precursors of active metals used in this study exist in the form of anion in the slurry, it could be expected that the favorable surface states of the support material should be in the state of positive charge. In Fig. 3, it was shown that the isoelectric points of activated carbons were under the pH of 3. Referred to these data, all the catalysts were prepared under the pH of 2.