Oxide-metal catalysts for the reforming of gasolines Communication 5. Some peculiar features of the catalytic and physical properties of palladium catalysts

Abstract

1. The following catalysts for reforming gasoline were investigated: No. 1-Pd on A12O3, No. 2-Pd on A12O3 which had been treated with HP and No. 3-sulfided Pd on A12O3 which had been treated with HF. The specific surfaces of catalysts No. 1 and 2 were the same, but that of the sulfided catalyst No. 3 was less by a factor of 1.5. Only catalyst No. 2 sintered appreciably. 2. There were no other crystalline phases in the catalysts besides γ-Al2O3 and Pd; any PdS in the sulfided catalyst No. 3 could only be present in the amorphous state or in the form of a surface compound. The order of the specific activities of the catalysts was the same for the dehydrogenation of cyclohexane and the reforming of gasoline reactions. 3. The temperature coefficient of the reaction velocity was greater for catalyst No. 3 than for No. 1 and 2. This explains the greater activity of catalyst No. 3 under gasoline reforming conditions. 4. It is suggested that the increased activity and stability of catalyst No. 3 was due to the presence in it of PdS.