Transformation of n-hexane on deposited iridium and copper-iridium catalysts

Transformation of n-hexane on deposited iridium (Ir/SiO2) and copper-iridium (Ir-Cu/SiO2) catalysts was studied in the temperature range 620-780 K. The dehydrocyclization reaction gave benzene, and cracking gave propane. Both catalysts were treated in a glow discharge plasma in oxygen. The yield of C6H6 on Ir/SiO2 increased many times after plasma treatment, but the activity of this catalyst was unstable and relaxed to its initial value. The activity of the Ir-Cu(5 wt %)/SiO2 catalyst increased 1.4-2 times and its selectivity with respect to benzene increased 1.3 times after plasma treatment. The selectivity was stable in time. The formation of stable active centers on the Ir-Cu/SiO2 catalyst was explained by the presence of copper in its structure.