The influence of plasma chemical treatment of nickel and nickel-rhenium catalysts deposited on sibunite on their activity in dehydrogenation

The dehydrogenation of isopropanol was studied at 440-680 K to find that the activity of the Ni(1 wt %)/sibunite catalyst decreased after annealings and quenchings and was stabilized after subsequent treatment with an (I) O 2 glow-discharge or (II) H2 high-frequency plasma. Treatments of both kinds decreased the activity of the catalyst below the Curie point (633 K) and increased it over the paramagnetic temperature range (635-680 K). The treatment of the (1 wt % Ni-1 wt %Re)/sibunite and (2 wt % Ni-2 wt % Re)/sibunite catalysts with plasma II weakly influenced their activity, whereas treatment with plasma I substantially increased it. The kinetic reaction parameters on the (2 wt % Ni-2 wt % Re)/sibunite catalyst were found to depend on the duration of treatment with plasma II. Treatment with plasma I much more effectively changed the state of the surface of all the catalysts studied than treatment with plasma II. © Nauka/Interperiodica 2007.