Re–Co/Al 2O 3 bimetallic catalysts prepared by mechanical treatment: CO hydrogenation and CH 4 conversion

Abstract

Re–Co/Al 2O 3 (M) bimetallic catalysts were prepared by ball milling in a high-energy shaker mill using a WC container and four WC balls. The structure and activity of the Re–Co/Al 2O 3 (M) are compared to a Re–Co/Al 2O 3 (IM) sample prepared by the incipient wetness technique. The mechanically treated sample contains disordered, probably partly amorphous metal particles. Heat treatment of the Re–Co/Al 2O 3 (M) sample was carried out in hydrogen at 450 and 650 °C. It affects the crystallinity and the catalytic properties of the metal particles. The rate measured for the CO hydrogenation over Re–Co/Al 2O 3 (IM) catalyst is significantly higher than that measured over the Re–Co/Al 2O 3 (M) sample. On the other hand, in the CH 4 conversion to higher hydrocarbons, the Re–Co/Al 2O 3 (M) showed higher activity after treatment at 650 °C. The opposite behavior of the M and IM samples is explained by the changing morphology of the active sites responsible for the two different reactions.