Activity for ethane hydrogenolysis and carbon gasification of highly-dispersed metallic iron catalysts

Abstract

The catalytic activities of graphite-, carbon black-, alumina-, and silica-supported metallic iron catalysts for the hydrogenolysis of ethane were measured. Turnover frequencies varied over a range of three orders of magnitude. Carbon black-supported catalysts prepared from ferric nitrate had higher activities than carbon black-supported catalysts prepared from Fe3(CO) 12, the latter having been shown to have more spherical and possibly more widely separated metallic iron particles within the pore structure of the carbon black support. The low catalytic activity of the cluster-derived catalyst may be due to the spherical morphology of the iron particles, giving rise to highly unsaturated iron surface atoms and altering the nature of the catalytic ensembles present, or to a partial coverage of the iron surface by carbon from the support. The iron carbonyl-derived catalyst was also inactive for support gasification in hydrogen, while the conventionally-prepared catalyst almost completely gasified the carbon support during treatment in hydrogen at 773 K for 2 h.