Synthesis of Gaseous Hydrocarbons from Carbon Monoxide and Hydrogen over Transition Metal Catalysts (Part 1)

The Activity and Selectivity of Graphite-Supported Metal Catalysts

Abstract

The catalytic activity and selectivity of Group VIII transition metals, except Os and Ir, supported on graphite for hydrocarbon synthesis from mixtures of carbon monoxide and hydrogen were investigated under atmospheric pressure at 300∼400°C. Methane was the main reaction product on all these catalysts. Some of the catalysts, however, exhibited considerably high selectivity for production of C₂ or higher gaseous hydrocarbons. The following sequence of selectivity for C₂ hydrocarbons was obtained: Fe>Pd>Rh>Ru>Pt>Co>Ni. Among the catalysts tested, the graphite-supported Rh catalyst showed the highest rate of production of C₂ hydrocarbons.
In the whole ragne of conversions, the graphite-supported Rh catalyst produced C₂ hydrocarbons more selectively than the alumina-supported or charcoal-supported catalysts. This difference was considered due to the strong metal-support interaction in the graphite-supported catalyst that involved electron transfer between rhodium and graphite.
Among the various pretreatments rendered using different gases, pretreatment in air enhanced most the activity of the graphite-supported Rh catalyst.