CATALYSIS OF THE CARBON–CARBON DIOXIDE REACTION BY IRON

Abstract

Iron in the form of carbonyl iron, ferric oxide, or ferric oxalate solution was added to a spectroscopically pure graphite powder. The graphite was molded in rod-form at 100,000 psi and room temperature. The rate of the reaction of the graphite rods with 1 atm of CO2 was measured from 900° to 1200°C. Some of the rods were reacted without previous heat treatment above reaction temperature; others were reacted following heat treatment at temperatures between 1400° and 2990°C. For the samples without previous heat treatment, the presence of iron is found to produce a very marked increase in graphite reactivity over that of the pure graphite. Even though heat treatment at temperatures of 1400° and 1635°C does not result in a loss of Fe, it does sharply decrease the catalytic efficiency of the Fe. This catalytic efficiency, in whole or in part, can be restored by a secondary pretreatment in H2 or O2 prior to reaction. Heat treatment between 1910° and 2990°C produces an additional decrease in reactivity of the graphite below that which it has following heat treatment at 1635°C. It appears that this additional reduction in reactivity is caused, primarily, by a loss of Fe upon its volatilization from the sample.