A comparative study on hydrogenation of carbon dioxide and carbon monoxideover iron catalyst

Hydrogenation of CO2 to hydrocarbons over iron catalysts reduced with hydro gen at 350 degrees C and 500 degrees C has been compared with that of CO. T he space time yield of hydrocarbons from CO2 at 250 degrees C is significan tly lower than from CO and the selectivity to olefin compounds is also lowe r from CO2. During the reaction with CO, chi-Fe2.2C is formed, and the surf ace, which is oxidized even after the reduction at 500 degrees C, is furthe r reduced. On the other hand, formation of the carbide species is slight in hydrogenation of CO2 while the surface is Father oxidized. The formation o f the carbide species, which is probably the active site of hydrocarbon for mation, is suppressed in the presence of CO2. (C) 2000 Elsevier Science B.V . All rights reserved.