The formation of filamentous carbon on iron and nickel catalysts : I. Thermodynamics

Abstract

The thermodynamic properties of filamentous carbon formed from CO and CH4 on iron and nickel catalysts have been determined in the temperature range 650–1000 K. Catalyst samples quenched from a steady-state growth of carbon have been studied using temperature-programmed hydrogenation, thermomagnetic analysis, and electron microscopic techniques. It is concluded that carbon is deposited as a metastable carbide intermediate, leading to filamentous carbon on decomposition. The presence of carbide intermediates has been demonstrated both by magnetic measurements and by temperature-programmed hydrogenation.