Fe catalysts for methane decomposition to produce hydrogen and carbon nano materials

Abstract

Conducting catalytic methane decomposition over Fe catalysts is a green and economic route to produce H2without CO/CO2contamination. Fused 65 wt% and impregnated 20 wt% Fe catalysts were synthesized with different additives to investigate their activity, whereas showing Fe-Al2O3combination as the best catalyst. Al2O3is speculated to expose more Fe0for the selective deposition of carbon nano tubes (CNTs). A fused Fe (65 wt%)-Al2O3sample was further investigated by means of H2-TPR, in-situ XRD, HRTEM and XAS to conclude 750 °C is the optimized temperature for H2pre-reduction and reaction to obtain a high activity. Based on density functional theory (DFT) study, a reaction mechanism over Fe catalysts was proposed to explain the formation of graphite from unstable supersaturated iron carbides decomposition. A carbon deposition model was further proposed which explains the formation of different carbon nano materials.