Co-Fe Nanoparticles Wrapped on N-Doped Graphitic Carbons as Highly Selective CO2 Methanation Catalysts.

Abstract

Pyrolysis of chitosan containing various loadings of Co and Fe renders Co–Fe alloy nanoparticles supported on N-doped graphitic carbon. Transmission electron microscopy (TEM) images show that the surface of Co–Fe NPs is partially covered by three or four graphene layers. These Co–Fe@(N)C samples catalyze the Sabatier CO2 hydrogenation, increasing the activity and CH4 selectivity with the reaction temperature in the range of 300–500 °C. Under optimal conditions, a CH4 selectivity of 91% at an 87% CO2 conversion was reached at 500 °C and a space velocity of 75 h–1 under 10 bar. The Co–Fe alloy nanoparticles supported on N-doped graphitic carbon are remarkably stable and behave differently as an analogous Co–Fe catalyst supported on TiO2.