Self-regenerable carbon nanofiber supported Fe – Mo2C catalyst for CH4-CO2 assisted reforming of biomass to hydrogen rich syngas

Abstract

In-situ self-regenerable Fe / Fe3C – Mo2C – CNF catalyst was developed and evaluated extensively over 15 cycles of CH4 – CO2 assisted biomass reforming. In-situ regeneration was observed through nucleation on carbon saturated Fe3Cx sites due to abundance of free-C from reaction and undercoordinated carbon in support. Molybdenum existed as stable β-Mo2C whereas Fe composition changed from Fe° sites to Fe3Cx. Due to highly dispersed small nanoclusters (< 5 nm) in lower Fe loading catalysts, graphene nanosheets (GNS) synthesis was observed whereas on 5 % Fe catalysts, large agglomerated nanoparticles (∼10 to 20 nm) facilitated CNF / CNT synthesis. Regeneration on 0.5 % Fe occurred through CNF growth while graphene cover regenerated 5 % Fe catalysts. Fe – Mo2C – CNF catalyzed reactions produce hydrogen rich syngas over 15 cycles with H2 concentration > 60 % and H2:CO ratio of 2–4. Hydrodeoxygenation reforming of biomass was typically between 40–60 % of the amount of oxygenates.