The Role of Fe in Ni-Fe/TiO2 Catalysts for the Dry Reforming of Methane

A series of nickel- and iron-modified titanium dioxide (Ni-Fe/TiO2) are studied for the dry reforming of methane (DRM) at 550 °C. Temperature-programmed surface reactions using CH4 and CO2 as probe molecules, as well as activity results, confirmed that both CO2 and CH4 conversion decreased with the addition of Fe. The XPS results obtained from reduced and used catalysts suggested changes in the surface nickel and iron species. Characterizations, particularly thermogravimetric analysis (TGA) and Raman spectroscopy over used catalysts, revealed that the addition of Fe can greatly inhibit the coke formation. In situ DRIFTS further identified that the addition of Fe favored the formation of carbonate species, which can facilitate the removal of coke deposited on the surface.