Catalytic conversion of syngas to olefins over Mn–Fe catalysts

Abstract

Abstract A series of MnO 2 –Fe 2 O 3 with various contents of Mn (0–40% atomic ratio) was synthesized by the co-precipitation method. XRD patterns indicate that the sharp and intense peaks are related to the excellent crystal quality of α-Fe 2 O 3 nanostructures. HR-TEM images showed that α-Fe 2 O 3 and MnO 2 , were partly in close contact and the lattice fringes exhibit the typical distances, i.e., α-Fe 2 O 3 (104) (2.7 A) and MnO 2 (310) (3.1 A). X-ray photoelectron spectroscopy (XPS) results of the Fe 2p core-level binding energy spectrum of the α-Fe 2 O 3 and Mn 2p, indicated the presence of Fe 3+ and Mn 4+ . The direct synthesis of olefins from syngas was carried out over the MnO 2 –Fe 2 O 3 catalysts under pressurized fixed-bed continuous flow conditions. The results showed that Mn–Fe catalyst had high catalytic activity and high olefins selectivity without the addition of any promoters at low pressure. It was found that the catalyst containing 20 at% Mn–Fe was an optimal catalyst for the conversion of synthesis gas to hydrocarbons especially light olefins. The maximum CO conversion rate was 15%, and the yield of olefins (totally about 23.77%) with a predominance of CH 4 (12.24%), and C 2 H 6 (2.80%) components. Mn–Fe catalyst can be regarded as a potential candidate for catalytic conversion of biomass-derived syngas to olefins.