Stability of Mo2C/carbon catalysts during dibenzofuran hydrodeoxygenation

Abstract

The stability of Mo2C/carbon catalysts was assessed for the hydrodeoxygenation (HDO) of dibenzofuran (DBF) at realistic operating conditions. Catalyst stability was determined by the degree of oxidation of the Mo2C, which in turn was determined by the Mo2C properties and the reaction conditions. Decreased Mo loading resulted in smaller Mo2C particles and faster oxidation. Increased concentration of DBF and reduced H-2 pressure (4.1-2.1 MPa) increased Mo2C oxidation. The dynamic oxidation of Mo2C during HDO depended on the oxidation history of the catalyst. Oxidation of the Mo2C reduced hydrogenation activity and increased selectivity to direct deoxygenation (DDO) products. DFT analysis showed that small amounts of O did not change the preferred surface adsorption geometry of DBF on Mo2C (101). H-2 dissociative adsorption was not weakened either. At 350 degrees C and low concentration of DBF (0.2 wt.%), the 2%Mo2C/APC catalyst was stable for > 10 h.