Tunable Syn-gas ratio via bireforming over coke-resistant Ni/Mo2C catalyst

This study demonstrates the ability of Ni/Mo2C to catalyze the Methane Bireforming Reaction (combined Dry Methane Reforming Reaction, CH4 + CO2 -> 2H(2) + 2CO and Steam Methane Reforming Reaction, CH4 + H2O -> 3H(2) + CO). By varying the ratio of CO2:H2O, the resulting H-2:CO ratio could be tuned from 0.91 to 3.0, covering a wide range of Syn-gas (H-2 + CO) ratios relevant to various hydrocarbon syntheses. We also document the unusual deactivation behavior of Ni/Mo2C in this system. The catalytic activity would change from very high (>50% conversion) to very low (<10% conversion) within 10 min. Despite running under conditions typically favorable for coking with a Ni catalyst (high temperature, 950 degrees C, and excess methane), XRD, TGA, TEM, SEM, and EDX results clearly show no evidence of coking during the reaction or after deactivation. In addition, the changes to the Ni/Mo2C catalyst seen after deactivation (oxidation of Mo2C to MoO2, Ni-phase changes, and catalyst morphology changes) could not be seen in the catalyst subjected to reaction conditions that were halted before deactivation could occur. This suggests a sudden, rapid deactivation event occurs in this catalytic system as opposed to gradual catalyst deactivation, a behavior more typically seen with catalysts. (C) 2016 Elsevier B.V. All rights reserved.