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

Abstract

This study demonstrates the ability of Ni/Mo2C to catalyze the Methane Bireforming Reaction (combined Dry Methane Reforming Reaction, CH4+CO2➔2H2+2CO, and Steam Methane Reforming Reaction, CH4+H2O➔3H2+CO). By varying the ratio of CO2:H2O, the resulting H2:CO ratio could be tuned from 0.91 to 3.0, covering a wide range of Syn-gas (H2+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 10min. Despite running under conditions typically favorable for coking with a Ni catalyst (high temperature, 950°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.