(178f) Catalytic Methane Steam Reforming with Ni-xMo2C/FAU: Formation Energetics and Promoting Role of Molybdenum Carbide Clusters Encapsulated
AIChE Annual Meeting
Monday, November 14, 2022 - 5:10pm to 5:30pm
Encapsulation of molybdenum carbides and oxides in zeolites leads to effective catalytic particles for methane conversion and biomass upgrading. Here, we report our recent study on methane steam reforming (MSR) for hydrogen production using Ni-xMo2C/FAU as the catalyst. It is found that the synergetic effects between Ni and Mo2C particles lead to enhanced activity and catalytic stability, in which Mo2C enhanced CH4 activation and conversion. In addition, sintering and coking are the major deactivation mechanisms, and Mo2C clusters demonstrate high thermal stability, sintering resistance, and high dispersion during and after the reactions. The conclusions in this catalytic investigation are supported by our experimental thermodynamic studies on the formation energetics of Mo2C and MoO3 under encapsulation in FAU with different Si/Al ratios using high-temperature oxide melt solution calorimetry. Specifically, at a fixed Mo loading, the formation enthalpies of both Mo2C/FAU and MoO3/FAU from constituent carbides and oxides tend to be less endothermic as the Si/Al ratio increases. The Mo2C â FAU interactions are energetically more favorable than the encapsulation of MoO3 in FAU by â¼30 kJ/mol per tetrahedron unit. Interestingly, the MoO3 clusters present high redox transition flexibility to reach energetically favorable states, yet strong interfacial bonding between Mo2C and FAU pays for the energetic cost leading to highly dispersed Mo2C particles with enhanced catalytic, thermal, and thermodynamic stability.