A simple procedure was developed to synthesize molybdenum carbide nanoparticles (Mo2C/BC) by carburization of molybdate salts supported on the biochar from pyrolysis of biomass without using extra carbon source or reducing gas. The molybdenum carbide formation procedure investigated by in-situ XRD and TGA-MS indicated that the phase transitions followed the path of (NH4)(6)Mo7O24 center dot 4H(2)O -> (NH4)(2)Mo3O10 -> (NH4)(2)Mo14O42 -> Mo8O23 -> Mo4O11 -> MoO2 -> Mo2C. The volatile gases CO, H-2, and CH4 evolved from biochar and the biochar solid carbon participated in the reduction of molybdenum species, while the biochar and CH4 served as carbon sources for the carburization.
Temperature programmed surface reactions of Mo2C/BC indicated that CH4 dissociated as CH4 C* reversible arrow + 2H(2) on the catalyst surface, and CO2 reacted as CO2 + C* 2CO + * due to oxidation of Mo2C. Both experiment data and thermodynamic analysis for the study of operation conditions of CO2 reforming of CH4 clearly demonstrated that the yields of H-2 and CO increased with the increased temperature and the reasonable conversions should be performed at 850 degrees C, at which both CH4 and CO2 conversions were higher than 80%.
