Studies on oxy-bromination of methane and coke deposition over FePO4/SiO2 catalysts

Different FePO4/SiO2 catalysts have been synthesized and employed for the oxy-bromination of methane reaction. The long-term stability experiments and the influences of FePO4 loading and reaction temperature have been investigated. It was demonstrated that the FePO4/SiO2 catalysts were very stable during 200 h time-on-stream. High total selectivity for CH3Br plus CO with equimolar ratio could be achieved by manipulating the reaction variables. However, coke deposition was found on the used catalysts after a long running period. Characterization techniques such as N2-adsorption, Fourier-transform infrared spectroscopy and temperature-programmed oxidation were employed to investigate the fresh and used samples. The characterization results implied that the accumulation of CH2Br2 during the reaction could be the direct cause of coke deposition.