Methane transformation into light olefins using methanol as co-reactant over Mo/HZSM-5

Direct conversion of methane into other value-added chemicals remains as a grand challenge due to its stable non-polar tetrahedral structure. Coupling methane with methanol over Mo-modified HZSM-5 is promising to activate methane at lower temperatures than for pure methane. This work investigates the effect of Si/Al ratio (25-250) and reaction conditions (reaction temperatures from 500 to 650 degrees C and methane-to-methanol molar ratios of 10 to 1 on methane conversion into light olefins (ethene, propene, butene)) using methanol as a co -reactant over 3Mo/HZSM-5. It was found that at 600 degrees C and CH4/CH3OH = 5 the 3Mo/HZSM-5 (Si/Al = 160) catalyst delivers the best performance of 0.72 mmol g -1 h- 1 methane conversion rate and 50 % light olefins selectivity. Through 13C-labeled methane, this study also provided the direct evidence on the involvement of methane carbon in the reaction products. The results of this study enabled us to propose a possible reaction pathway for the methane-methanol coupling reaction.