Enhancement of La2O3 to Li-Mn/WO3/TiO2 for Oxidative Coupling of Methane

Abstract A series of La2O3-promoted Li-Mn/WO3/TiO2 catalysts were prepared by varying the concentration of La2O3 promoter. The effect of La2O3 promoter on its properties and catalytic performance for OCM was elucidated characterized with XRD, FT-IR, O2-TPD, Raman, CO2-TPD, H2-TPR, XPS and CH4-TPSR. The results show that all the La2O3-promoted Li-Mn/WO3/TiO2 catalysts possess a larger amount of strong basic sites and more abundant chemisorbed oxygen species in comparison with Li-Mn/WO3/TiO2, which is beneficial to OCM reaction. Furthermore, La2O3 promoter can enhance the mobility of the oxygen species and the Mn species redox ability, which can also be favorable for the improvement of the catalytic performance for OCM. Due to the optimal synergistic interaction of these factors, 5 wt%La2O3-Li-Mn/WO3/TiO2 exhibits the best performance among all the catalysts, on which the highest C2 yield of 19.2% is achieved at 750 °C.