Effect of TiO2 on the Performance of Mn/Na2WO4 Catalysts in Oxidative Coupling of Methane

The oxidation coupling of methane (OCM) has received attention as a direct route to produce C-2 chemicals. Although the OCM is energetically more efficient than the conventional process, however, it provides relatively low C-2 yield and CH4 conversion at lower temperatures. In this study, TiO2 and Ce were used as a support and a promoter to facilitate CH4 conversion by providing more available oxygen species in the Mn/Na2WO4-based catalysts. Additionally, the performance of TiO2-supported catalysts was compared with that of the conventional Mn/Na2WO4/SiO2 catalyst. Various techniques including X-ray diffraction, X-ray photoelectron spectroscopy, and H-2 temperature-programmed reduction were conducted to evaluate the effect of TiO2 and Ce. The 1.9 % Mn-5% Na2WO4-5% Ce/TiO2 showed the best performance, with a maximum C-2 yield of 26.1% at 775 degrees C and the CH4/O-2 ratio of 2. This yield was higher than that of the Mn/Na2WO4-based catalysts examined in this study, indicating that TiO2 is a promising support for OCM catalysts.

Automated summary

By using TiO2 and Ce as support and promoter in Mn/Na2WO4-based catalysts, the conversion efficiency of CH4 was enhanced, leading to a significant increase in the C-2 yield.