Oxidative coupling of methane (OCM) is a highly promising approach for the catalytical conversion of methane to C₂ products. However, the oxygen with very-high purity has to be incorporated into the OCM process, resulting in the decreased efficiency and the risk of explosion. To overcome these issues, the chemical looping technology was employed with oxygen carriers to provide oxygen rather than using the high-purity gaseous oxygen. Here, we developed a series of TiO₂ doped Na₂WO₄/Mn₂O₃/SiO₂ and investigated their performances as catalytic oxygen carriers for chemical looping OCM. The results show that 5% TiO₂ doped Na₂WO₄/Mn₂O₃/SiO₂ exhibited 31.2% methane conversion and 68.7% C₂₊ selectivity. The improved performance is attributed to the formation of MnTiO₃, which facilitates the transformation between Mn³⁺ and Mn²⁺ during the redox cycles. The study also stimulates other engineering attempts for the search of effective dopants to further improve the performance of Na₂WO₄/Mn₂O₃/SiO₂ for chemical looping OCM.
 

Oxidative coupling of methane,chemical looping,catalytic oxygen carrier,Doping strategy