Separation of MnWO and NaWSiO Phases Boosts Oxidative Coupling of Methane.

The oxidative coupling of methane (OCM) is an attractive approach for methane transformations, but achieving a satisfactory combination of activity and selectivity remains challenging, even with the promising Mn-NaWO/SiO catalyst. Herein, we demonstrate that nanoscale separation of Mn-based and NaWO-based phases results in a highly efficient catalyst, achieving a remarkable 79% selectivity for C-C hydrocarbons at a 32% CH conversion at 775 °C, outperforming most previously reported catalysts. Our studies reveal that MnWO phases with adjustable surface Mn/W ratios and redox activities are more effective for the selective activation of O, thereby enhancing the OCM of CH. The assembly of MnWO and NaWO/SiO components in nanoscale proximity significantly promotes the formation of C-C hydrocarbons by suppressing deep oxidation. We propose a bifunctional mechanism involving the transfer of active oxygen species from MnWO to NaWO/SiO, which induces selective activation and coupling of CH on the NaWO/SiO surface.