Selective CVD-driven engineering of W single-atom catalyst architecture for highly active and stable oxidative coupling of methane

Abstract

Oxidative coupling of methane (OCM) is a promising route for methane valorization, yet achieving high activity, selectivity, and stability through rational engineering of active-species distribution remains a major challenge. Herein, a selective chemical vapor deposition (CVD) strategy was developed to enable site-selective deposition of tungsten (W) atomic species on manganese (Mn) surfaces, creating a distribution of active species that is inaccessible through conventional impregnation methods. Structural characterization revealed that W species were selectively anchored as isolated atoms or sub-nanometric clusters on Mn surfaces, forming a highly dispersed core (Mn)-shell (W atomic species) configuration. The CVD-prepared W-Na-Mn/SiO2 catalyst exhibited 7.49 times higher mass activity (based on CH4 conversion), 2.58 times higher turnover frequency (TOF), and 28.02 times higher mass activity (based on C2 yield) than its impregnated counterpart after 30 h of reaction. The optimized architecture enabled efficient utilization of W species while maintaining high C2 selectivity and stability after 180 h of operation. This study demonstrates that selective CVD-driven deposition governs the spatial distribution of active species and thereby catalytic functionality. The findings establish a catalyst manufacturing strategy based on site-selective atomic deposition, providing a transformative paradigm for highly active, stable, and selective OCM catalysts.