Scheme 1. Diagram of
plasma-driven direct oxidation of methane to methanol on Cu-MOR
catalysts, aiming to emphasize the active sites of zeolite-confined
Cu2+ species.
This study presents an investigation into the performance of Cu-MOR
catalysts prepared using both wetness
impregnation and ion exchange methods in plasma-catalytic DOMtM. The
results reveal that ion exchange mainly leads to the formation of
zeolite-confined Cu2+ species in Cu-MOR, exhibiting
excellent catalytic performance (7.9% CH4 conversion
and 51% CH3OH selectivity), as shown in Scheme 1. In
contrast, wetness impregnation predominantly results in the formation of
CuO particles in Cu-MOR, hindering the DOMtM reaction while inducing
over-oxidation into CO and CO2. The correlation of the
catalytic performance with catalyst characterization results
unequivocally demonstrates that zeolite-confined Cu2+species serve as the active sites for DOMtM, providing valuable
information to the advancement of plasma-catalytic systems in the
context of DOMtM.
Experimental section