Intrinsic microkinetic effects of spray-drying and SiC co-support on Mn–Na2WO4/SiO2 catalysts used in oxidative coupling of methane†

This paper presents a microkinetic model to evaluate the effects of a silicon carbide (SiC) co-support and the shaping method on Mn–Na₂WO₄/SiO₂ catalysts used for the oxidative coupling of methane. The model considers mass transfer, catalytic, and gas-phase kinetics, and it is trained with experimental values (product composition) of three Mn–Na₂WO₄ catalysts for calculating the kinetic parameters using catalytic descriptors while maintaining thermodynamic consistency. The catalysts were an SiO₂-supported catalyst prepared through impregnation and two SiO₂–SiC-supported catalysts (with βSiC and α + βSiC) prepared via spray-drying. Our analysis shows how the type of SiC and preparation method affect the textural properties and result in distinct CH₃˙ radical oxidation, HO₂˙ quenching, C₂H₄ oxidation, and CO_X transformation pathways, eventually leading to CH₄ conversion and C₂ selectivity. Our approach facilitates the assessment of the effects of the promoter and support on individual and global reaction networks.