Plasma-assisted catalytic dry reforming of methane (DRM) over metal-organic frameworks (MOFs)-based catalysts

Plasma-assisted dry reforming of methane (DRM) was performed in a dielectric barrier discharge (DBD) reactor. The effect of different packing materials including ZrO₂, UiO-67 MOF and PtNP@UiO-67 on plasma discharge was investigated, showing that ZrO₂ suppressed the plasma generation while UiO-67 improves it due to its porous nature which favours the formation of filamentary microdischarges and surface discharges. The improved plasma discharge increased the conversion of CH₄ and CO₂ by about 18% and 10%, respectively, compared to the plasma-alone mode. In addition, the distribution of hydrocarbon products changed from dominant C₂H₆ in the plasma-alone mode to C₂H₂ and C₂H₄ in the UiO-67 promoted plasma-assisted DRM. The UiO-67 MOF was stable in plasma, showing no significant changes in its properties under different treatment times, discharge powers and gases. Pt nanoparticles (NPs) on UiO-67 improved plasma-assisted DRM, especially the selectivity due to the presence of surface reactions. Due to the dehydrogenation of hydrocarbons over Pt NPs, the selectivity to hydrocarbons decreased by 30%, compared to the UiO-67 packing. In situ diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS) was carried out to probe the surface reactions on PtNP@UiO-67 catalyst, showing the decomposition of surface formats to CO and C₂H₄ dehydrogenation over the metallic Pt. The PtNP@UiO-67 catalyst showed good reusability in the plasma-assisted DRM, and H₂ production was improved by high CH₄/CO₂ molar ratio and low feed flow rate.