Finned Zn-MFI zeolite encapsulated noble metal nanoparticle catalysts for the oxidative dehydrogenation of propane with carbon dioxide

Oxidative dehydrogenation of propane with carbon dioxide (CO₂-ODP) characterizes the tandem dehydrogenation of propane to propylene with the reduction of the greenhouse gas of CO₂ to valuable CO. However, the existing catalyst is limited due to the poor activity and stability, which hinders its industrialization. Herein, we design the finned Zn-MFI zeolite encapsulated noble metal nanoparticles (NPs) as bifunctional catalysts (NPs@Zn-MFI) for CO₂-ODP. Characterization results reveal that the Zn²⁺ species are coordinated with the MFI zeolite matrix as isolated cations and the NPs of Pt, Rh, or RhPt are highly dispersed in the zeolite crystals. The isolated Zn²⁺ cations are very effective for activating the propane and the small NPs are favorable for activating the CO₂, which synergistically promote the selective transformation of propane and CO₂ to propylene and CO. As a result, the optimal 0.25%Rh0.50%Pt@Zn-MFI catalyst shows the best propylene yield, satisfactory CO₂ conversion, and long-term stability. Moreover, considering the tunable synergetic effects between the isolated cations and NPs, the developed approach offers a general guideline to design more efficient CO₂-ODP catalysts, which is validated by the improved performance of the bifunctional catalysts via simply substituting Sn⁴⁺ cations for Zn²⁺ cations in the MFI zeolite matrix.