Catalytic deoxygenation of stearic acid into olefins over Pt catalysts supported on MOF-derived metal oxides

In this study, three different metal oxides derived from metal–organic frameworks (MOFs), including CeO2, ZrO2, and Fe2O3 were used as porous supports for loading Pt nanoparticles, and the supported catalysts (viz., Pt/CeO2, Pt/ZrO2, and Pt/Fe2O3) were evaluated for the catalytic deoxygenation of stearic acid to produce olefins by analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Interestingly, Pt/CeO2 and Pt/Fe2O3 catalysts demonstrated high selectivity for olefins or aromatics, respectively, with alkanes as minor products, while the Pt/ZrO2 catalyst demonstrated the lowest deoxygenation efficiency. Among them, the Pt/CeO2 catalyst demonstrated the highest deoxygenation efficiency due to its highest oxygen vacancy density and the largest specific surface area (53 m2 g−1). It also demonstrated the highest selectivity for olefins (41%) due to the in situ partial formation of the bimetallic PtCe phase during the catalytic reaction at high temperature, which facilitates the decarbonylation pathway and leads to the formation of olefins as the main product. In addition, experimental optimizations of the reaction parameters were conducted on the designed Pt/CeO2 catalyst to further enhance olefin selectivity. Importantly, the Pt/CeO2 catalyst also maintained high olefin selectivity and stearic acid conversion even after six consecutive cycles. Therefore, this work has provided an alternative route to produce olefins via the decarbonylation of stearic acid over a supported Pt/CeO2 catalyst.