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

• Published in: Catalysis science & technology 2024-06, Vol.14 (12), p.3436-3447
• Main Authors: Tan, Kok Bing, Liu, Yiping, Wang, Youting, Ali, Sajid, Wang, Wendong, Li, Jingru, Shang, Longmei, Yan, Xing, Zhang, Xiaodong, Zhan, Guowu
• Format: Article
• Language: English
• Subjects: Acids; Alkanes; Alkenes; Bimetals; Catalysts; Cerium oxides; Deoxygenation; Ferric oxide; Gas chromatography; High temperature; Mass spectrometry; Metal oxides; Metal-organic frameworks; Pyrolysis; Stearic acid; Zirconium dioxide
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/d4cy00189c

In this study, three different metal oxides derived from metal-organic frameworks (MOFs), including CeO 2 , ZrO 2 , and Fe 2 O 3 were used as porous supports for loading Pt nanoparticles, and the supported catalysts ( viz. , Pt/CeO 2 , Pt/ZrO 2 , and Pt/Fe 2 O 3 ) were evaluated for the catalytic deoxygenation of stearic acid to produce olefins by analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Interestingly, Pt/CeO 2 and Pt/Fe 2 O 3 catalysts demonstrated high selectivity for olefins or aromatics, respectively, with alkanes as minor products, while the Pt/ZrO 2 catalyst demonstrated the lowest deoxygenation efficiency. Among them, the Pt/CeO 2 catalyst demonstrated the highest deoxygenation efficiency due to its highest oxygen vacancy density and the largest specific surface area (53 m 2 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/CeO 2 catalyst to further enhance olefin selectivity. Importantly, the Pt/CeO 2 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/CeO 2 catalyst. The deoxygenation of stearic acid over Pt supported on different metal oxides can affect the product selectivity.