Morphology engineered PtSn/CeO2 catalysts for oxidative dehydrogenation of propane with carbon dioxide
The oxidative dehydrogenation of propane with carbon dioxide (CO 2 -ODP) has received significant attention as an environmentally benign route for the propene production. However, the development of high-performance catalysts remains a critical challenge hindering its industrial implementation. In this work, CeO 2 samples with distinct morphologies resembling flowers (F-CeO 2 ), rods (R-CeO 2 ), spindles (SP-CeO 2 ), and sheets (SH-CeO 2 ) were successfully synthesized by simply changing the hydrothermal conditions, and the shape-dependent impact of oxygen-defect contents over CeO 2 on the structural and electronic properties of the impregnated PtSn/CeO 2 catalysts was studied for CO 2 -ODP. Characterizations reveal a positive correlation between the Pt electron density and oxygen-defect contents in an increasing order of PtSn/F-CeO 2 < PtSn/R-CeO 2 < PtSn/SP-CeO 2 < PtSn/SH-CeO 2 . In the case of the catalytic results, the same changing pattern is observed for the initial C 3 H 8 conversion and C 3 H 6 selectivity. Moreover, the highest initial propene space-time yield of 0.71 achieving over the PtSn/SH-CeO 2 catalyst is still retained at 0.35 after a time on stream of 200 min. This performance surpasses those of most reported CO 2 -ODP catalysts. The morphology-dependent catalytic phenomena are attributed mainly to the varied activation energies of CO 2 -ODP, which are determined by the oxygen defect-induced electronic and structural interplay between Pt, Sn, and CeO 2 . These findings provide valuable insights for the rational design and optimization of Pt-based catalysts for CO 2 -ODP, particularly in the selection of oxide supports.
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