Comparative study on transition metal promoted Pt/SiO2 for oxidative dehydrogenation of propane with carbon dioxide

Transition metal is quantitatively investigated as a promoter of Pt-supported catalysts for the oxidative dehydrogenation of propane with CO 2 (CO 2 -ODP). However, the criteria for selecting the transition metal are largely from trial and error. In this work, Pt/SiO 2 catalysts promoted with 3d transition metals (TMs) of Mn, Fe, Co or Ni (PtTM/SiO 2 ) are comparatively studied for CO 2 -ODP. We found that the C 3 H 6 selectivity and conversions of propane and CO 2 are clearly improved when TMs are introduced into Pt/SiO 2 . Moreover, the apparent activation energy for the C 3 H 6 formation during CO 2 -ODP is decreased in the order of PtNi/SiO 2 > PtCo/SiO 2 > PtFe/SiO 2 > PtMn/SiO 2 . Among the investigated catalysts, PtMn/SiO 2 is the most active and selective catalyst for the activation of C-H bonds in propane to produce C 3 H 6 while PtNi/SiO 2 is the most favorable catalyst for the formation of by-products via the dry reforming of propane with CO 2 and propane cracking. Essentially, the catalytic results are well explained as the increased electron density of Pt over the PtTM/SiO 2 catalysts via the enhanced electron transfer from TM having a smaller electronegativity. This understanding is important for the rational design of a high-performance Pt-based bimetallic catalyst for CO 2 -ODP.