A theoretical investigation of propane dehydrogenation on Pt and Ni-based alloys

The alloy effect with post-transition metals (Sn, Ga and Bi) were investigated for Pt and Ni catalysts during the propane dehydrogenation (PDH) reaction using density functional theory calculations and descriptor-based microkinetic analysis. Alloying with Sn and Bi increases the propylene selectivity of Pt and Ni catalysts at the expense of activity, especially, Bi alloys exhibit the highest propylene selectivity among all catalysts. Ni3Ga outperforms Ni in both PDH activity and propylene selectivity. The formation energies of C3H6 and H (EC3H6 and EH) were identified as two activity descriptors, the former of which can also serve as the selectivity descriptor. Further investigation on the structure–activity relationship indicated at least two descriptors, one geometric parameter (the normalized atom radius) and one electronic parameter (such as d-band center, d-band width, electronegativity), were required to depict the PDH reaction on Pt and Ni-based alloys.