The effects of alloying platinum with transition metals and main group elements on the kinetic and thermodynamics of dehydrogenation and coke formation pathways during light alkane dehydrogenation have been studied using density functional theory. Due to the recent shale boom, light alkane prices have dropped significantly; ethane is now the same price as methane and is flared in some areas. Light alkane dehydrogenation to olefins can add significant value to and reduce greenhouse gas emissions from hydrocarbon processes that generate alkanes by converting low value commodity fuels to high-value chemical and polymer precursors.
Supported Pt catalysts are known to be active for light alkane dehydrogenation, but the high temperatures required by these endothermic reactions leads to significant coke formation and deactivation. Numerous Pt alloys have been shown to decrease coke formation and deactivation, including with Sn, Ga, In, Cu, Au, and Re. Using periodic density functional theory, we have calculated potential energy surfaces and activations barriers on these alloys to better understand the reduction in surface carbon formation during ethane dehydrogenation. The alloying element influences the electronic properties of Pt, and we find that with increasing Pt d-band center, dehydrogenation reactions become more difficult and binding energies become weaker. The binding energy of carbon correlates well with reaction energies, but Pt-main group element and Pt-transition metal element alloys form separate trend lines.