Investigation of Platinum Alloys for Light Alkane Dehydrogenation

Economical and efficient conversion of feedstock to product is central in designing a sophisticated and sustainable process strategy. Specifically, the recent discovery of shale gas sourced from horizontal drilling and hydraulic fracturing of naturally occurring shale formations has dramatically increased the abundance of light alkanes and has consequently reduced the price of natural gas to an all-time low. Shale gas reserves are predicted to have an impact on the production of chemicals by providing a cheap and abundant feedstock supply. A majority of shale gas is comprised of methane with the balance being a mixture of light alkanes like ethane or propane. These light alkane species are also a major byproduct of many industrial hydrocarbon processing pathways like petroleum cracking. Often, these light alkanes are flared which releases greenhouse gases, but by utilizing them as feedstock to produce olefins via alkane dehydrogenation, they stand to increase the profitability and sustainability of this process. Olefins are versatile chemical intermediates that are used to produce a diverse collection of value-added chemicals in a variety of industries including pharmaceuticals, bulk and fine chemicals, and fuels. Industrially, a supported platinum alloy catalyst is typically employed, but the overall process suffers from the formation of carbonaceous species on the catalyst surface. This work synthesizes, characterizes, and analyzes promising novel bi-metallic alloy catalyst materials for alkane dehydrogenation predicted by Density Functional Theory (DFT) calculations. Hydrotalcite-like materials are used to support the bi-metallic alloys because of their thermal and chemical stability, high surface area, and moderate basicity which reduces coking tendencies. Thermocatalytic activity and selectivity is quantified by the conversion of ethane to ethene via alkane dehydrogenation in a continuous flow system. While the formation of alkene has been studied, the mechanism for coke formation is unknown and this project culminates in a fundamental understanding of how carbonaceous species interact with catalyst surfaces which will provide useful insight for industrial applications.