Tin Addition Modifies the Chemical and Electrical Properties of Pt-Based Catalysts for Radio-Frequency-Heated Propane Dehydrogenation

Abstract

Tin is often added as a component of supported platinum catalysts for propane dehydrogenation (PDH) to improve selectivity to propene and hydrogen. We have previously demonstrated that monolith-supported Pt catalysts achieve catalytic performance comparable to conventional thermal heating when heated by radio frequency (RF). In this work, we extend this comparison to tin-promoted platinum catalysts and show that tin promotion influences not only catalytic selectivity but also RF heating behavior through changes in catalyst electrical properties. RF-heated PtSn catalysts achieved propane conversions and propylene selectivities comparable to, and in some cases exceeding, those obtained using conventional oven heating. Systematic variation of the Sn/Pt ratio showed that Sn addition improves propylene selectivity by suppressing C1–C2 side product formation, but also changes RF heating behavior by modifying the electrical conductance of the catalyst. At fixed RF power input, increasing electrical conductance leads to a maximum in catalyst temperature; increasing conductance beyond this level results in lower catalyst temperatures at fixed power. These results highlight the importance of considering catalyst electrical properties as well as chemical reactivity in electrothermal reactor design.