Dynamic Behavior of\nPt Multimetallic Alloys for Active\nand Stable Propane Dehydrogenation Catalysts

Improving the use of platinum in propane dehydrogenation\ncatalysts\nis a crucial aspect to increasing the efficiency and sustainability\nof propylene production. A known and practiced strategy involves incorporating\nmore abundant metals in supported platinum catalysts, increasing its\nactivity and stability while decreasing the overall loading. Here,\nusing colloidal techniques to control the size and composition of\nthe active phase, we show that Pt/Cu alloy nanoparticles supported\non alumina (Pt/Cu/Al<sub>2</sub>O<sub>3</sub>) displayed elevated\nrates for propane dehydrogenation at low temperature compared to a\nmonometallic Pt/Al<sub>2</sub>O<sub>3</sub> catalyst. We demonstrate\nthat the enhanced catalytic activity is correlated with a higher surface\nCu content and formation of a Pt-rich core and Cu-rich shell that\nisolates Pt sites and increases their intrinsic activity. However,\nrates declined on stream because of dynamic metal diffusion processes\nthat led to a more uniform alloy structure. This transformation was\nonly partially inhibited by adding excess hydrogen to the feed stream.\nInstead, cobalt was introduced to provide trimetallic Pt/Cu/Co catalysts\nwith stabilized surface structure and stable activity and higher rates\nthan the original Pt/Cu system. The structure–activity relationship\ninsights in this work offer improved knowledge of propane dehydrogenation\ncatalyst development featuring reduced Pt loadings and notable thermal\nstability for propylene production.