Impact of Alloying and Metal-Oxide Interface on PtGa Propane Dehydrogenation Catalysis from Tailored Catalysts on Carbon

Propane Dehydrogenation is a key technology, where Pt-based catalysts have been widely investigated, with development focusing on optimising promoters (Sn, Ga, etc.) towards improved catalytic performances. Recent studies have focused on Ga promotional effect: while Pt-site isolation by Ga has been proposed to play a key role in enhancing catalytic stability and selectivity, other effects, such as morphological changes as well as the role of supports and additives, remain poorly understood. Here, we develop a methodology to generate (bi)metallic – Pt and PtGa – nanoparticles on tailored interfaces by combining surface organometallic chemistry on carbon and specific thermolytic molecular precursors, containing or not Si. This approach enables detailed characterization via electron microscopy and X-ray absorption spectroscopy, and shows that the introduction of Ga yields amorphous PtGa nanoparticles, that display higher catalytic performances, than the corresponding highly crystalline Pt nanoparticles, as suggested earlier by computational studies. Furthermore, this study also shows that the presence of an oxide interface increases the catalyst activity, at the expense of selectivity (formation of cracking side-products, methane/ethene), hence, the use of additives such as Na/K/Ca in industrial catalysts.