Gallium‐Assisted Platinum Isolation: Formation of Multiple Pt Species in Ga‐Pt Liquid Metal Catalysts

Ga‐Pt liquid metal catalysts have emerged as promising catalysts, offering improved catalytic performance compared to pure platinum for reactions such as propane dehydrogenation. Previous studies suggest that the active species formed in Ga‐Pt catalysts differ from traditional metallic Pt. In this study, we explore multiple potential active Pt species by focusing on the surface‐derived electronic and chemical structures assessed via X‐ray photoelectron spectroscopy (XPS) and the correlating structural composition analyzed by scanning transmission electron microscopy (STEM). While XPS indicates that Pt is present in different chemical environments, STEM reveals different topographic structures varying from Pt single atom to Pt agglomerates and Ga‐Pt intermetallic compounds (IMCs). The variation in the chemical, electronic, and topographic structure of Pt depends on its amount, as well as on the surrounding environment (e.g., gallium‐oxide shell versus liquid Ga matrix). Further, XPS and STEM in situ investigations at elevated temperature (T) shed light on the high dynamic surfaces, demonstrating the dissolution of Ga‐Pt IMCs due to the enhanced solubility of Pt in Ga with increasing T. The chemical and electronic structure of the Pt species is discussed in conjunction with density‐functional theory and molecular dynamics simulations, providing an unprecedented conceptual understanding of Ga‐Pt catalysts.