O₂ Dissociation on α-Fe₂O₃(11 ̅02)-(1×1)

Abstract

Single-atom catalysis (SAC) is a rapidly growing field of research motivated by the desire to decrease the amount of precious metals used for facilitating catalytic reactions. Similar to homogeneous catalysis, SACs also lead to well defined single-atom centers required for selectivity. However, for reactions like molecular O2 dissociation, two active sites in close proximity are generally needed. In this poster, we will be examining the question: Can the diatomic molecule O2 dissociate at a single Pt atom on a well-defined hematite surface, α-Fe2O3(11 ̅02)-(1×1)? Scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) have recently been used to characterize Pt single atoms on hematite [1]. Here, we have intentionally oxidized Pt SAC by annealing in an O2 background and studied the surface using non-contact atomic force microscopy (nc-AFM) with a well-defined copper oxide (CuOx) tip [2]. The images show an attractive species, the Pt adatoms, and two repulsive features, presumably the dissociated oxygen atoms. Additionally, the Pt2+ component increases in the XPS measurements, indicating an oxidation of the Pt atoms. Computational studies aimed at understanding the structure of these species are in progress.