Digging Its Own Site: Linear Coordination Stabilizes a Pt₁/Fe₂O₃ Single-Atom Catalyst.

Area of Science:

• Materials Science
• Catalysis
• Surface Chemistry

Background:

• Accurate modeling of single-atom catalysts (SACs) requires understanding active site coordination.
• Current methods often rely on idealized support surfaces, potentially misrepresenting real-world catalyst behavior.

Purpose of the Study:

• Investigate the binding and coordination of platinum (Pt) atoms on the α-Fe2O3 (11̅02) facet.
• Determine the preferred atomic configuration of Pt on this common SAC support material.

Main Methods:

• Combined experimental techniques: scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS).
• Extensive computational modeling using an evolutionary search algorithm based on density functional theory (DFT).

Main Results:

• Pt atoms induce significant reconfiguration of the α-Fe2O3 surface.
• A pseudolinear O-Pt-O coordination is energetically favored (0.84 eV) over configurations on an unperturbed surface.
• This involves breaking Fe-O bonds, highlighting the dynamic nature of the active site.

Conclusions:

• The linear coordination of Pt on α-Fe2O3 is a stable and reactive configuration.
• This geometry likely balances thermal stability with reactant adsorption in Pt-based SACs.
• Comprehensive structural searches are essential for accurate single-atom catalysis modeling.