Coordination and Penetration Depth of Dopant P Atoms Determine the Electronic Properties of -Al₂O₃ Surfaces

Doping gamma-Al2O3 has commonly been employed to adjust the electronic, mechanical, and optical properties of alumina. Our study aims to elucidate the arrangement and local atom-level structure of P atoms on gamma-Al2O3 surfaces. We also seek to establish structure-function relationships in particular regarding the surface's electronic properties. Utilizing a previously established surface template [Phys. Chem. Chem. Phys., 2019, 21, 15080], we present pseudopotential-based periodic density functional theory (DFT) simulations, exploring 72 distinct surface models encompassing various P positions, as well as O- and OH-terminated structures. These simulations yield comprehensive atom-level characterization of the doped surfaces. In order to mimic real-world systems that align with synthesized P-doped gamma-Al2O3 nanoparticles, our surface models encompass several concentrations of P atoms and various P-O-P chain motifs. Our computational analyses reveal that the electronic properties of the surface are profoundly influenced by the spatial arrangement and coordination of P dopant atoms and are less sensitive to the concentration of P atoms on the surface.