Formation of a Pt-MgO Solid Solution: Analysis by X-ray Absorption Fine Structure Spectroscopy

Kazu Okumura; Hitomi Hoshi; Hikaru Iiyoshi; Hiromitsu Takaba

doi:10.1021/acsomega.2c02486

Formation of a Pt-MgO Solid Solution: Analysis by X-ray Absorption Fine Structure Spectroscopy

ACS Omega. 2022 Jul 29;7(31):27458-27468. doi: 10.1021/acsomega.2c02486. eCollection 2022 Aug 9.

Authors

Kazu Okumura¹, Hitomi Hoshi¹, Hikaru Iiyoshi¹, Hiromitsu Takaba²

Affiliations

¹ Department of Applied Chemistry, School of Advanced Engineering, Kogakuin University, 2665-1 Nakano-machi, Hachioji 192-0015, Tokyo, Japan.
² Department of Environmental Chemistry and Chemical Engineering, School of Advanced Engineering, Kogakuin University, 2665-1 Nakano-machi, Hachioji 192-0015, Tokyo, Japan.

Abstract

Thermal treatment of Pt nanoparticles or Pt(acac)₂ supported on MgO resulted in the formation of a solid solution of Pt-MgO, as evidenced by Pt L₃-edge X-ray absorption fine structure spectroscopy. The valence of Pt in the Pt-MgO solid solution was determined to be 4+. A characteristic shrinkage of the Pt-O bond distance was observed in comparison with that of the nearest-neighboring Mg-O bond in MgO, which agreed with the density functional theory (DFT) calculations. The segregation of Pt and MgO proceeded with a further increase in the thermal treatment temperature up to 1273 K. The dispersion of Pt on MgO measured through CO adsorption was much higher than that on Al₂O₃ or SiO₂ owing to the formation of the Pt-MgO solid solution.