A Theoretical Study on the Structural Evolution and Stability of PtxCuy Heteronuclear Clusters Supported on t-ZrO2(101) Surface

Abstract

The supported PtCu bimetallic catalyst, with Pt sites facilitating propane dehydrogenation and Cu sites promoting CO2 activation, is anticipated to exhibit exceptional catalytic performance in the CO2-mediated oxidative dehydrogenation of propane (CO2-ODHP). Here, the structural evolution and stability of PtxCuy (x + y = 1 ~ 5) clusters on t-ZrO2(101) surface with oxygen vacancy have been theoretically investigated at the GGA-PBE/DNP level. On t-ZrO2(101) surface, there are two kinds of sites, i.e., near an oxygen vacancy and atop one. Among the homonuclear Ptx/ZrO2 (x = 1 ~ 5) or Cuy/ZrO2 (y = 1 ~ 5) systems, the vertical triangular Pt3/ZrO2 and Cu3/ZrO2 configurations are identified as the most stable near the oxygen vacancy, while the planar triangular Pt3/ZrO2 and Cu3/ZrO2 configurations are found to be the most favorable at the atop site of the oxygen vacancy. For heteronuclear PtxCuy/ZrO2 (x + y = 2 ~ 5), the vertical triangular Pt1Cu2, the tetrahedral Pt2Cu2 , the tetrahedral Pt2Cu2, and the pentahedral Pt1Cu4 configurations are energetically favored near the oxygen vacancy, while the planar triangular Pt1Cu2, the tetrahedral Pt2Cu2, and the pentahedral Pt4Cu1 configuration are preferred atop the oxygen vacancy site. This behavior stems from the synergistic interaction between Pt and Cu atoms, which promotes cluster nucleation on the ZrO2 support. Across all Ptx, Cuy, and PtxCuy clusters supported on ZrO2, smaller clusters preferentially nucleate near an oxygen vacancy, whereas larger clusters tend to nucleate directly atop the vacancy site. This work should provide some rational clues to design oligoatomic clusters supported catalysts for CO2-ODPH.