A combination of ultrahigh resolution spectroscopy and microscopy techniques (ultrahigh magnetic field solid state magic angle spinning nuclear magnetic resonance (MAS-NMR) and high-resolution scanning transmission electron microscopy (HR-STEM)) coupled with first principles DFT calculations reveal the nature of anchoring sites of a catalytically active phase onto the surface of ?-Al2O3. The results obtained unambiguously prove that coordinatively unsaturated penta-coordinate Al3+ (Al3+penta) centers present on the (100) facets of the ?-Al2O3 surface are the sites where the anchoring of Pt occurs. At low loadings, the active catalytic phase is atomically dispersed on the support surface (Pt/ Al3+penta=1), while two dimensional Pt rafts form at higher coverages.
Revised: October 2, 2009 |
Published: September 24, 2009
Citation
Kwak J., J.Z. Hu, D. Mei, C.W. Yi, D. Kim, C.H. Peden, and L. Allard, et al. 2009.Coordinatively unsaturated Al3+ centers as binding sites for active catalyst phases on ?-Al2O3.Science 325, no. 5948:1670-1673.PNNL-SA-67165.doi:10.1126/science.1176745