Fig. 1: Metallic and nonmetallic model catalysts.
From: Electronic communications between active sites on individual metallic nanoparticles in catalysis
a, b VB XPS of Rhmet/Al2O3 (a) and Rhnon/Al2O3 (b). A red shade in (a) shows the electronic state density near EF (the Fermi level) for Rhmet/Al2O3, and onset of the electronic state density of Rhnon/Al2O3 is analyzed to appear at −0.6 eV in (b). The curves were slightly smoothed. c, d AC-STEM images of Rhmet/Al2O3 (c) and Rhnon/Al2O3 (d). Rh nanoparticles in (c) and Rh clusters in (d) are selectively circled with yellow dashed lines. Insets: the size distribution of Rh particles or clusters. e, f Atom-resolution AC-STEM images of Rhmet/Al2O3 (e) and Rhnon/Al2O3 (f). Insets: two Wulff models in (e) are constructed according to the corresponding image of one typical Rh nanoparticle closed by white dashed lines (The gold, purple, and green balls represent Rh atoms at vertex sites, edge sites, and on the nanofacets) and 12-atom raft models on the Al2O3 surface are also drawn on the basis of the image of one Rh cluster in (f). g, h WT EXAFS spectra of Rhmet/Al2O3 (g) and Rhnon/Al2O3 (h) at Rh K-edge.
