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. 2017 Jul 24;8:15938. doi: 10.1038/ncomms15938

Figure 1. Physical characterization of different catalysts.

Figure 1

HAADF-STEM images of Pt1-N/BP (a) and Pt1/BP (b; corresponding scale bar, 5 nm (a) and 1 nm (b)). In sample Pt1-N/BP, Pt single atoms (bright spots) are seen to be uniformly dispersed on carbon, while in sample Pt1/BP, besides Pt single atoms, small Pt clusters can be found. (c) XPS spectra for N 1s in Pt1-N/BP. (d,e) XPS spectra for Pt 4f in Pt1-N/BP (d) and Pt1/BP (e). (f) Pt L3-edge XANES for all the samples. (g) The k2-weighted R-space FT spectra from EXAFS. Δk=3.1–10.6 Å−1 for Pt1-N/BP and Pt1/BP, but Δk=3.1–13.8 Å−1for Pt foil and PtO2. EXAFS fitting in R-space for (h) Pt1/BP, (i) Pt1-N/BP.