Fig. 1: Structure characterizations.
From: Spin occupancy regulation of the Pt d-orbital for a robust low-Pt catalyst towards oxygen reduction
a Scheme of PtFe@FeSAs-N-C. b TEM images of the PtFe@FeSAs-N-C showing a uniform distribution of Pt nanocrystals. c HAADF-STEM image and d corresponding EELS analysis to verify the coexistence of PtFe and atomic level Fe in the PtFe@FeSAs-N-C electrocatalyst (the spots in the red dashed circles is ascribed to the Fe single atoms, inset: differences in mass content between Fe and Pt in PtFe alloy nanoparticles.). e HAADF-STEM image of an individual PtFe nanocrystals. f FFT pattern of Fig. 1e. g The enlarged HAADF-STEM image in the blue box in e. h Crystal structure of PtFe with ordered, tetragonal structure and its projection along the (001) zone axis (blue and red spheres represent Pt and Fe, respectively). i Intensity profile across the PtFe particle from (002) and (001) directions measured from h. The distance between the strong intensities matches with the separation between Pt atoms. j EDS mapping results of PtFe@FeSAs-N-C.
