Fig. 1: Characterizations for pristine NCNS, Co-NPs/NCNS, and proposed synthesis strategies for Co SAC.

a HAADF-STEM image of NCNS. b XANES of NCNS at N K edge. c FT-EXAFS of Co-NPs/NCNS, as well as Co foil and Co3O4 reference at Co K edge, respectively. d Assumption of the Co ALD process on pristine NCNS and Pt1/NCNS. The white, brown, blue, and orange spheres represent H, C, N, and Co, respectively.