Nitrogen doped carbon supported metal catalysts (Me/CNs) have been widely developed in the last decade in view of the promotional effects derived from N doping. However, the nature of the interaction between N and metal nanoparticles (NPs) is still not well illustrated. In this work, we suggest that graphitic N (N-g) may help nucleate and disperse, while pyridinic N (N-p) serves as both anchors and dispersants. However, the interaction between NPs and CNs may not be localized just between NPs and N since the electron donated by NPs are not reserved by N. In fact, it is the energy gap of the Fermi levels between NPs and supports that could be the vital factor to determine the electron transfer. And this delocalization of electron transfer reduces the polarization between NPs and supports, which in turn suppresses the deep oxidation of NPs and keeps the higher metallic ratio for Me/CNs. (C) 2019 Elsevier Inc. All rights reserved.