fig1

Figure 1. (A) Graphical abstract of FeACs-VNNCs (1:1)/NFC; (B) Calculated d orbital centers of FeNCs/NFC, VNNCs/NFC and FeACs-VNNCs (1:1)/NFC^[68]; (C) XPS survey spectrum of Zn 2p, N 1s of ZnCo-Te@NC, and Co 2p XPS spectrum of ZnCo-Te@NC and ZnCo@NC^[69]; (D) Performance of zinc-air batteries assembled by FeCo@CNTs-60; (E) Stabilized adsorption configurations of ORR/OER intermediates^[46]; (F) TEM and HRTEM (inset) images of CoN/UNG^[57]; (G) HRTEM images of CoFe-NCNFs^[81]; (H) Illustration of Fe₃C@NPW^[94]. NFC: N-doped carbon framework; FeACs: iron-based activated carbons; VNNCs: vanadium-based nanostructured catalysts; XPS: X-ray photoelectron spectroscopy; CNTs: carbon nanotubes; ORR: oxygen reduction reaction; OER: oxygen evolution reaction; TEM: transmission electron microscopy; HRTEM: high-resolution transmission electron microscopy; NCNFs: N-doped carbon nanoflowers.