These results indicate that (NiFeCo) 2P/NF is the structure of crystalline metal phosphide nanoparticles supported by N-C layer. Compared with (NiFeCo)2P/NF, the TEM image of (NiFeCo)2P-PA/NF (Fig. 2f) shows a relatively uniform lamellar structure. There is a contrastbetween light and dark in the lamellar structure, but no obvious attachment particles are observed. It can be observed from Fig. 2g that the edge of the lamellarstructure is NC layer, and there are differences in homogeneity and contrast in the lamellar structure, but no lattice stripes are observed.