fig3

Figure 3. Structures and compositions of CoP/Co₂P/C nanofibers: XRD patterns (A); Raman spectra (B); high-resolution XPS survey spectra of Co 2p (C), P 2p (D), C 1s (E), and N 1s (F). CoP/Co₂P/C: CoP/Co₂P nanoparticles onto N, P co-doped carbon substrate; XRD: X-ray diffraction; XPS: X-ray photoelectron spectroscopy.