Figure 3: Chemical analysis of the carbon microspheres.

(a) XPS survey spectrum of CM-NFs; and (b–d) high-resolution XPS spectra of C 1 s, N 1 s and F 1 s of CM-NFs, respectively.

(a) XPS survey spectrum of CM-NFs; and (b–d) high-resolution XPS spectra of C 1 s, N 1 s and F 1 s of CM-NFs, respectively.