“…[21,40] From the high resolution O 1s spectra, it can be known that there are several oxygencontaining functional peaks of ~284.6, ~285.3 and ~288.7 eV can be observed in the C1s spectrum, and the corresponding functional groups are CÀ C, C-N and C=O, respectively. [21,40] From the high resolution O 1s spectra, it can be known that there are several oxygen-containing functional groups: C=O quinone functional group (~531.6 eV), CÀ OH phenol type or CÀ OÀ C ether type functional group (~532.8 eV) and À COOH (~535.3 eV). [14,41] From the N 1s spectrum, pyridine nitrogen (N-6), pyrrole nitrogen (N-5) and quaternary nitrogen (N-Q) can be analyzed, which are located at ~398.7 eV, ~400.1 eV and ~401.1 eV, respectively.…”