Table 2.

Parameters used for C1s and N1s XPS spectra.

Peak	Species	Binding energy (eV)	Refs
C 1s	C-H/C-C	~284.6	[48,49]
	C-N	~285.4	[48,49]
	C-O	~286.2	[48,49]
	C=N	~287.1	[33,50]
	O=C-N	~288.3	[48,49]
N 1s	C-N	~399.4	[33]
	C=O-NH	~400.0	[33,[51], [52], [53]]