Table 2.

The element components of S-4 surface for EDS analysis.

Element	Atomic %	Atomic %
C	55.30	56.04
N	11.63	11.55
O	29.91	28.42
S	1.72	1.98
Mg	0.61	0.85
Si	0.83	1.16
Total	100.00	100.00