Table 6. WSC C 1s and O 1s XPS Data.

	peak position			content %			peak position		content %
sample	C1	C2	C3	C1	C2	C3	O2	O1	O2	O1	nO2/nO1
WSC	284.71	285.98	287.01	65.17	10.79	24.04	531.35	532.91	32.25	67.75	0.47
KOH	284.80	286.30		69.76	30.25		531.66	533.24	24.88	75.12	0.33
ZnCl2	284.67	285.8	289.25	49.42	28.93	21.65	531.93	533.22	17.66	82.34	0.21
H2SO4	284.76	286.51		71.29	28.71		531.80	533.27	29.66	70.34	0.42
H3PO4	284.71	286.28		69.32	30.68		531.65	533.17	15.90	84.10	0.19