Table 4.

XPS atomic concentrations (%) and relevant atomic ratios.

	AuNPs/ rGO	AuNPs/ GO	AuNPs/ G	rGO	GO	G
Atomic Concentrations (%)
C	86.2	66.5	92.8	87.2	71.2	93.9
O	13.4	32.3	7.1	12.6	27.3	6.1
Au	0.12	0.03	0.06
S		0.8			1.0
Si	0.2	0.4		0.2	0.6
Atomic ratios
Au/C	0.0014	0.0004	0.0006
O/C	0.15	0.44	0.08	0.14	0.33	0.06