Figure 1.

XPS survey scans and the overall surface composition of the graphene oxide (GO) and reduced graphene oxide functionalized with cysteamine (rGO–SH). Two functionalized rGO–SH samples were measured. They are designated on the plot as rGO–SH-1 and rGO–SH-2. The peaks at approximately 980 and 1200 eV are the oxygen and carbon O–KLL and C–KLL Auger peaks, respectively.