C-H bond formation at the graphite surface studied with core level spectroscopy

We studied the formation of C-H bonds at the surface of graphite under atomic hydrogen treatment using X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). We found that the amount of hydrogenation of the graphite surface at saturation coverage measured by C1s XPS coincides with the amount of hydrogen measured by temperature programmed desorption. This directly indicates that C1s XPS measurements provide reliable information about the amount of hydrogen stored in carboneous materials through the formation of C-H bonds. From angle resolved XAS measurements we found that the C-H bonds are not perpendicular to the surface of the graphite and that the hydrogenated carbon atoms are buckled up from the highly oriented pyrolitic graphite surface.