The hydrogenation features of gold nanoparticles deposited on highly oriented pyrolytic graphite were determined, and composite nanostructures consisting of pure and hydrogenized gold were synthesized. Methods of scanning tunneling microscopy and spectroscopy have been successfully used to probe the bottom of the conductive band and to determine the shape of the electron energy barrier in hydrogenized gold. Considering models of surface and volume hydrogenation, we have shown that no hydrogen dissolution occurred in gold nanoparticles, but all changes in their electronic structure were associated with surface processes. The results of the quantum chemical simulation also corresponded with this conclusion.