The surface morphology and electronic structure of hexagonal graphene onion rings (HGORs), a modified graphene structure, were investigated to confirm the possibility as an efficient catalyst when compared to graphene. After confirming the formation of HGORs with a smaller width (~4.2 μm) from scanning electron microscopy (SEM) and optical microscopy images, we compared the catalytic activities of HGORs and graphene by measuring the rate of oxidation of thiophenol using high-resolution photoemission spectroscopy (HRPES). In addition, we also assessed in 4-chlorophenol degradation and the OH radical formation with a benzoic acid to confirm the possibility for photocatalytic activities of HGORs. As a result, we confirmed that HGORs, which has an increased active site due to its three-dimensional structure formed by the reaction of graphene with hydrogen, can act as an effective catalyst. In addition, we could also realize the possibility of optical applicability by observing the 0.13 eV of band gap opening of HGORs.