Nitrogen-doped graphene nanosheets as metal-free catalysts for dehydrogenation reaction of ethanol

Abstract

The catalytic performance of nitrogen-doped graphenes for the dehydrogenation of ethanol is investigated in this study. N-Doped graphene is synthesized by using urea and graphene oxide as nitrogen source and precursor, respectively. XRD, Raman spectra, XPS, SEM and HRTEM are utilized to characterize the structure of the synthesized N-doped graphenes. XPS reveals that the doped nitrogens on the surface exist in three forms of nitrogen atom: pyridinic, pyrrolic and graphitic. Moreover, it shows that the contents of the three states of doped N obtained from various nitrogen doped contents are different. Dehydrogenation results show that the N-doped graphene efficiently catalyzes the dehydrogenation of ethanol, and acetaldehyde is obtained as the only product without any byproduct in all the cases. In addition, the nitrogen-doped content and reaction temperature obviously have significant effects on the catalytic performance of NG. The dehydrogenation mechanism for ethanol under the catalysis of NG has also been proposed.