Mattia Scardamaglia: Spectroscopic observation of oxygen dissociation on nitrogen-doped graphene

posted 2 Jun 2017, 02:23 by Peter Boggild
1 Chemistry of Interaction Plasma Surface (ChIPS), University of Mons, Belgium
2 University of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090 Vienna, Austria
3 Elettra Sincrotrone Trieste, Strada Statale 14 km 163.5, 34149 Trieste, Italy

Carbon nanomaterials’ reactivity towards oxygen is very poor, limiting their potential applications. However, nitrogen doping is an established way to introduce active sites that facilitate interaction with gases. This boosts the materials’ reactivity for bio-/gas sensing and enhances their catalytic performance for the oxygen reduction reaction [1]. Despite this interest, the role of differently bonded nitrogen dopants in the interaction with oxygen is obscured by experimental challenges and has so far resisted clear conclusions. We study the interaction of molecular oxygen with graphene doped via nitrogen plasma by in situ high-resolution synchrotron techniques [2], supported by density functional theory core level simulations. The interaction leads to oxygen dissociation and the formation of carbon-oxygen single bonds on graphene, along with a band gap opening and a rounding of the Dirac cone. The change of the N 1s core level signal indicates that graphitic nitrogen is involved in the observed mechanism: the adsorbed oxygen molecule is dissociated and the two O atoms chemisorb with epoxy bonds to the nearest carbon neighbours of the graphitic nitrogen [3]. Our findings help resolve existing controversies and offer compelling new evidence of the oxidation reduction reaction pathway.

[1] Liu, X., Dai, L. (2016) Nat. Rev. Mater., 1, 16064.
[2] Scardamaglia, M. et al., (2016) 2D Mater., 3, 11001.
[3] Scardamaglia, M. et al., (2017) Submitted

Born in Rome, Italy, Mattia Scardamaglia received his Ph.D. in Materials Science (2012) from Sapienza University studying the growth morphology, electronic properties and interaction of organo-metallic molecules adsorbed on graphene. After moving to Belgium for a postdoc at the University of Mons, he received funding for a three-years project from the Fund for Scientific Research FNRS (2015). His main interests are mostly devoted to the heteroatom doping and characterization of carbon nanotubes and graphene by means of synchrotron-based spectromicroscopy techniques.