Hydrogen peroxide reduction on a carboxyl functionalized graphene sheet: a DFT study

GUILLERMINA LETICIA LUQUE; MARIANA ISABEL ROJAS; EZEQUIEL PEDRO MARCOS LEIVA

Nice, France

Congreso; 61th Meeting of the International Society of Electrochemistry; 2010

International Society of Electrochemistry

Hydrogen peroxide reduction on a carboxyl functionalized graphene sheet: a DFT study G.L. Luque, M.I. Rojas, E.P.M. Leiva Unidad de Matemática y Física, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina. mrojas@fcq.unc.edu.ar   Graphene has attracted considerable attention from both the experimental and theoretical scientific communities since it was discovered and successfully isolated from bulk graphite just a few years ago [1]. Its unique properties such as high surface area, fast electron transfer rate, high thermal conductivity, excellent mechanical stiffness, good biocompatibility [2] and low fabrication procedure cost, makes it a perfect alternative to carbon nanotubes in the construction of electrochemical (bio)sensors. In the present work, the adsorption of hydrogen peroxide on pristine and modified graphene sheets is studied by means of Density Functional Theory (DFT) calculations. The system involves perfect and defective layers which can be pristine or functionalized with carboxyl groups. We consider Stone-Wales (SW) defects which are common types of stable sidewall defects on carbon nanotubes and graphene. The chemical functionalization of these surfaces with carboxyl groups modifies their physical and chemical properties [3], so it is of technological importance to understand where this functionalization takes place and how the properties change. We find that functionalization increases (in absolute value) the adsorption energy of hydrogen peroxide and improves its reduction reaction. The electric properties and the mechanism of the reduction reaction of hydrogen peroxide on these surfaces are studied. The local minima where found through the conjugate gradient (CG) technique, employing DFT calculations with spin polarization (sp) as implemented in SIESTA [4]. In order to study the minimum energy path for the present reaction and determine the energy barriers we performed state-of-the-art calculation methods using the nudged elastic band method (NEB) [5].   [1] K.S. Novoselov, A.K. Geim, S.V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, Science 306 (2004) 666. [2] H. Chen, M.B. Müller, K.J. Gilmore, G.G. Wallace, D. Li, Adv. Mater. 20 (2008) 3557. [3] C.Wang, G. Zhou, H. Lui, J. W,Y. Qiu, B.Gu, W. Duan, J. Phys. Chem. B 110 10266-10271 (2006). [4] J. M. Soler, E. Artacho, J. D. Gale, A. García, J. Junquera, P. Ordejón, D. Sánchez-Portal, J. Phys.: Condens. Matter 14 2745 (2002). [5] G. Henkelman, B.P. Uberuaga, H. Jonsson, J. Chem. Phys. 113 (2000) 9901-04.   G. Henkelman, H. Jonsson, J. Chem. Phys. 113 (2000) 9978-85.