Authors: Garcia-Argumanez, A; Llorente, I; Caballero-Calero, O; Gonzalez, Z; Menendez, R; Escudero, ML; Garcia-Alonso, MC

Appl. Surf. Sci.. vol: 465. page: 0169-4332.
Date: JAN 28. 2019.
Doi: 10.1016/j.apsusc.2018.09.188.

In the present work, the characterization of Electrochemically Reduced Graphene Oxide (ErGO) films on a biomedical grade CoCr alloy has been performed. The direct electrodeposition process was carried out by means of two electrochemical techniques: chronoamperometry and cyclic voltammetry experiments, both taking into account the influence of oxygen in the solution. Characterization of the resulting ErGO films on CoCr alloys was carried out by SEM, AFM, Raman spectroscopy and XPS. Both electrochemical reduction procedures led to the deposition of graphene-based films on the CoCr surfaces after the partial removal of the oxygenated functional groups present in the graphene network of the starting material. The deconvolution of the XPS high-resolution C1s and O1s spectra mainly showed Csp(2) bonding and the presence of C=O and C-O residual groups covering the CoCr surface. Moreover, the ErGO films that were stacked on the CoCr surfaces exhibited non-uniform thickness reaching values corresponding to the presence of 80 layers of the graphene material. In addition, Raman spectroscopy revealed a certain structural disorder in the ErGO films deposited by means of the different electrochemical techniques investigated. This fact was more evident on the film from the chronoamperometric experiments, as the fastest electrochemical reduction rate provided by the application of a high reduction potential (-2.1 V-vs. (Ag/AgCl)) could induce the development of defects in the resulting film, so the peaks corresponding to the CoCr substrate could be observed..