Synergism of nitrogen and reduced graphene in the electrocatalytic behavior of resorcinol - Formaldehyde based carbon aerogels

Graphene oxide (GO) containing resorcinol - formaldehyde and resorcinol - formaldehyde - melamine polymer aerogels were converted to carbon aerogels in order to study the cooperative effect of the reduced GO and nitrogen functionalities on the electrochemical behavior of carbon aerogels. The morphology of the carbon gel was characterized by scanning and transmission electron microscopy, and low temperature nitrogen adsorption/desorption. X-ray photoelectron spectroscopy was used to study their surface chemistry. The thermal behavior was investigated by thermogravimetric analysis. The electrochemical performance was tested with cyclic- and linear sweep voltammetry (CV and LSV, respectively). The final N content was ca 1 atomic%. The nitrogen atoms are in a C=N-C type chemical environment or replace a carbon atom in the graphene-like layer. Either N or the reduced GO enhance the activity in oxygen reduction reaction. When both are present in the matrix the dominant reduction pathway changes from the slow 2e(-) to the more efficient 4e(-) route. It is also probable that the in situ formed H2O2 improves the wettability of the basically hydrophobic carbon surface and increases the electrochemically active surface. (C) 2018 Elsevier Ltd. All rights reserved.