Nitrogen doped Graphene Oxides as an efficient electrocatalyst for the Hydrogen evolution Reaction; Composition based Electrodics Investigation

Electrodics of hydrogen evolution reaction (HER) has been studied for N-doped graphene oxide (N-GO) based electrodes with varied N-content; from graphene oxide (0% Nitrogen) to graphitic carbon nitride (GCN, 66.6% Nitrogen). In between compositions have been prepared by co-heating GO with melamine. These were characterized in detail by XRD, Raman, FESEM, EDAX, XPS, FTIR and Thermal analysis. Electrodics of HER have been studied by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and forced convection hydrodynamic methods using Rotating Disc Electrode (RDE). The overpotential for the HER have been noted to decease systematically with an increase in the N-content and attend minima at −0.21V vs. RHE for GCN. Tafel plot based on exchange current density (Jo) have been increased in sigmoidal fashion with N-content and saturated for GCN at ∼0.1 mA cm−2. This value is almost double comparable to the one reported for 3D-MoS2; the best non-platinum catalyst known for HER, to date. The standard rate constants (k°) as a function of composition have been estimated from Koutecky-Levich plots. These values have been increased systematically with increase in the N-content from ∼10−5 cm s−1 for GO to more than 10−3 cm s−1in case of GCN.