Nitrogen and nitrogen-sulfur doped graphene nanosheets for efficient hydrogen productions for HER studies

Abstract

Carbon based electrocatalysts are promising candidates to achieve the production of hydrogen energy in a sustainable wayby simple water splitting technique. Thermally treated reduced graphene oxide (RGO) and N–S doped RGO employing urea and thiourea as electrocatalysts for hydrogen evolution reaction (HER). The performance of electrochemical HER has been thoroughly examined via linear sweep voltammetry, electrochemical impedance spectroscopy and chronoamperometry. Furthermore, the Raman ID/IG ratio of RGO, N-RGO and NS-RGO were found to be 1.43, 1.10 and 1.11 respectively. From electrochemical HER analysis, we found that the NS-doped RGO exposed the low overpotential, low Tafel slope and low solution resistance value of 211 mV, 197 mV/dec and 0.34 Ω respectively. In addition, the chronoamperometry study revealed, the electrocatalyst NS-RGO showed an excellent stability (81.3% retention) with low 211 mV and remained unchanged for more than 16 h. Therefore, this work concludes that heteroatom dopant participate in improving electrocatalytic HER action.