Hexagonal cage like structured reduced graphene Oxide-NiCo2S4 nanocomposite for high performance hydrogen evolution reaction

Abstract

In the present study, a facile and simple hydrothermal technique was employed for the preparation of reduced graphene oxide (rGO) incorporated NiCo2S4 and analyzed the hydrogen evolution reaction (HER) activity in alkaline media. The face centered cubic crystal structure is confirmed from the X-ray diffraction analysis and hexagonal cage like structure of NiCo2S4 was visualized by FESEM analysis. With the increased number of facets in hexagonal cage structure, the electrochemical-active surface area (ECSA) gets increased, and the HER performance gets increased for bare NiCo2S4. The additional ECSA is caused by the existence of rGO in the case of ternary nanocomposite (rGO-NiCo2S4). The obtained small over potential (370 mV) and small Tafel slope (139 mV/dec) proves the excellent HER activity of rGO-NiCo2S4 nanocomposite. The optimized rGO-NiCo2S4 as excellent HER electrocatalyst provides a highly stable polarization curve up to 10 h and it can be more useful to replace the high-cost platinum noble electrocatalyst.