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

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.