Marigold shaped N-rGO-MoS2-Ni(OH)2 nanocomposite as a bifunctional electrocatalyst for the promotion of overall water splitting in alkaline medium

Abstract

The economically suitable and energy efficient catalysts are highly necessary for the substantial application in renewable energy production and storage aspirations. However, the high cost and instability of noble metal based catalysts are major concern in their sustainable use. Therefore, the electroactive and non-noble metal based nanostructures are promptly occupying the places of noble metal based catalysts (Pt, RuO2, IrO2 etc.), in electrochemical water splitting and metal-air energy systems. In this work, for the first time, we have reported a non-noble metal based bifunctional (OER/HER) marigold like N-rGO-MoS2-Ni(OH)2 nanocomposite, which has been synthesized by two-step hydrothermal method. This material was found to possess an exciting surface morphological feature with excellent electrocatalytic activity, resulting from the highly exposed surface area, porous structure and synergistic effect of rGO, MoS2 and Ni(OH)2 with the additional contribution from N-doping in the material. The overpotentials of 0.271 V and −0.223 V @|10 mA/cm2| and considerably lower Tafel slope of 106.5 and 86.0 mV/dec were achieved for OER and HER respectively. High stability of N-rGO-MoS2-Ni(OH)2 nanocomposite in both HER and OER adds more value to the material as an active catalyst for energy generation by electrochemical water splitting. With these exciting properties N-rGO-MoS2-Ni(OH)2 paves the way towards designing efficient energy production and storage devices.