Facile Fabrication of Ni<sub>9</sub>S<sub>8</sub>/Ag<sub>2</sub>S Intertwined Structures for Oxygen and Hydrogen Evolution Reactions
Rathindranath Biswas, Imtiaz Ahmed, Priyanka Manna, Partha Mahata, Rajendra S. Dhayal, Amol Singh, Jouko Lahtinen, Krishna Kanta Haldar
Abstract
Abstract Here, we report the fabrication of the unique intertwined Ni 9 S 8 /Ag 2 S composite structure with hexagonal shape from their molecular precursors by one‐pot thermal decomposition. Various spectroscopic and microscopic techniques were utilized to confirm the Ni 9 S 8 /Ag 2 S intertwined structure. Powder X‐ray Powder Diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS) analysis suggest that there is an enrichment of Ni 9 S 8 phase in Ni 9 S 8 /Ag 2 S. The presence of Ag 2 S in Ni 9 S 8 /Ag 2 S improves the conductivity by reducing the interfacial energy and charge transfer resistance. When Ni 9 S 8 /Ag 2 S is employed as an electrocatalyst for electrochemical oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activity, it requires a low overpotential of 152 mV for HER and 277 mV for OER to obtain the geometrical current density of 10 mA cm −2 , which is definitely superior to that of its components Ni 9 S 8 and Ag 2 S. This work provides a simple design route to develop an efficient and durable electrocatalyst with outstanding OER and HER performance and the present catalyst (Ni 9 S 8 /Ag 2 S) deserves as a potential candidate in the field of energy conversion systems.