Advancing Oxygen Evolution Catalysis with Dual-Phase Nickel Sulfide Nanostructures
Neelakandan M. Santhosh, Suraj Gupta, Vasyl Shvalya, Martin Košiček, Janez Zavašnik, Uroš Cvelbar
Abstract
High Resolution Image Download MS PowerPoint Slide The production, conversion and storage of energy based on electrocatalysis, mainly assisted by oxygen evolution reaction (OER), plays a crucial role in alkaline water electrolyzers (AWEs) and fuel cells. Nevertheless, the insufficient availability of highly efficient catalyst materials at a reasonable cost that overcome the sluggish electrochemical kinetics of the OER is one of the significant obstacles. Herein, we report a fast and facile synthesis of vapor phase deposition of dual-phase nickel sulfide (Ni-sulfide) using low-temperature annealing in the presence of H 2 S and demonstrated as an efficient catalyst for OER to address the issues with sluggish electrochemical kinetics. The dual-phase Ni-sulfide structures consist of densely packed 10–50 μm microcrystals with 40–50 individual dual-phase layers, such as NiS and Ni 7 S 6 . As an electrocatalyst, the dual-phase Ni-sulfide exhibits excellent OER activity by achieving a current density of 10 mA/cm 2 at an overpotential (η 10 ) of 0.29 V and excellent electrochemical stability over 50 h. Besides, the Ni-sulfide displays considerable electrochemical robustness in alkaline conditions and forms OER-active Ni-oxide/hydroxide species during the process. Using an energy-efficient synthesis method, the fabricated unique crystalline nanodesign of dual-phase Ni-sulfide could open new pathways for the controlled synthesis of a high-efficiency group of electrocatalysts for a long-time stable electrochemical catalytic activity.