Modulating electronic and structural properties of NiCo- layered double hydroxide with iodine: As an efficient electro-catalyst for the oxygen evolution reaction

Abstract

The development of an earth-abundant, highly active, long-lasting electro-catalyst for the oxygen evolution reaction (OER) with a novel and improved chemical composition and structure is basically needed since the oxygen evolution reaction is the primary reaction for splitting of water. In this article, we have adopted precipitation technique to create a 2D iodine doped Ni0.5Co0.5 layered double hydroxide (LDH) based electro-catalyst. Several techniques were used to characterize the structural and morphological properties of the electro-catalyst, including powder X-ray diffraction (PXRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), and BET analysis. Using cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) in an alkaline environment, OER performance was evaluated. The iodine-doped Ni0.5Co0.5 LDH had exceptional OER performance and required 250 mV (vs RHE) less overpotential to drive geometric catalytic current density of 40 mA cm-2 and lower Tafel slope (98 mVdec-1) than its counterparts. Excellent OER activity was achieved by iodine-doped Ni0.5Co0.5 LDH due to the abundance of active sites, lower charge transfer resistance (Rct), induced oxygen vacancies, and increased pore size to pore diameter ratio. Additionally, the iodine-doped Ni0.5Co0.5 LDH displayed strong long-term stability without degrading throughout the course of the prolonged time period. This case study of iodine doping to Ni0.5Co0.5 LDH illustrates a crucial technique for producing high-performance earth-abundant energy conversion electro-catalysts. © 2023 Hydrogen Energy Publications LLC