Facile one-step deposition of nanosized Ni(OH)2–MoS2 heterostructure electrodes for efficient oxygen evolution reaction
Deepto Roy, Muhammad Shehroze Malik, Doo‐Man Chun, A.G. Abd-Elrahim
Abstract
There is an increasing need for environmentally friendly and sustainable energy sources that rely on efficient and abundant electrocatalysts for the oxygen evolution reaction (OER). OER plays a key role in energy conversion and storage applications. Using a vacuum kinetic spray technique operating at room temperature, electrocatalysts based on nano-sized Ni(OH) 2 –MoS 2 nanocomposites (NCs) on nickel foam are fabricated from the corresponding micron powders. The Ni(OH) 2 –MoS 2 NC modified working electrodes were exploited to investigate the OER at different weight ratios of MoS 2 (25, 50, and 75 wt%). To comprehensively investigate and elucidate the surface state and morphology of the electrode, x-ray diffraction, scanning electron microscopy (SEM), Raman spectroscopy , and x-ray photoelectron spectroscopy (XPS) were assessed. SEM images showed that the micro-sized particles were fragmented into smaller nanoscale particles . XPS spectra revealed the synergy enhancement in the Ni(OH) 2 –MoS 2 NCs that resulted in a strong improvement in the OER activity. Ni(OH) 2 –MoS 2 hybrid NCs with 75 wt% MoS 2 exhibited the lowest overpotential of 282 mV at 10 mA cm −2 and a small Tafel slope of 54 mV⋅dec −1 . Alongside, the prolonged OER durability at 50 mA cm −2 is verified for up to 50 h.