Facile one-step deposition of nanosized Ni(OH)2–MoS2 heterostructure electrodes for efficient oxygen evolution reaction

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–MoS2 nanocomposites (NCs) on nickel foam are fabricated from the corresponding micron powders. The Ni(OH)2–MoS2 NC modified working electrodes were exploited to investigate the OER at different weight ratios of MoS2 (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–MoS2 NCs that resulted in a strong improvement in the OER activity. Ni(OH)2–MoS2 hybrid NCs with 75 wt% MoS2 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.