Amorphous Fe hydroxide nanoparticles embedded in Ni3S2 as high-efficiency and low-cost electrocatalysts for oxygen evolution reaction

Abstract

For hydrogen production from water splitting, the development of low-cost while high-efficiency electrocatalysts for oxygen evolution reaction (OER) is of great significance. Here, via facile hydrolysis at room temperature, amorphous Fe hydroxide nanoparticles are attached to the Ni3S2 which is intergrown in situ on nickel foam, forming a novel hierarchical system of Fe(OH)3@Ni3S2/NF as outstanding electrocatalysts for OER. By changing the immersion time (0.5, 1, and 2 days) of the synthesized Ni3S2/NF and the Fe3+concentrations (10, 30 and 50 mM), the optimized material of Fe(OH)3@Ni3S2/NF-D1–30 (D1 refers to the immersion time of one day, and 30 means the Fe3+concentration of 30 mM) exhibits excellent OER performance in alkaline medium (1 M KOH). Making good use of interfacial interaction and synergistic effect between Fe(OH)3 and Ni3S2, this novel catalyst require extremely low overpotentials of 173 and 242 mV to achieve the current densities of 10 and 50 mA cm−2, and the Tafel slope of 45 mV dec−1 is even smaller than that (66 mV/dec) of RuO2/NF. At the same time, the Fe(OH)3@Ni3S2/NF-D1–30 exhibits extraordinary strong durability (≥ 80 h) at the high current density of 50 mA cm−2. The presence of Fe hydroxide nanoparticles in amorphous state brings out more active sites, and the interface between Fe(OH)3 and Ni3S2 may accelerate the electron transport, which both contribute to the improved OER performance. This study offers neoteric research ideas for the design and fabrication of novel OER electrocatalysts by constructing interfacial structure of nanomaterials, thus having far-reaching value.