Insight into the Boosted Electrocatalytic Oxygen Evolution Performance of Highly Hydrophilic Nickel–Iron Hydroxide

Abstract

Nickel–iron based materials are well-known catalysts for the oxygen evolution reaction (OER) and have been widely investigated. However, the synergy between these two components is still controversial. Herein, we report a facile immersion method for the synthesis of binder-free nickel–iron hydroxide loaded on Ni foam (NiFe-OH/NF) with superior hydrophilic property and high OER catalytic activity. The strong hydrophilic property of the binder-free NiFe-OH/NF electrode significantly enhances an effective contact between electrocatalyst and aqueous electrolyte and favors the bubble detachment from the electrode, facilitating the electron transfer and improving the OER activity. The hydrophilic NiFe-OH/NF can achieve a geometrical current density of 100 mA cm–1 at an extremely low overpotential (219 mV), along with a Tafel slope of 56 mV dec–1 and superior long-term stability at high current density in alkaline media, strongly indicating that the hydrophilicity plays an important role in improving the OER performance in the NiFe-OH/NF.

Chemical etching induced microporous nickel backbones decorated with metallic Fe@hydroxide nanocatalysts: an efficient and sustainable OER anode toward industrial alkaline water-splitting

“…1d) exhibited a doublet at 873.38 eV (Ni 2p 1/2 ) and 855.81 eV (Ni 2p 3/2 ), which was in accordance with Ni 2+ in Ni(OH) 2 . 37,38 On the other hand, the doublet observed in the Fe 2p spectrum (Fig. 1e) at 724.55 eV and 712.86 eV was ascribed to Fe 3+ in Fe(OH) 3 .…”

Principles of Water Electrolysis and Recent Progress in Cobalt‐, Nickel‐, and Iron‐Based Oxides for the Oxygen Evolution Reaction

“…Due to the different surface properties and conductivity of these materials, a dramatic difference can be observed in the OER performance regardless of the catalysts. For instance, Ni foam has a very high background current in an alkaline electrolyte as the surface of NF is easily converted to nickel (oxy)‐hydroxide, which shows very good OER activity [34] . The conductivity as well as the activity of the catalyst can be also enhanced by deposition on a suitable substrate.…”

“…For instance, Ni foam has a very high background current in an alkaline electrolyte as the surface of NF is easily converted to nickel (oxy)‐hydroxide, which shows very good OER activity. [34] The conductivity as well as the activity of the catalyst can be also enhanced by deposition on a suitable substrate. For instance, Co‐, Mn‐, Ni‐, and Fe‐based catalysts function more effectively when they are deposited on Au substrates, while Ti substrates gives a synergistic effect when coupled with a Ir‐based catalyst.…”

Advances and Challenges in Industrial-Scale Water Oxidation on Layered Double Hydroxides

“…Superhydrophilic and super wetting properties that can be achieved via micro/nano-structuring can be favorable for bubble bursting. While metal hydroxides are already hydrophilic, the petal-like structure of NiFeOOH grown on Ni foam or porous carbon was shown to be favorable for superhydrophilicity and easing bubble detachment. − Similarly, a superaerophobic 3D heterostructure composed of NiSe 2 and NiFe 2 Se 4 nanowrinkles that is in situ transformed to oxyhydroxide has been reported . Modifying the Ni foam support with hydrophilic Ti 3 C 2 T x resulted in anodes with water contact angle close to 0°, and modifying carbon paper support to become hydrophilic was also shown beneficial …”