Electrodeposition of hierarchically structured three-dimensional nickel–iron electrodes for efficient oxygen evolution at high current densities

Abstract

Large-scale industrial application of electrolytic splitting of water has called for the development of oxygen evolution electrodes that are inexpensive, robust and can deliver large current density (>500 mA cm−2) at low applied potentials. Here we show that an efficient oxygen electrode can be developed by electrodepositing amorphous mesoporous nickel–iron composite nanosheets directly onto macroporous nickel foam substrates. The as-prepared oxygen electrode exhibits high catalytic activity towards water oxidation in alkaline solutions, which only requires an overpotential of 200 mV to initiate the reaction, and is capable of delivering current densities of 500 and 1,000 mA cm−2 at overpotentials of 240 and 270 mV, respectively. The electrode also shows prolonged stability against bulk water electrolysis at large current. Collectively, the as-prepared three-dimensional structured electrode is the most efficient oxygen evolution electrode in alkaline electrolytes reported to the best of our knowledge, and can potentially be applied for industrial scale water electrolysis.

Facile and Scalable Synthesis of Robust Ni(OH)2 Nanoplate Arrays on NiAl Foil as Hierarchical Active Scaffold for Highly Efficient Overall Water Splitting

“…XPS (Figure S5, Supporting Information) and EDS (Figure S6, Supporting Information) analysis evidenced the existence of metallic Ni and Fe elements. The binding energy peak of Ni 2 p 3/2 at 856 eV and Fe 2 p 3/2 at 712 eV were well consistent with the previous report, corroborating the successful deposition of NiFe 5. The electrodepositions of NiFe composites on Ni(OH) 2 /NiAl scaffold and blank Ni foil were optimized through varying the electrodeposition time and measuring their OER performance as shown in Figure S7 in the Supporting Information.…”

“…Among those non‐noble‐metal electrocatalysts for OER, Ni(OH) 2 as a typical transition metal hydroxides has received attention because of its high activity and stability. While NiMo alloy4 and NiFe composites5 are known as the highly active electrocatalysts for OER and HER, respectively. The high OER activity of NiFe catalysts originates from a strong synergistic effect from the incorporation of Fe, although the clear structural characterization and catalytic mechanisms are not fully understood yet 6.…”

“…It was found that the Ni(OH) 2 /NiAl prepared by this facile route showed impressive electrocatalytic activities for OER with a small overpotential of 289 mV at 10 mA cm −2 . Moreover, this 2D Ni(OH) 2 nanoplate arrays could be used as an active scaffold to easily couple other more active components by diverse methods such as the electrodeposition which is a versatile and scalable process with the capability of precise control of nucleation, growth for nanomaterials via a simple and low‐cost equipment 5. For example, the coupled NiFe/Ni(OH) 2 /NiAl hybrid exhibited excellent OER performance with low overpotentials of 246, 315, and 374 mV to reach 10, 100, and 500 mA cm −2 , respectively, and the outstanding durability with no appreciable degradation during 10 h test.…”

Recent Progress on Layered Double Hydroxides and Their Derivatives for Electrocatalytic Water Splitting

“…Having this unique structure, the new electrocatalyst exhibits a low overpotential of 210 mV for OER and 133 mV for HER to reach 10 mA cm −2 in 1 m KOH, in addition to the low potential of 1.59 V at 10 mA cm −2 in 1 m KOH and superior durability when it is used for overall water splitting as a bifunctional electrocatalyst 145. Another example was reported by Lu and Zhao, who prepared an OER electrocatalyst by electrodepositing amorphous mesoporous nickel–iron composite nanosheets directly onto macroporous NF substrates 146. The as‐prepared oxygen electrode exhibits a high level of catalytic activity toward water oxidation in alkaline solution, which only requires an overpotential of 200 mV to initiate the reaction, and is able of delivering current densities of 500 and 1000 mA cm −2 at overpotentials of 240 and 270 mV, respectively.…”

Porous Nickel–Iron Oxide as a Highly Efficient Electrocatalyst for Oxygen Evolution Reaction

“…[[qv: 7a]],12 However, thermal treatment has been rarely applied to Ni–Fe electrocatalysts as it can largely reduce the surface area and thus the activity of the materials. [[qv: 4b]] Although considerable efforts have been devoted to fabricating electrode materials with optimized surface active sites via porous structure or 3D architecture,[[qv: 5b]],7,[[qv: 14a]],15 limited work has been documented on porous electrocatalysts with improved crystallinity for enhanced stability without the damage of their efficient OER performance. Thus, it is highly desirable to develop novel protocols for the synthesis of porous Ni–Fe materials with abundant surface active sites, and meanwhile, with improved crystallinity for ameliorative electrochemical stability.…”